Ball Screw Shifting Actuator With Integrated Shift Fork Fixing
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Solution Overview
Problem
Existing shifting actuators for double clutch transmissions face challenges in efficiently transmitting a wide variety of forces and tilting forces without the need for additional fixing elements, while also requiring complex manufacturing processes for the ball screw drive components.
Innovation Solution
The shifting actuator incorporates a compact ball screw drive design with an electric-motor-driven threaded spindle, a multi-part spindle nut, and rolling elements, where the shift fork is fixed relative to the sleeve and main nut body, eliminating the need for additional fixing elements and simplifying manufacturing by pre-profiling the spindle nut profile, which reduces the complexity and cost of producing the ball screw drive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional fixing elements (screws, bolts, rivets) are used to secure the shift fork and main nut body in the sleeve, then the force transmission reliability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The sleeve is designed to perform multiple functions simultaneously: it guides the spindle nut, secures the shift fork and main nut body through deformation, and transmits forces between components. By merging the securing function into the sleeve itself rather than using separate fixing elements, the patent reduces device complexity while maintaining force transmission reliability.
Solution Approach 2:
The sleeve performs self-securing through its own deformation. The deformation regions of the sleeve create frictional and positive engagement with the shift fork and main nut body, eliminating the need for external fixing elements. The sleeve serves itself to secure the components it contains.
2Ease of manufacture
If the spindle nut is designed as a compact module with integrated shift fork, then the manufacturing complexity is reduced, but the ability to transmit tilting forces may be compromised
Solution Approach 1:
The sleeve acts as a flexible shell that can deform to create securing engagement. This deformation capability allows the sleeve to adapt to and secure components with slight misalignments or tilting forces, maintaining force transmission capability while keeping the design compact and simple to manufacture.
Solution Approach 2:
The spindle nut is segmented into modular components (sleeve, main nut body, shift fork) that can be manufactured separately and then assembled. This segmentation allows each component to be optimized for its specific function while maintaining overall compactness and simplifying manufacturing processes.
3Device complexity
If the sleeve deforms to secure components through frictional and positive engagement, then additional fixing elements are eliminated, but the manufacturing precision requirements for the deformation regions increase
Solution Approach 1:
The sleeve's deformation regions are designed with specific geometric parameters (cross-sectional shapes, positioning element configurations) that enable reliable engagement. By carefully selecting and optimizing these parameters, the design achieves secure component fixation through deformation while keeping manufacturing precision requirements within practical limits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively transmits forces and tilting forces between the shift fork and other components of the spindle nut, enhancing the actuator's functionality and reducing manufacturing costs through simplified production steps, resulting in a more efficient and cost-effective shifting actuator for double clutch transmissions.
Implementation Method 1
a ball screw drive, which comprises an electric-motor-driven threaded spindle (3), a multi-part spindle nut (4), and rolling elements, namely balls (7), which roll between the threaded spindle (3) and the spindle nut (4)
Implementation Method 2
rolling elements, namely balls (7), which roll between the threaded spindle (3) and the spindle nut (4)
Implementation Method 3
an electric-motor-driven threaded spindle (3)
Data Source
AI summary
A shifting actuator for a transmission including a ball screw drive, having an electric-motor-driven threaded spindle, a multi-part spindle nut, and rolling elements, namely balls, which roll between the threaded spindle and the spindle nut. The nut body has a ball groove, in which there roll balls that are also in contact with the threaded spindle, and is within the sleeve. The shift fork protrudes from the sleeve and is fixed relative to the sleeve and to the main nut body.