Roller Screw Spindle Drive With Grooved Spindle for Steer-by-Wire
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing spindle drives for steer-by-wire steering systems are costly due to manufacturing tolerances and complexity, particularly in producing multiple planetary rollers with evenly spaced grooves.
Innovation Solution
A spindle drive design featuring a spindle with evenly spaced grooves and a thread roll with an external thread, where the thread roll is guided by synchronizing rings, allowing for low-friction operation and easier manufacturing, and optionally using a brushless Vernier motor for compact and efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple planetary rollers with evenly spaced grooves are manufactured, then the spindle drive achieves proper engagement and low-friction operation, but the manufacturing cost increases due to high tolerance requirements and complexity
Solution Approach 1:
Instead of machining grooves into multiple planetary rollers, the invention inverts the approach by providing grooves on the spindle itself and using smooth-threaded rollers. This reversal transfers the complexity from multiple complex components to a single component (spindle), reducing manufacturing difficulty and cost while maintaining proper engagement.
Solution Approach 2:
The invention merges the groove features from multiple planetary rollers into a single spindle component. By consolidating the grooved structure into one spindle rather than distributing it across multiple rollers, the design reduces the number of complex components that need to be manufactured with high precision, thereby lowering overall manufacturing cost.
2Reliability
If multiple planetary rollers with evenly spaced grooves are manufactured, then the spindle drive achieves proper engagement, but the device complexity increases
Solution Approach 1:
The invention inverts the traditional planetary roller screw design by placing grooves on the spindle rather than on the rollers. This inversion simplifies the roller components (making them smooth and easier to manufacture) while concentrating the structural features in the spindle, thereby reducing overall device complexity.
Solution Approach 2:
The invention extracts the groove features from the planetary rollers and relocates them to the spindle. By removing the complex grooved structure from multiple rollers and placing it solely on the spindle, the design reduces structural complexity while maintaining the necessary engagement functionality.
3Reliability
If conventional spindle drives are used, then the system achieves adequate performance, but the installation space and energy consumption increase
Solution Approach 1:
The invention replaces the conventional mechanical planetary roller screw mechanism with a simplified groove-spindle and smooth-roller system. This substitution eliminates the need for complex planetary gear arrangements and multiple grooved rollers, resulting in a more compact design that requires less installation space while maintaining system performance.
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 reduces manufacturing costs and achieves high accuracy with low-friction operation, enabling a compact and efficient steer-by-wire steering system with reduced installation space and energy consumption.
Implementation Method 1
The external thread of the thread roll is permanently in rolling engagement with the grooves evenly distributed on the threaded spindle
Implementation Method 2
the at least one thread roller being guided radially and axially by synchronizing rings arranged inside the spindle nut
Implementation Method 3
the ends of the at least one thread roll being designed with external teeth and each meshing with internal teeth of a ring gear
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a spindle drive (50, 60) for an actuator (10) of steer-by-wire steering, having a spindle (57, 67) which is arranged linearly movably in a spindle nut (55, 65), wherein the spindle drive (50, 60) is in the form of a roller screw drive with at least one threaded roller (46), wherein the ends of the at least one threaded roller (56, 66) have an external toothing (56v) and each mesh with an internal toothing (49i) of one gear rim (59), wherein the gear rims are arranged on the end sides within the spindle nut (55, 56), and wherein the at least one threaded roller (56, 66) is guided radially and axially by synchronizing rings (58) arranged within the spindle nut (55, 65). The invention is characterized in that the spindle (57, 67) has grooves (57r) spaced apart uniformly from one another in the longitudinal direction, and the at least one threaded roller (56, 66) has an external thread which is permanently in rolling engagement with the grooves (57r) of the threaded spindle such that the spindle (57, 67) is moved linearly by rotation of the spindle nut (55, 65).