GB2498385A - Apparatus for applying lubricant to a wheel of a railway vehicle - Google Patents

Abstract

The apparatus has a supply of lubricant 116 leading to a first dispensing nozzle 140 arranged to deliver lubricant to at least a part of the field side part of the wheel tread but not at least a part of the tread central running part. The apparatus is carried by the rail vehicle and its supply of lubricant 116 may be a low coefficient of friction lubricant. The apparatus may be used to reduce rolling contact fatigue In the field side part of the wheel. There may be a second nozzle directed toward a different part of the wheel tread, e.g. the flange. The apparatus has also a means 106 for introducing compressed air to drive lubricant 116 through to the nozzles. The apparatus has GPS or an RFID tag to determine the vehicle position for possible lubricant dispensation.

Description

Apparatus and Method for Applying Lubricant to Railway Vehicle Wheels The present invention relates to an apparatus and method for applying lubricant to railway vehicle wheels.

Railway vehicles have a number of wheels 3 that sit on and are guided by two substantially parallel rails S which together form a track. The rails 5 are linked to one another by a series of sleepers 7 that support the rails 5 via corresponding rail pads 9 that sit between the rail S and the sleeper 7. The rail pads 9 are arranged to support the rails 5 at a slight incline toward the gauge side 11 of the rail and away from the field side of the rail 13. The region of the wheel 3 that contacts the rail 5.is known as the wheel tread 15. This region is substantially frustroconical and has its largest diameter toward the gauge side of the rail S and its smallest diameter toward the field side of the rail 5 to help restrict the railway vehicle to the tract. A wheel flange Is formed on the gauge side of wheel 17 and is arranged to keep the wheels 3 from running off the rails 5 when in motion.

One of the largest costs in the rail industry relates to the renewal of railway vehicle wheels and track. Railway vehicle wheels and track gradually become damaged and compromised due to the Large forces generated by heavy vehicles travelling on a small contact area between the wheels and the track. Two of the primary causes of wheel and track damage are metal wear and rolling contact fatigue (RCF). Metal wear in the track rail and the wheel tends to occur due to slippage between the rail and the wheel, in a contact patch, under conditions of.high pressure and friction.

The contact patch leads to deformation of the metal of the rail In the direction of wheel slippage.

Rolling contact fatigue occurs due to the combination of the rail profile, contact patch energy, rail metallurgy, rail bending moments and fluid entrapment in the rail's metal fatigued surface cracks.

RCF occurs in both the wheel and the rail and, if left untreated, can lead to rail fracture and vehicle derailments.

Friction between the wheel 3 and the rail 5 can cause thinning of the wheel flange 17 at regions known as the flange root 19 and flange face 21 which extend from the flange toe 23. It can also cause wear of the wheel tread 15 to the extent its conicity is removed, and the creation of a false flange on the field-side part of the tread 15 adjacent the field side chamfer area 24. Friction between the wheel 3 and the rail 5 can also result in rail wear at regions of the rail 5 known as the gauge face 25, gauge corner 27, gauge shoulder 29, crown 31, field shoulder 33, field corner 35 and

field face 37,

One approach to try and minimise wear and rolling contact fatigue is to apply a medium coefficient of friction lubricant to the top of the raiL However, this causes lubricant to be distributed and spread across the whole of the wheel's running tread 15 which can reduce braking efficiency without reducing the friction sufficiently to alleviate RCF in the wheel. Another approach is to apply a low coefficient of friction lubricant to the flange root and to apply a medium coeffiCient of friction lubricant to the central running tread of the wheel but this can again endanger braking performance without sufficiently reducing RCF, Traclcside systems are also implemented which apply medium coefficIent of friction lubricant to the rail top and a low coefficient of friction lubricant to the gauge corner which again does not tackle the problem of RCF in the wheel and can affect braking performance. Furthermore, existing lubrication systems are prone to applying too much or too little lubricant. Too much lubricant can result in soiling of the vehicle's underside and wastage of lubricant and too little lubricant fails to reduce wear, metal fatigue and noise.

