Electrical transmission or interconnection systems – Vehicle mounted systems – Automobile
Reexamination Certificate
1999-04-26
2001-05-22
Paladini, Albert W. (Department: 2836)
Electrical transmission or interconnection systems
Vehicle mounted systems
Automobile
C180S400000, C280S005510, C701S041000
Reexamination Certificate
active
06236119
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a device for determining the angular position of the steering wheel in a motor vehicle.
BACKGROUND OF THE INVENTION
Inductive and optical steering angle sensors are known to determine the angular position of the steering wheel. The measured values which can be determined with these means are supplied to an electronics circuit on the output side for determining the steering angle. The known steering angle sensors are fixed as a separate part underneath the drop arm switch in the vehicle. The drawback with this arrangement is that additional structural space is required for the steering angle sensor and additional costs are incurred.
SUMMARY OF THE INVENTION
The object of the invention is to allow the determination of the steering angle without additional structural space and with lower costs.
This is achieved according to a device for determining the angular position of the steering wheel in a motor vehicle by using a steering angle sensor and an electronic evaluation device for determining the angular position. According to the invention, the steering angle sensor is integrated in a contact unit for transferring energy and data from stationary structural groups of the motor vehicle to the steering wheel and vice versa.
More particularly, the steering angle sensor is mounted as a component part of the stator and rotor in a contact unit having a stator and rotor and operating in contactless manner. Through this integration of the steering angle sensor into the contact unit which is present in any case, it is possible both to reduce the structural space and costs as required. The steering angle sensor and the different types of contact units are combined into one system and can thus be supplied as a structural unit to the automobile industry.
In a first embodiment, an optical steering angle sensor is provided which has on the rotor or stator a bar code representing the angular position of the steering wheel. The bar code is associated with a structural group on the stator or rotor for detecting and transferring the angular position determined by the bar code. The bar code can be injection moulded on the rotor or stator by the 2-component technique. A pulsating light source is preferably associated with the bar code so that the unlit bar code is illuminated pulsating in operation thereby saving energy. With the arrangement of the optical steering angle sensor in an optical contact unit the bar code is lit up by the LED which is provided for the energy transfer so that additional lighting is not required.
As a structural group for detection and transfer, at least one transmitter and receiver is provided which are mounted id radially spaced from each other in a ring on the stator and between these a partition wall is provided on which the bar code is attached. The transmitter, receiver and partition wall are preferably arranged concentric relative to each other or lie opposite one another in the axial direction.
The transmitter and receiver preferably operate in the infrared wavelength range. The signals are transferred from the infrared transmitter to the infrared receiver via the code track.
The steering angle is measured incrementally in a known way, i.e. a micro-controller counts the impulses of the reflected light beams and from this forms the steering angle. Thus a dependence is produced for the permissible rotational speed and micro-controller contact.
In a further embodiment, it is proposed that a CCD element with a magnifying glass is provided as a structural group for the detection and transfer. Greater axial and radial tolerances can be compensated by the focusing thereby achieved.
With this optical steering angle sensor the bar code thus receives information on the angular position of the steering wheel. This data is detected by means of the diodes or CCD element and transferred to the electronics (known per se) on the output side. The angular position is calculated there from the coded measured value.
In one embodiment, it is proposed that the bar code is attached to a ring-shaped carrier with which the CCD elements are associated in the radial direction. It is however also possible to provide the bar code on a data ring for the multi-functions in the steering wheel with which the CCD elements are associated.
Apart from the radial association of the bar code and CCD elements, an axial association is also possible. Thus in one embodiment it is proposed that the bar code is attached to the steering wheel and the CCD elements axially on the stator.
In a further embodiment, a telemetric steering angle sensor is provided which has on the stator or rotor, a ring-shaped transmitter aerial (or module) which is associated with a ring-shaped receiver aerial (or module) on the rotor or stator whereby the axes of the rings run in different directions. Preferably, the transmitter aerial is fixed on the stator and its axis runs in the direction of the steering column axis, and the receiver aerial is fixed on the rotor and its axis runs at an angle to the steering column axis.
Thus with this embodiment, the ring-shaped transmitter and receiver aerials have a different spacing over their circumference. Particularly in the case of the last-mentioned embodiment, the receiver aerial fixed on the rotor executes a tumbling motion relative to the transmitter aerial. Through rotation of the rotor, a rising magnetic field is produced starting from a zero point and this is converted into angular degrees through the attached electronics.
In another embodiment, an inductive steering angle sensor is provided which has on the stator and rotor, respectively, a resistance path attached to an alternating current source and a collector path running in the same direction associated with a probe on the rotor and stator, respectively, for transferring data from the resistance path to the collector path. The probe provided is one suitable for the capacitive decline of the displacement current. The displacement current is transferred to the collector path and supplied from there to the evaluator electronics.
In an embodiment of the inductive steering angle sensor, the resistance and collector paths are mounted inside on the ring-shaped stator and the probe is provided outside on the rotor which is concentric with the stator.
In another embodiment of the inductive steering angle sensor, the probe is attached directly on the steering wheel hub or on a plastic ring fixed on the steering wheel. The resistance and collector paths are fixed axially opposite one another on the stator.
A further embodiment of the steering angle sensor is characterised in that a metal ring is mounted in the rotor part of the contact unit and is associated with an echo sensor in the stator part of the contact unit whereby the metal ring has a continuously rising width and is formed as a magnetic ring. With rotation of the steering wheel and thus of the metal ring, a different sized echo voltage is produced in dependence on the rotary angle and is then used as a measure for the rotary angle.
The changing width of the metal ring is preferably achieved through an inclined lower edge.
Contact units, in which the steering angle sensor is mounted, preferably provide inductive or telemetric or optical contact units, whereby the steering angle sensors are preferably provided in the identical contact units. It is however also possible to provide throughout, for example, optical steering angle sensors in inductive or telemetric contact units or inductive or telemetric steering angle sensors in the other said contact units.
In order to reliably prevent the optical component parts from misting up in the case of an optical steering angle sensor or with an arrangement of the steering angle sensor in an electrical contact unit, moisture extraction means or a metal ring can be provided on the optical transfer section. These can be provided directly on the optical transfer section or in a labyrinth which surrounds the optical transfer section.
REFERENCES:
patent: 5611704 (1997-03-01), Kamizono et al.
Bonn Helmut
Hössbacher Gerhard
Zawidzki Ulrich
Christie Parker & Hale LLP
Paladini Albert W.
Petri AG
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