CV Joint Outer Member Forging With Track Groove Phase Alignment
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Solution Overview
Problem
The existing forging methods for outer joint members of constant velocity universal joints face challenges in stably forming track grooves with an arc shape inclined in the circumferential direction and a diameter of the track groove bottom at the center portion larger than that on the opening side, due to misalignment of phases between the pre-processing material and the punch set, leading to forming failures and die breakage.
Innovation Solution
A forging apparatus and method that includes a phase alignment mechanism with a pair of convex portions and a rotary mechanism to align the phases of the grooves in the pre-processing material with the track groove forming surfaces of the punch set, allowing the punch set to be radially expanded and contracted to fit into the cylindrical portion, ensuring proper alignment and preventing forming failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pre-processing material is placed on the punch set without phase alignment, then the placement process is simple, but the phases of the grooves and track groove forming surfaces become misaligned, causing forming failures and die breakage
Solution Approach 1:
The pre-processing material has grooves formed on its inner peripheral surface that serve as self-positioning features. When the material is placed on the punch set, the grooves automatically align with the corresponding track groove forming surfaces through geometric constraint, eliminating the need for external alignment mechanisms or complex positioning procedures.
Solution Approach 2:
The grooves on the pre-processing material are designed with asymmetric positioning features relative to the punch set geometry. This asymmetric design creates a unique fit between the grooves and the track groove forming surfaces, ensuring that only one correct rotational position is possible, thereby achieving precise phase alignment automatically during placement.
2Manufacturing precision
If a complex positioning mechanism with phase alignment pins and rotary mechanisms is used, then phase alignment precision is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The pre-processing material itself provides the alignment function through its groove features, eliminating the need for separate positioning mechanisms. The grooves act as self-aligning elements that automatically ensure correct phase relationship between the material and punch set during the placement operation.
Solution Approach 2:
The alignment function is extracted from the punch set and integrated directly into the pre-processing material geometry. By forming grooves on the material's inner peripheral surface, the alignment capability is built into the workpiece itself, removing the need for external positioning devices such as alignment pins, rotary mechanisms, or complex fixtures.
3Reliability
If the track grooves are formed with arc shape inclined in circumferential direction and varying diameter, then the outer joint member performance is improved, but the forming process becomes more difficult and prone to failures
Solution Approach 1:
The pre-processing material is prepared in advance with grooves formed on its inner peripheral surface that pre-establish the correct geometric framework for the final track grooves. This preliminary grooving creates a guided structure that directs the material flow during the subsequent ironing process, making it easier to form the complex arc-shaped inclined track grooves with varying diameter without forming failures.
Solution Approach 2:
The grooves on the pre-processing material are designed with specific local geometric properties that correspond to the required final track groove shape. By creating these localized geometric features in advance on the inner peripheral surface, the material is pre-conditioned to facilitate the formation of the complex inclined arc-shaped track grooves with the desired diameter variation during ironing.
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 approach enables stable formation of outer joint members with the desired track groove geometry, reduces the risk of forming failures and die breakage, and allows the use of existing ironing mechanisms, thereby achieving cost reduction.
Implementation Method 1
a compression coil spring 55 incorporated between the spring receiving portion 53b and the spring receiving member 54
Implementation Method 2
a hydraulic press 49 configured to press the pressing member 53
Implementation Method 3
a plurality of balls 4, which are interposed between the track grooves 7 of the outer joint member 2 and the track grooves 9 of the inner joint member 3, and are configured to transmit torque
Data Source
AI summary
A forging apparatus includes an ironing mechanism and a phase alignment mechanism. The ironing mechanism includes: a punch set, which is fitted into a cylindrical portion of a pre-processing material to be formed into the outer joint member, and is radially expandable and contractible, the cylindrical portion having grooves formed in an inner peripheral surface thereof; and a die having a hole into which the cylindrical portion is press-fitted. The phase alignment mechanism is configured to align phases of the grooves in the inner peripheral surface of the pre-processing material and phases of track groove portion forming surfaces of the punch set with each other before the pre-processing material is fitted to the punch set.