One conventional lubrication system uses a closed circuit of lubricant which is dispensed onto the wheels via one or more nozzles. The lubricant is driven along the circuit to the nozzles by a motor where It Is atornised using pressurised air to direct a cone of spray toward the wheel. Such systems are not very flexible and can take a very long time to charge owing to the requirement to fill relatively long pipes with lubricant. Another conventional lubrication system comprises one or more nozzles each of which is connected to a supply of lubricant by a respective pipe. Each pipe and nozzle is associated with a pump which is driven by compressed air to dispense lubricant into the pipe so that it can be ejected via the nozzle. Since one pump Is required for each nozzle and since each pump is relatively expensive, a problem with such a system is that it is expensive and complicated to build and operate. Furthermore, where it is desired to dispense larger volumes of lubricant in a given time frame, a larger pump is required and hence a larger supply of lubricant to house the pumps.

This adds further to the cost and also the footprint of the system which must be installed on a railway vehicle.

The problem of tackling wear and RCF is further compounded by variations in the contact area between the wheel and the rail as the vehicle travels along and encounters deviations In the track.

It is an object of embodiments of the Invention to reduce wear and fatigue of the rails and wheels whilst mitigating the above difficulties.

According to a first aspect of the present invention, there is provided apparatus for applying lubricant to a wheel of a railway vehicle, the wheel comprising a tread having a central running part, a field side part and a flange side part each of which may contact a rail, the apparatus comprising a supply of lubricant and a first nozzle through which lubricant from the supply of lubricant can be dispensed, characterised in that the first nozzle is arranged to deliver lubricant to at least a part of the field side part of the tread but not at least a part of the central running part.

Advantageously, the ability to apply lubricant specifically to the field side of the tread and not at least a part of the central running tread enables rolling contact fatigue in the wheel to be reduced without significantly affecting braking efficiency of the railway vehicle. By reducing rolling contact fatigue in the wheel, the frequency of wheel renewal Is reduced and, thus, so tools the cost of renewal.

The lubricant may be a low coeffident of friction lubricant. The lubricant may result in a coefficient of friction between the wheel and a rail of between 0.05 and 0.15. The lubricant may result in a coefficient of friction between the wheel and a rail of 0.1.

There may be a second nozzle through which lubricant from the supply of lubricant can be S dispensed, characterised In that the second nozzle is arranged to deliver lubricant to a different pact of the tread from the first nozzle. The second nozzle may be arranged to deliver lubricant to at least a part of the flange side of the tread but not at least a part of the central running tread, The first and/or second nozzles may be arranged so that they do not deliver any lubricant to the central running part of the wheel tread.

The first and second nozzles may be connected to the supply of lubricant by a conduit and the apparatus may further comprise means for introducing lubricant into the conduit and means for introducing compressed air into the conduit to drive lubricant through the conduit, Advantageously, the use of compressed air to dispense lubricant enables a high degree of control over the application of lubricant to the railway vehicle wheels at appropriate track positions.

Thus, wear of the wheels and rails, squealing and rolling contact fatigue can be effectively reduced thereby prolonging the life of the wheels and the rails and helping to reduce the cost of track and wheel renewal. Further, an air and grease based lubrIcation system is more robust because the pipes used in such systems are larger in diameter than a lubricant only system and therefore less prone to damage. Another key advantage is that it permits the use of priming cycles to vary the quantity of lubricant in the system to be dispensed. This enables accurate quantities of lubricant to be dispensed in a given time frame as desired, The means for introducing lubricant into the conduit may be arranged to coat the inside surface of the conduit with a film of lubricant. The means for introducing lubricant may be operated by compressed air. The conduft may comprise a first valve operable to permit air to flow and entrain

S

lubricant through the conduit to one or more nozzles. The conduit may further comprise a second valve operable to permit air arid lubricant to flow through the conduit to one or more nozzles.

The apparatus may be configured to operate the first valve to permit a volume of air to flow through the conduit so that a voiume of lubricant is introduced into the conduit by the means for introducing lubicant, and the apparatus may be further configured to operate both valves to release the air from the conduit.

There may be a second supply of lubricant containing a different lubricant from the first supply of lubricant and the first nozzle may be arranged to dispense lubricant from the first supply of lubricant and the second nozzle may be arranged to dispense lubricant from the second supply of lubricant. The lubricant in the second supply may be chosen such that its application results in a coefficient of friction between the wheel and a rail which is different from the lubricant In the first supply of lubricant.

Each nozzle may comprise an orifice and the cross sectional area of the conduit relative to the cross sectional area of the or each nozzle orifice may be chosen such that the resistance to flow of air through the conduit is low relative to the or each nozzle orifice.

