Patent Application
20120037455
The present invention concerns a lubricant applicator for a wheel of a trackbound vehicle, which applicator comprises an applicator cylinder for a lubricant stick.
The present invention also concerns a method of lubricating a wheel of a trackbound vehicle with the help of a lubricant applicator which comprises an applicator cylinder for a lubricant stick.
A wheel intended for a railway carriage, a railway engine, a railcar, or some other trackbound vehicle, has a tread surface, which is intended for rolling against the upper part of that rail over which the wheel is to roll, and a flange, which is responsible for the guiding against the rail, such that the trackbound vehicle does not leave the rails.
The tread surface of a wheel of the above described type rolls, with very low friction, against the upper side of the rail. The flange of a wheel of the type described above will, however, come into sliding contact with the sides of the rail. This sliding contact causes friction and an unwanted wear on the both the wheel and the rail.
U.S. Pat. No. 5,054,582 describes a lubricant applicator which is arranged to press a solid lubricant stick against that position on a wheel where a tread surface and a flange are joined in order to decrease the friction described hereinbefore.
A problem with the lubricant applicator which is disclosed in U.S. Pat. No. 5,054,582, is that the lubricant stick easily gets stuck in its holder and is not transported forward in the desired manner.
A purpose of the present invention is to provide a lubricant applicator for application of lubricant on a flange which is comprised in a wheel for a trackbound vehicle, which lubricant applicator requires little maintenance.
This purpose is achieved by means of a lubricant applicator for a wheel of a trackbound vehicle, which applicator comprises an applicator cylinder for a lubricant stick, characterized in that the lubricant applicator further comprises
a piston, which is arranged to run in the applicator cylinder and to press the lubricant stick against said wheel, and
a space inside the applicator cylinder which is arranged to receive a pressurized fluid for pressing the piston against the lubricant stick.
An advantage of this lubricant applicator is that a reliable lubrication is ensured. A further advantage is that the pressure with which the stick is pressed against the wheel is substantially independent of how worn the stick is.
According to a preferred embodiment the applicator cylinder has a circular cross-section. An advantage of this embodiment is that efficient sealings between the applicator cylinder and lubricant stick can be easily achieved, with the help of, for example, O-rings.
According to a preferred embodiment a control device is arranged to receive at least one signal from a sensor, which senses at least one operating parameter of the trackbound vehicle, and to control the pressure of the pressurized fluid supplied to the space depending on this signal. An advantage of this embodiment is that it becomes possible to apply lubricant depending on the present need for lubricant. In for example curves more lubricant can be applied, and less lubricant may be applied at straight stretches. This reduces the average consumption of lubricant.
According to a preferred embodiment both the lubricant stick and the applicator cylinder are formed from electrically conductive material and are in electric contact with each other, wherein currents that pass from a rail to said wheel can be conducted via the lubricant stick and the applicator cylinder further to the trackbound vehicle. An advantage of this embodiment is that the electric load on bearings of the wheels, caused by current being conducted through these, can be reduced, with reduced maintenance costs as a consequence.
According to a preferred embodiment the lubricant stick is formed from a material comprising graphite. Graphite has the advantage that it both has lubrication qualities and is also electrically conductive.
According to one embodiment a part of the lubricant stick forms that piston which runs in the applicator cylinder. An advantage of this embodiment is that very few parts are required, since the lubricant stick will both work as stick, at its end being directed towards the wheel, and as piston, at its end being directed towards said space.
According to another preferred embodiment a separate piston is arranged to run in the applicator cylinder and to be pressed against the lubricant stick. An advantage of this embodiment is that the safety to leakage of pressurized fluid is increased, which is particularly important if pressurized fluids that should not leak into the surroundings, such as hydraulic oil, are used.
According to a preferred embodiment the applicator cylinder is releasably attached to a bracket which is mounted on the trackbound vehicle. An advantage of this embodiment is that exchange and maintenance of the lubricant stick becomes very neat.
A further purpose of the present invention is to provide an efficient and reliable method of applying lubricant to a wheel of a trackbound vehicle.
