CA2199452C - Wheel failure detection and warning system - Google Patents
Wheel failure detection and warning system Download PDFInfo
- Publication number
- CA2199452C CA2199452C CA002199452A CA2199452A CA2199452C CA 2199452 C CA2199452 C CA 2199452C CA 002199452 A CA002199452 A CA 002199452A CA 2199452 A CA2199452 A CA 2199452A CA 2199452 C CA2199452 C CA 2199452C
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- Canada
- Prior art keywords
- wheel
- vehicle
- signal
- sensor
- indicator
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
- B60Q9/00—Arrangement or adaptation of signal devices not provided for in one of main groups B60Q1/00 - B60Q7/00, e.g. haptic signalling
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M17/00—Testing of vehicles
- G01M17/007—Wheeled or endless-tracked vehicles
- G01M17/013—Wheels
Abstract
A system for detecting and signalling the failure of a wheel or a wheel set of a truck or trailer type of vehicle includes a plurality of equiangularly spaced magnets fixed to the wheel rim and facing inwardly of the vehicle to define a magnet plane. An induction-type sensor is mounted to a non-rotating axle support opposite the magnets so as to have a train of electrical pulses magnetically induced therein should a rotating magnetic field created by the rotating magnets intrude into a predetermined acceptable spacing of the magnet plane from the sensor. The sensor is connected to a transformer which will step up the sensor signal to activate an indicator in the vehicle cab to warn the operator of an imminent wheel failure. The threshold signal strength is determined for each wheel of the vehicle and is based on the acceptable spacing of the magnet plane from the sensor accommodating vehicle loading and dynamic effects such a vehicle speed and anticipated road conditions. If the magnet plane intrudes into the acceptable spacing, due for example to a wheel failure caused by broken lug bolts or due to excessive overloading, the induced signal at the sensor will be stepped up by the transformer to a level that will activate the indicator in the cab. The indicator will give an audible or a visible signal to the operator and the operator should, in response thereto, stop his vehicle, inspect the wheel, and take appropriate action to correct the problem.
Description
The present invention relates to the trucking industry in general, and in particular to a system for detecting and signalling a possible failure of a rotating wheel on a truck or a trailer.
R~R~PCUND OF THB INVENTION
There have been numerous incidents recently of wheels or wheel sets catastrophically separating from a truck or a trailer travelling at speed and then moving in a direction away from the vehicle. In some cases the wheel sets, which can weigh several hundred pounds and may be travelling at more than 100 Kph, have struck vehicles travelling in the immediate vicinity, causing severe damage and even death.
The trucking industry is being held accountable for these tragic incidents and the maintenance practices of the industry as a whole has come under close scrutiny. In some instances wheel failure has been the result of improperly tightened wheel bolts which have fractured, allowing the wheel set to separate from its support. In other cases, the vehicle has been consistently overloaded so as to place undue stress and strain on the axle with the result that there has been a structural failure at the end of the axle. Wheel failures that occur on major arteries and result in tragic accidents receive considerable media coverage and prompt much outrage. The number of such reported incidents appears to be rising, however, and there now appears to be a need for an ineYr~n~ive system which can detect wheel problems and communicate the unacceptable condition to the vehicle driver so that he can take immediate action that will avoid the catastrophic separation of wheel from vehicle.
The present invention provides two relatively simple and inexpensive systems that can be attached to new trucks or trailers and which also can be retrofitted to existing vehicles. Each system includes a plurality of magnets that positioned about the inside of a wheel rim, with equiangular spacing therebetween. The magnets are located close to the outer edge of the rim on the side facing inwardly of the vehicle and can be attached thereto in the same manner that a wheel weight, used for balancing a wheel, might be attached.
Preferably four magnets are provided, spaced apart by 90~, although more or fewer magnets could be used. If the vehicle is provided with wheel sets made up of a pair of wheels, i.e.
dual wheels, then the magnets are located on the innermost wheel of the wheel set.
In the case of a set of driven wheels the drive axle therefor will be contained within a non-rotating axle tube or support. In the case of non-driven wheels there will be a non-rotating support carrying a wheel mounting assembly and hub at the end thereof. For the present invention at least one sensor is mounted to the non-rotating support for the wheel, the sensor being positioned at the same distance from the wheel axis as the magnet~ and also being positioned at a predetermined distance or spacing from the plane containing the magnet faces. The sensor is preferably in the form of an induction coil such as might be used in the ignition system of a two-stroke engine.
When subjected to a moving magnetic field, a signal in the form of a train of electrical pulses is generated in the coil. If the magnet members are rotating in a magnet plane outside a predetermined acceptable distance from the sensor the magnetic field generated thereby will not be strong enough to create a signal at the sensor. If the magnet members come close to the sensor, within the predetermined acceptable distance, the magnetic field will generate a signal at the sensor.
In its simplest form the present invention includes a DC transformer connected to the sensor. When a signal from the sensor, measurable in minivolts is passed to the transformer it is stepped up considerably thereby so that the stepped up signal may be used to activate an indicator in the cab of the vehicle to which the invention is attached. In another embodiment, if the predetermined distance is such that the sensor will always generate a signal, the strength of which is dependent on the spacing of the magnet plane from the sensor, a discriminator connected to the sensor analyses the signal to determine if it exceeds a threshold value and if it does, the discriminator will activate an indicator to signal the vehicle operator that an unsafe condition has been detected. With each embodiment the signal to the operator will preferably be in the form of a flashing light or a beeping horn, in response to which the operator should slow down and bring his vehicle to a halt so as to investigate the situation which gave rise to the warning signal. The indicator could also be tied into a computer programmed to reduce the fuel supply to the vehicle's engine or to gently apply the brakes, so as to start to slow the vehicle down, should the operator fail to heed the warning signal after a set period of time. The indicator, in addition to providing a warning signal, would preferably include a chart or other means to identify the wheel on the truck or trailer which is generating the fault signal.