The apparatus may further comprise a control unit arranged to selectively cause lubrkant to be dispensed through the or each nozzle on to a wheel depending on the configuration of the track the wheel is on or approaching. The control unit may be software driven. The apparatus may further comprise a sensor to determine the configuration of the track on which the railway vehicle is* travelling or approaching so that the control unit can select the or each nozzle through which lubricant is dispensed. The sensor may be an inertial sensor operable to determine the angular velocity of the railway vehicle about its vertical axis. There may be a speed sensor operable to determine the speed of the railway vehicle. The sensor may be a GPS sensor operable to determine the position of the railway vehicle and the control unit may be operable to compare the determined posftion of the vehicle with stored information regarding the configuration of the track at that position. Alternatively, the sensor may be an RFID tag reader operable to determine the position of the railway vehicle relative to local RFID tags and the control unit may be operable to compare the determined position of the vehicle with stored information regarding the configuration of the track at that position.

Advantageously, it is possIble to determine the position of a vehicle on a track without having to rely on satellite signals to determine when lubricant should be applied and to which regions of the wheel. Thus, accurate track position can be determined and, hence, accurate application of lubricant can be achieved in places where satellite signals are not receivable, e.g. underground. Further, many railway networks have existing RFID tags in place along the track so the installation costs necessary to determine vehicle position based upon relative RFID tag position is minimised, The use of bend sensors in combination with speed sensors can be used when REID tag positioning andfor GPS positioning is not available to determine the tightness of a bend on which a railway vehicle travels so that the lubrication requirements can be ascertained and the wheels lubricated accordingly, on a variable time dispense basis.

There may be a second pair ol nozzles through which lubricant can be dispensed end arranged in corresponding fashion In relation to the tread of a second wheel as the first pair of nozzles. The apparatus may be configured to dispense lubricant through the first nozzle of one pair when the wheel with which it is associated is on or is approaching the low rail of a bend and to simultaneously dispense lubricant through the second nozzle of the other pair when the wheel with* which it is associated with is on or is approaching the high rail of a bend.

The apparatus may be arranged to not deliver lubricant to at least 90% of the surface area of the central running part. The apparatus may be arranged to not deliver lubricant to substantially all of the surface area of the central running part.

According to a second aspect of the present invention, there is provided a method of varying the volume of lubricant to be applied to railway vehicle wheels comprising the steps of: providing apparatus having a conduit, means for introducing compressed air into the conduit and a means for introducing lubricant Into the conduit which is operated by compressed air; S allowing compressed air to enter the conduit so that the means for introducing lubricant introduces a volume of lubricant into the conduit for dispensing purposes; and allowing the compressed air to exit the conduit.

The apparatus may further comprise a first valve associated with the conduit and arranged to permit or restrict air flow through the conduit, and the step of allowing compressed air to enter the conduit may include operating the first valve.

The apparatus further comprises a second valve associated with theconduit and arranged to permit or restrict air flow through the conduit, and the step of allowing the compressed air to exit the conduit may include operating the second valve to permit the air to travel through the conduit.

According to a third aspect of the present invention, there is provided a method of applying IS lubricant to railway vehicle wheels comprising the steps of: using an RFiD tag reader to determine the position of a railway vehicle on a track; using the determined position to determine the lubrication requirements for the wheels on the railway vehicle; and applying lubricant to one or more wheels depending on the lubrication requirements.

In order that the invention may be more clearly understood embodiments thereof will now be described, by way of example, with reference to the accompanying drawings of which: Fig. 1 shows a railway vehicle mono-block on a substantially straight railway track, wherein the centre of the wheel's running tread is touching the ail's gauge shoulder and rail crown; Fig. 2 shows an enlarged sectional view of an outer edge of a railway vehicle wheel; Fig. S shows an enlarged sectional view of an outer edge of a railway vehicle wheel seated on a rail; Fig. 4 shows an aerial view of a railway vehicle travelling along a railway track and encountering a series of bends; Fig. 5 shows an enlarged sectional view of a railway vehicle wheel in normal wheel tread -contact with a rail when on a substantially straight region of track; Fig. 6 shows an enlarged sectional view of a railway vehicle wheel in contact with the Inner rail of a bend of track; Fig. 7 shows an enlarged sectional view of a railway vehicle wheel in contact with the outer rail of a bend of track; Fig. 8 shows an internal schematic of a pneumatic circuit used as part of an apparatus according to the present invention; -Fig. 9 shows a schematic representation of an apparatus according to the present invention including the pneumatic circuit shown in Fig. 8; Fig. 10 is an enlarged view of two nozzles shown in Figs. Sand 9 mounted relative to a wheel; Pig. 11 shows part of a railway vehicle to which is mounted apparatus as shown in Fig. 9; Fig. 12 shows an internal schematic representation of a pneumatic circuit used as part of another apparatus according to the present invention; and Fig. 13 shows a schematic representation of an apparatus according to the present invention including the pneumatic circuit shown in Fig. 12.