This purpose is achieved by means of a method of lubricating a wheel of a trackbound vehicle with the help of a lubricant applicator which comprises an applicator cylinder for a lubricant stick, wherein the lubricant applicator further comprises a piston, which is arranged to run in the applicator cylinder and to press the lubricant stick against said wheel, and a space inside the applicator cylinder which is arranged to receive a pressurized fluid for pressing the piston against the lubricant stick, wherein at least one operating parameter which describes the present operating condition of the trackbound vehicle is measured, and
that the pressure in said space is adapted to provide a desired lubrication of said wheel with regard to said present operating condition.
An advantage of this method is that an efficient and controlled lubrication of the wheel is achieved.
Preferably said at least one operating parameter comprises at least one of the present curve position of the trackbound vehicle and the present speed of the trackbound vehicle. The curve position, that is, whether the vehicle is in a curve or not, and how tight such curve is, and the speed are two of those parameters that have the largest influence on the need for lubrication.
Further advantages and features of the invention will become apparent from the below description and the claims.
The invention will hereafter be described with the help of examples of embodiments and with reference to the enclosed drawings.
a is a cross-section and shows a lubricant holder forming part of the lubricant applicator as seen from the side thereof.
b is a cross-section and shows the lubricant holder illustrated in
The wheel 8 has a tread surface 10 which is arranged for rolling against the upper side of a rail 12. The wheel 8 also has a flange 14 which guides the position of the wheel 8 in relation to rail 12. The lubricant holder 2 of the lubricant applicator 1 is mounted on the trackbound vehicle 9, schematically illustrated in
The lubricant holder 2 will now be described in more detail with reference to
The bracket 20 is provided with a shelf 24, which is open in the middle. An applicator cylinder 26 abuts this shelf 24, as is best illustrated in
In its rear part 27, the applicator cylinder 26 has, as is clear from
The rear part of the solid lubricant stick 6 is arranged for functioning as a piston 36 inside the applicator cylinder 26. When a pressurized fluid, for example pressurized air, is supplied to the applicator cylinder 26 this fluid will, via the pipe 34 and the connection opening 32, enter a cylinder space 37, which is formed between the piston 36, the gable 30 and the walls of the applicator cylinder 26, and press the piston 36, i.e. the lubricant stick 6, against the root 16 of the flange 14 and provide the desired lubrication. Hence in this embodiment a part of the lubricant stick 6, and rather its rear part, forms that piston 36 which under influence of the pressurized fluid in the space 37 presses the lubricant stick 6 against the wheel 8.
The sealing 44 is suitably a circular sealing ring, such as a so-called O-ring, for example made of rubber material, and provides a sealing between the case 40 and the stick 6. The sealing 44 has two purposes. One purpose is to provide a sealing between the stick 6 and the applicator cylinder 26 such that pressurized fluid which is supplied to the cylinder space 37 does not leak out there from. The other purpose is to provide a sealing such that dirt, for example dust, water, snow, etc, that whirl up around the wheel 8 cannot enter the interior of the applicator cylinder 26 and cause operating problems caused by the stick (6) not being able to slide in the desired manner inside the cylinder 26.
The applicator cylinder 26 is, according to a preferred embodiment, formed from an electrically conductive material, such as a metal, for example steel. Furthermore the lubricant stick 6 is in accordance with this preferred embodiment also formed from an electrically conductive material. An example of such material which is both electrically conductive and has good lubricating qualities is graphite. According to this preferred embodiment electric current can be conducted from the rail 12 to the wheel 8, further from the wheel 8 to the stick 6 and from there via the applicator cylinder 26 and the bracket 20 directly to the trackbound vehicle 9. In this case the lubricant applicator 1 also works as a ground connection. An advantage of this is that electric current need not be conducted via bearings of the wheel 8, or at least needs to be conducted via bearings of the wheel 8 to a limited extent, which reduces the risk of current damages to these bearings. Electric contact between the stick 6 and the applicator cylinder 26 normally arises by itself, since the stick 6 normally will be somewhat inclined inside the applicator cylinder 26, such that there will be electric contact between the applicator cylinder 26 and the stick 6. Sometimes it may be suitable to improve this electric contact by means of for example a contact ring 43 made from a conductive material.