The present invention is based on the premise that a moving magnet can generate a signal through induction in a suitable sensor. If the magnet faces are arranged in a plane that is normal to the wheel axis, which axis coincides with the axis of the axle, then any departure of the magnet plane from normal relative to the axle axis will increase or decrease the distance between the magnet plane and the sensor as the wheel wobbles and the magnets pass the sensor. Wheel wobble could be the result of loose wheel lug nuts, broken or cracked lugs, a damaged wheel hub, or a bent axle caused by overloading or impact. For any given wheel and axle combination and vehicle load rating it should be possible to determine an optimum spacing between the magnet plane and the sensor and also to determine maximum acceptable and expected wheel movement relative to the sensor. The maximum expected and acceptable wheel movement will determine the maximum distance or spacing of the magnet plane relative to the sensor. As long as the rotating wheel maintains the magnet plane beyond the maximum spacing the sensor will not generate a train of pulses strong enough to generate a failure signal.
However, should for example one of the wheel lugs crack so that the movement of the wheel exceeds the expected range then the magnet plane will intrude into the acceptable spacing, the sensor will generate the necessary train of pulses threshold, and a failure signal will be transmitted to the indicator adjacent the operator so that he is warned of the possible failure of the wheel. He can then stop his vehicle, inspect the problem wheel, and take appropriate remedial action.
Generally speaking, the present invention in its first embodiment may be considered as providing a system for detecting and signalling a possible failure of a rotating 0 2 1 9 9 4 5 ~
wheel on a vehicle, which wheel includes a rim having a central axis and a tire mounted to the rim and is affixed to rotatable axle means carried by suitable non-rotating support means, the system comprising: a plurality of magnetic members equiangularly spaced apart on the wheel rim at a uniform distance from the axis, defining a magnet plane normal to the axis, and facing inwardly of the vehicle; at least one sensor member mounted to the support means and positioned relative thereto so as to be spaced from the plane by a predetermined distance representing a safe operating condition for the wheel, rotation of the wheel and the magnets creating a rotating magnetic field which induces a signal in the form of a train of electrical pulses in the sensor member if the magnet plane is within the predetermined distance; transformer means connected to the at least one sensor member for increasing the strength of the signal; and indicator means connected to the transformer means; whereby should the sensor means generate a signal, the transformer means will activate the indicator means to warn the vehicle operator of a possible wheel failure.
In its second embodiment the present invention may be considered as providing a system for detecting and signalling a possible failure of a rotating wheel on a vehicle, which wheel includes a rim having a central axis and a tire mounted to the rim and is affixed to rotatable axle means carried by suitable non-rotating support means, the system comprising:
a plurality of magnetic members equiangularly spaced apart on the wheel rim at a uniform distance from the axis, defining a magnet plane normal to the axis, and facing inwardly of the vehicle, rotation of the magnet members with the wheel creating a rotating magnetic field; at least one sensor member mounted to the support means and positioned relative thereto so as to be spaced from the plane by a predetermined distance representing a safe operating condition for the wheel, the rotating magnetic field inducing a signal in the form of a train of electrical pulses in the sensor member, the strength of the signal being dependent on the spacing of the magnet members from the at least one sensor member;
discriminator means connected to the at least one sensor member for analysing the signal; and indicator means connected to the discriminator means; whereby should the discriminator means detect a signal of a strength beyond a threshold representing a safe operating condition, the discriminator means will activate the indicator means to warn the vehicle operator of a possible wheel failure.
Figure 1 shows schematically the system of the first embodiment of the present invention.
Figure 2 shows a wheel rim face with a plurality of magnets mounted thereto.
Figure 3 is an enlarged view of a mounting arrangement for a sensor.
Figure 4 shows schematically the system of the second embodiment of the invention.
n~A-pTpTIoN OF THE PREFERRED ENBODI~ENT
Figure 1 of the drawings illustrates schematically the system 10 of the present invention. The system is applicable to any type of wheeled vehicle but it has particular relevance to transport vehicles such as trucks and trailers. It will work on the driven wheels of a truck or on the non-driven wheels of a truck or a trailer. The system 10 includes a 12 volt power supply 12, such as a vehicle battery, which is connected to a step up transformer 1~. The transformer 1~ is capable of transforming a weak input signal, in millivolts, to a 12 volt, or so, signal which can be utilized in the vehicle's electrical system. The signal received by the transformer 1~ is provided by a sensor 16, the sensor being fixedly mounted to a bracket 18 and the bracket in turn being mounted to a non-rotating portion 20 of the vehicle's suspension system. If the system of the invention is being used with a driven wheel or wheel set of the vehicle the bracket 18 is preferably connected to the non-rotating tube or support that carries a rotating axle therein. If the system is being used with a non-driven wheel or wheel set then the bracket 18 is attached to the non-rotating support member that carries the wheel hub or othermounting means at the outer end thereof.