S

With reference to the drawings, and initially to Fig. 8, there is shown a pneumatic circuit 100 which comprises part of an apparatus that carl be installed on a railway vehicle 37 and arranged to apply lubricant to the railway vehicle wheels 3, The circuit 100 has a distribution unit 101 comprising a valve block 102 which, in this example, is made from aluminium through which is formed a passage or inlet 104 for the intake of air. The air inlet 104 leads to an air solenoid valve 112 which controls the flow of air from the inlet.104 to an outlet passage 114 which is also formed through the block 102. In use, when the apparatus is installed on a railway vehicle, the air inlet 104 is connected to the vehicle's air compressor/reservoir 106 via an air inlet supply pipe 108 to provide a supply of compressed air to the inlet 104. The supply of air from the reservoir 106 is controlled by an air prethure regulator 110 disposed in the air supply pipe 108 and arranged to limit the passage of air supplied to the system to about 8 bar.

The air outlet passage 114 is connected by a pipe 118, 126 to a second inlet passage 124 formed in the valve block 102. The pipe 118, 126 extends from the outlet 114 to the inlet 124 via a grease (or other lubricant) tank 116.

A grease outlet 122 from the grease tank 116 connects the tank to the pipe 126 extending from the tank 116 to the second inlet 124 of the valve block 102. The grease tank comprises an air operated piston pump. The pump is connected to an outlet 120 from the pipe 118 extending from the outlet passage 114 of the valve block 102 to the grease tank 116. The pump is driven by change in air pressure at the outlet 120. An increase in pressure causes the pump to deliver a quantity of grease via outlet 122 into the pipe 126 leading from the tank 116 to the valve block 102. The outlet* 122 is arranged to distribute grease onto the inside wall of the pipe 126. To cause the pump to deliver a further quantity of grease, the air pressure at outlet 120 must be reduced, and Increased again in order to cause the pump to operate another cycle.

The second inlet passage 124 in the valve block extends to a manifold within the block where it divides (in this embodiment) into four channels 128 each having a respective air/grease solenoid valve 130 for controlling flow through the conduit to a respective outlet 132 from the block 102. The outlets 132 are each connected to air/grease supply pipes 134. A divider 136 is attached to S the end of each supply pipe 134 and serves to split the pipe 134 into two separate nozzle supply pipes 138 along which air and grease may flow. The pipes 108, 118, 126, 134, 138, inlets 104, 124 and outlets 114, 132 have a bore size of around 8mm whilst the valves 112, 130 have a bore size/internal diameter of around 3mm.

The nozzle supply pipes 138 are each connected to corresponding nozzles 140 having a bore size/internal diameter of around 1mm and capable of delIvering a well-defined cone of grease particles. Thus, each air/grease supply pipe 134 leads to a pair of nozzles 140. An adjustable dual nozzle mounting block 142 is provided to which two nozzles 140 may be mounted so that the position of the nozzles 140 relative to a wheel 3 can be adjusted. In the example shown in Fig. 10, one nozzle 140 is arranged to direct a cone of grease toward the gauge/flange side periphery of the wheel tread 15 which includes the flange root 19 and the other nozzle 140 is arranged to direct a cone of grease toward the field side 13 of the wheel tread 15.

The apparatus further comprises an electronic control unit 144 which is connectable to the railway vehicle's electrical power supply 146 via an electrical cable 148, The control unit 144 is connected to the railway vehicle's zero speed and forward signals 150 which are used to determine when the vehicle is stationary and the direction of travel. When the vehicle is stationary, the control* unit is programmed to suppress the application of lubricant from the system since this is unnecessary and would result In wastage of lubricant. Knowledge of the direction of travel is useful since this enables the control unit to apply lubricant only to the leading wheels i.e. the wheels at the front of the railway vehicle depending on the direction of travel. Thus, when the railway vehicle travels in an opposite direction, the wheels at the opposite end of the vehicle are determined to be the front wheels and lubricant is dispensed toward those wheels accordingly. In addition, the control unit is connected to the raiFway vehicle's global positioning satellite or passenger information system 152 for determining railway vehicle position.

