Double Involute Pinion-Face Gear Drive System
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Solution Overview
Problem
Existing gear systems for non-intersecting orthogonal shafts face challenges in being bi-directional and bi-rotational, with limited range of low gear speed ratios, and are prone to interference and undercutting, especially when using hypoid or worm-face gears which are sensitive to location and suffer from low speed reduction ratios.
Innovation Solution
A double involute pinion-face gear drive system with a cylindrical pinion and face gear, where both components have teeth curved in a shortened, normal, or extended involute shape, allowing for bi-directional and bi-rotational operation with a wide range of speed ratios, and methods for manufacturing these teeth using various cutting tools and processes to avoid interference and improve load capacity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hypoid gears are used to transmit torque between non-intersecting orthogonal shafts, then torque transmission capability is improved, but sensitivity to location and thermal growth increases, and manufacturing complexity increases
Solution Approach 1:
The gear system is divided into two independent but complementary components: a pinion with double involute teeth and a face gear with corresponding teeth. This segmentation allows each component to be manufactured separately with standard procedures, reducing overall manufacturing complexity while maintaining torque transmission capability.
Solution Approach 2:
The invention changes the fundamental geometric parameters of the gear teeth by using double involute curves instead of traditional hypoid or worm gear profiles. This parameter change enables the gears to be manufactured with conventional tools and methods, significantly reducing manufacturing and assembly complexity while preserving torque transmission functionality.
2Strength
If hypoid gears are used for torque transmission, then load capacity is improved, but sensitivity to thermal growth and deflection increases
Solution Approach 1:
Instead of making the pinion conical with helical teeth as in hypoid gears, the invention inverts the approach by making the face gear the larger component with curved teeth and the pinion the smaller component with double involute teeth. This inversion reduces sensitivity to thermal growth and deflection while maintaining load capacity.
Solution Approach 2:
The invention changes the geometric parameters by using double involute tooth profiles with specific curvature radii that are less sensitive to thermal expansion and structural deflection. This parameter optimization maintains load capacity while improving reliability under thermal and mechanical variations.
3Ease of manufacture
If conventional gear systems are used for non-intersecting orthogonal shafts, then manufacturing is simplified, but bi-directional and bi-rotational operation is limited
Solution Approach 1:
The face gear teeth are designed with asymmetric curvature - convex on one side and concave on the other side. This asymmetry enables the gear to function in both rotational directions and bidirectional operation while still being manufacturable with conventional tools, thus achieving both manufacturing simplicity and operational versatility.
Solution Approach 2:
The double involute pinion-face gear system is designed to perform multiple functions: it can operate in both rotational directions (bi-rotational) and with either component serving as the driver or driven (bi-directional). This multi-functionality is achieved while maintaining compatibility with conventional manufacturing methods.
4Volume of moving object
If worm-face gears are used for non-intersecting orthogonal shafts, then compact arrangement is achieved, but speed reduction ratio range is limited
Solution Approach 1:
The face gear teeth are designed with curved profiles having specific radii of curvature that allow for a wide range of speed reduction ratios within a compact form factor. The curvature enables efficient torque transmission while maintaining a compact arrangement, overcoming the limitation of conventional worm-face gears.
Data Source
AI summary
Methods for generating gear teeth of a double involute-face gear drive system, curved in their longitudinal direction in form of either shortened, normal or an extended involute curve, include methods for generating the teeth of both components. Methods for generating the teeth of a double involute pinion, shaped in form of a normal involute in their profile direction and curved in their longitudinal direction in form of an either shortened, a normal or an extended involute curve, include the use of one of the following tools (1) a face hob and (2) a conical hob. Methods for generating the teeth of a face gear curved in their longitudinal direction in form of an either shortened, a normal or an extended involute curve include the use of one of the following tools (1) a rack cutter, (2) a shaper cutter and (3) a conical hob.