Fixed CV Joint Mouth Geometry for Coaxial Cage Insertion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing fixed type constant velocity universal joints have a large axial dimension and weight due to the requirement of a specific space for cage insertion, which increases their size and weight, limiting further reduction in size and weight while maintaining strength and load capacity.
Innovation Solution
A fixed type constant velocity universal joint design with an outer joint member having a cup-shaped mouth section and an inner joint member with spherical track grooves, where the cage is inserted coaxially without needing orthogonal alignment, reducing the internal space and axial dimension of the outer joint member, and optimizing the operating angle to reduce the size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the bottom surface of the outer joint member is arranged on a deep side with respect to the imaginary spherical surface to ensure space for orthogonal cage insertion, then the cage can be assembled with orthogonal alignment, but the axial dimension and weight of the outer joint member increase
Solution Approach 1:
Instead of assembling the cage orthogonally to the outer joint member axis as in conventional designs, the present invention inverts the assembly approach by inserting the cage coaxially with the outer joint member axis. This requires the opening end diameter to be larger than the cage outer diameter, but eliminates the need for deep internal space, thereby reducing axial dimension and weight while simplifying the assembly process.
Solution Approach 2:
The invention changes the assembly dimension from orthogonal insertion (requiring deep axial space) to coaxial insertion (requiring larger opening diameter). This dimensional change in the assembly approach allows the bottom surface to be arranged on the imaginary spherical surface, reducing the axial dimension without compromising assembly ease.
2Ease of manufacture
If the bottom surface of the outer joint member is arranged on a deep side with respect to the imaginary spherical surface, then space for cage insertion is ensured, but the axial dimension of the outer joint member is increased
Solution Approach 1:
The invention inverts the conventional assembly method from orthogonal cage insertion (requiring deep axial space) to coaxial cage insertion. This inversion allows the bottom surface to be positioned on the imaginary spherical surface, significantly reducing the axial dimension while ensuring adequate space for cage insertion through the enlarged opening end diameter.
Solution Approach 2:
By changing the cage insertion dimension from axial (orthogonal) to radial (coaxial), the invention resolves the contradiction between insertion space and axial dimension. The opening end diameter is increased to accommodate the cage, while the axial dimension is minimized by positioning the bottom surface on the imaginary spherical surface.
3Weight of stationary object
If eight torque transmission balls are used instead of six, then weight and size can be reduced while maintaining strength, but the device complexity increases
Solution Approach 1:
The invention changes the parameter of the number of torque transmission balls from six to eight. This parameter change, combined with the coaxial cage insertion design, allows for reduced weight and size while maintaining strength and load capacity. The increased number of balls distributes the load more effectively, compensating for the added complexity.
Data Source
AI summary
A fixed type constant velocity universal joint (3) includes an outer joint member (31), an inner joint member (32), eight balls (33), and a cage (34). A diameter (D31c) of the outer joint member (31) at an opening end of an inner peripheral surface (31c) is set larger than an outer diameter (D34b) of the cage (34) at a center portion in a circumferential direction of pockets (34a) when the cage (34) is seen from an axial direction of the joint. A bottom surface (31f) of a mouth section (31a) of the outer joint member (31) is arranged so as to interfere with an imaginary spherical surface (Q) being an extension of the inner peripheral surface (31c) of the outer joint member (31) toward a deep-side.