The electronic control unit 144 is also connected to the railway vehicle's GPS antenna feed or Its REiD reader 154, and is equipped wiLh a wheel speed detector 15 whIch may be used with the railway vehicle's wheel speed encoder disc 158 to determine the speed of the vehicle. The detected railway vehicle speed can be used to determine the distance travelled which enables lubricant to be dispensed at specific distance intervals. The electronic control unit 144 further comprises inertial detection electronics or bend sensors for measuring the rotation of the vehicle about the horizontal plane and the railway vehicle yaw or angular velocity about the vehicle's vertical axis, and air valve driver control electronics for controlling the operation of the solenoid valves 112, 130 and hence the flow of air and grease through the pneumatic circuit 100. The control unit 144 is operated by software which determines and records the vehicle speed, position and angular velocity (yaw), and operates the valves accordingly to prime the pneumatic circuit 100 with grease and dispense an appropriate volume of grease to particular regions of the wheeL The apparatus may be mounted to the underside or inside of the railway vehicle during construction or it may he retrofitted. The nozzle mounting blocks 142 are arranged to the side of and about halfway up the vehicle wheels 3so that, when the nozzles 140 are mounted in place, they can direct a cone of grease toward the outer circumference of the wheel. In this embodiment, the nozzles 140 are directed toward either the flange root area 19 of the wheel or the field side area of the wheel tread 15 Thus, when the wheels rotate and the nozzles 140 are activated, the regions of the tread to which the nozzles are directed are coated with lubricant around the circumference of the wheel 3.

One nozzle 140 of a pair of nozzles supplied by a single air/grease supply pipe 134 is mounted adjacent a first wheel on one side of the vehicle and directed toward the flange root region 19 of that wheel 3. The other nozzle 140 of the pair is mounted adjacent a second wheel on the opposite side of the vehicle and is directed toward the field side region of the wheel tread 15. In this S embodiment, the field side part of the tread 15 is the region adjacent the main rolling part of the tread that comes into contact with the rail when the wheel is on the low rail. Thus, when on a bend such that the first wheel is on the high rail 41 and the second wheel is on the low rail 43 the application of grease through the pair of nozzles from the common supply pipe 134 targets the appropriate portion of each wheel 3 (as shown in Fig. 10). Likewise, one nozzle 140 of another pair is mounted adjacent the first wheel 3 and is directed toward the field side of the wheel tread 15 and the other nozzle 140 of the pair is mounted adjacent the second wheel 3 and directed toward the flange side of the wheel 3. Two other pairs are mounted to another pair of wheels 3 on respective sides of the vehicle in corresponding fashion.

In use, in order to dispense grease from the nozzles to the vehicle wheels 3 grease must first be introduced into the pipe 126 extendIng from the grease tank to the valve block 102. To achieve this, the air inlet solenoid valve 112 is opened whilst the air and grease outlet solenoid valves 130 remain closed. This causes the air pressure at the outlet 120 leading to the grease pump to increase and causes the pump to deliver a quantity of grease into the pipe. To deliver further quantities of grease into the pipe 126 the air pressure at the outlet 120 must be decreased and Increased again.

This is achieved by closing the air inlet solenoid valve 112 and opening one or more of the air and grease outlet valves 130 to allow compressed air to flow from the system, Release of compressed air trapped within the system produces a relatively small air flow from the nozzles, which will result in little or no grease being dispensed from the nozzles. This priming cycle can he repeated as often as necessary, briefly opening the inlet valve 112 to pressurlse the system and briefly opening one or more outlet valves 130 to release pressure, to introduce a desired quantity of grease into the pipework. In this way, the pipework acts as a reservoir for lubricant before It Is dispensed.

To dispense grease from the nozzles the air inlet valve 112 is opened and one or more selected air/grease outlet valves 130 are opened. this allows a significant volume of compressed air to flow from the air supply and out through two or more nozzles 140. The flow of air Is sufficient to entrain grease disposed on the inside of the pipework and channels downstream of the grease tank to produce a fine mist of grease from the nozzles. Since the grease has a slow flow rate through the pipes compared to air, the volume of grease dispensed at each nozzle 140 is largely determined by the duration of air flow through the selected nozzles 140. So, the total quantity of grease dispensed is arrived at by controlling the quantity of grease introduced into the system from the grease tank and the duration of operation of the nozzles 140.