The bracket 18 is attached to the non-rotating support member adjacent the outer end thereof so that the sensor 16 can be positioned close to a plane P defined adjacent the inner edge or face of a wheel rim 22, the rim 22 mounting a tire 24 thereon. The rim 22 is provided with a plurality of equiangularly spaced permanent magnets 26 facing inwardly of the vehicle, the inwardly directed magnet faces 28 defining the plane P, which plane is normal to the axis A
of the axle and the wheel rim 22. As the wheel rim rotates at speed the moving magnets will create a moving magnetic field, the strength of which is dependent on the strength of the magnets, the number of magnets, and the speed of wheel rotation. Preferably, four magnets 26 are provided, at 90~
intervals around the edge of the wheel rim, although fewer or more could be used. The magnets may be mounted to the wheel rim 22 by an adhesive or they could be attached in the same manner as the weights used when balancing a wheel, that is, by way of small tangs which can be hammered between the sidewall of the tire 2~ and the adjacent surface of the rim 22.
The transformer 1~ is grounded as at 30 and it is also connected to an indicator device 32 that is positioned within the cab of the vehicle, close to the vehicle operator's position and preferably within his field of vision. The indicator can be provided with audible and/or visual warning means to catch the attention of the operator whenever the indicator is activated. The indicator 32 preferably is sectioned to include a plurality of zones 34, each of which represents a particular wheel or wheel set of the vehicle.
The present invention operates on the principles of electrical induction, such that the sensor 16, being subjected to a rotating magnetic field generated by the rotating wheel rim, will be induced to generate a signal in the form of a train of electrical pulses. The strength of that signal will depend on the speed of the rotating wheel and the proximity of the magnet plane P to the sensor. If the magnet plane P lies outside a predetermined acceptable distance D the magnetic field will not be capable of generating a detectable signal at the sensor 16. If the magnet plane P becomes tilted so as to bring the magnets closer to the sensor in the vicinity thereof the magnetic field will then induce a detectable train of electrical pulses in the sensor.
For any vehicle and wheel combination it will be possible to calculate an acceptable distance D that represents the maximum allowable inwards tilt of the magnet plane P near the sensor. Some tilt of the plane can be expected under normal operating conditions, due to impact of the wheel with obstructions such as potholes or debris, or minor permanent deflection or hen~ing of the axle or its non-rotating support. If the allowable predetermined tolerance for tilt of the magnet plane is exceeded, it is likely that there is a problem with the wheel. Such a problem could be a bent axle or axle support resulting from constant overloading of the vehicle or a structurally damaging impact, or failure of one or more of the wheel retaining lugs. Should such a situation develop on a vehicle equipped with the present invention, the magnet plane P will tilt inwards towards the sensor 16 and the weak induced train of electrical pulses will be stepped up by the transformer 1~ so that vehicle electrical power flows to the indicator 32 and sets off a warning signal that tells the operator that a failure condition is imminent. As previously suggested, the warning signal may be an audible one, such as a horn or a siren sound, or it may be a visual one such as a flashing light.
Simultaneously with this primary warning signal the zone 3 on the indicator 32 that corresponds to the failing wheel will light up so that the operator can immediately tell which wheel is at fault.
In addition to activating the indicator 32 the transformer could also be connected to the engine management computer of the vehicle to signal that computer to reduce the fuel flow to the engine so as to cause the vehicle to lose speed. This option would only be exercised should the driver fail to take appropriate action, as by stopping the vehicle to investigate the problem giving rise to the failure warning signal. Arbitrarily slowing the vehicle down is a drastic step and one which should only be activated after the driver has been given ample opportunity to stop the vehicle on his own volition. Certainly, a reduction in fuel flow would have to be gradual in order to avoid a dangerous condition that could easily affect following traffic.
As an alternative, the transformer could be connected to the vehicle braking system and programmed to gently apply the vehicle brakes in the event that the driver does not heed the failure warning signal after a predetermined period of time. Again, any non-operator controlled application of the brakes would have to be very gradual in order to avoid sudden braking manoeuvres that could affect following traffic. It is hoped and expected that if fuel flow control or braking control were exercised by the discriminator the operator would sense these conditions, realise that some control is being taken away from him, and take his own action to slow the vehicle and bring it to a halt for inspection of the problem wheel.
The magnets and the sensor will be located in areas of the vehicle that are subjected to water, slush, snow, ice and dirt. However, it is expected that centrifugal force effects due to rotation of the wheel will tend to keep the magnets clean. Should debris or other material, including ferromagnetic material, accumulate on the magnets, it is expected that the close proximity of the magnets to the sensor and its mounting bracket will permit the bracket or the sensor housing to skim such debris or material from the magnets. Similarly, any buildup of debris on the sensor should be removed by the rotating magnets close thereto.
Also, as seen in Figure 3, the sensor 16 should be recessed slightly within a surrounding, non-magnetic housing 36 carried by the bracket 18 so as to reduce the risk of damage or contamination.
If the present invention is used with a wheel set that includes a pair of wheels affixed together, i.e. dual wheels, the magnets would be attached to the innermost wheel of the pair.
