Steering Angle Sensor Mounting via Pre-rotated Rotor

Solution Overview

Problem

Mounting a steering angle and steering torque sensor to a steering gear in the zero position is challenging due to spatial constraints, making it difficult to ensure accurate alignment and connection within the steering gear components.

Innovation Solution

The method involves rotating the sensor's rotor relative to its housing by a predetermined angular amount before assembly, using a toothed rack and pinion toothing system to accurately position the sensor, allowing for precise alignment and connection outside the steering gear, and then fixing the sensor housing non-rotatably to the steering gear, ensuring the sensor returns to the zero position during assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the sensor is mounted in the steering gear in the zero position, then the sensor alignment accuracy is improved, but the assembly difficulty increases due to spatial constraints and inaccessibility of components

Engineering Contradiction:

Improvesensor alignment accuracyVSAvoidassembly difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The sensor is pre-adjusted to the zero position outside the steering gear before final installation. This preliminary positioning allows for accurate alignment to be achieved in an accessible workspace, and then the sensor is mounted to the steering shaft and housing in the predetermined angular position, which ensures that after assembly the sensor will be in the correct zero position despite the steering shaft's rotation during installation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The assembly process is divided into separate stages: first adjusting and positioning the sensor outside the steering gear where components are accessible, then installing the sensor to the steering shaft and housing, and finally assembling the complete steering gear. This segmentation allows the critical sensor alignment operation to be performed in an accessible environment rather than attempting to align the sensor during final assembly within the constrained steering gear space

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If the steering shaft is rotated during assembly to engage the pinion toothing with the toothed rack, then the sensor achieves correct zero position alignment, but the sensor position accuracy deteriorates due to rotation-induced misalignment

Engineering Contradiction:

Improvesensor zero position alignmentVSAvoidsensor position accuracy

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The sensor is pre-adjusted to the zero position outside the steering gear before final installation. This preliminary positioning allows for accurate alignment to be achieved in an accessible workspace, and then the sensor is mounted to the steering shaft and housing in the predetermined angular position, which ensures that after assembly the sensor will be in the correct zero position despite the steering shaft's rotation during installation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The rotor of the sensor is deliberately rotated by a predetermined angular amount away from the zero position during assembly preparation. This preliminary anti-action compensates for the expected rotation of the steering shaft during installation, so that when the steering shaft rotates to engage the pinion toothing with the toothed rack, the sensor automatically returns to the correct zero position alignment

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS7350617B2Method for mounting a steering angle and steering torque sensor and steering gear including a steering angle and steering torque sensor

Publication Date: 2008.04.01 ZF AUTOMOTIVE GERMANY GMBH

AI summary

A method for mounting a steering angle and steering torque sensor to a steering has the following steps: At first, there is provided a steering angle and steering torque sensor which includes a housing and a rotor. Then, the rotor and the housing are rotated through a predetermined angular amount with respect to a zero position, and the rotor is attached to a steering shaft that is provided with a pinion toothing. Finally, the steering shaft is inserted into a steering gear which includes a toothed rack, the housing being fixed in place at the steering gear in a predetermined angular position, and the steering shaft being rotated together with the rotor by the pinion toothing engaging in the toothed rack, until the rotor has returned to the zero position relative to the housing.