The inlet and outlet valves are operated under programmed control of the control unit 144.

The control unit 144 is arranged to operate the valves, as discussed above, to prime the system with a desired quantity of grease. It subsequently causes grease to be dispensed from selected pairs of nozzles to apply lubricant to selected areas of the vehicle's wheels 3 when certain track conditions are met. ARernatively, the system may have a plurality of nozzles each supplied by Its own air/grease supply pipe via a respective second valve such that each nozzle can be selected Independently of any other nozzle for the application of grease.

Primarily, the control unit 144 is arranged to cause lubricant to be applied to the gauge corner of wheels 3 about to travel on the high rail of a bend and to the field side of wheels about to travel on the low rail of the bend just before the wheels enter the bend. Lubricant may also be dispensed whilst the wheels travel around the bend. The volume of lubricant dispensed may be dependent on the radius of the bend.

The control unit 144 can determine the configuration of the track the vehicle is apprnaching by comparing the vehicle position determined by the GPS sensor, possibly in addition to the vehicle's speed and/or distance travelled, measured from the vehicle's wheels, to stored information about the configuration of the track, effectively a map.

S The control unit 144 may in addition, or as an alternative when 61'S cannot be obtained.

such as in a tunnel, determine the position of the vehicle by using the REID tag reader 154 to detect existing REID tags located periodically along the railway network, for example, on the datum plates.

Knowing the position of each datum plate along the network and detecting the datum plate to which the train is adjacent using the REID tag reader enables the position of the railway vehicle to be determined. Specific RFID tags that are associated with datum plates that are positioned before a bend can be used by the control unit 144 to trigger the application of lubricant from the nozzles 140 to the appropriate regions of the wheels 3, A low coefficient of friction lubricant which gives rise to a coefficient of friction between the wheel and the track of around 0.1 can be directed toward the flange root area 19 of the wheel 3 before contact is made between the flange 17 and the gauge shoulder 29 or gauge corner 27 of the railhead. The application of lubricant prior to contact between these regions of the wheel 3 and rail S reduces wheel flange wear, flange squeal and rollIng contact fatigue in the railhead, A ow coefficient of friction lubricant can also be directed by a nozzle 140 toward the field side of the running tread of the wheel 3 at regions where rolling contact fatigue in the wheel 3 is known to occur such as on the low rail of a bend. Application of lubricant to this region of the wheel before it encounters a bend in the track reduces wear in the railhead, squealing and rolling contact fatigue in the wheel 3. To avoid affecting the braking performance of the railway vehicle beyond nomal limits, lubricant is directed by the nozzles to the edges of the wheel's main rolling surface rather than the main rolling surface itself where the majority of braking occurs.

The respective bore sizes of the pipes 108, 118, 126, 134, 138, valves 112, 130, inlets 104, 124, outlets 114, 132 and nozzles 140 is such that the air rEsistance of the pipework and valves is low relative to the nozzle orifices from which the grease is dispensed. Thus, almost the full regulated air pressure will drop across the nozzles 140 when they are selected by a corresponding air/grease solenoid valve 130. Consequently, when a nozzle 140 is selected the air flow speed from the reservoir 106 through the distribution unit 101 to the nozzles 140 will be substantially constant and the dispense volume for a given dispense time will also he substantially constant, It is therefore possible to dispense a known quantity of grease over a given period of time and thereby apply an appropriate amount of lubricant to a particular region of the wheel tread 15 along a specific part of the ftack.

The control unit 144 may also use data from the bend/yaw sensors to determine when the vehicle is running on straight or curved track. This enables information about the track to be determined when neither GPS nor RFID data is obtainable or where the local configuration of the track is not known to the control unit. A straight portion of track is defined as a yaw signal detected by the bend sensor oft degree per second or less. When the railway vehicle is on a straight portion of track, the apparatus is programmed to dispense lubricant at specific time intervals such as every seconds or at specific distance intervals such as every 500 metres. A bend is defined as a yaw signal detected by the bend sensor of greater than 1 degree per second. The system is configured to dispense lubricant on a variable time basis using the bend sensor and speed measurements to determine the tightness of a bend and hence how often to apply lubricant to the train wheels. Thus, even when the railway vehicle's track location cannot be determined, it is still possible to detect when the railway vehicle is on a straight region of track or a bend and therefore adjust the application of lubricant accordingly.

