Abstract:
Device for lubricating a wheel flange of a railway vehicle based on the spraying of a pressurized jet of lubricant, comprising an electromagnetic pump with a pump body ( 5 ) in which a piston ( 20 ) is displaced, and a means ( 19 ) for guiding the piston ( 20 ) in a bore ( 22 ), the guidance means ( 19 ) including an opening ( 32 ) designed to communicate with a lubricant transfer channel ( 17 ) in the pump body ( 5 ), said opening ( 32 ) opening out into a compression chamber ( 23 ) situated in a downstream part of the bore ( 22 ), the device comprising a heating block ( 7 ) arranged so as to transfer heat energy to the lubricant before spraying.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to lubricating devices, more particularly to a lubrication device that can be used, for example, to lubricate a wheel flange of a railway vehicle. 
     On a railway wheel, a distinction is made between the generally tapered rolling surface in contact with the top surface of the rail and the wheel flange. The wheels are guided on the rails in a straight line by the tapered nature of the rolling surfaces and in the curves by the wheel flange which bears on the lateral faces of the rail. The wheel flange exceeds the rolling surface by a number of centimeters, and prevents any risk of the transit car being derailed. The friction forces between the wheel flange and the lateral surface of the rail result in wear of the flange, energy losses through friction and noise. 
     In order to reduce these drawbacks, lubrication devices are generally provided which deposit lubricant on the wheel flange or on the lateral faces of the rails by spraying a jet of lubricant. 
     Current lubrication devices typically use compressed air mixed with a lubricant, this mixture being sprayed in the form of a jet produced through the intermediary of a nozzle positioned in the vicinity of the wheel flange. Such devices are, for example, described in U.S. Pat. Nos. 3,760,904 and 6,186,411. These lubrication devices increase the storage volumes needed to compress the air, which makes the air compressors installed on the motor coaches and used for other equipment relatively costly. Moreover, they do not allow the quantity of lubricant sprayed onto the wheel flange to be delivered accurately because of the non-uniform nature of the air-lubricant mixture. 
     Another type of lubrication device described in patent of invention BE 893171 comprises an electromagnetic pump which directly sprays the lubricant onto the flange without compressed air, which allows this pump to deliver the quantity of lubricant sprayed onto the flange with accuracy. By providing an inlet valve and an outlet valve actuated in time in a deferred manner, this pump makes it possible to suck the lubricant into a chamber and to discharge it under pressure. Nevertheless, this pump does not make it possible to spray an adequate jet of lubricant onto the wheel flange because of the viscosity of the lubricant and the path the lubricant follows in the lubrication device. Such a pump is not suited to all types of lubricant and to the variations in outside temperatures that range, for example, in certain circumstances, between −30° C. and +50° C., which alters the viscosity of the lubricant, making an accurate adjustment of the quantity of lubricant sprayed very difficult. 
     SUMMARY OF THE INVENTION 
     The present invention aims at solving these problems. In particular, the invention proposes a lubrication device making it possible to spray an accurate and easily-adjusted quantity of lubricant. 
     Another subject of the invention is a lubrication device of simple and compact structure. 
     Finally, another subject of the invention is a lubrication device in which guidance of the lubricating jet is enhanced. 
     The invention proposes a lubrication device based on the spraying of a pressurized jet of lubricant, comprising an electromagnetic pump with a pump body in which a piston is displaced, and a means for guiding the piston in a bore, the guidance means including an opening designed to communicate with a lubricant transfer channel, said opening opening out into a compression chamber situated in a downstream part of the bore, the device having a heating block arranged so as to transfer heat energy to the lubricant before spraying. 
     In one embodiment, the heating block is mounted on the pump body and is traversed by the lubricant transfer channel. 
     The heating block can include a lubricant storage chamber linked to the lubricant transfer channel. 
     A lubricant spraying nozzle can be mounted directly on the pump body, for example around an end of reduced diameter of the pump body. 
     In another embodiment, the heating block is mounted down-stream of the pump body. 
     A lubricant spraying nozzle can comprise an elongated nozzle body with a through-passage for the lubricant. The nozzle body is advantageously mounted downstream of the pump body and comes into contact with the heating block. 
     Preferably, the heating block includes means for attachment to the pump body and for securing the spraying nozzle in position. 
     In all the embodiments, the heating block is advantageously made of a heat-conducting material and includes an electric heating element. 
     Furthermore, the lubrication device includes an isolating plug mounted to move in a guide sleeve housed in the downstream part of said bore. The plug can be activated by an elastic means tending to displace it to the closed position. The guide sleeve can include a radial annular lip on which the isolating plug bears in the closed position. 
     The guidance means can advantageously be displaced with respect to the lubricant transfer channel so as to adjust the volume of the compression chamber. 
