Patent Application
20110303117
The present invention relates to the field of monorail bogies for supporting monorail cars, and more specifically, to single axle monorail bogies that include traction/pitching control assemblies.
Monorail bogies for supporting monorail cars are known in the art, and are used in many monorail car assemblies. The monorail bogies are generally used for supporting the running wheels and guide wheels beneath the monorail cars.
Historically, in order to control pitching movement, single axle monorail bogies utilize stiff dual parallel traction rods that are located on the bogie transverse center line, vertically displaced above each other and above the monorail guidebeam running surface. This arrangement provides both traction restraint and pitching stability of the single axle bogie. However, the traction rods are mounted above the running surface of the monorail guide beam and thus require additional wheel well undercar space (particularly for low floor height applications) to accommodate the traction rods. This increased wheel well results in reduced passenger compartment space thus having the detrimental effect of reducing the potential passenger carrying capacity of the monorail vehicle. In addition, the location of the traction links above the running surface of the monorail guide beam inherently results in an induced pitching moment when traction forces are applied to the bogie. This pitching moment when reacted by the offset traction rods will inherently result in a detrimental pitching angle of the bogie relative to the monorail guide beam, resulting in guide tire scrubbing and increased guide tire wear. In order to minimize this detrimental pitching angle of the bogie, the traction linkage is typically set to a high stiffness which in turn has the detrimental effect of reduced vibration isolation between the bogie and the monorail car body resulting in reduced ride quality.
In light of the above, it can be seen that there is a need in the industry for an improved monorail bogie that includes a traction restraint and pitch control mechanism that permits independent selection of pitch control stiffness and longitudinal stiffness relative to the car body, and that alleviates, at least in part, the deficiencies of the prior art, and improves on the overall functionality of existing monorail bogies.
In accordance with a first broad aspect, the present invention provides a traction/pitching control assembly adapted to be connected to a monorail bogie frame. The traction/pitching control assembly comprises at least a first and a second traction link and a first linking member. Each traction link has a first end and a second end and the first linking member has a first end and a second end. The first ends of the first and second traction links are connected to the respective first and second ends of the first linking member and the second ends of the first and second traction links are connected to the bogie frame.
In accordance with a second broad aspect, the present invention provides a monorail bogie assembly for supporting a monorail car. The monorail bogie assembly comprises a monorail bogie body portion that includes at least one load bearing wheel and at least one guide wheel and one stabilizing wheel on either side, and a traction/pitching control assembly connected to the monorail bogie assembly. The traction/pitching control assembly comprises at least a first and a second traction link, each having a first end and a second end and a first linking member having a first end and a second end. The first ends of the first and second traction links are connected to the first and second ends of the first linking member and the second ends of the first and second traction links are connected to at least one of the monorail bogie body portion and the monorail car.
In accordance with a third broad aspect, the present invention provides a method for manufacturing a single-axle monorail bogie having traction/pitching control. The method comprises providing a body portion of a single-axle monorail bogie capable of supporting a monorail car over a monorail track, the monorail track has a running surface, a first side surface and a second side surface. The method further comprises providing at least a set of guide wheels on the body portion. Each guide wheel is adapted to contact at least one of the first and the second side surfaces of the monorail track. The method further comprises providing at least a set of stabilizing wheels on the body portion. Each stabilizing wheel is adapted to contact at least one of the first and the second side surface of the monorail track. The method further comprises mounting a traction/pitching control assembly to the body portion of the monorail bogie.
These and other aspects and features of the present invention will now become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention and the accompanying drawings. It will also be apparent that this invention could be applied to other technologies having single axle bogies including but not limited to rail vehicles, trolleys, wheeled carts without guide wheels, automotive applications, etc.
In the accompanying drawings:
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
Referring to the drawings and particularly to
Although the monorail car 12 shown in
Illustrated in
As described below, the traction/pitching control assembly 40 of the present invention enables the simultaneous restraint of traction movement and pitching movement, while permitting free yaw rotation as well as free vertical, lateral and roll movement of the single-axle bogie 14 in relation to the monorail car 12. In so doing, the traction/pitching control assembly 40 provides noise and vibration isolation of the passenger compartment while maintaining firm guide tire alignment and adjustment. In addition, the present traction/pitching control assembly 40 permits the stiffness and damping characteristics for each of the traction restraints and pitching restraints to be selected and defined independently.
