Field of the invention
The present invention relates to a bogie for use in railway cars, such as railway carriages and railway locomotives. Background of the invention
Railway bogies typically comprise a bogie frame that has two or more wheel sets mounted thereto. The wheel sets each comprise two wheels joined by a rigid axle. A primary suspension is used to mount the wheel sets to the bogie frame.
Bogies also include a secondary suspension that provides a suspension between the bogie and the railway car. The secondary suspension provides vertical support and roll resistance to the railway car. A typically secondary suspension used in Australian passenger trains consists of two air springs, with each air spring being mounted near a respective outer edge of the bogie frame. The two air springs control vertical movements and roll motion of the railway car. Summary of the invention
In a first aspect, the present invention provides a bogie for use with a railway car comprising a bogie frame, at least two wheel sets mounted to the bogie frame, at least one spring means carried by the bogie frame for providing vertical support to a railway car to which the bogie is attached, and a roll control arrangement for passive control of roll of the railway car, wherein the roll control arrangement is separate to the at least one spring means.
In one embodiment of the first aspect of the present invention, the roll control arrangement includes a first arm, a second arm and an anti-roll bar wherein roll of the railway car causes movement of the first arm and the second arm and said movement of the first arm and the second arm causes a force to be applied to the anti-roll bar.
In a second aspect, the present invention provides a bogie for use with a railway car comprising a bogie frame, at least two wheel sets mounted to the bogie frame and a roll control arrangement including a first arm that moves when the railway car rolls, a
second arm that moves when the railway car rolls and an anti-roll bar, wherein the first arm and second arm interact with the anti-roll bar to control roll of the railway car.
The first and second arms may be connected directly to the anti-roll bar, or they may be connected by one or more intermediate members to the anti-roll bar. The roll control arrangement is suitably arranged such that movement of the first arm and the second arm, as caused by roll of the railway car, causes a torsion force to be applied to the anti-roll bar. In this embodiment, the anti-roll bar is acting as a torsion bar, which acts to control the roll motion of the railway car.
The bogie may be arranged such that the first arm is positioned near a lateral edge of the bogie frame and the second arm is positioned near an opposed lateral edge of the bogie frame. Even more suitably, the first arm is positioned on an outer side of the lateral edge of the bogie frame and the second arm is positioned on an outer side of the opposed lateral edge of the bogie frame. hi one arrangement, the first arm is offset from the anti-roll bar in a longitudinal direction of the bogie and the second arm is offset from the anti-roll bar in a longitudinal direction of the bogie. The first arm and the second arm may suitably be connected to the anti-roll bar by respective intermediate members. Alternatively, the first arm and the second arm may comprises offset cranks connected to the anti-roll bar. In either case, in this arrangement, roll of the railway car causes one of the first or second arms to move downwardly and the other of the first or second arms to move upwardly. As the first and second arms are offset from the anti-roll bar, this applies a torque, moment or torsion to the anti-roll bar. Thus, the anti-roll bar controls the roll motion of the railway car by acting as a torsion rod.
The upper ends of the first and second arms are suitably provided with mounting means to mount the first and second arms to the railway car. For example, the upper end of the first arm may be mounted to a first housing or bracket and the upper end of the second arm may be mounted to a second housing or bracket, with the first housing or bracket and the second housing or bracket being adapted for attachment to the railway car.
The bogie of the present invention also includes a least one spring means. The at least one spring means suitably comprises a single spring means. The spring means may be an air spring, and this preferred as control of the height of the spring and the rebound characteristics can be controlled by controlling the air pressure within the spring. Where a single air spring is used, the air spring may be mounted to a central part of the bogie frame. This provides good vertical support and control of the vertical motion of the railway car without unduly interfering in the operation of the roll control arrangement of the bogie. Thus, in this embodiment, the control of vertical movement and the control of roll motion in the railway car are effectively separated and each can be individually optimised to obtain desirable ride characteristics in the railway car whilst ensuring that the suspension characteristics maintain the railway car within its kinematic envelope.