Because the present invention requires that the distance between the magnet plane P and the sensor 16 be set for the particular vehicle to which the invention is applied, that distance should also be available to roadside vehicle inspectors at vehicle inspection stations, presumably as part of the vehicle documentation. An inspector, knowing that distance, and equipped with a suitable gauge can slip the gauge between the sensor and a magnet positioned opposite the sensor. If the gauge slips easily between the sensor and the magnet it is likely that there are no imminent problems associated with the wheel being inspected. If the gauge does not slip between the sensor and the magnet this is an indication that there is a problem with the wheel and that further investigation is necessary before the driver is permitted to take his rig out on the road again. Of course, all vehicle operators driving vehicles equipped with the present invention would also be provided with the necessary gauges so that they can check the wheel condition each time that they perform their own inspection of the vehicle.
The second embodiment of the invention is illustrated schematically in Figure 4, wherein it is seen that the transformer 1~ of the first embodiment is replaced by a discriminator 38. The discriminator is preferably a small micro-computer which can analyse an incoming electrical signal, in the form of a train of electrical pulses, and determine whether the strength of the signal exceeds a predetermined threshold value. The signal received by the discriminator 38 is provided by the sensor 16, the sensor being fixedly mounted as in the first embodiment.
The discriminator 38 is grounded as at ~o and it is also connected to an indicator device 32 that is positioned within the cab of the vehicle, close to the vehicle operator's position and preferably within his field of vision. The indicator is the same as is used with the first embodiment .
With this embodiment, the sensor 16, being subjected to a rotating magnetic field generated by the magnets on the rotating wheel rim, will always be induced to generate a signal in the form of a train of electrical pulses. The strength of that signal will depend on the speed of the rotating wheel and the proximity of the magnet plane P to the sensor. The discriminator can be programmed to take into consideration the component of the signal attributable to wheel speed so that it can therefore determine whether any increase in signal strength is attributable to the magnet plane P being tilted so as to bring the magnets closer to the sensor in the vicinity thereof.
For any vehicle and wheel combination it will be possible to calculate a threshold signal strength that represent the maximum allowable inwards tilt of the magnet plane P near the sensor. If the allowable predetermined tolerance for tilt of the magnet plane is exceeded, it is likely that there is a problem with the wheel. Should such a situation develop on a vehicle equipped with this embodiment of the present invention, the magnet plane P will tilt inwards towards the sensor lC and the induced train of electrical pulses will be of such a strength to cross the predetermined threshold established in the discriminator 38.
When that occurs the discriminator will close a relay therein allowing vehicle electrical power to flow to the indicator 32 and set off a warning signal that tells the operator that a failure condition is imminent. As previously suggested, the warning signal may be an audible one, such as a horn or a siren sound, or it may be a visual one such as a flashing light. Simultaneously with this primary warning signal the zone 3~ on the indicator 32 that corresponds to the failing wheel will light up so that the operator can immediately tell which wheel is at fault.
In addition to activating the indicator 32 the discriminator 38 could also be connected to the engine management computer of the vehicle and programmed to signal that computer to reduce the fuel flow to the engine so as to cause the vehicle to lose speed. As an alternative, the discriminator could be connected to the vehicle braking system and programmed to gently apply the vehicle brakes in the event that the driver does not heed the failure warning signal after a predetermined period of time.
The present invention provides inexpensive systems for ensuring that heavy vehicles on our roads are safer than they are now. Use of either warning system of this invention should reduce the number of catastrophic wheel failures and the dangerous effects of runaway wheels travelling at highway speeds. While the preferred forms of the invention have been described herein it is understood that persons skilled in the art would be able to modify the invention without departing from the spirit thereof and accordingly the protection to be afforded the invention is to be determined from the claims appended hereto.
R~R~PCUND OF THB INVENTION
There have been numerous incidents recently of wheels or wheel sets catastrophically separating from a truck or a trailer travelling at speed and then moving in a direction away from the vehicle. In some cases the wheel sets, which can weigh several hundred pounds and may be travelling at more than 100 Kph, have struck vehicles travelling in the immediate vicinity, causing severe damage and even death.
The trucking industry is being held accountable for these tragic incidents and the maintenance practices of the industry as a whole has come under close scrutiny. In some instances wheel failure has been the result of improperly tightened wheel bolts which have fractured, allowing the wheel set to separate from its support. In other cases, the vehicle has been consistently overloaded so as to place undue stress and strain on the axle with the result that there has been a structural failure at the end of the axle. Wheel failures that occur on major arteries and result in tragic accidents receive considerable media coverage and prompt much outrage. The number of such reported incidents appears to be rising, however, and there now appears to be a need for an ineYr~n~ive system which can detect wheel problems and communicate the unacceptable condition to the vehicle driver so that he can take immediate action that will avoid the catastrophic separation of wheel from vehicle.
The present invention provides two relatively simple and inexpensive systems that can be attached to new trucks or trailers and which also can be retrofitted to existing vehicles. Each system includes a plurality of magnets that positioned about the inside of a wheel rim, with equiangular spacing therebetween. The magnets are located close to the outer edge of the rim on the side facing inwardly of the vehicle and can be attached thereto in the same manner that a wheel weight, used for balancing a wheel, might be attached.
Preferably four magnets are provided, spaced apart by 90~, although more or fewer magnets could be used. If the vehicle is provided with wheel sets made up of a pair of wheels, i.e.
dual wheels, then the magnets are located on the innermost wheel of the wheel set.
