NTN Has Developed an Intelligent Axle Unit with Force Detection Sensors
for More Accuracy Vehicle Stability Control

NTN has recently developed an intelligent axle unit with force detection sensors, which detect vehicle cornering force and traction force without a time lag. The unit comprised of a hub and a constant velocity joint (CV joint) can help enhance more accurate and detailed vehicle stability control.

Two types of sensors installed in the hub bearing and CV joint detect small amounts of distortions in the hub bearing due to vehicle cornering force, and in the CV joint due to traction force respectively without a time lag. The detected distortions are then converted into the force acting between tires and road.

Recently, various technologies have been put in practical use for enhancing vehicle safety and stability, and among them are the vehicle stability control (VSC) systems, which help prevent vehicle from slipping and skidding when entering a curve at an excessive speed or during abrupt steering. The existing VSC systems control braking force and engine output in response to vehicle dynamic behavior detected based on information from a yaw-rate sensor and a lateral acceleration sensor in addition to the operational information from steering wheel, throttle valve and brake pedals, however, there is a certain time lag in detecting the force between tire and road because the sensors are usually attached on the sprung body and thus affected by the suspension system of vehicle.

On the other hand, the developed unit detects the force acting between tire and road without a time lag, since the sensors are attached on the unsprung side, Furthermore, the independent detection of cornering and traction forces on each wheel helps realize more accurate and detailed vehicle stability control.

[Feature]

1. Possible to sense for each wheel the force acting between the tires and road.
   • Cornering force: Detection with high-sensitivity distortion detection sensor unit housed in the hub bearing.
   • Traction force: Detection with contactless angle sensor unit attached to the CV joint .
2. Real-time sensing of force acting between tires and road.
   • Cornering force and traction force are measured on the axle  that is not influenced by suspension characteristics to realize sensing without time delays.

[Photograph (with sensor attached)]