The friction between the flange 14 of the wheel 8 and the rail 12 is normally at its largest upon cornering, and thereby the need for lubrication is largest when the vehicle is in a curve.
The control device 46 sends signals to a control valve 50 which is arranged on the pipe 34, which at one end is connected to the gable 30 of the applicator cylinder 26. At its other end the pipe 34 is connected to a supply of pressurized fluid, not shown, for example the pipe 34 may be connected to a pressure tank for pressurized air.
When the control device 46 receives signals from the curve sensor 48 that the trackbound vehicle has entered a curve the control device 46 sends a signal to the control valve 50 that it should open. When the control valve 50 opens pressurized fluid, such as pressurized air, flows into the cylinder space 37 and exerts, thanks to the pressure that arises in the space 37, a pressure against the piston 36, i.e. against the stick 6, which thereby will be pressed against the root 16 of the flange 14 and generate the lubrication that is needed in the curve.
When the control device 46 then receives signals from the curve sensor 48 that the trackbound vehicle has again entered a straight portion of the track the control valve 50 is closed again. The pressure in the space 37 decreases again. This can either occur gradually by the pressurized fluid slowly leaking out through the sealing 44, illustrated in
Hence the control device 46 controls the supply of lubricant in such a manner that lubricant is supplied to the wheel 8 when it is needed, for example at cornering, but is not supplied when there is no need for lubricant, for example in straight stretches. The control device 46 can also be arranged to control the pressure gradually depending on how tight the present curve is. For example the control device 46 can be arranged to control the control valve 50 to supply a first pressure at moderately tight curves, and can be arranged to control the control valve 50 to supply a second pressure, which is higher than the first pressure, at very tight curves. Of course the control device 46 can also be arranged to continuously control the pressure in the space 37 depending on the signal from the curve sensor 48, for example according to the principle of a PID regulator. The control device 46 can also be arranged to achieve a certain lubrication also at straight stretches, if that is desired, wherein this lubrication is normally smaller than the lubrication in cornering.
The control device 46 may also receive other signals, for example concerning the speed of the trackbound vehicle, the ambient temperature, etc, and allow these signals to influence the degree of opening of the control valve 50.
As the lubricant stick 6 is consumed the space 37 will be larger. Thanks to the fact that the pressure of the fluid supplied to the space 37 is controlled to the same value at a certain operating condition, regardless of how long the stick 6 has been used, the pressure with which the stick 6 is pressed against the root 16 of the flange 14 will be the same, at the same setting of the control valve 50, regardless of whether the stick 6 is almost new, or if the stick 6 is almost worn out.
When the lubricant stick 6 is worn out it can easily be changed. This is made by releasing the pipe 34 shown in
In its rear part 127 the applicator cylinder 126 has a gable 130 and a connection opening 132 for connecting a pipe 134 intended for supplying a pressurized fluid to the applicator cylinder 126.
Contrary to the applicator cylinder 26 illustrated in
When a pressurized fluid, such as pressurized air, is supplied to the applicator cylinder 126 this fluid will enter a cylinder space 137 which is formed between the piston 136, the gable 130 and the walls of the cylinder 126, and to press the piston 136 against a lubricant stick 106, which is thereby pressed against the root 16 of the flange 14 and achieves the desired lubrication.
The applicator cylinder 126 is provided with a sealing ring 144 which seals against the stick 106. In this embodiment the main task of the sealing ring 144 is to prevent dirt from entering the applicator cylinder 126. The sealing ring 144 may also work as a stop which retains the piston 136, and thereby the fluid in the space 137, inside the cylinder 126 when the stick 106 has been completely worn out.
It will be appreciated that numerous variations of the embodiments described above are possible within the scope of the invention as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0900230-4 | Feb 2009 | SE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/SE2010/050202 | 2/23/2010 | WO | 00 | 11/1/2011 |
