Constant-velocity joint groove positioning for weight reduction
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Solution Overview
Problem
Conventional constant-velocity joints face a challenge in balancing strength and weight, as the formation of engagement grooves to enhance strength leads to increased weight.
Innovation Solution
The design incorporates an inner and outer ring member with intermediate members in raceway grooves, and an engagement groove on the outer ring member positioned to avoid raceway grooves, allowing for rotational torque transmission while minimizing weight increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an engagement groove is formed at a position overlapping with a raceway groove to enhance strength, then the strength of the outer ring member is improved, but the weight of the constant-velocity joint increases due to the need to thicken the member
Solution Approach 1:
The engagement groove is repositioned from overlapping with the raceway groove in the axial direction to a position that avoids the raceway groove, utilizing the circumferential direction for placement. This dimensional repositioning allows the engagement groove to provide necessary strength while avoiding the need to thicken the member at the raceway groove location, thereby preventing weight increase.
Solution Approach 2:
The engagement groove is specifically positioned to avoid the raceway groove region, applying the engagement function only where it is needed (at the outer circumferential surface) without interfering with the torque transmission function of the raceway groove. This localized placement optimizes both strength and weight by avoiding unnecessary material addition.
2Strength
If the member is thickened to provide strength for the engagement groove, then the strength is improved, but the weight increases
Solution Approach 1:
The engagement groove is placed at a specific location on the outer circumferential surface where it can provide engagement strength without requiring overall thickening of the member. By concentrating the engagement function at a localized position that avoids the raceway groove, the member maintains sufficient strength while avoiding unnecessary weight increase from generalized thickening.
Solution Approach 2:
Instead of adding thickness in the radial direction to provide strength, the engagement groove is repositioned to utilize the circumferential direction for its placement. This allows the groove to engage with the engagement member effectively without requiring the member to be thickened, thereby maintaining weight efficiency while providing necessary strength.
3Ease of operation
If an engagement groove is formed in the outer ring member, then engagement with the engagement member is enabled, but interference with the raceway groove may occur affecting torque transmission
Solution Approach 1:
The engagement groove is repositioned from the axial direction overlap with the raceway groove to the circumferential direction placement. This dimensional change ensures that the engagement groove and raceway groove occupy different spatial zones, eliminating interference between the engagement function and torque transmission function while maintaining both capabilities effectively.
Solution Approach 2:
The engagement groove is localized to a specific position on the outer circumferential surface that avoids the raceway groove region. This localized placement ensures that the engagement groove can engage with the engagement member without interfering with the raceway groove's torque transmission function, maintaining both engagement capability and torque transmission reliability.
Data Source
AI summary
The first constant-velocity joint has an inner ring member, an outer ring member housing the inner ring member, and balls, which are installed in raceway grooves formed at prescribed intervals in a circumferential direction in the outer ring member and which extend along an axial direction, for transmitting rotational torque between the inner ring member and the outer ring member. Furthermore, the constant-velocity joint is formed so that one of the inner ring member and the outer ring member connects to an attaching member installed to a vehicle side with a spline, and so that the other of them connects to a power transmission shaft. In outside wall of the outer ring member, an engagement groove is formed so as to engage with an engagement member applied to connection or release thereof in a range avoiding positions corresponding to the raceway grooves in an axial direction or a circumferential direction.