Vehicles, such as diesel-electric locomotives, may be configured with truck assemblies including two trucks per assembly, and three axles per truck, for example. The three axles may include at least one powered axle and at least one non-powered axle. The axles may be mounted to the truck via lift mechanisms, such as suspension assemblies including one or more springs, for adjusting a distribution of locomotive weight (including a locomotive body weight and a locomotive truck weight) between the axles.
As the vehicle travels along the rails, the amount of load on each of the axles of the truck can vary, with each axle also having a maximum load weight. In certain conditions, such as during inclement weather, proper traction with the track may be lost, thereby resulting in one or more wheels slipping. Accordingly, the tractive effort for these vehicles may be less than optimized. For example, the tractive effort may be affected on trains, particularly for heavy trains or hauls, during start-up, on inclines, and during adverse rail conditions, such as caused by inclement weather or other environmental conditions.
In known rail vehicle systems, the springs of the suspension systems for the trucks are preloaded. For example, each of the springs is preloaded based on a normal amount of weight to be supported by the suspension system for the axles. As a result, under certain conditions, the preloaded springs may not provide the sufficient normal force to maintain proper contact between the wheels of the truck and the track, especially during inclement or adverse rail conditions.
In accordance with various embodiments, systems and method for weight transfer in a vehicle are provided. One embodiment includes a plurality of springs and a plurality of movable spring seats configured to adjust a length of the plurality of springs. Additionally, an electromechanical actuator is provide that is connected to the plurality of movable springs and configured to move the movable spring seats to adjust the length of the plurality of springs. Further, a controller is provided that is coupled to the electromechanical actuator to control the electromechanical actuator to adjust the length of the plurality of springs.
The present invention will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below:
To the extent that the figures illustrate diagrams of the functional blocks of various embodiments, the functional blocks are not necessarily indicative of the division components. Thus, for example, one or more of the functional blocks may be implemented in a single piece of hardware or multiple pieces of hardware. It should be understood that the various embodiments are not limited to the arrangements and instrumentality shown in the drawings.
As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property.
It should be noted that although one or more embodiments may be described in connection with powered rail vehicle systems having locomotives with trailing passenger or cargo cars, the embodiments described herein are not limited to trains. In particular, one or more embodiments may be implemented in connection with different types of vehicles including wheeled vehicles, other rail vehicles, and track vehicles.
Example embodiments of one or more apparatus and methods for changing the load of the axles to redistribute the load on the axles of a truck in a vehicle are provided. As described below, one or more of these embodiments provide dynamic weight transfer among the axles, for example, to redistribute the load to provide more load on the powered axles. By practicing the various embodiments, and at least one technical effect is increased traction on the powered axles, which may facilitate the tractive effort during certain traction limited modes of operation. Moreover, by practicing the various embodiments, less traction motors may be used to generate the same amount of tractive force or effort. For example, on a six axle truck, traction motors may be provided on only four of the axles instead of all six axles.
The rail vehicle 100 includes a controller, such as a control module 114 that is communicatively coupled with the traction motors 110 and/or an actuator 117 for controlling the load on springs 132 of a suspension system 142 (both shown in
The control module 114 may include a processor, such as a computer processor, controller, microcontroller, or other type of logic device, that operates based on sets of instructions stored on a tangible and non-transitory computer readable storage medium. The computer readable storage mediu
m may be an electrically erasable programmable read only memory (EEPROM), simple read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), FLASH memory, a hard drive, or other type of computer memory.
Thus, as illustrated by the locomotive 122 shown in
The weight redistribution in some embodiments includes a transfer of the weight from the inner axle 118b equally to the outer axles 118a and 118c. The weight redistribution is provided by changing the preload of springs in connection with the each of the axles 118a-c. For example, in some embodiments, four springs are provided per axle 118a-c. However, the redistribution of weight is achieved by changing the preload of some, but not all of the springs.
Various embodiments redistribute weight among the axles 118a-c by changing a spring length, for example, a working spring length. Thus, a preload on the spring is changed such that variable spring displacement is provided. For example, in one embodiment as illustrated in
In one embodiment, as shown in
In
Thus, the preload and effective pre-compression of the springs 132 may be dynamically adjusted, which affects the working length of the springs 132 and the load on the axle 118. In some embodiments, changing of the preloading of the springs 132 may be initiated based on a user input, for example, based on a user identifying a traction limited mode of operation (e.g., wheel slipping or upcoming rail incline or adverse rail condition). In other embodiments, the changing of the preloading of the springs 132 may be initiated automatically, for example, based on a sensed or detected traction limited modes of operation using one or more sensor. In these embodiments, upon detecting the traction limited mode of operation or an upcoming traction limited mode of operation, such as based on an identification of the traction limited mode of operation by the sensor, which is communicated to the control module 114, the control module 114 automatically changes the preloading of the springs 132. A notification of the automatic preloading change may be provided to an operator, such as via an audible and/or visual indicator.