     In an embodiment more particularly suited to the lubrication of a wheel flange of a railway vehicle, an air baffle is positioned so as to orient an air stream toward the outlet of the spraying nozzle. The baffle can have an air sampling means comprising an air intake orifice oriented in the direction of travel of the railway vehicle. 
     According to another aspect of the invention, a lubrication device as mentioned hereinabove is used to lubricate at least one wheel of a railway vehicle bogie. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Other features and benefits of the invention will become apparent from reading the detailed description of an embodiment, taken by way of non-limiting example and illustrated by the appended drawings, in which: 
         FIG. 1  represents a lubrication device according to one embodiment positioned above a wheel of the railway vehicle; 
         FIG. 2  diagrammatically represents the lubrication device of  FIG. 1 , in elevation; 
         FIG. 3  diagrammatically represents a cross-sectional view of a heating block along the axis III-III of  FIG. 2 ; 
         FIG. 4  diagrammatically represents an enlarged cross-sectional view along the axis IV-IV of  FIG. 2  of the body of an electromagnetic pump; 
         FIG. 5  diagrammatically represents an enlarged detail view of a nozzle attached to the pump body; 
         FIGS. 6   a  and  6   b  illustrate the operation of the pump; 
         FIG. 7  represents a lubrication device according to the invention equipped with an air sampling means; and 
         FIG. 8  diagrammatically represents in cross section the pump body of a lubrication device according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  represents a lubrication device  1 , according to the invention, positioned above a wheel  2  of a railway vehicle that is not represented in the figures. The rail  2  has a rolling surface  3  of generally tapered form and a wheel flange  4  projecting with respect to the rolling surface  3 . 
     The device comprises an electromagnetic pump body  5  linked to an electric actuator  6 , and a heating block  7  linked to an electrical power supply  8 , the heating block  7  being attached lengthwise to the length of the pump body  5 . The device  1  is secured to the frame of the railway vehicle at an appropriate distance from the flange  4 , the axis of the pump body  5  and of the nozzle  9  being inclined relative to the rotation axis of the wheel  2  by an appropriate angle for the lubricant to be deposited roughly at the junction of the flange  4  and the rolling surface  3 . This angle can be, for example, between 45° and 65°. 
     Hereinafter in the description, the adjective longitudinal relates to the lengthwise direction of the pump or of the heating block, and the adjective transversal to a direction perpendicular to this length. 
     A nozzle  9  is positioned on the front face  9   a  of the pump body  5  facing the flange  4 , in order to spray lubricant onto the latter. 
     A longitudinal connection  10  and an elbow  11  passing through the heating block  7  allow the pump body  5  to be supplied with lubricant by a lubricant tank that is not represented. An orifice that can be blocked by a screw  13  makes it possible to drain the pump body  5 . 
       FIG. 2  represents an enlarged view of the heating block  7  and of the pump body  5 . Lubricant is circulated from the heating block  7  to the pump body  5  via a channel  17  linked to the transversal elbow  11 . 
       FIG. 3  represents a cross-sectional view of the heating block  7  along the axis III-III of  FIG. 2 . 
     The heating block  7  has a parallelepipedal body made of a heat-conducting material in which are housed a heating element  14  such as an electrical resistance and a thermostat  15  both connected to the electrical power supply  8 . A lubricant storage chamber  16  is linked to the channel  17  conveying the lubricant into the pump body  5 . 
     The chamber  16  is linked to the transversal elbow  11 . The chamber  16  and the lubricant-conveying channel  17  make it possible to store a volume of lubricant in the heating block  7  upstream from and close to the pump body  5 . Since the heating block  7  is made of a heat-conducting material, it heats the stored volume of lubricant when the heating element  14  is operating, making it possible to send a more free-flowing lubricant into the pump body  5 . 
     The lubrication device  1  is attached to the frame of the railway vehicle so that the lubricant can flow by gravity as far as the chamber  16  of the heating block  7 . The drain screw  13  allows communication between the channel  17  and the atmosphere, so as to balance the pressure inside the lubrication device  1  with the atmospheric pressure. 
       FIG. 4  is an enlarged view in cross section along the axis IV-IV of the pump body  5 . The pump body  5  includes a recess  18  in which is housed a means  19  of guiding a piston rod  20 . The nozzle  9  is attached to an end of reduced diameter  21  of the pump body  5  projecting from the front face  9   a . The guidance means  19  has a through-bore  22  linking the lubricant-conveying channel  17  represented by broken lines in  FIG. 4  to a compression chamber  23 . This compression chamber  23  is separated from an outlet channel  24  situated in the nozzle  9  by an isolating plug  25 . The guidance means  19  is of generally cylindrical form, and includes a central part  26   b  situated between a front part  26   a  and a rear part  26   c , the central part  26   b  having a diameter greater than that of the front  26   a  and rear  26   c  parts. 