As shown in
Interconnecting the traction links 62a, 62b is a first linking member 68 and interconnecting the traction links 62c 62d is a second linking member 70. The first linking member 68 and the second linking member 70 can each be considered a torsion bar that in combination with the traction links 62a, 62c (namely the upper traction links) and the traction links 62b, 62d (namely the lower traction links), control the pitching movement of the monorail bogie 14. It should be noted that either linking member 68 or linking member 70 in combination with either the traction links 62a, 62b or the traction links 62c, 62d is sufficient to provide pitching control for the bogie 14. It will be appreciated by those skilled in the art that for the arrangement having redundant linking members 68 and 70, it will be possible to retain traction and pitch control even in the event of a single failure of any one of the traction links 62a, 62b, 62c, or 62d.
As mentioned above, at the area of juncture between the traction link 62a, the first linking member 68 and the cross-link 72 is a first attachment member 74a. In addition, at the area of juncture between the traction link 62c, the second linking member 70 and the cross-link 72 is a second attachment member 74b. In the embodiment shown, the first attachment member 74a, in conjunction with cross-linking member 72 and the traction link 62a forms a bell crank watts mechanism. Likewise, the second attachment member 74b, in conjunction with cross-linking member 72 and the traction link 62c forms another bell crank watts mechanism. For the remainder of the specification, these attachment members 74a, 74b will be referred to as bell crank watts mechanisms 74a and 74b. As best shown in
Similarly, the bell crank watts mechanism 74b is also “L” shaped, with the traction link 62c pivotally attached at a first corner, the second linking member 70 pivotally attached to a second corner and the cross link 72 pivotally attached to the pivot point. As such, the bell crank watts mechanism 74b creates an arm between the second linking member 70 and the traction link 62c and another arm between the second linking member 70 and the cross link 72. These two arms that are created by the bell crank watts mechanism 74b always remain in the same configuration with respect to each other.
Referring back to
As best shown in
As will be described in more detail below, the traction/pitching control assembly 40 shown in
Shown in
In the embodiment shown in
Positioned at the ends of the traction links 62a-62d are pivotal ends 63 for connecting the traction/pitching control assembly 40 to the monorail bogie 14. The traction link 62a, the traction link 62b, the traction link 62c and the traction link 62d can be attached to the body portion 22 of the bogie 14 via any suitable attachment mechanism that permits the traction links 62a, 62b, 62c and 62d to pivot in relation to the body portion 22 of the bogie 14. For example, the traction link 62a and the traction link 62b may be attached to the monorail bogie 14 via a spherical ball joint (either a resilient or sliding ball joint depending on the desired characteristics in a particular application to establish a desired combination of pitch stiffness, damping and longitudinal traction stiffness and damping). The traction link 62c and the traction link 62d are attached to the monorail bogie 14 in the same manner.
In an alternative arrangement that will be described in more detail with respect to
The following sections describe a non-limiting example of a single axle monorail bogie 14 to which the traction/pitching control assembly 40 of the present invention can be connected. The shapes and proportions of the various components that form the monorail bogie 14 shown in the drawings are purely used for illustration purposes and should be considered as being non-limiting. Deviation in the form of making the components wider, longer or thinner can be made by a person skilled in the art to make the bogie perform in the environment that the system is designed to operate in. In certain places, due to the difference in orientation, certain reference numbers may not be found in certain ones of the figures.
Referring back to
When the single-axle bogie 14 is positioned on the monorail track 16, the front joining portion 28 and the rear joining portion 29 extend over the running surface 18 of the monorail track 16. In addition, the first side portion 24 and the second side portion 26 are positioned such that they are adjacent respective ones of the two side surfaces 20 of the monorail track 16. In the embodiment shown, the front joining portion 28 and the rear-joining portion 29 are in the form of rectangular shaped beams. It should, however, be appreciated that the front joining portion 28 and the rear joining portion 29 could be of any shape, size and configuration that is suitable for joining the first side portion 24 and the second side portion 26 of the single-axle bogie 14 together. In addition, the front joining portion 28 and the rear-joining portion 29 are not necessarily required to be facing frontward or rearward when the single-axle bogie 14 is attached to the monorail car 12. Instead, the front-joining portion 28 and the rear-joining portion 29 can be positioned in either direction of travel.
