Patent Application
20080282818
1. Field of the Invention
This invention relates generally to sensors, and more particularly to sensors that are more wear resistant.
2. Description of the Related Art
Position sensing is used to monitor the position or movement of a mechanical component. The position sensor produces a signal that varies as the position of the component in question varies. By way of illustration, position sensors allow the status of various automotive actuations and processes to be monitored and controlled electronically.
A position sensor must be accurate, in that it must give an appropriate signal based upon the position measured. If inaccurate, a position sensor will hinder the proper evaluation and control of the position of the component being monitored. A position sensor must also be adequately precise in its measurement. The precision needed in measuring a position will obviously vary depending upon the particular circumstances of use. For some purposes only a rough indication of position is necessary. For instance, an indication of whether a valve is mostly open or mostly closed. In other applications more precise indication of position may be needed.
A position sensor must also be sufficiently durable for the environment in which it is placed. For example, a position sensor used on an automotive valve will experience almost constant movement while the automobile is in operation. Such a position sensor must be constructed of mechanical and electrical components which are assembled in such a manner as to allow it to remain sufficiently accurate and precise during its projected lifetime, despite considerable mechanical vibrations and thermal extremes and gradients.
Contact position sensors require physical contact between a signal generator and a sensing element to produce the signal. Contacting position sensors typically consist of a potentiometer to produce electrical signals that vary as a function of the component's position. Contacting position sensors are generally accurate and precise. Unfortunately, the wear due to contact during movement of contacting position sensors has limited their durability. Also, the friction resulting from the contact can result in the sensor affecting the operation of the component. Further, water intrusion into a potentiometric sensor can disable the sensor.
There is a need for an improved position sensor that has reduced wear. There is a further need for an improved position sensor that has an increased lifetime. Yet there is a further need for an improved position sensor with longer life, and consistent and reliable performance in demanding industrial applications and environmental conditions.
Accordingly, an object of the present invention is to provide an improved position sensor.
Another object of the present invention is to provide an improved position sensor that has an increased lifetime.
A further object of the present invention is to provide an improved position sensor with longer life, and consistent and reliable performance in demanding industrial applications and environmental conditions.
Yet another object of the present invention is to provide an improved position sensor that improves the wear resistance of the resistive track and the contact device.
These and other objects of the present invention are achieved in a sensor that has a base with at least one resistive track which includes a nano particle based conductive ink. A contact device makes contact along at least a portion of the resistive track and provides an indication of position or movement.
In one embodiment of the present invention, as illustrated in
The resistive track 14 increases the robustness of the sensor 10 and makes it is less dependent on wear of the contact device 18 on the resistive track 14. The nano particle based conductive ink 16 improves wear resistance of the resistive track 14 and the contact device 18.
In various embodiments, the sensor 10 can be, a rotary sensor, a linear sensor and the like. In one embodiment, the sensor 10 detects motion or movement at any angle above 0 degrees and can have multiple turns. The sensor 10 can be used to detect motion or movement, and can be used in a variety of different applications including but not limited to, land vehicle, marine, industrial, aerospace, agricultural applications and the like.
The contact device 18 can include a nano-film 20 or can be a nano-film. In various embodiments, the contact device 18 makes a single contact or multiple point contacts with the resistive track 14.
Referring now to
Referring not to
In one embodiment, the nano tubes are 34, single-walled nano tubes (SWNTs), double-walled nano tubes (DWNTs), multi-walled nano tubes (MWNTs), and mixtures thereof.
As illustrated in
The resistive tracks 14 and 38 can contain carbon. In one embodiment, the resistive track includes at least one of a, metal, organic, ceramic, metal oxide, metal nitride, metal-organic, metal carbides and the like. The metal oxides can be, tin-indium mixed oxide (ITO), antimony-tin mixed oxide (ATO), fluorine-doped tin oxide (FTO) or aluminum-doped zinc oxide (FZO), zirconium, aluminum, cobalt, yttrium, vanadium and/or cadmium oxides. The metal nitrides can be titanium, boron and the like. The metal carbides can be, wolfram, tantalum, titanium and the like.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the appended claims.