     An elastic means, such as a helical spring  29 , bears at one end on a washer  28  attached to the end of the piston rod  20 , and at the other end on a shoulder  28   a  of the central part  26   b . The spring  29  is used to return the piston rod  20  to an initial position with respect to the guidance means  19 . A guide sleeve  31  is housed in the bore  22  at its downstream end opposite to that where the piston rod  20  leaves the bore  22  and has the spring  29 . The isolating plug  25  is mounted in the guide sleeve  31  for its travel. 
     The compression chamber  23  corresponds to the volume situated between a transversal opening  32  in the guidance means  19  and the isolating plug  25  housed in a downstream part of the bore  22 . The transversal opening  32  communicates with the lubricant-conveying channel  17 . 
     A number of gaskets  45  are arranged in the guidance means  19  so as to ensure seal-tightness between the guidance means  19 , the pump body  5  and the piston rod  20 . 
     The elements that form the nozzle  9  can be better seen in  FIG. 5  which represents an enlarged detail view of the nozzle  9 . The nozzle  9  has a form that is symmetrically tapered with respect to the axis X-X′ and includes a radial internal shoulder  40 , a tapered area  41  and a longitudinal conduit part  41   a . The nozzle  9  is attached by its tapped base  43  to the end  21  which has a threaded cylindrical surface  47  projecting from the front face  9   a  of the pump body  5 . 
     The outlet channel  24  for the lubricant jet leaving the nozzle  9  is made up by the longitudinal arrangement, from the isolating plug  25 , of a first passage  33  in the sleeve  31 , followed by a second passage  34  in a hollow body  35  serving as a spacer between the nozzle  9  and the sleeve  31 , then a third passage  36  in the nozzle  9  through which the lubricant is ejected onto the wheel flange  4 . 
     The guide sleeve  31  is housed by a cylindrical portion  37  in the downstream end  30  of the bore  22 . A radial end flange  38  bears on a shoulder of the hollow body  35 , on a shoulder  39  of the end  21 . The radical flange  38  also bears on the shoulder  40  of the nozzle  9 . The sleeve  31  includes an orifice  27  delimited by a radial annular lip  37   a . The void  27  is capable of allowing the lubricant to pass when the isolating plug  25  opens. 
     An elastic means such as a helical spring  42  is mounted between the hollow body  35  and the isolating plug  25  so as to stress the isolating plug in the closure direction. 
     The downstream end  30  of the guidance means  19  is situated at the end  21 . 
     As represented in  FIGS. 4 ,  6   a  and  6   b , the volume of the compression chamber  23  can be adjusted by the longitudinal travel of the guidance means  19  with respect to the conveying channel  17 , this travel being produced by the action of a thrust bearing  49  mounted in a groove  49   a  in the guidance means  19  and capable of being displaced by a cam  50 . 
     In the position illustrated in  FIG. 4 , the compression chamber  23  is larger than in the positions illustrated in  FIG. 6   a  or  6   b , which results from the positioning of the transversal opening  32  closer to the conveying channel  17 , the opening  32  having a section in common with and larger than the section of the lubricant conveying channel  17 .  FIGS. 6   a  and  6   b  show the result of a longitudinal travel of the front part  26   a  of the guidance means  19 . The guidance means  19  has been displaced inside the pump body  5 , its front part  26   a  being guided inside the end  21  and by its bore guided along the cylindrical surface  37  of the sleeve  31 . The central part  26   b  is displaced longitudinally by being guided by the bore  18  of the pump body  5 . 
       FIG. 6   a  shows a position corresponding to the suction of the lubricant through the conveying channel  17 , the lubricant entering into the compression chamber  23  situated in the pump body  5  through the transversal opening  32  of the guidance means  19 .  FIG. 6   b  shows a position corresponding to the discharging of the lubricant out of the compression chamber  23  into the outlet channel  24  after the isolating plug  25  has opened, which follows the movement of the piston rod  20  toward the downstream part of the bore  22  situated on the right in  FIGS. 6   a  and  6   b.    
     In the two positions illustrated in  FIGS. 6   a  and  6   b , the guidance means  19  has been displaced relative to the position illustrated in  FIG. 4 , the front face  30  of the guidance means  19  coming into contact with the flange  38  of the sleeve  31 . In the position illustrated in  FIG. 6   a , the piston rod  20  is held toward the left of the figure by the spring  29  so that the volume of the compression chamber  23  is maximum. In the position illustrated in  FIG. 6   b , the piston rod  20  is actuated against the force of the spring  29  by discharging the lubricant situated in the chamber  23 . 