In the various embodiments, the control module 114 instructs the electromechanical actuation system 150 to change the preloading of the springs 132, for example, by operating the motor 154 to linearly translate the spring seat 138. The translation of the spring seat 138 that changes the preloading and working length of the springs 132 redistributes the load among the axles 118 (shown in
More particularly, referring to the example in
The spring seats 138 may be any suitable device for engaging and abutting an end of the springs 132 for translating the springs 132. For example, the spring seats 138 may be a washer or other end support for the springs 132, such as a support plate. Additionally, the springs 132 may be any type of spring, such as any spring suitable for a locomotive suspension.
In an initial state of preloading, such as when a traction limited mode of operation is not detected, all of the springs 132a, 132b and 132c are preloaded the same. Thus, all of the springs 132a, 132b and 132c have the same or about the same working length. As the working length of the center springs 132b, which is an effective length of the springs, is increased, the net preload on the inner axle 118b (center axle) changes and the load or weight is redistributed to the outer axles 118a and 118c.
As an example, if the rated load of each of the three axles 118a, 118b and 118c is 70,000 pounds (also referred to as 70,000 pounds-force (lbf), the axles 118a, 118b and 118c may be precompressed to have the same preloading. In this state, the working length of the springs 132a, 132b and 132c may be about 20.5 inches. In such an embodiment, the limits of the springs 132a, 132b and 132c defined by the solid length and the free length of the springs 132a, 132b and 132c may be about 17 inches to about 25 inches. By changing the compression of one or more of the springs, such as the inner springs 132b (also referred to as the center springs), the load on all of the axles 118a, 118b and 118c is redistributed. For example, if the length of the inner springs 132b is increased by about 1.5 inches, approximately 40,000 lbf is transferred about equally from the inner axle 118b (also referred to as the center axle) to the outer axles 118a and 118c. Thus, the inner axle 118b supports a load of 30,000 lbf, while each of the outer axles 118a and 118c, to which the extra load of 40,000 lbf has been redistributed about equally, now supports 90,000 lbf each, thereby increasing the traction of the wheels 112 (shown in
The electromechanical actuation system 150 may be implemented in different configurations and arrangements. In some embodiments, the electromechanical actuation system 150 converts rotational movement into translational or linear movement to change the preloading of springs to redistribute the load among the axles 118. It should be noted that other actuation methods may be used. For example, the actuator may be one or more of a linear actuator, a pneumatic actuator, a hydraulic actuator, an electric actuator, an electro-magnetic actuator, a high pressure gas actuator, a mechanical actuator, and the like, that provides spring seat displacement.
In general, the various embodiments provide spring seat displacement using the electromechanical actuation system 150. For example, the electromechanical actuation system 150 may cause movement, such as vertical movement of the spring seat 138, which may be located at a top or bottom of the springs 132. As illustrated in
The actuator 170 includes a gearing arrangement 172, illustrated as a gear pair having a pinion 174 and a gear 176 as shown more clearly in
As illustrated in
In operation, the motor shaft 180 is driven by the motor 178, which may be an electric motor, and causes rotation of the pinion 174. The rotation of the pinion 174 causes rotation of the gear 176, thereby rotating the power screw 182. It should be noted that the power screw 182 may be any type of screw capable of being driven by a motor and/or gearing arrangement such that rotational motion is converted to translational or linear motion. Thus, as the power screw 182 rotates, the spring cap 184 is moved upward or downward, thereby causing movement of the spring 132 that is positioned between the spring cap 184 and the non-moving spring seat 190. Accordingly, rotational movement of the power screw 182 causes translational movement of the spring cap 184 to change the length of the spring 132 as described in more detail herein.
As another example, which is illustrated in detail herein, which may be coupled to the axles 118a and 118c with gearing arrangements. It should be appreciated that the truck frame 160 may be provided in any suitable manner to support and move a vehicle such that the variable spring preloading of various embodiments may be implemented in connection therewith.
