Patent Application
20080098925
The present invention relates, in general, to railway trucks and, more particularly, this invention relates to a railway truck having improved directional stability.
As is generally well known, trucks for railway cars and, more particularly, freight railway cars are available in two design types. The first design type employs an H-frame that combines bolster and side frames into one component. This H-frame is connected to the wheel-set axles by way of helical coil springs, friction/viscous dampers and pedestals. This arrangement is widely known in the railroad industry as a primary suspension truck.
Another design type employs a 3-piece construction, wherein the bolster is oriented laterally between two longitudinally disposed side frames. The side frames in turn are connected to two wheel-set axles by way of bearing adapters and bearings. Main suspension elements include helical coil springs and friction wedge dampers, which connect the bolster and the side frames. This arrangement is widely known in the railroad industry as a secondary suspension of the truck.
Either truck design type is mounted for movement in vertical, lateral and longitudinal directions in order to accommodate various operational conditions.
The disadvantage of either the primary suspension truck or the secondary suspension truck is that when the truck is forced to move in any one direction, the coil spring groups, due to an inherent stiffness, also generate forces in the remaining two directions. Accordingly, prior to the present invention, some trucks enable operation of the railway car up to speed of 110 mph. Above this speed, the trucks become directionally and, more particularly, laterally unstable resulting in increased wear of the wheels, rails and truck components and potentially causing unsafe operations, including derailment. Such lateral instability is commonly known as hunting oscillation.
Lately, there is a growing need for a high-speed freight transport in the railroad industry wherein the railway cars would need to travel at speeds greater than 110 mph. Therefore, there is a need for an improved truck that allows high-speed operation of the railway car at speeds greater than 110 mph and without lateral instability of the presently available trucks.
The invention provides a truck apparatus for a railway car. The truck apparatus includes a pair of wheel sets each having a pair of wheels joined by an axle. A frame is provided for carrying one end of a railway car body. There is a system for positioning the frame from each axle end in order to decouple from each other vertical, lateral and longitudinal forces which are applied by the wheel sets to the frame during operation of the railway car.
It is, therefore, one of the primary objects of the present invention to provide an improved truck apparatus for a railway car.
Another object of the present invention is to provide an improved truck apparatus for a railway car which is directionally stable at speeds higher than 110 mph.
Yet another object of the present invention is to provide an improved truck apparatus for a railway car which decouples vertical, lateral and longitudinal forces which are applied to the truck frame by the wheel sets.
A further object of the present invention is to provide an improved truck apparatus for a railway car which employs a suspended frame.
An additional object of the present invention is to provide an improved truck apparatus for a railway car which employs spring means and pivot members for decoupling vertical, lateral and longitudinal forces between the wheel sets and truck frame. Another object of the present invention is to provide an improved truck apparatus for a railway car which enables travel of the railway car at speeds greater than 110 mph and which fits within the space envelope mandated by the industry standards for ease of interchangeability.
In addition to the several objects and advantages of the present invention which have been described with some degree of specificity above, various other objects and advantages of the invention will become more readily apparent to those persons who are skilled in the relevant art, particularly, when such description is taken in conjunction with the attached drawing Figures and with the appended claims.
Prior to proceeding to the more detailed description of the present invention, it should be noted that, for the sake of clarity and understanding, identical components which have identical functions have been identified with identical reference numerals throughout the several views illustrated in the drawing figures.
The present invention overcomes the disadvantage of the prior art trucks for a railway car by providing an improved truck apparatus incorporating a frame which is suspended below wheel axles in a pendulum like arrangement.
Reference is now made, to
The frame means 20 of the present invention includes a first member 22 which is aligned laterally relative to the railway car body 4. The first member 22 functions as a conventional bolster member including a conventional center bowl 24 for receiving a center plate (not shown) of the railway car body 2 and a pair of apertures 26 for receiving force transmitting linkage of the brake rigging (not shown). A pair of side members 30 are positioned at opposite ends respectively of the first member 22 and are aligned longitudinally relative to the railway car body 4. It is presently preferred for such frame means 20 to be manufactured as a unitary construction either by welding or casting method. By way of example, in
In the presently preferred embodiment of the invention, the suspension means 40 includes a pedestal housing 42 which has a predetermined shape. To accommodate mounting of various components whose structure and function will be described below and to operatively engage the axle end, the pedestal housing 42 is formed as a generally U-shaped member 42 having a horizontally disposed portion 44 and a pair of trapezoidally shaped side portions 46 which are vertically positioned and which extend from the portion 44. A bearing adapter 48 is rigidly attached to the pedestal housing 42, and more particularly, to free ends of such pair of portions 46, for operatively engaging the bearing housing 18 mounted on the axle end.
To provide for directional stability of the truck apparatus 10, the suspension means 40 includes a triad of means each engageable with the housing member 42 and the frame 20 for decoupling, from each other, forces applied to the frame means 20 in vertical, lateral and longitudinal directions by the wheel sets 12.
