Propeller Shaft CV Joint Cage Offset for Compact High-Speed Operation
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Solution Overview
Problem
Existing plunging type constant velocity universal joints for propeller shafts face challenges in achieving size and weight reduction while maintaining performance and durability, especially in high rotation speeds and varying operating angles.
Innovation Solution
A plunging type constant velocity universal joint with a dedicated design for propeller shafts, featuring a reduced maximum operating angle of 15° or less, optimized component dimensions, and reduced offset of the cage, which allows for radial and axial size reduction, weight reduction, and improved torque transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the maximum operating angle is limited to a low value (15° or less), then radial size and weight are reduced, but the operating range is restricted
Solution Approach 1:
The invention applies local quality by optimizing the cage offset specifically for the propeller shaft application context, where the operating angle is naturally limited. The cage offset is reduced to a specific range (0.05-0.15 times the ball pitch circle diameter) to achieve weight reduction while maintaining adequate performance for the intended application, rather than designing for maximum versatility across all possible operating conditions.
2Weight of moving object
If the wall thickness of each component is reduced, then radial size and weight are reduced, but the strength and durability decrease
Solution Approach 1:
The invention applies parameter changes by precisely controlling the cage offset within a specific range (0.05-0.15 times the ball pitch circle diameter). This parameter optimization allows for reduced wall thickness and weight while maintaining sufficient strength, as the optimized offset improves load distribution and reduces stress concentrations on the thinned components.
Solution Approach 2:
The invention applies dynamics by considering the high rotation speed characteristics of propeller shafts in the design. The dynamic loading conditions at high speeds are accounted for in the cage offset optimization, allowing the components to be designed with reduced thickness while maintaining durability under the specific dynamic conditions of propeller shaft operation.
3Volume of moving object
If the pitch circle diameter of the balls is reduced, then radial size is reduced, but the torque transmission capacity decreases
Solution Approach 1:
The invention applies parameter changes by optimizing the cage offset to work in conjunction with reduced ball pitch circle diameter. The specific offset range (0.05-0.15 times the ball PCD) compensates for the reduced ball size by improving the mechanical advantage and load distribution, allowing smaller balls to transmit adequate torque for propeller shaft applications.
Data Source
AI summary
A plunging type constant velocity universal joint 1 for a propeller shaft includes an outer joint member 2, an inner joint member 3, eight torque transmitting balls 4, and a cage 5. A center of curvature O1 of a spherical outer surface 12 and a center of curvature O2 of a spherical inner surface 13 of the cage 5 each have an equal and axially opposite offset (f) with respect to a center O3 of pockets 5a. A ratio f/PCDBALL between the offset (f) of the cage 5 and a pitch circle diameter (PCDBALL) of the torque transmitting balls 4 is 0.07 or more and 0.09 or less.