In general, and as shown in
As illustrated more clearly in
In operation, and referring to
The rotation of the power screw 208 illustrated by the arrow R1 causes rotation of the gear 212 (caused by the motor 206 and pinion 228) and vertical motion of the shaft 214 illustrated by the arrow V. The vertical motion of the shaft 214 actuates the actuating beam 210, and in particular, causes pivoting motion of the actuating beam 210. The pivoting actuating beam 210 causes the plunger 218 to move, for example, push or pull, such that the spring 132 is compressed or released. Once the desired or required actuation is complete, such as compressing or releasing the spring to decrease or increase, respectively, the length of the spring 132, the plunger 218 may be locked in position using any suitable locking mechanism. It should be noted that one or more thrust bearings 240 may be provided in connection with the gear 212.
Thus, the threads 232 on the end of the shaft 214 (forming the power screw 208) mates with threads on the frame structure, illustrated as the support member 224. Rotation of the power screw 208 results in linear motion of the shaft 214 relative to the truck frame 160, thereby varying the relative position of the spring 132 to the mounting platform 236. Accordingly, the power screw 208 translates or converts rotational movement into linear or translational movement. Thus, linear movement of the collar 234 causes the springs 132 to move up or down via pivot points 242. For example, as illustrated in
It should be noted that in the various embodiments, the gears are mounted using bearings (e.g., thrust or ball bearings), which are not necessarily illustrated in the Figures.
Thus, various embodiments provide variable spring preloading of a vehicle suspension system. The variable spring preloading causes load redistribution among the axles of the vehicle. For example, dynamic weight transfer may be provided from a center axle to outer axles in a locomotive truck.
A method 260 as shown in
The method 260 then includes mounting the preloading mechanism to the vehicle at 264. For example, springs having the preloading mechanism may be mounted to the vehicle or a portion thereof, such as the axle box. In some embodiments, the preloading mechanism is provided on springs of an inner axle and not on the outer axles of a three axle truck, with two trucks provided per vehicle.
With the preloading mechanism mounted with the springs, the length of the springs is controlled at 266 to provide variable preloading and load/weight redistribution among the axles of the vehicle. For example, by varying the length of one or more of the springs, the preloading of the spring is changed, which redistributes the load among the axles of the vehicle. The controlling may be provided using a control module that dynamically adjusts the length of the springs using an actuator, for example, an electromechanical actuator. The changes to the preloading may be based on different factors, such as traction limited modes of operation.
Various embodiments may dynamically control preloading of springs in a vehicle. For example, variable spring preloading may be provided on the center axle suspension (spring) pocket on the two trucks in a vehicle. The spring pocket is translated vertically within the axle box. A counter sunk cavity may replace the spring seat on the axle box. Alternatively, the spring pocket may translate on the truck side as well. The translation is affected by a power screw driven by a motorized drive through an appropriate gear reduction. With the translation of spring pocket, the effective preload on the spring can be varied. This varied preloading results in changing the overall load distribution on the three axles of the truck, leading to a distribution of the vehicle load to put more load on the powered outer axles. The higher load on the powered outer axles helps improve traction.
Thus, a counter sunk cavity may be machined in the axle box. The spring seat is mounted on a power screw that is mounted in this cavity in the axle box. The power screw is rotated with a geared motorized drive. The rotary motion is, thus, converted into translatory motion for the power screw, which in turn drives the spring seat and accordingly the spring up or down. The rotational motion can be controlled to provide the adequate translation for the spring seat.
Alternatively the spring may be configured to translate on the truck side with a similar mechanism. A single power screw with a motorized drive can be employed to translate all the four spring seats simultaneously through a lever mechanism.
In operation, and for example, the variable preloading redistributes the load on the three axles of a truck in a vehicle. The redistribution provides more load on the powered axles and may be used, for example, in locomotives that have six load carrying axles, but has traction motors on only four axles (the outer ones for each truck). The load redistribution enables more traction to be generated on the powered axles, such as during traction limited modes of operation for these locomotives. Thus, the locomotive may be driven with four traction motors.
The various embodiments may be implemented with no changes to the truck frame. For example, the motor and the variable spring preload mechanism can be mounted on the truck frame on either the inside or outside of the frame.
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the disclosed subject matter, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the subject matter described herein should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. §112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
This written description uses examples to disclose several embodiments of the above subject matter, including the best mode, and also to enable any person skilled in the art to practice the embodiments of subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter described herein is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.