The single axle monorail bogie 14 shown in
The load-bearing wheels 30, guide wheels 32a, 32b, 34a, 34b and stabilizing wheels 36a, 36b are generally made of rubber; however, they can also be pneumatic tires, semi-pneumatic tires, solid rubber tires, plastic tires, metal wheels or any other type of tire or wheel known in the art.
As shown in
The traction links 62a, 62c (namely the upper traction links) are attached to the monorail bogie 14 such that their longitudinal axes are positioned substantially parallel to the running surface 18 of the monorail track 16. In addition, the traction links 62a, 62c are positioned such that they are offset to either side of the running surface 18 of the monorail track 16 and are positioned in substantially the same plane as the running surface 18 of the monorail track 16. By placing the upper traction links 62a, 62c co-planar with the running surface 18, the torque pitching of the bogie frame is minimized. More specifically, if mounted at the level of the running surface 18, the two traction links 62a, 62c take the majority of the traction forces and the two lower traction links 62b, 62d simply provide pitch stabilization in combination with the first and second linking members 68 and 70. In addition, by placing the upper traction links 62a, 62b on the sides of the running surface 18, they do not extend into the passenger compartment of the monorail vehicle.
The first and second linking members 68, 70 are positioned such that their longitudinal axes are positioned substantially perpendicular to the running surface 18 of the monorail track 16, when in use. As such, the linking members 68, 70 have a substantially vertical orientation in relation to the running surface 18 of the monorail track 16. The linking members 68 and 70 are positioned substantially below the running surface 18 of the monorail track 16, and extend from the bell crank watts mechanisms 74a, 74b to the arms 76a, 76b. The two linking members 68 and 70, together with the lower traction links 62b, 62d, provide pitch stabilization forces.
As mentioned above, the traction links 62a, 62c are suitable for absorbing the traction forces created by the monorail car assembly 10. The traction forces are also absorbed by the cross link 72, which helps to transfer these forces to the traction links 62a, 62c via the bell crank watts mechanisms 74a, 74b. The traction links 62b, 62d are pitch stabilizing rods for providing pitch stabilization in combination with the first and second linking members 68, 70, so as to prevent the monorail bogie 14 from pitching in relation to the monorail car 12. The combination of the linking members 68, 70 and the lower traction links 62b, 62d enable the bogie pitch to be adjusted and stabilised. More specifically, the adjustment of the lower pitch traction links 62b, 62d provides pitch alignment of the bogie frame and guide tires. Similarly, in an alternate embodiment, it is also possible to adjust pitch by adjusting the upper traction links 62a and 62c. The adjustment of the traction links 62b, 62d can be made by shimming the ball joint connections (the connection arrangements 63) or by using a male/female pair of threaded rods for the lower placed traction links (namely traction links 62b and 62d) or by using any other technique known in the art. This adjustment of the pitch stabilization helps to reduce the wear on the guide tires. In another alternate embodiment, the upper traction links 62a and 62c may be adjusted to set the desired pitch and/or longitudinal position of the monorail bogie.
The bell crank watts mechanisms 74a, 74b help the traction links 62a, 62c to absorb the traction loads, and help to take the traction loads outside of the monorail track envelope. More specifically, by taking the traction forces to each side of the monorail track 16, the traction links 62a, 62c can be positioned at the height of the monorail track running surface 18. This reduces the pitching moments caused by traction forces such that the majority of the traction forces are absorbed by the upper traction links 62a, 62c. As such, the traction links 62b, 62d do not need to absorb any traction forces and instead are used to stabilize any remaining pitching moment forces.
In the case where the upper traction links 62a, 62c are not positioned in substantially the same plane as the running surface 18, then some of the traction forces are transferred to the lower traction links 62b, 62d. More specifically, when the traction links 62a, 62c are not aligned with the running surface 18 of the monorail track 16, there is progressive interaction between the traction forces and the pitching alignment.
It should be appreciated that the bell crank watts mechanisms 74a, 74b can be adjusted such that the distance between the linking members 68 and 70, and the respective traction links 62a and 62c can change. In such a case the length of the arms 76a and 76b will also be adjusted such that the length of the arms 76a and 76b matches the length of the distance between the linking members 68 and 70, and the respective traction links 62a and 62c. By adjusting these lengths, the movement and force balance in the crosslink 72 of the monorail bogie 14 in relation to the car frame 12 can be optimized for any desired application.