In the case of a set of driven wheels the drive axle therefor will be contained within a non-rotating axle tube or support. In the case of non-driven wheels there will be a non-rotating support carrying a wheel mounting assembly and hub at the end thereof. For the present invention at least one sensor is mounted to the non-rotating support for the wheel, the sensor being positioned at the same distance from the wheel axis as the magnet~ and also being positioned at a predetermined distance or spacing from the plane containing the magnet faces. The sensor is preferably in the form of an induction coil such as might be used in the ignition system of a two-stroke engine.
When subjected to a moving magnetic field, a signal in the form of a train of electrical pulses is generated in the coil. If the magnet members are rotating in a magnet plane outside a predetermined acceptable distance from the sensor the magnetic field generated thereby will not be strong enough to create a signal at the sensor. If the magnet members come close to the sensor, within the predetermined acceptable distance, the magnetic field will generate a signal at the sensor.
In its simplest form the present invention includes a DC transformer connected to the sensor. When a signal from the sensor, measurable in minivolts is passed to the transformer it is stepped up considerably thereby so that the stepped up signal may be used to activate an indicator in the cab of the vehicle to which the invention is attached. In another embodiment, if the predetermined distance is such that the sensor will always generate a signal, the strength of which is dependent on the spacing of the magnet plane from the sensor, a discriminator connected to the sensor analyses the signal to determine if it exceeds a threshold value and if it does, the discriminator will activate an indicator to signal the vehicle operator that an unsafe condition has been detected. With each embodiment the signal to the operator will preferably be in the form of a flashing light or a beeping horn, in response to which the operator should slow down and bring his vehicle to a halt so as to investigate the situation which gave rise to the warning signal. The indicator could also be tied into a computer programmed to reduce the fuel supply to the vehicle's engine or to gently apply the brakes, so as to start to slow the vehicle down, should the operator fail to heed the warning signal after a set period of time. The indicator, in addition to providing a warning signal, would preferably include a chart or other means to identify the wheel on the truck or trailer which is generating the fault signal.
The present invention is based on the premise that a moving magnet can generate a signal through induction in a suitable sensor. If the magnet faces are arranged in a plane that is normal to the wheel axis, which axis coincides with the axis of the axle, then any departure of the magnet plane from normal relative to the axle axis will increase or decrease the distance between the magnet plane and the sensor as the wheel wobbles and the magnets pass the sensor. Wheel wobble could be the result of loose wheel lug nuts, broken or cracked lugs, a damaged wheel hub, or a bent axle caused by overloading or impact. For any given wheel and axle combination and vehicle load rating it should be possible to determine an optimum spacing between the magnet plane and the sensor and also to determine maximum acceptable and expected wheel movement relative to the sensor. The maximum expected and acceptable wheel movement will determine the maximum distance or spacing of the magnet plane relative to the sensor. As long as the rotating wheel maintains the magnet plane beyond the maximum spacing the sensor will not generate a train of pulses strong enough to generate a failure signal.
However, should for example one of the wheel lugs crack so that the movement of the wheel exceeds the expected range then the magnet plane will intrude into the acceptable spacing, the sensor will generate the necessary train of pulses threshold, and a failure signal will be transmitted to the indicator adjacent the operator so that he is warned of the possible failure of the wheel. He can then stop his vehicle, inspect the problem wheel, and take appropriate remedial action.
Generally speaking, the present invention in its first embodiment may be considered as providing a system for detecting and signalling a possible failure of a rotating 0 2 1 9 9 4 5 ~
wheel on a vehicle, which wheel includes a rim having a central axis and a tire mounted to the rim and is affixed to rotatable axle means carried by suitable non-rotating support means, the system comprising: a plurality of magnetic members equiangularly spaced apart on the wheel rim at a uniform distance from the axis, defining a magnet plane normal to the axis, and facing inwardly of the vehicle; at least one sensor member mounted to the support means and positioned relative thereto so as to be spaced from the plane by a predetermined distance representing a safe operating condition for the wheel, rotation of the wheel and the magnets creating a rotating magnetic field which induces a signal in the form of a train of electrical pulses in the sensor member if the magnet plane is within the predetermined distance; transformer means connected to the at least one sensor member for increasing the strength of the signal; and indicator means connected to the transformer means; whereby should the sensor means generate a signal, the transformer means will activate the indicator means to warn the vehicle operator of a possible wheel failure.
In its second embodiment the present invention may be considered as providing a system for detecting and signalling a possible failure of a rotating wheel on a vehicle, which wheel includes a rim having a central axis and a tire mounted to the rim and is affixed to rotatable axle means carried by suitable non-rotating support means, the system comprising:
a plurality of magnetic members equiangularly spaced apart on the wheel rim at a uniform distance from the axis, defining a magnet plane normal to the axis, and facing inwardly of the vehicle, rotation of the magnet members with the wheel creating a rotating magnetic field; at least one sensor member mounted to the support means and positioned relative thereto so as to be spaced from the plane by a predetermined distance representing a safe operating condition for the wheel, the rotating magnetic field inducing a signal in the form of a train of electrical pulses in the sensor member, the strength of the signal being dependent on the spacing of the magnet members from the at least one sensor member;
discriminator means connected to the at least one sensor member for analysing the signal; and indicator means connected to the discriminator means; whereby should the discriminator means detect a signal of a strength beyond a threshold representing a safe operating condition, the discriminator means will activate the indicator means to warn the vehicle operator of a possible wheel failure.
Figure 1 shows schematically the system of the first embodiment of the present invention.
