Cotter Holder Stabilizes Retainer Assembly on Shaft
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Solution Overview
Problem
The existing methods for assembling a retainer and a cotter to a shaft member are prone to inaccurate positioning, leading to a risk of defective products due to unstable cotter positioning and the difficulty in fitting the protrusion of the cotter into the recess of the shaft member.
Innovation Solution
A retainer-and-cotter assembling device that includes a cotter holder, first moving means for inserting the shaft member along the inner periphery of the cotter, a cotter pressing mechanism for pressing the cotter from the outer periphery, and second moving means for taper-fitting the retainer onto the cotter, ensuring stable positioning and fitting of the protrusion and recess.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the shaft member is inserted from below the cotter and the cotter is pressed from the outer periphery, then the cotter and shaft member can be fitted to each other, but the positioning of the cotter becomes unstable and inaccurate
Solution Approach 1:
The patent inverts the conventional assembly approach by inserting the shaft member from above the cotter instead of from below. The large-diameter-side end surface of the cotter is supported from below by the cotter holder, while the shaft member is inserted downward along the inner periphery of the cotter. This inversion stabilizes the cotter positioning and enables accurate fitting of the protrusion into the recess.
2Ease of operation
If the cotter is moved to a radially inner side to reach the inner hole portion of the retainer, then the retainer and cotter can be assembled, but the cotter is likely to be fitted into the inner hole of the retainer causing positioning failure
Solution Approach 1:
The patent introduces a guide pin as an intermediary element that extends along the inner periphery of the cotter. The guide pin guides the cotter during assembly, preventing it from being incorrectly fitted into the inner hole of the retainer. This intermediary component ensures reliable positioning and prevents assembly errors.
3Productivity
If the protrusion and recess are not satisfactorily fitted due to inaccurate positioning, then assembly can proceed, but defective products increase
Solution Approach 1:
The patent performs preliminary positioning actions before the final assembly step. The cotter is preliminarily positioned by the guide pin and supported by the cotter holder, ensuring correct alignment before the shaft member is fully inserted and the protrusion engages with the recess. This preliminary action prevents defective products by ensuring accurate fitting.
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 device reliably assembles the retainer and cotter to the shaft member, reducing the occurrence of defective products by stabilizing the cotter positioning and improving work efficiency by allowing the spring and spring sheet to be placed on the assembling device side before assembly.
Implementation Method 1
an outer peripheral surface of the cotter and an inner peripheral surface of the retainer are taper-fitted to each other
Implementation Method 2
the retainer and a pressing member sandwich the cotter from both sides in the axial direction of the cotter
Data Source
AI summary
A large-diameter-side end surface (104a) of a cotter (104) can be supported by a cotter holder (32) from below through inserting a shaft member (102) along an inner periphery of the cotter (104) from above the cotter (104). In this state, a protrusion (104b) of the cotter (104) and an annular groove (102a) of the shaft member (102) are fitted to each other, and the cotter (104) and a retainer (103) are taper-fitted to each other. Consequently, the cotter is prevented from being unstable, and hence it is possible to assemble the retainer (103) and the cotter (104) to the shaft member (102) with good accuracy.