It will be appreciated that where the apparatus relies only on speed and bend sensors to give an indication of the radius of a bend It Is only able to determine th instantaneous configuration of the track rather than predict it.

The control unit 144 may be arranged to dispense lubricant to the wheels other than when bends are encountered. For example, it may be arranged to dispense lubricant when the vehicle travels over points. The points at which the lubricant is dispensed may be determined by GE'S position with reference to a GPS map of stored locations.

With reference to Figs. 11 and 12, an alternative embodiment comprises two grease tanks 116, 216 both of which are connectable to the railway vehicle's air reservoir 106 via a common inlet supply pipe 108 and respective inlets 104, air solenoid valves 112 and outlet pipes 114, 118. In this embodiment, one grease tank its supplies one set 160 of nozzLes 140 and the other grease tank 216 supplies another set 162 of nozzles 140. Since the apparatus is larger than that of the first embodiment, there are no dividers 136 present; rather there is one nozzle supply pipe 134 and a corresponding air/grease solenoid valve 130 associated with each nozzle 140. This provides even greater control and flexibility over the dispensing of grease than the first embodiment since individual nozzles 140 can be activated independently of any other nozzles 140 by operating the appropriate air/grease solenoid valve 130. such an arrangement permits different lubricants to be applied to different parts of the wheel tread.

The apparatus may be mounted to a railway vehicle such that each nozzle 140 of one set 160 is directed toward the flange root area 19 of a wheel 3 and each nozzle 140 of the other set 162 is directed toward the wheel tread area 15 of a wheel 3. this is useful where it is desirable to apply different types of lubricant to different regions of the wheel 3 One such instance is where the objective is to reduce flange wear and suppress wheel squeal. In this case, a lubricant having a coefficient of friction of around 0.1 (low coefficient) is stored in the first grease tank 116 and applied to the wheel flange root area 19 via the nozzles 140 of the first set 160. A lubricant having a coefficient of friction of around 0.2 to OS (medtum cocffident} is stored in the second grease tank 216 and applied to the centre of the wheel tread area 15 via the respective nozzles 140 of the second set 162. The coeffident of friction of the second lubricant is chosen to keep friction between S the wheel tread 15 and the rail 5 to an acceptable level without compromising the braking performance of the vehicle, since braking takes place at this region. Since the flange root area 19 of the wheel 3 Is not used in the braking process, a low coefficient of friction lubricant may be used.

It is of course to be understood that the above embodiment has been described by way of e>ample only and that many variations are possible without departing from the scope of the invention as defined by the appended claims.

Claims (1)

