Double Pinion Steering Gear Torque Distribution
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Solution Overview
Problem
Existing steering gears for heavier motor vehicles are either too expensive, have large construction volumes, or suffer from mechanical overdetermination and noise issues due to complex designs and the need for multiple thrust pieces.
Innovation Solution
A steering gear system with two opposing steering pinions, where one pinion is non-rotatably connected to the steering shaft and the other to a servo drive, using a spring element for coupling and torque distribution, eliminating the need for a complex pressure piece and allowing for efficient torque transmission without mechanical overdetermination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single large steering pinion is used to transmit high torques for heavy vehicles, then the torque transmission capability is improved, but the pinion diameter increases which adversely affects the steering gear compactness and transmission ratio
Solution Approach 1:
The steering gear is segmented into two opposing pinions instead of using one large pinion. Each pinion has a manageable diameter that maintains compact steering gear dimensions, while together they transmit the high torques required for heavy vehicles through distributed loading.
2Force
If two opposing pinions are used to transmit high torques, then the torque transmission capability is improved, but mechanical overdetermination and complexity increase
Solution Approach 1:
A spring element is introduced as an intermediary between the two opposing pinions. This spring element couples the pinions together, allowing them to rotate in opposite directions while maintaining synchronization. The spring element absorbs differential movements and prevents mechanical overdetermination by providing flexible coupling rather than rigid constraint.
3Force
If a second separate servo drive with a second pinion is used to provide steering assist for heavy vehicles, then the steering assist capability is improved, but the construction volume increases
Solution Approach 1:
The steering assist function is merged into the existing pinion-rack engagement by using two opposing pinions instead of adding a separate servo drive system. This integration allows the steering assist capability to be achieved within the compact space of the original pinion-rack assembly, eliminating the need for additional separate components.
4Force
If a ball screw is added to the rack to reduce pinion load, then the torque distribution is improved, but the manufacturing cost increases
Solution Approach 1:
Instead of adding a complex ball screw mechanism, the patent uses two simplified pinions that replicate the steering assist function. Each pinion independently engages with the rack, distributing the torque load without requiring expensive ball screw components or complex lead screw mechanisms.
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 allows for compact, cost-effective steering assist in heavy vehicles, reducing production costs and noise while enabling higher torque transmission without play in the toothing engagements, making it suitable for heavier vehicles.
Implementation Method 1
At least one spring element is arranged between the first pinion and the second pinion, so that freedom from play is achieved via the forced coupling and the spring element
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a motor vehicle steering system comprising a steering housing (7), in which a toothed rack (6) is mounted in a longitudinally displaceable manner and is connected to tie rods (8) for pivoting steerable wheels (9). The toothed rack (6) is provided with a first toothed segment (5) that meshes with a first steering pinion (4), and the steering pinion (4) is rotationally fixed to a steering wheel (1) via a steering shaft (2, 3). The toothed rack (6) has a second toothed segment (13) that lies opposite the first toothed segment (4) with respect to the longitudinal axis of the toothed rack (6), and a second steering pinion (12) is provided which is engaged with the second toothed segment (13).