     The piston  20  is actuated in a conventional manner by the electric actuator  6 . 
       FIG. 7  represents an embodiment of a lubrication device as described hereinabove associated with an air sampling means  46  which is used to better guide the jet of lubricant at the outlet of the nozzle  9  onto the flange  4  and protect it from external air turbulences. 
     The air sampling means  46  comprises an air intake orifice  51  with a protection mesh  52 . The orifice  51  is linked to a conduit  53  which opens out around the nozzle  9 . In other words, the air sampling means  46  generates an air stream that envelopes and guides the jet of lubricant between the outlet of the nozzle  9  and the flange  4 . The orifice  51  is oriented in the direction of travel of the rail transit car. Thus, as soon as the transit car reaches a sufficient speed, air is directed around the nozzle  9 , in the direction of spraying of the jet of lubricant so as to enhance the guidance of the jet of lubricant. This effect increases with the speed of the transit car, which makes it possible to enhance the lubrication as the speed of the transit car increases. The air sampling means  46  that has just been described can be replaced by a simple air baffle such as a flange appropriately positioned so as to orient a flow of air toward the nozzle  9 . 
     The heating block  7  is used to adjust the viscosity of the lubricant at the inlet of the pump body  5 . The temperature of the heating block is adjusted for the lubricant to be sufficiently fluid to be sprayed in a fine jet through the nozzle  9  following the movement of the piston rod  20 . The lubricant is sprayed at high speed by the travel of the piston rod  20  and reaches the wheel flange  4  by virtue of the proximity of the lubrication device to the flange  4 , for example of the order of a few tens of mm. 
     Advantageously, the fact that the lubrication device  1  has roughly the form of a pencil reduces the length of travel of the lubricant between the lubricant storage volume and the wheel flange  4 , which makes it more accurate for delivery. The heating block  7  is also used, by virtue of the chamber  16 , as a buffer storage volume and is situated close to the pump body  5  to which it is linked by the lubricant-conveying channel  17 . Furthermore, the nozzle  9  attached to the pump body  5  avoids having the lubricant travel through a hose at the outlet of the pump  5 . 
       FIG. 8  illustrates a second embodiment of a lubrication device according to the invention, which is distinguished from the first embodiment illustrated in the preceding figures only by the arrangement and the structure of the heating block referenced  54  in  FIG. 8 . In this embodiment, as is illustrated in  FIG. 8 , in which similar elements are given the same references as in the preceding figures, the nozzle  9  comprises an elongated nozzle body  55  with a through-passage  56  for the lubricant. The nozzle body  55  includes, at one of its ends, the actual nozzle with its outlet channel  24  and, at its other end, a peripheral shoulder  57  which can bear against the flange  38  of the sleeve  31 . The nozzle body  55  also has a tapered area  41  which bears on the hollow body  35  in the same way as in the embodiment illustrated in  FIG. 4 . 
     The heating block  54  has an annular structure and surrounds the nozzle body  55  while being in contact with the latter over its entire length. The heating block  54  has an annular recess in which a heating ring  58  is mounted. The heating block  54  has a portion in the form of a tapped ring  59  which cooperates with the threaded cylindrical surface  47  projecting from the end of reduced diameter  21  of the pump body  5 . Furthermore, a shoulder  60  of the heating block  54  bears on the shoulder  57  of the nozzle body  55 . In this way, mounting the heating block  54  by screwing onto the end  21  of the pump body  5  makes it possible both to attach the heating block  54  to the pump body and keep in position the nozzle  9  which is thus clamped between the heating block  54  and the pump body  5  with the radial flange  38  inserted between them. During this mounting procedure, the heating ring  58  is also held against the pump body  5 . 
     In this embodiment, the heat energy produced by the heating ring  58  is transmitted by the heating block  54 , made as previously of a heat-conducting material, as far as the nozzle body  55 , which makes it possible to heat up the lubricant passing through the passage  56  before its output through the orifice  24  of the nozzle  9 . In this embodiment, the lubricant is therefore heated downstream of the pump body, unlike the case in the embodiment illustrated in the preceding figures, in which the heating takes place upstream of the pump body. 
     In all cases, the inventive device is compact and easy to put in place, notably on a railway vehicle. 
     Preferably, the lubrication device is positioned on the front bogie of a railway vehicle, which is in turn preferably at the front of a train. In this way, the lubricant deposited on the wheel flange at the front of the transit car or at the front of the train is partly deposited onto the rails and makes it possible to also lubricate the other wheels of the transit car and of the train. 
     The inventive device can also be used to lubricate other moving members operating outdoors and consequently likely to be subject to low temperatures, such as dockside cranes, materials or goods transportation systems, conveyor articulations or even elevators.