Figure 2 shows a wheel rim face with a plurality of magnets mounted thereto.
Figure 3 is an enlarged view of a mounting arrangement for a sensor.
Figure 4 shows schematically the system of the second embodiment of the invention.
n~A-pTpTIoN OF THE PREFERRED ENBODI~ENT
Figure 1 of the drawings illustrates schematically the system 10 of the present invention. The system is applicable to any type of wheeled vehicle but it has particular relevance to transport vehicles such as trucks and trailers. It will work on the driven wheels of a truck or on the non-driven wheels of a truck or a trailer. The system 10 includes a 12 volt power supply 12, such as a vehicle battery, which is connected to a step up transformer 1~. The transformer 1~ is capable of transforming a weak input signal, in millivolts, to a 12 volt, or so, signal which can be utilized in the vehicle's electrical system. The signal received by the transformer 1~ is provided by a sensor 16, the sensor being fixedly mounted to a bracket 18 and the bracket in turn being mounted to a non-rotating portion 20 of the vehicle's suspension system. If the system of the invention is being used with a driven wheel or wheel set of the vehicle the bracket 18 is preferably connected to the non-rotating tube or support that carries a rotating axle therein. If the system is being used with a non-driven wheel or wheel set then the bracket 18 is attached to the non-rotating support member that carries the wheel hub or othermounting means at the outer end thereof.
The bracket 18 is attached to the non-rotating support member adjacent the outer end thereof so that the sensor 16 can be positioned close to a plane P defined adjacent the inner edge or face of a wheel rim 22, the rim 22 mounting a tire 24 thereon. The rim 22 is provided with a plurality of equiangularly spaced permanent magnets 26 facing inwardly of the vehicle, the inwardly directed magnet faces 28 defining the plane P, which plane is normal to the axis A
of the axle and the wheel rim 22. As the wheel rim rotates at speed the moving magnets will create a moving magnetic field, the strength of which is dependent on the strength of the magnets, the number of magnets, and the speed of wheel rotation. Preferably, four magnets 26 are provided, at 90~
intervals around the edge of the wheel rim, although fewer or more could be used. The magnets may be mounted to the wheel rim 22 by an adhesive or they could be attached in the same manner as the weights used when balancing a wheel, that is, by way of small tangs which can be hammered between the sidewall of the tire 2~ and the adjacent surface of the rim 22.
The transformer 1~ is grounded as at 30 and it is also connected to an indicator device 32 that is positioned within the cab of the vehicle, close to the vehicle operator's position and preferably within his field of vision. The indicator can be provided with audible and/or visual warning means to catch the attention of the operator whenever the indicator is activated. The indicator 32 preferably is sectioned to include a plurality of zones 34, each of which represents a particular wheel or wheel set of the vehicle.
The present invention operates on the principles of electrical induction, such that the sensor 16, being subjected to a rotating magnetic field generated by the rotating wheel rim, will be induced to generate a signal in the form of a train of electrical pulses. The strength of that signal will depend on the speed of the rotating wheel and the proximity of the magnet plane P to the sensor. If the magnet plane P lies outside a predetermined acceptable distance D the magnetic field will not be capable of generating a detectable signal at the sensor 16. If the magnet plane P becomes tilted so as to bring the magnets closer to the sensor in the vicinity thereof the magnetic field will then induce a detectable train of electrical pulses in the sensor.
For any vehicle and wheel combination it will be possible to calculate an acceptable distance D that represents the maximum allowable inwards tilt of the magnet plane P near the sensor. Some tilt of the plane can be expected under normal operating conditions, due to impact of the wheel with obstructions such as potholes or debris, or minor permanent deflection or hen~ing of the axle or its non-rotating support. If the allowable predetermined tolerance for tilt of the magnet plane is exceeded, it is likely that there is a problem with the wheel. Such a problem could be a bent axle or axle support resulting from constant overloading of the vehicle or a structurally damaging impact, or failure of one or more of the wheel retaining lugs. Should such a situation develop on a vehicle equipped with the present invention, the magnet plane P will tilt inwards towards the sensor 16 and the weak induced train of electrical pulses will be stepped up by the transformer 1~ so that vehicle electrical power flows to the indicator 32 and sets off a warning signal that tells the operator that a failure condition is imminent. As previously suggested, the warning signal may be an audible one, such as a horn or a siren sound, or it may be a visual one such as a flashing light.
Simultaneously with this primary warning signal the zone 3 on the indicator 32 that corresponds to the failing wheel will light up so that the operator can immediately tell which wheel is at fault.
In addition to activating the indicator 32 the transformer could also be connected to the engine management computer of the vehicle to signal that computer to reduce the fuel flow to the engine so as to cause the vehicle to lose speed. This option would only be exercised should the driver fail to take appropriate action, as by stopping the vehicle to investigate the problem giving rise to the failure warning signal. Arbitrarily slowing the vehicle down is a drastic step and one which should only be activated after the driver has been given ample opportunity to stop the vehicle on his own volition. Certainly, a reduction in fuel flow would have to be gradual in order to avoid a dangerous condition that could easily affect following traffic.
As an alternative, the transformer could be connected to the vehicle braking system and programmed to gently apply the vehicle brakes in the event that the driver does not heed the failure warning signal after a predetermined period of time. Again, any non-operator controlled application of the brakes would have to be very gradual in order to avoid sudden braking manoeuvres that could affect following traffic. It is hoped and expected that if fuel flow control or braking control were exercised by the discriminator the operator would sense these conditions, realise that some control is being taken away from him, and take his own action to slow the vehicle and bring it to a halt for inspection of the problem wheel.