A vertical force decoupling means includes a pair of assemblies, generally designated as 50 and best shown in
Now in a particular reference to
The lateral force decoupling means includes a first pivot means, generally designated as 60, for pivotally attaching upper end of the hollow housing 52 to the pedestal housing 42 and a second pivot means, generally designated as 70, for pivotally attaching a lower end of the at least one elongated rod member 52 to the frame means 20. By way of example of
Like wise, the second pivot means 70 includes at least a pair of members 72 which are attached to the side member 30 of the frame means 20 and at least one member 74 which is attached to the lower end of the rod member 54 being operatively interposed with each other and joined by a shaft member 76 for enabling the pivotal movement.
It will be apparent to those skilled in the art that any other pivot means 60 and 70, for example of a well known ball joint arrangement (not shown), may be employed in the present invention.
The longitudinal force decoupling means, generally designated as 80, includes a bracket means 82 which is rigidly attached to the side member 30 of the frame means 20 and which has a pair of vertically disposed surfaces 84 and 86. The means 80 further includes a pair of resilient assemblies 90 attached to the housing 52. Each resilient assembly 90 includes an aperture 92 which is formed in the pedestal housing 42 and which has axis thereof disposed in a longitudinal direction relative to such railway truck body 2. A shaft member 94 is mounted for a linear movement within each aperture 92 and has a mushroom head 96 engaging the respective surface 84, 86 of the bracket means 82. A spring means 98 is caged within each aperture 92 for biasing the mushroom head 96 for engagement with such respective surface 84, 86 of the bracket means 82 and, more particularly, for biasing the bracket means 82 in opposed longitudinal directions. Advantageously, employment of the mushroom head 96 enables the vertical movement of the bracket means 82 and the frame means 20 attached thereto.
The apparatus may include an optional damper means, generally designated as 100, for absorbing energy generated by the frame means 20 during at least one of the vertical and lateral movement thereof. Now in further reference to
The construction of the suspension means 40 and, more particularly the construction of the vertical force decoupling means 50, is advantageous for incorporating means for sensing a condition of the load carried by such car body 4 by way of determining vertical travel of the frame means 20 and correlating such vertical travel to various load conditions. In further references to
It will be apparent to those skilled in the relevant art form that for improved operation of the railway car 2 it is essential to maintain each truck apparatus 10 of such railway car 2 as close to its equilibrium as possible. In this condition, all forces acting on to the truck apparatus 10 cancel each other so that a static or dynamically balanced situation results. Because, the prior art trucks utilize simple compression springs rigidly attached at each end, vertical forces resulting from vertical oscillations of the truck cause lateral and longitudinal oscillations further explained by a coupling effect of all directional forces within such compression spring. Like wise, lateral forces resulting from lateral oscillations of the wheel sets 12 cause vertical and longitudinal oscillations.
The truck apparatus 10 of the present invention essentially decouples each directional force from the other two and further provides dampening arrangement for each directional force.
In operation, movement of the wheel sets 12 follows perturbations and irregularities which are present in conventional rail tracks. This, in turn, results in undesirable movements of the wheel sets 12 relative to the frame means 20. Forces which are generated by the wheel sets 12 in the lateral and longitudinal direction and which are applied to the frame means 20 and subsequently are transferred to the car body 4 create a dynamically unstable operation of the railway car 2. The present invention allows for effective decoupling between the wheel sets 12 and the frame means 20 in the lateral and longitudinal direction and, more particularly, decoupling the forces applied to the frame means 20 and the car body 4 and, thus improving the dynamic stability of the railway car 2 during operation at speeds greater than 110 mph.
When the wheel sets 12 oscillate in a vertical direction, such oscillation causes like movements of the housing members 52. The spring means 56 compensates for a vertical movement of the housing member 52 and the damper means 100 absorbs the energy generated due to the vertical movement. Employment, of the first pivot means 60 and the second pivot means 70 decouples forces generated by the wheel sets 12 in the lateral direction from the forces generated in the vertical direction. Employment of the resilient assemblies 90 further decouples forces generated by the wheel sets 12 in the longitudinal direction from the forces generated in each of the vertical and longitudinal direction. Advantageously, employment of a pair of oppositely operative resilient assemblies 90 limits longitudinal movement of the wheel sets 12.
It would be further apparent to those skilled in the art that suspending the frame means 20 under the axles 16 provides for a pendulum like arrangement of the tuck apparatus 10 enabling the gravitational forces on the frame means 20 to easily compensate for any lateral and/or longitudinal disturbances of the truck apparatus 10.
Dynamic simulations of the truck apparatus 10 of the present invention achieved excellent performance results at speeds greater than 150 mph while providing for directional stability of the truck apparatus 10 and dynamic stability of the railway car 2 during operation.
Furthermore, the construction of the frame means 20 and the suspension means 40 meets various space envelop requirements mandated by the industry standards.
Thus, the present invention has been described in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains to make and use the same. It will be understood that variations, modifications, equivalents and substitutions for components of the specifically described embodiments of the invention may be made by those skilled in the art without departing from the spirit and scope of the invention as set forth in the appended claims.
