Universal Joint Stop Structure for Bearing Failure Travel Limitation
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Solution Overview
Problem
Conventional universal joints suffer from bearing failures that cause the pin cross to shift excessively, leading to increased spatial volume and potential damage to surrounding components, inefficient use of installation space, and risk of further damage.
Innovation Solution
The universal joint design incorporates protrusions on the pin cross or joint forks that act as stops to limit the shift of the pin cross relative to the joint fork upon bearing failure, maintaining compact size and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional universal joints are used without additional stop structures, then the structure remains simple and compact for normal operation, but the pin cross shifts excessively and rotational diameter enlarges when bearing failure occurs
Solution Approach 1:
The patent applies preliminary action by pre-installing stop structures (protrusions or recesses) on the pin cross and joint fork before bearing failure occurs. These stops are positioned in advance to limit the maximum travel distance of the pin cross, so that when bearing failure happens, the pin cross cannot shift beyond the predetermined limit, thereby preventing rotational diameter enlargement and protecting surrounding components.
Solution Approach 2:
The stop structures act as intermediary elements between the pin cross and the joint fork. When bearing failure occurs, these intermediary stops engage to prevent direct contact between the shifted pin cross and surrounding components, thereby mediating the harmful effects of bearing failure and limiting the pin cross displacement.
2Object-affected harmful factors
If the pin cross is allowed to shift freely upon bearing failure, then no additional components are required, but the rotational diameter enlarges and surrounding components may be damaged
Solution Approach 1:
The stop structures are pre-configured on the pin cross and joint fork to establish maximum travel limits before bearing failure occurs. This preliminary arrangement ensures that when bearing failure happens, the pin cross displacement is automatically constrained, preventing it from sweeping through a larger area and damaging surrounding components.
Solution Approach 2:
The patent converts the potentially harmful uncontrolled pin cross shift into a beneficial constrained movement. By designing stop structures that engage upon bearing failure, the harmful effect of bearing failure is transformed into a controlled emergency operation mode where the pin cross is limited to a safe displacement range, protecting the system while still allowing continued operation.
3Reliability
If stop structures are added to limit pin cross shift, then emergency operating properties improve, but the installation space and device complexity increase
Solution Approach 1:
The stop structures are nested within the existing geometry of the pin cross and joint fork components. The protrusions and recesses are integrated into the component bodies rather than being separate external additions, allowing the stop function to be achieved without significantly increasing the overall installation space or rotational diameter of the universal joint assembly.
Solution Approach 2:
The stop structures are implemented as localized features (protrusions and recesses) at specific positions on the pin cross and joint fork, rather than requiring overall enlargement of components. This local quality approach allows the emergency limiting function to be achieved with minimal impact on the overall installation space and maintains compactness for normal operation.
Data Source
AI summary
A universal joint includes two joint forks and a pin cross. The pin cross has a central body and four pins, which project in a common plane from the central body in two directions perpendicularly to one another, and each have a bearing point at which the respective pin is mounted in a respective corresponding fork bore of the joint forks. Next to at least one of the pins, at least one protrusion is formed which protrudes beyond the respective pin perpendicularly to its central longitudinal axis and has at least one stop face, which stands perpendicularly to a common plane and serves as a stop. Only in an event of fault of a bearing of the respective pin, for supporting the pin cross on an inner side, facing the pin cross, of the corresponding joint fork in order to limit a shift of the pin cross relative to the corresponding joint fork along a central longitudinal axis of the respective pin.