The magnets and the sensor will be located in areas of the vehicle that are subjected to water, slush, snow, ice and dirt. However, it is expected that centrifugal force effects due to rotation of the wheel will tend to keep the magnets clean. Should debris or other material, including ferromagnetic material, accumulate on the magnets, it is expected that the close proximity of the magnets to the sensor and its mounting bracket will permit the bracket or the sensor housing to skim such debris or material from the magnets. Similarly, any buildup of debris on the sensor should be removed by the rotating magnets close thereto.
Also, as seen in Figure 3, the sensor 16 should be recessed slightly within a surrounding, non-magnetic housing 36 carried by the bracket 18 so as to reduce the risk of damage or contamination.
If the present invention is used with a wheel set that includes a pair of wheels affixed together, i.e. dual wheels, the magnets would be attached to the innermost wheel of the pair.
Because the present invention requires that the distance between the magnet plane P and the sensor 16 be set for the particular vehicle to which the invention is applied, that distance should also be available to roadside vehicle inspectors at vehicle inspection stations, presumably as part of the vehicle documentation. An inspector, knowing that distance, and equipped with a suitable gauge can slip the gauge between the sensor and a magnet positioned opposite the sensor. If the gauge slips easily between the sensor and the magnet it is likely that there are no imminent problems associated with the wheel being inspected. If the gauge does not slip between the sensor and the magnet this is an indication that there is a problem with the wheel and that further investigation is necessary before the driver is permitted to take his rig out on the road again. Of course, all vehicle operators driving vehicles equipped with the present invention would also be provided with the necessary gauges so that they can check the wheel condition each time that they perform their own inspection of the vehicle.
The second embodiment of the invention is illustrated schematically in Figure 4, wherein it is seen that the transformer 1~ of the first embodiment is replaced by a discriminator 38. The discriminator is preferably a small micro-computer which can analyse an incoming electrical signal, in the form of a train of electrical pulses, and determine whether the strength of the signal exceeds a predetermined threshold value. The signal received by the discriminator 38 is provided by the sensor 16, the sensor being fixedly mounted as in the first embodiment.
The discriminator 38 is grounded as at ~o and it is also connected to an indicator device 32 that is positioned within the cab of the vehicle, close to the vehicle operator's position and preferably within his field of vision. The indicator is the same as is used with the first embodiment .
With this embodiment, the sensor 16, being subjected to a rotating magnetic field generated by the magnets on the rotating wheel rim, will always be induced to generate a signal in the form of a train of electrical pulses. The strength of that signal will depend on the speed of the rotating wheel and the proximity of the magnet plane P to the sensor. The discriminator can be programmed to take into consideration the component of the signal attributable to wheel speed so that it can therefore determine whether any increase in signal strength is attributable to the magnet plane P being tilted so as to bring the magnets closer to the sensor in the vicinity thereof.
For any vehicle and wheel combination it will be possible to calculate a threshold signal strength that represent the maximum allowable inwards tilt of the magnet plane P near the sensor. If the allowable predetermined tolerance for tilt of the magnet plane is exceeded, it is likely that there is a problem with the wheel. Should such a situation develop on a vehicle equipped with this embodiment of the present invention, the magnet plane P will tilt inwards towards the sensor lC and the induced train of electrical pulses will be of such a strength to cross the predetermined threshold established in the discriminator 38.
When that occurs the discriminator will close a relay therein allowing vehicle electrical power to flow to the indicator 32 and set off a warning signal that tells the operator that a failure condition is imminent. As previously suggested, the warning signal may be an audible one, such as a horn or a siren sound, or it may be a visual one such as a flashing light. Simultaneously with this primary warning signal the zone 3~ on the indicator 32 that corresponds to the failing wheel will light up so that the operator can immediately tell which wheel is at fault.
In addition to activating the indicator 32 the discriminator 38 could also be connected to the engine management computer of the vehicle and programmed to signal that computer to reduce the fuel flow to the engine so as to cause the vehicle to lose speed. As an alternative, the discriminator could be connected to the vehicle braking system and programmed to gently apply the vehicle brakes in the event that the driver does not heed the failure warning signal after a predetermined period of time.
The present invention provides inexpensive systems for ensuring that heavy vehicles on our roads are safer than they are now. Use of either warning system of this invention should reduce the number of catastrophic wheel failures and the dangerous effects of runaway wheels travelling at highway speeds. While the preferred forms of the invention have been described herein it is understood that persons skilled in the art would be able to modify the invention without departing from the spirit thereof and accordingly the protection to be afforded the invention is to be determined from the claims appended hereto.
