Ball Screw Nut-Pulley Integration for Compact Steering Drives
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Solution Overview
Problem
Existing ball screw drive systems for motor vehicle steering are complex and space-consuming due to the need for torque transmission elements, which require additional recesses and complex designs to deflect balls, increasing costs and complexity.
Innovation Solution
A ball screw drive design where the ball deflection is integrated into the shaft-hub connection with a pulley as a torque transmission element, allowing for a more compact and cost-effective structure by using a pulley and a ball deflection that forms a channel with the threaded nut, reducing the need for additional fixation elements and optimizing the geometry for ball guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a torque transmission element is mounted on the ball screw nut, then torque can be transmitted to the ball screw nut, but the overall construction becomes complex and space-consuming
Solution Approach 1:
The ball deflector is merged with the torque transmission element into a single integrated component. The ball deflector forms a shaft-hub connection with the ball screw nut, where the shaft portion transmits torque while the hub portion deflects balls. This combination eliminates the need for separate torque transmission elements and reduces overall construction complexity.
Solution Approach 2:
The ball deflector is designed to perform multiple functions simultaneously: it deflects balls from the ball circulation path, transmits torque from the drive mechanism to the ball screw nut, and provides axial positioning of the ball screw nut. This multi-functionality reduces the number of separate components needed in the system.
2Device complexity
If the ball deflector is integrated into the shaft-hub connection, then the structure becomes more compact and cost-effective, but additional functions must be fulfilled by the ball deflector
Solution Approach 1:
The ball deflector is designed as a multi-functional component that simultaneously: (1) deflects balls via its channel structure, (2) transmits torque through its shaft-hub connection to the ball screw nut, and (3) provides axial positioning of the ball screw nut. This consolidates multiple functions into a single component, reducing overall structural complexity.
3Strength
If the ball deflector forms a channel with the threaded nut, then ball guidance is optimized and material stresses are reduced, but the design requires precise geometric cooperation
Solution Approach 1:
The ball deflector and ball screw nut are designed as cooperating components that together form the ball circulation channel. The ball deflector provides the return path while the ball screw nut provides the forward path, creating a continuous channel that guides balls efficiently and distributes material stresses along the channel walls.
Data Source
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AI summary
The invention relates to a ball screw drive (10) with a ball screw nut (12) and a torque transmission element (28), in particular a pulley, mounted on the ball screw nut (12) for transmitting torque to the ball screw nut (12). The ball screw nut (12) has at least one recess (38) passable by balls (24) of the ball screw drive (10) for the purpose of deflecting these balls (24), wherein the ball screw drive (10) has a ball deflection mechanism for deflecting the balls (24). The ball deflection mechanism is part of a shaft-hub connection between the ball screw nut (12) and the torque transmission element (28).