Direct Pinion Mount CV Joint Sleeve for Higher Joint Angle
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Solution Overview
Problem
Conventional direct pinion mount constant velocity joints face issues with increased weight and cost due to material requirements, inadequate boot robustness to sustain internal pressures, potential disengagement of the pinion shaft, and limited maximum joint angle, which restricts operability and increases production time and cost.
Innovation Solution
The design features a joint assembly with axially extending circumferential splines on the inner and outer surfaces of the sleeve, a hardened and heat-treated abutment portion, a robust boot with boot cycles for enhanced strength, and a larger maximum joint angle, eliminating the need for venting systems and ensuring secure pinion shaft retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the end portion of the sleeve is made longer to contact the stopper at maximum joint angle, then the joint angle limitation is prevented, but the weight and cost of the sleeve increase due to additional material
Solution Approach 1:
The invention applies local quality by creating a hardened and heat-treated abutment portion at the end of the sleeve that contacts the stopper. This localized hardening allows the end portion to withstand contact stresses without requiring the entire sleeve to be made from heavier, stronger material, thus maintaining joint angle capability while controlling weight.
Solution Approach 2:
The invention changes the material parameters of the abutment portion through hardening and heat treatment processes. This transforms the local mechanical properties (increasing hardness and strength) of the sleeve end, enabling it to function as an effective stopper contact surface without increasing overall sleeve dimensions or weight.
2Reliability
If a conventional rubber boot is used, then the joint can be sealed, but the boot cannot sustain internal lubricant and air pressures generated during operation
Solution Approach 1:
The invention changes the material parameters of the boot by specifying rubber compounds with higher strength and elasticity characteristics. This allows the boot to sustain the internal lubricant and air pressures generated during joint operation without requiring vent holes or pressure relief systems.
Solution Approach 2:
The invention extracts the venting system (plug and vent holes) from the joint design by using a sufficiently robust boot that can contain the internal pressures. This eliminates the need for pressure relief features while maintaining reliable sealing.
3Reliability
If the boot can and clamp are used to attach the boot, then the boot is secured, but the maximum joint angle is limited due to contact between the boot can and clamp
Solution Approach 1:
The invention resolves the spatial conflict between boot attachment components by transitioning from a radial attachment geometry to an axial attachment geometry. The boot can and clamp are positioned axially on the sleeve rather than radially, allowing the joint to articulate to larger angles without the boot can and clamp contacting each other.
4Ease of manufacture
If a snap ring is used to retain the pinion shaft and nut, then assembly is simplified, but the pinion shaft may disengage if the snap ring axial strength is insufficient
Solution Approach 1:
The invention uses a composite retention system combining a snap ring for easy assembly with an interference-fit abutment portion for secure mechanical retention. The hardened abutment portion of the sleeve creates a positive mechanical stop that prevents pinion shaft disengagement, while the snap ring maintains assembly simplicity.
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 solution reduces weight and cost, enhances boot durability, prevents pinion shaft disengagement, and increases the maximum joint angle, thereby improving operational flexibility and reducing production complexity.
Implementation Method 1
the abutment portion on the intermediate portion of the sleeve is hardened and heat-treated
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A joint assembly for a motor vehicle. The joint (100) includes an inner race (104), an outer race (102), a plurality of balls (106) and a cage (108). The inner race is drivingly connected to a sleeve (110) having an axially inboard portion, an intermediate portion and an axially outboard portion. Circumferentially extending from the intermediate portion of the sleeve is an abutment portion (136). At least a portion of the abutment portion is in direct contact with an end of the inner race. Axially outboard from the abutment portion is a stepped portion (137). A shaft (168) is drivingly connected to an inner surface of a hollow interior portion of the axially outboard portion of the sleeve. A first end portion of a boot (186) is connected to an outer surface of the outer race and a second end portion of the boot is connected to an outer surface of the axially outboard portion of the sleeve.