Claims (13)
1. A system for detecting and signalling a possible failure of a rotating wheel on a vehicle, which wheel includes a rim having a central axis and a tire mounted to the rim and is affixed to rotatable axle means carried by suitable non-rotating support means, the system comprising:
a plurality of magnetic members equiangularly spaced apart on the wheel rim at a uniform distance from said axis, defining a magnet plane normal to said axis, and facing inwardly of the vehicle;
at least one sensor member mounted to said support means and positioned relative thereto so as to be spaced from said plane by a predetermined distance representing a safe operating condition for the wheel, rotation of said magnet members with the wheels creating a rotating magnetic field which induces a signal in the form of a train of electrical pulses in said sensor member if said magnet plane is within said predetermined distance;
transformer means connected to said at least one sensor member for increasing the strength of the signal; and indicator means connected to said transformer means;
whereby should the sensor member generate a signal, said transformer means will activate said indicator means to warn the vehicle operator of a possible wheel failure.
a plurality of magnetic members equiangularly spaced apart on the wheel rim at a uniform distance from said axis, defining a magnet plane normal to said axis, and facing inwardly of the vehicle;
at least one sensor member mounted to said support means and positioned relative thereto so as to be spaced from said plane by a predetermined distance representing a safe operating condition for the wheel, rotation of said magnet members with the wheels creating a rotating magnetic field which induces a signal in the form of a train of electrical pulses in said sensor member if said magnet plane is within said predetermined distance;
transformer means connected to said at least one sensor member for increasing the strength of the signal; and indicator means connected to said transformer means;
whereby should the sensor member generate a signal, said transformer means will activate said indicator means to warn the vehicle operator of a possible wheel failure.
2. The system of claim 1 wherein there are four magnetic members spaced apart on said rim at 90° intervals and there is a single sensor member secured to a bracket attached to said support means.
3. The system of claim 1 wherein said indicator means includes one or more of a selection of visible warning means, audible warning means, brake actuation means, and engine control means.
4. The system of claim 3 wherein said sensor means is an induction coil means which will generate an electrical signal within the magnetic field created by said magnet members.
5. The system of claim 3 wherein said indicator means includes a plurality of zones, each corresponding to a particular wheel of the vehicle, and adapted to identify the particular wheel that is the source of a failure signal.
6. The system of claim 5 wherein each of said zones of said indicator means includes a lamp that is energized upon receipt of a suitable activation signal from said transformer means.
7. A system for detecting and signalling a possible failure of a rotating wheel on a vehicle, which wheel includes a rim having a central axis and a tire mounted to the rim and is affixed to rotatable axle means carried by suitable non-rotating support means, said system comprising:
a plurality of magnetic members equiangularly spaced apart on the wheel rim at a uniform distance from said axis, defining a plane normal to said axis, and facing inwardly of said vehicle, rotation of said magnet members with said wheel creating a rotating magnetic field;
at least one sensor member mounted to said support means and positioned relative thereto so as to be spaced from said plane by a predetermined distance representing a safe operating condition for said wheel, said rotating magnetic field inducing a signal in the form of a train of electrical pulses in said sensor member, the strength of said signal being dependent on the spacing of said magnet members from said at least one sensor member;
discriminator means connected to said at least one sensor member for analysing said signal; and indicator means connected to said discriminator means;
whereby should said discriminator means detect a signal of a strength beyond a threshold representing the safe operating condition, said discriminator means will activate said indicator means to warn the vehicle operator of a possible wheel failure.
a plurality of magnetic members equiangularly spaced apart on the wheel rim at a uniform distance from said axis, defining a plane normal to said axis, and facing inwardly of said vehicle, rotation of said magnet members with said wheel creating a rotating magnetic field;
at least one sensor member mounted to said support means and positioned relative thereto so as to be spaced from said plane by a predetermined distance representing a safe operating condition for said wheel, said rotating magnetic field inducing a signal in the form of a train of electrical pulses in said sensor member, the strength of said signal being dependent on the spacing of said magnet members from said at least one sensor member;
discriminator means connected to said at least one sensor member for analysing said signal; and indicator means connected to said discriminator means;
whereby should said discriminator means detect a signal of a strength beyond a threshold representing the safe operating condition, said discriminator means will activate said indicator means to warn the vehicle operator of a possible wheel failure.
8. The system of claim 7 wherein there are four magnetic members spaced apart on said rim at 90° intervals and there is a single sensor member secured to a bracket attached to said support means.
9. The system of claim 7 wherein said indicator means includes one or more of a selection of visible warning means, audible warning means, brake actuation means, and engine control means.
10. The system of claim 9 wherein said sensor means is an induction coil means which will generate an electrical signal within the magnetic field created by said magnet members.
11. The system of claim 7 wherein said discriminator means is a programmable micro-computer.
12. The system of claim 9 wherein said indicator means includes a plurality of zones, each corresponding to a particular wheel of the vehicle, and adapted to identify the particular wheel that is the source of a failure signal.
13. The system of claim 12 wherein each of said zones of said indicator means includes a lamp that is energized upon receipt of a suitable activation signal from said discriminator means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002199452A CA2199452C (en) | 1997-03-07 | 1997-03-07 | Wheel failure detection and warning system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002199452A CA2199452C (en) | 1997-03-07 | 1997-03-07 | Wheel failure detection and warning system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2199452A1 CA2199452A1 (en) | 1998-09-07 |
| CA2199452C true CA2199452C (en) | 2000-10-10 |
Family
ID=4160125
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002199452A Expired - Fee Related CA2199452C (en) | 1997-03-07 | 1997-03-07 | Wheel failure detection and warning system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2199452C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114216701A (en) * | 2020-12-01 | 2022-03-22 | 襄阳达安汽车检测中心有限公司 | Automobile wheel speed simulator with electromagnetic compatibility and wheel speed adaptability |
-
1997
- 1997-03-07 CA CA002199452A patent/CA2199452C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2199452A1 (en) | 1998-09-07 |
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