In the embodiment shown, the traction links 62a, 62b are solid, bone-shaped rods that have a suitable thickness and material strength to be able to handle the traction forces generated. In the embodiment shown, the traction links 62b, 62d are also solid, bone-shaped rods that have a suitable thickness and material strength to be able to handle the pitching stabilisation required. Each of the traction links 62a-62d can be of any shape, size, and configuration, so long as they are able to meet their intended function. In addition, it is possible for the upper traction links 62a, 62c to be different from the lower traction links 62b, 62d, such that the lower traction links 62b, 62d can be of lighter duty material than the traction links 62a and 62c.
The first and second linking members 68 and 70 that are operative for absorbing any torsion forces experienced by the traction/pitching control assembly 40 are hollow tubes. However, it should be understood that the linking members 68 and 70 can have any shape, size and configuration that is suitable for absorbing the torsion forces that will be experienced by a given traction/pitching control assembly 40.
The design, and material characteristics of each of the traction links 62a-62d, as well as the design and material characteristics of the first and second linking members 68 and 70 can be selected based on the desired characteristics of the traction/pitching control assembly 40. For example, the selection of the stiffness (which could be based on material characteristics, or design) of the traction links 62a-62d as well as of the first and second linking members 68 and 70, the bell crank watts mechanisms 74a, 74b and the cross link 72 provide the ability to independently select the bogie traction (longitudinal) stiffness and pitch stiffness.
The materials and design of each individual one of the traction links 62a-62d as well as the first and second linking members 68 and 70, the cross link 72 and the bell crank watts mechanisms 74a, 74b can be chosen separately so as to customise the handling of the traction/pitching control assembly 40. More specifically, the stiffness of the traction links 62a, 62b; the bell crank watts mechanisms 74a, 74b and the stiffness of the linking members 68 and 70, can be selected independently for customizing the functionality of the traction/pitch control assembly 40. For example, when the traction links 62a-62d are quite stiff, the pitching control assembly 40 will provide stiff control of the bogie pitch and tire alignment. In addition, if the bell crank mechanisms 74a and 74b are soft, then the bogie 14 is effectively isolated from vibration, with low longitudinal stiffness relative to the monorail car body. The cross bar 72 can be a stiff crossbar 72 with resilient bell crank mechanisms 74 at each connecting end in order to reduce noise and vibration and to prevent dynamic interactions between the monorail bogie 14 and the frame of the monorail car 12.
By customizing the pitch stiffness and longitudinal stiffness of the bogie 14 relative to the monorail car body 12, the resonance and vibration transmission to the monorail car body 12 as well as undesirable noise, and/or undesirable guide tire wear can be minimized.
As mentioned above, once the traction/pitching control assembly 40 is attached between the monorail bogie 14 and the monorail car body 12, the traction/pitching control assembly 40 is able to prevent the pitching and longitudinal traction movement of the bogie 14 in relation to the monorail car 12. It is also able to prevent longitudinal traction movement, while still permitting yaw movement between the two. For example, as the monorail bogie 12 travels around a curve in the monorail track 16, the linking members 68 and 70 will pivot in relation to the monorail bogie 14, which will push or pull the bell crank mechanisms 74a, 74b on each of the linking members 68, 70. This, in turn, will cause the linking members 68 and 70 to pivot, thus permitting yaw movement between the monorail bogie 14 and the frame of the monorail car 12. As this happens, the cross link 72 acts to enforce equal and opposite rotation of the linking members 68 and 70 such that the bogie 14 is free to yaw relative to the monorail car 12 but is restrained from longitudinal traction displacement relative to the car 12.
It should be appreciated that although the traction/pitching control assembly 40 shown in
In addition, regardless of whether the traction/pitching control assembly 40 includes two pairs of traction links 62a-62d or only one pair of traction links 62a, 62b, the traction/pitching control assembly 40 is able to transmit traction forces and provide pitch control in such a way that the traction stiffness can be defined independently from the pitching stiffness.
As shown in
Based on the above description, it should be appreciated that the traction/pitching control assembly 40 enables simultaneous traction restraint via the traction links 62a, 62c, pitching control via the linking members 68, 70 and the lower traction links 62b, 62d as well as vibration isolation via the bell crank watts mechanisms 74a, 74b. In addition, the arrangement of the traction links 62a-62d and the linking members 68, 70 permits independent control of the traction restraint and pitch control. This is all accomplished while permitting yaw movement between the monorail bogie 14 and the monorail car 12.