1. <claim-text>CLAIMS1. Apparatus for applying lubricant to a wheel of a railway vehicle, the wheel comprising a tread having a central running part, a field side part and a flange side part each of which may contact a rail, the apparatus comprising a supply of Lubricant and a first nozzle through S which lubricant from the supply of lubricant can be dispensed, characterised in that the first nozzle is arranged to deliver lubricant to at least a part of the field side part of the tread but not at least a part of the central running part.</claim-text> <claim-text>2. Apparatus as claimed in claim 1, wherein the lubricant is a low coefficient of friction lubricant.</claim-text> <claim-text>3. Apparatus as claimed in claim 2, wherein application of the lubricant to a wheel results in a coefficient of friction between the wheel and a rail of between 0.05 and 0.15.</claim-text> <claim-text>4. Apparatus as claimed in any preceding claim, wherein there is a second nozzle through which lubricant from the supply of lubricant can be dispensed, characterised in that the second nozzle is arranged to deliver lubricant to a different part of the tread.</claim-text> <claim-text>5. Apparatus as claimed in claim 4, wherein the second nozzLe is arranged to deliver lubricant to at least a part of the flange side of the tread but not at least a part of the central running tread.</claim-text> <claim-text>6. Apparatus as claimed in any preceding claim, wherein the first and second nozzles are connected to the supply of lubricant by a conduit and the apparatus further comprises means for introducing lubricant into the conduit and means for introducing compressed air into the conduit to drive lubricant through the conduit.</claim-text> <claim-text>7. Apparatus as claimed in claim 6, wherein the means for introducing lubricant into the conduit is arranged to coat the inside surface of the conduit with a film of lubricant.</claim-text> <claim-text>8. Apparatus as claimed in claim 6 or claim 7, wherein the means for introducing lubricant is operated by compressed air.</claim-text> <claim-text>9. Apparatus as claimed in any of claims 6 to 8, wherein the conduit comprises a first valve operable to permit aIr to flow and entrain lubricant through the conduit to one or more nozzles- 10. Apparatus as claimed in claim 9, wherein the conduit further comprises a second valve operable to permit air and grease to flow through the conduit to one or more nozzles.11. Apparatus as claimed in claim 10 when dependent directly or indirectly on claim 8, wherein -the apparatus is configured to operate the first valve to permit a volume of air to flow through the conduit so that a volume of lubricant Is introduced Into the conduit by the means for introducing lubricant, and the apparatus is further configured to operate both valves to release the air from the conduit.12. Apparatus as claimed in any preceding claim, wherein there Is a second supply of lubricant containing a different lubricant from the first supply of lubricant and wherein the first nozzle is arranged to dispense lubricant from the first supply of lubricant and the second nozzle is arranged to dispense lubricant from the second supply of lubricant.13. Apparatus as claimed in any of claims 7 toll when dependent directly or indirectly on claim 6, wherein each nozzle comprises an orifice and the cross sectional area of the conduit relative to the cross sectional area of the or each nozzle orifice Is chosen such that the resistance to flow of air through the conduit Is low relative to the or each nozzle orifice.14. Apparatus as claimed in any preceding claim, further comprising a control unit arranged to selectively cause lubricant to be dispensed through the or each nozzle on to a wheel depending on the configuration of the track the wheel is on or approaching.Apparatus as claimed in claim 14, further comprising a sensor to determine the configuration of the track on which the railway vehicle is travelling so that the control unit can selectively control the or each nozzle through which lubricant is dispensed.16. Apparatus as claimed in claim 15, wherein the sensor is an inertial sensor operable to determine the angular velocity of the railway vehicle about its vertical axis measured in degrees per second.17. Apparatus as claimed in claim 15, wherein the sensor is a GPS sensor operable to determine the position of the railway vehicle and wherein the control unit is operable to compare the determined position of the vehicle with stored information regarding the configuration of the track at that position.18. Apparatus as claimed in claim 15, wherein the sensor is an REID tag sensor operable to determine the position of the railway vehicle relative to local RF]D tags and wherein the control unit is operable to compare the determined position of the vehicle with stored in-formation regarding the configuration of the track at that position.19. Apparatus as claimed in any of claims 5 to 18 when dependent directly or indirectly on claim 4, further comprisIng a second pair of nozzles through which lubricant can be dispensed and arranged in correspondingfashlon in relation to the tread of a second wheel as the first pair of nozzles, wherein the apparatus is configured to dispense lubricant through the first nozzle of one pair when the wheel with which it is associated is on or is approaching the low rail of a bend and to simultaneously dispense lubricant through the second nozzle of the other pair when the wheel with which it is associated is on or is approaching the high rail of a bend.20. Apparatus as claimed in any preceding claim, arranged to not apply lubricant to at least 90% of the surface area of the central running part.21. Apparatus as claimed in claim 20, arranged to not apply lubricant to substantially all of the surface area of the central running part.22. Apparatus as substantially hereinbefore described with reference to the accompanying drawings.23. A method of varying the volume of lubricant to be applied to railway vehicle wheels comprising the steps of: providing apparatus having a conduit means for introducing compressed air into the conduit and a means for introducing lubricant into the conduit which is operated by compressed air; -allowing compressed air to enter the conduit so that the means for introducing lubricant introduces a volume of lubricant into the conduit for dispensing purposes; and allowing the compressed air to exit the conduit.24. A method as claimed in claim 23, wherein the apparatus comprises a first valve associated with the conduit and arranged to permit or restrict air flow through the conduit, and the step of allowing compressed air to enter the conduit includes operating the first valve.25. A method as claimed in claim 24, wherein the apparatus further comprises a second vah'e associated with the conduit and arranged to permit or restrict air flow through the conduit, and the step of allowing the compressed air to exit the conduit includes operating the second valve to permit the air to travel through the conduit.26, A method of applying lubricant to railway vehicle wheels comprising the steps of: using an REID tag reader to determine the position of a railway vehicle on a track; using the determined position to determine the lubrication requirements for the wheels on the railway vehicle; and applying lubricant to one or more wheels depending on the lubrication requirements.</claim-text>