Constant Velocity Joint Spherical Arms Stabilizing Mechanism
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Solution Overview
Problem
Current constant velocity joints, such as the Rzeppa-type or 'Ball-Type CV joint', suffer from high friction, limited performance, short lifespan, and inability to transmit axial loads due to high contact tension and sliding friction, making them inefficient and prone to heat production, especially at larger angles of tilting.
Innovation Solution
A new constant velocity joint design utilizing pairs of spherical arms with rotation hubs and a stabilizing mechanism that fixes the spherical arms to a homokinetic plane, allowing each arm to rotate around a single axis, reducing friction and enabling the joint to handle axial loads by distributing the load evenly across multiple points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Rzeppa-type ball joints are used to transfer torque between shafts, then constant velocity transmission is achieved, but high contact tension and sliding friction occur leading to heat production and limited performance
Solution Approach 1:
The patent replaces the traditional ball-and-cage mechanical system with a spherical arm mechanism that uses rotation hubs and rolling elements. This substitution eliminates the sliding friction between balls and cage while maintaining constant velocity transmission, directly addressing the energy loss problem.
Solution Approach 2:
The invention changes the fundamental operating parameters by transitioning from sliding friction to rolling friction through the use of rolling elements in rotation hubs. This parameter change reduces contact tension and heat production while preserving the constant velocity function.
2Reliability
If Rzeppa-type ball joints are used with massive metal cage, then homokineticity is maintained, but the joint cannot transmit axial loads and has zero tolerance to axial forces
Solution Approach 1:
The patent segments the monolithic cage structure into individual spherical arms that are independently mounted on the shafts. This segmentation allows each arm to handle axial loads independently while collectively maintaining homokineticity, enabling the joint to transmit axial forces that the traditional cage cannot handle.
Solution Approach 2:
The invention adds the capability to handle axial forces by introducing a new dimensional capability to the joint mechanism. The spherical arms can accommodate forces in the axial direction while maintaining the radial constant velocity transmission, effectively adding a new degree of freedom in force handling.
3Power
If Rzeppa-type ball joints are used, then torque transfer between shafts is achieved, but the design requires special machines for manufacture and grinding of rolling paths
Solution Approach 1:
The patent applies preliminary action by pre-mounting the rolling elements into the rotation hubs during assembly rather than requiring complex post-manufacturing grinding operations. This approach simplifies manufacturing by using standard rolling element bearing assembly techniques instead of specialized grinding machines.
4Reliability
If traditional ball joints are used, then constant velocity transmission is achieved, but the joint structure is complex and bulky making it unsuitable for mass use
Solution Approach 1:
The patent extracts and removes the complex cage structure from the joint design, retaining only the essential spherical arms mounted on the shafts. This extraction simplifies the overall joint structure while preserving the constant velocity transmission function, making the design more suitable for mass production and application.
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 new joint design achieves true homokineticity, significantly reduces friction, increases the maximum tilting angle, and extends the joint's lifespan, while being simpler and less costly to produce compared to existing designs.
Implementation Method 1
The rolling elements 8, serving as radial and axial bearings, mount the spherical arms 4L and 4R to the stabilising segments 3.1, 3.2 and 3.3, and also mount the rotating hubs 1.1, 1.2 and 2.1, 2.2 to the input shaft 1 and the output shaft 2, respectively
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The constant velocity joint consists of the input shaft (1), the output shaft (2), three spherical left arms (4L), three spherical right arms (4P), and the stabilising mechanism (3). The stabilising mechanism (3) is made up of three stabilising segments (3.1), (3.2), and (3.3). Stabilising segments have limited all degrees of freedom except the possibility of partial rotation around the axis of the stabilising mechanism (3). Each stabilising segment (3.1), (3.2) or (3.3) has one spherical arm (4L) and one spherical arm (4P) attached by means of a bolt (6), two groups of rolling elements (8), and a distance ring (12) in away they can only rotate around the axis of the bolt (6). The input shaft (1) carries on his body three arms (1.1), (1.2), and (1.3). The output shaft (2) carries on his body three arms (2.1), (2.2), and (2.3). In arms of both shafts there are outer rolling paths created for groups of rolling elements (9), which perform the function of radial-axial bearings. The input shaft (1) is attached to the set of the stabilising mechanism and spherical arms through three bolts (7), which pass through radial-axial bearings in arms of the shaft (1.1), (1.2), and (1.3), and are attached into spurs on spherical arms (4P). The output shaft is connected in the same way.