WO1984000406A1

WO1984000406A1 - Heat sensors for overheating brakes and wheels

Info

Publication number: WO1984000406A1
Application number: PCT/AU1982/000219
Authority: WO
Inventors: Shawky Shafeek Michael
Original assignee: Shawky Shafeek Michael
Priority date: 1982-07-14
Filing date: 1982-12-31
Publication date: 1984-02-02
Also published as: WO1984000407A1; EP0114821A1; EP0113722A1

Abstract

Placing heat sensor (4) as close to the braking surface (3) as possible will give early warning in case of overheating due to brake (2) locking or bearing problem, warning the driver before any damage has occurred. Heat sensors (4) are connected to an electronic monitor to locate one or more wheels with an anomalously high temperature compared to other wheels, so as to prevent a warning when all wheels are overheating due to steep descent and long use of brake. Said electronic monitor will send a warning sound and signal to the driver on a meter panel display, giving said driver the location of the overheating.

Description

HEAT SENSORS FOR OVERHEATING BRAKES AND WHEELS

FIELD OF INVENTION

This invention relates to brake systems and applies in all fields of the automotive industry.

By utilising heat sensors nearby the brake shoe pads, disc, wheel or wheel drum, this invention has the advantage of warning the driver of a vehicle in the case of the bearing overheating due to the lack of lubricant and where locking of the shoe pad occurs without the knowledge of the driver. The warning is the result of the high temperature which is generated by the friction between the shoe pad and the wheel, disc, or wheel drum or within the wheel bearing assembly.

Search in previous publications and patents revealed that there is no prior art compatible with this invention in the field of using temperature sensors to locate and warn of an overheating wheel and consequently an indication of brake locking or a problem with the bearing.

PROBLEMS REQUIRING THIS INVENTION

Until now little or no work has been done on monitoring wheel bearing and the brake assemblies sections of any transport vehicle, which has the resulted in severe damage to said sections of the vehicle on many occasions. Said damage is mainly due to the brake locking or the lack of lubricant or damage in the wheel bearing without the knowledge of the driver because of the high power of the engine particularly in large transport vehicles such as semi-trailers. The main wheels' overheating problems are largely attributed to brake locking in comparison to bearing overheating; the result in either case ranges from brake drum overheating and tyre wear to complete melting of the bearing assembly or the brake drum and the ignition of the brake fluid, tyres, and on many occasions the setting on fire of the vehicle itself. Furthermore, for long vehicles, brake locking of one wheel usually causes an imbalance in the vehicle at high speeds which generally decreases the safety of the vehicle.

SUMMARY OF THE INVENTION This invention is designed so as to monitor the temperatures as close to the brake drums and disc brakes as possible and gives the driver a warning signal of the location of the heating wheel if a temperature anomaly occurs in one or more wheels compared to the temperature of the other wheels of the vehicle. An electronic comparator differentiates between the normal heat generated over a long distance of heavy braking such as on a hilly or mountainous descent or with a general rise of ambient temperature such as on hot days during summer driving.

DESCRIPTION OF THE INVENTION Figure 1 is a cross section view of a conventional wheel and brake assembly of a motor vehicle where the brake is of the drum type.

Figure 2 is a schematic view of a brake assembly of the disc brake type. Figure 3 represents the logic flow of the system} and

Figure •% illustrates a schematic perspective view of the panel display gauge for the driver. The brake assemblies shown in Figures 1 and 2 are usually very well housed to prevent water from entering into the assembly. Figure 1 shows the wheel assembly of a conventional brake drum type where 1 is the wheel backing plate, 2 is the brake shoe, 3 is the brake drum, 5 is the main axle, while 6 and 7 are the wheel rim and tyre respectively.

The temperature sensor is drilled into the shown position in the backing plate as only an illustration, as such a sensor could also be mounted on the brake shoe, wheel cylinder; however in the opinion of the inventor, the backing plate is one of the most stable parts of the wheel assembly due to its non-mobility, and its close distance to the wheel drum, which makes it respond much faster to any temperature rise.

The temperature sensor is of any type such as thermocouple, switching sensor which is triggered at a set temperature, diode, or electronic type; and they are all fitted securely to said backing plate or any other position by means of nuts, washers and bolts.

Figure 2 shows the disc brake assembly 1, braking pads 2 and wheel braking disc 3; and Figure 2 illustrates the most appropriate position to install the said heat sensor 4 in the case of a disc brake assembly, where it could be mounted on one of the two lock clips 5 which exist with every disc brake assembly system; or said sensor 4 could be simply mounted in a hole drilled in the assembly 1 and as close to the disc as possible. In the case of the electric switch sensors which will close or open (depending on the type) at a pre-set temperature limit, a direct wiring to the electronic circuit is connected. Furthermore, it is recommended to place a"higher set temperature sensor on the front wheel,for example 200°C triggering point, compared to the back wheels due to the fact that when braking, the heavier load is usually on the front wheels compared to the back wheels; this will consequently cause higher temperatures to be generated in the front wheels than those in the back wheels. Tempjerature sensors in the back wheels could be set, for example to be triggered at 150 C. These pre-set temperature sensors are fitted with different ranges to suit the type of vehicle and the size of the wheel assembly. It must be understood, that although there is the factor of an air gap between the sensor and the disc or drum and the cooling effect of the wind during the movement of the vehicle, in the case of wheel overheating the temperature easily exceeds 500 C and reaches u to more than 1000 C, and accordingly, a few millimetres of an air gap is not an obstable for a sensor to be activated, for example at 200 C.

