Thermal measuring and testing – Temperature measurement – Combined with diverse art device
Patent
1999-03-30
2000-08-22
Chapman, John E.
Thermal measuring and testing
Temperature measurement
Combined with diverse art device
324166, G01P 348
Patent
active
061061514
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a sensor arranged in a casing which is partly filled with a fluid and which comprises a rotatable shaft situated in the casing, where the sensor comprises a revolution counter sensor for measuring the revolutions of the shaft and also a temperature sensor for measuring the temperature of the fluid.
DESCRIPTION OF THE RELATED ART
Sensors of the above stated type are present amongst others in a gearbox for a motor vehicle. A gearbox for a motor vehicle comprises a number of shafts on which gear wheels are mounted. The shafts and the gear wheels are surrounded by a gearbox casing which is partly filled with oil. In order to monitor the number of revolutions of the engine of the vehicle a revolution counter sensor is arranged in a hole in the wall of the gearbox casing. The revolution counter sensor is, for example, designed as an induction sensor which cooperates with a toothed or pulse wheel which is arranged, for example, on the input shaft in the gearbox. For manufacturing reasons the revolution counter sensor is placed in the upper part of the gearbox, above the oil level. In order to measure the temperature of the oil a temperature sensor is arranged in a hole in the wall of the gearbox casing. The temperature sensor is usually provided with a thermoelement which is in contact with the oil. Cables are connected to the revolution counter resp. temperature sensor which lead to an indicator, such as a meter or a lamp on the instrument panel of the vehicle.
In this prior art, a hole for the revolution counter sensor and another hole for the temperature sensor must be formed in the wall of the gearbox casing. At the same time, a cable must be connected to the revolution counter sensor and another cable connected to the temperature sensor. This involves quite a number of parts which lead to increased manufacturing and mounting costs.
A problem with this prior art is that the temperature sensor must be surrounded by the oil, the temperature of which is to be determined, wherefore the temperature sensor is placed under the surface of the oil while at the same time the revolution counter sensor for manufacturing reasons must be placed above the surface of the fluid.
In order to protect the temperature sensor from splashes and stones flying up from the road the outer parts of the temperature sensor are in general placed on the upper side of the gearbox casing, or alternatively on one of its sides, because the underside of the casing is too exposed. Because the temperature sensor according to the prior art must be immersed under the surface of the oil, the sensor is unnecessarily long and often requires to be protected from vibrations, which leads to increased costs.
SUMMARY OF THE RELATED ART
The object of the invention is to provide a sensor arranged in a casing of the type mentioned in the introduction, which eliminates the above mentioned disadvantages during monitoring of the speed of rotation of a shaft and the temperature of the fluid inside a casing.
This is achieved according to the invention through the first sensor and the second sensor forming a unit which is situated in the casing and above the surface of the fluid.
With such a solution a single sensor unit is obtained which is well protected against, for example, stones flying up from the road, where earlier two sensors were required, where at least one of them often was insufficiently protected on the underside of the casing. Furthermore, only one hole is required in the wall of the casing which leads to a simpler and less expensive mounting. The wiring is also simplified as only one cable is required to be connected to the unit, as opposed to the two required earlier.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described more closely below with reference to the appended drawings showing examples of embodiments, where
FIG. 1 shows a schematic view of a gearbox for a motor vehicle according to a first embodiment,
FIG. 2 shows a schematic view of a gearbox according to a
REFERENCES:
patent: 4659235 (1987-04-01), Gilmore, Jr. et al.
patent: 5880584 (1999-03-01), Arai et al.
Chapman John E.
Volvo Lastvagnar AB
LandOfFree
Sensor for measuring rotational speed and temperature does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sensor for measuring rotational speed and temperature, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sensor for measuring rotational speed and temperature will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-572953