As will be described in more detail below, the traction/pitching control assembly 40 can be mounted between the monorail bogie 14 and the monorail car 12 in accordance with many different embodiments. A first, non-limiting, embodiment was shown and described above with respect to
Shown in
Shown in
In this second embodiment, the first and second linking members 68, 70 are attached to the monorail bogie 14 via the pillow blocks 81. As shown in
In order to attach the pillow blocks 81 to monorail bogie 14, the pillow blocks 81 can be bolted or welded to the monorail bogie 14. The pillow blocks 81 form the pivots for the linking members 68 and 70 on the bogie frame 22, such that once attached, the first and second linking members 68, 70 are able to pivot in relation to the monorail bogie 14.
In addition, the connection arrangements 63 that are positioned at the end of each of the traction links 62a-62d are adapted for being connected to the monorail car body 12. Given that the monorail car body 12 is not depicted in
The connection arrangements 63 located on the traction links 62a-62d may be attached to the car body 12 via a spherical ball joint (either a resilient or sliding ball joint depending on the desired characteristics in a particular application to establish a desired combination of pitch stiffness, damping and longitudinal traction stiffness and damping). Other manners of pivotally connecting the traction links 62a-62d to the monorail car body 12 can also be used without departing from the spirit of the present invention.
Regardless of how the traction/pitching control assembly 40 is attached between the monorail bogie 14 and the monorail car body 12, it should be appreciated that once the traction/pitching control assembly 40 is attached, the traction/pitching control assembly 40 is able to prevent the pitching and longitudinal traction movement of the bogie 14 in relation to the monorail car 12, while still permitting yaw movement between the two. Additionally, this arrangement also permits lateral and vertical movement, and roll movement between the bogie 14 and the monorail car 12.
As mentioned above, the traction/pitching control assembly 40 is operative for minimizing the pitching and traction movement experienced by the monorail bogie 14. When mounted between the monorail car 12 and the monorail bogie 14 (in either of the configurations described above), the traction links 62a, 62c are preferably aligned with the running surface 18 of the monorail track 16. By aligning the traction links 62a, 62c with the running surface 18 of the monorail track 16, the torque pitching between the monorail bogie 14 and the monorail car 12 is minimized under reaction to traction forces. Moreover, the traction links 62a, 62c (which are the upper placed rods) absorb all of the traction forces, such that the traction links 62b, 62d provide for the pitch stabilisation. The adjustment of the traction links 62b, 62d (which are the lower placed rods) enables pitch alignment of the bogie frame 14 and of the guide tires 32a, 32b, 34a and 34b. In addition, by including the traction links 62a-62d at the same height as, or below, the running surface 18 of the monorail track 16, there is added space in the passenger compartment. This is not presently possible in existing assemblies that include the traction links that are positioned above the running surface of the monorail track 16, and transposed above each other on the lateral centreline of the monorail track 16.
An exemplary method of assembling a monorail bogie 14 that has a traction/pitching control assembly 40 in accordance with the present invention will be described below with reference to the flow chart of
The traction/pitching control assembly 40 further comprises a traction link 62c and a cross link 72 that has a first end and a second end. At the first end, the cross link 72 is pivotally connected to the traction link 62a and the linking member 68 via a first attachment member 74a, and at the second end, the cross link 72 is pivotally connected via a second attachment member 74b to the traction link 62c. As such, although not shown in
Furthermore, an exemplary method of retrofitting an existing single-axle monorail bogie 14 with a traction/pitching control assembly 40 will be described below. The single axle monorail bogie will comprise a body portion that is suitable for supporting a monorail car over a monorail track. The monorail track has a running surface, a first side surface and a second side surface. The method comprises providing a traction/pitching control assembly 40 that comprises a traction link 62a, a traction link 62b and a linking member 68 having a first end portion and a second end portion. The traction link 62a is attached to the first end portion of the linking member 68 and the traction link 62b is attached to the second end portion of the linking member 68. The method further comprises pivotally attaching the traction link 62a and the traction link 62b to one of the body portion of the single axle bogie 14 and the monorail car 12, and pivotally attaching the linking member to the other one of the body portion of the single bogie 14 and the monorail car 12.
Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, variations and refinements are possible without departing from the spirit of the invention. Therefore, the scope of the invention should be limited only by the appended claims and their equivalents.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CA2009/001487 | 10/16/2009 | WO | 00 | 8/5/2011 |