Temperature sensors of any type may be synchronised with the electronics so as to give two levels of warnings; say one for overheating but not reaching any dangerous level, and the other for if and when the overheating continues to increase giving a very high and dangerous level of heat. Said two levels of warning gives the driver an indication of the level of danger and if that level is not very high he does not have to stop immediately , which may cause traffic inconvenience. Furthermore, said warnings will give him the chance to drive to the nearest repair station or town. Furthermore, temperature sensors could also be fitted on parts of the motor vehicle which are likely to be damaged due to lack of lubricant such as the gearbox, and differential box(es).

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W>r In the case of a railway vehicle, it is suggested that the sensor be placed on the wheel axle box where heavy duty nuts are available on the said box.

Using electronic sensors such as thermocouples & diodes, would require more electronic decoders to convert the signals from volts or amperes into a usable temperature which in turn is pre-set electronically for an upper temperature limit. When said limit is reached the information is relayed into another electronic comparator which in simple terms looks at all wheels at the same time and immediately gives a warning to the driver after locating the position of the wheel when said wheel shows an anomalously high temperature compared to other wheels.

Figure 4 shows a schematic front view of a standard size gauge 1 similar to those on the panel such as the speedometer. Figure 4 illustrates a large type of motor vehicle consisting of truck with its schematic presentation in the form of wheels 4, 2 and trailer with its schematic presentation 3. Button 6 is for testing and when pressed lights all warning lights 5; and if the trailer is not attached to the truck, no light appears in the trailer warning lights. Furthermore if the situation arises that the wires are disconnected or there is a faulty circuit, said situation is indicated when switch 6 is pressed, and for safety a warning light and sound also appear,in the case of a faulty circuit during driving,on the light next to WIRES DISCONNECTED.

Lights 5, 7 and 8 automatically appear on gauge 1, Figure 4, to correspond to the same overheating wheel, gearbox or differential so as to save the driver the time of checking all wheels for the one(s) which is/are overheating. Gauge 1, Figure 4, will vary according

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^• to the type of vehicle and it is suggested in the case of railway trains that said gauge be of the digital reading type giving a number which corresponds to the sequence number of the railway wagon together with a general warning light and warning sound. Lights 5, 7 and 8 could be made of two different bulbs or one diode which has the capacity to give two colours, say orange and red so as to indicate to the driver the level of heating.

Further modifications could be added to this gauge, in case of attaching heat sensors to monitor the temperature of the other parts of the vehicle such as gearbox 7 or differential assembly 8 as illustrated in Figure 4.

THE ADVANTAGES OF THIS INVENTION

The main advantages of this invention are:-

1- It increases the safety and reliability of all transport vehicles.

2- It provides a unique and low priced monitoring system.

3- It reduces the fuel consumption together with the wear of tyres, brake pads, clutch pads and the vehicle engine in general.

4- The device provides a very unique warning display system for the driver so as to reduce the time taken in finding the faulty wheel.

Claims

THE CLAIMS DEFINING THIS INVENTION ARE AS FOLLOWS;- 1. Temperature warning device to warn the driver of motor vehicle, railway train and aeroplane,of any overheating problem in areas of high friction within the vehicle, such as wheels due to brake locking and/or lack of lubricant within the bearing, gearbox and differential assembly. Said temperature warning device consists of any type of temperature sensors which are firmly attached to the non moving parts of said wheel drums, discs, bearing, gearbox and differential. Said temperature sensors are synchronised electronically so as to check on all said sensors spontaneously and give a light and sound warning to driver when an anomaly in temperature occurs within any of said sensors. Said sensing of an anomaly avoids giving a false warning during normal temperature rise from ambient temperature or due to usual braking over a distance. The warning is given in the form of light and warning sound display which gives the location of the overheating section and in the case of trailway trains, said warning is given as a digital display so as to locate the railway wagon where the overheating has occurred.

2. A device as claimed in claim 1 wherein said temperature sensors are made of any type adjustable or non-adjustable which are mechanically or electronically triggered to measure the temperature.

3. A device as claimed in claims 1 and 2 wherein said temperatur sensors are installed on any non-rotating part of the wheel assembly, gearbox or differential with an earthing system so as to give a warning in the case of displacement from its sensing position.

4. A device as claimed in claim.-. 1 where sensors are connected to an electronic comparator which simply keeps a continuous monitor on all sensors and compares said sensors together . In the case of an anomalously high temperature for one wheel, gearbox, or differential compared to other positions, the monitor will automatically give the appropriate warning signals.

5. A device as claimed in claims 1 and 4 where an electronic comparator is adjustable to any level of te-nperature and capable of monitoring and giving two levels of warnings at say high and very high temperature.

6. A device as claimed in claim 1, 4 and 5 wherein said electron monitoring is capable of checking the circuit and the sensors for any faults or damage and gives a warning with the corresponding position on said display before the driver commences driving the vehicle.

7. A device as claimed in claim 1 wherein said motor vehicle display is designed to resemble a meter panel with the contained art work designed to suit the vehicle chassis and the number of wheels and differentials; said gauge also allows for a trailer or trailers' art work in the case of semi-trailers.

8. A device as claimed in claim 1 and 7 wherein said motor vehicle display is designed to give lights using the readily available Light Emission Diodes (LED) with say 3 different colour lights :green for testing the system, orange for high temperature and red for very high temperature or danger. The device also contains an electric buzzer for sound warning and have at least one button to test the whole circuit and to display a light in the case of fault or dislocated said sensor.

9. A device as claimed in claim 1 herein said railway vehicle display is designed so as to give a warning on a similarly designed art work with an extra digital display to give the number of the railway wagon where the overheating has occurred. This will save time and effort in locating the fault particularly where there are many railway wagons, say more than 100.

10. Heat sensors for overheating brakes, wheels, gearboxes, and differentials, substantially as herein described with reference to accompanying drawings.

CV.