This system provides the ability to optimise and control the roll component of stiffness independently to the vertical component of stiffness. This system also provides the ability to handle rough or poor track with the independent control over lateral and vertical movement.
Brief description of the drawings
Preferred embodiments of the present invention will now be described with reference to the following figures, in which: Figure 1 is a pictorial representation of a bogie in accordance with an embodiment of the present invention;
Figure 2 is a side elevation of the bogie of figure 1;
Figure 3 is a plan view of the bogie of figure 1;
Figure 4 is a bottom view of the bogie of figure 1 ; Figure 5 is a plan view of the roll control arrangement of the bogie of figure 1, with the bogie frame removed for clarity;
Figure 6 is a pictorial view of the roll control arrangement shown in figure 5;
Figure 7 is a more detailed underneath view of "Detail A" of figure 6;
Figure 8 is a cross-sectional view of the connection between the anti-roll bar and the connecting arms;
Figure 9 is a cross-sectional view of the upper part of an arm mounted in the housing that attaches to a railway car; and Figure 10 is a pictorial view of another embodiment of a bogie in accordance with the present invention which includes a power pack.
Detailed description of the embodiments
It will be appreciated that the accompanying drawings are provided for the purposes of illustrating preferred embodiments of the present invention. The present invention should not be construed to be limited solely to the features as depicted in the accompanying drawings.
Figures 1 to 4 show various views of a bogie in accordance with the present invention. The bogie 10 comprises a bogie frame 12. The bogie frame 12 is a fabricated H-shaped frame having large box sections side frames 14, 16 and a transom 18. The side frame 14, 16 and transom 18 are suitably connected together using generous transition radii. Two wheel sets 20, 22 are mounted to the bogie frame 12. The wheel set 20 incorporates axle 24 and wheels 26, 28. Wheel set 20 also includes brake discs 30. Wheel set 22 is similar to wheel set 20, although reference numerals denoting each of the features of wheel set 22 have been omitted from figures 1 to 4 for clarity. The wheel sets 20, 22 are mounted to the bogie frame 12 by use of appropriate bearings and primary suspension. Such bearings and primary suspension may be as conventionally known and used in railway bogies, hi the embodiment shown in figures 1 to 4, the primary suspension is of the winged axle box type incorporating rubber/metal conical springs that provide both the load carrying capacity and resilient guidance for the wheel sets. The primary springs are a bonded conical rubber design with a progressive vertical characteristic that minimises the wheel unloading under sever track twist conditions.
One feature of the bogie shown in figures 1 to 4 is that the bogie pitch inertia is low. As a result, the inherent damping of the rubber primary springs is sufficient to
control the primary vertical movement at the maximum design speed for the bogie. Separate primary dampers are not necessary.
Railway bogies are also provided with a secondary suspension. The secondary suspension provides a suspension system between the bogie and the railway car. The secondary suspension is responsible for control of the motion of the railway car relative to the bogie.
The secondary suspension on the railway bogie shown in figures 1 to 4 incorporates two main elements: a) a single, central air spring 32; and b) a roll control arrangement 34 (see figures 5 and 6).
The central air spring 32 is primarily responsible for providing vertical support to the railway car. The roll control arrangement 34 is primarily responsible for controlling the roll motion of the railway car.
The air spring 32 is bolted to the top of the bogie frame 12. In this way, the air spring 32 sits between the bogie frame 12 and the railway car. The top surface of the air spring has a central spigot 33. This spigot 33 has the purpose of locating the top of the air spring 32 in the car body and resisting the lateral shear component of force between the car body and bogie to provide the lateral stiffness to the system.
The air spring 32 is connected to the pneumatic air supply of the train and levelling valves can suitably be used to control the height of the air spring 32. Such valves are conventional and need not be described further. To provide a low vertical natural frequency, it is preferred that each air spring 32 is connected to a large air reservoir. The air spring is also suitably equipped with a central emergency spring (not shown) that provides an air-gap of 36mm in case of a failure in the pneumatic air system. The roll control arrangement 34 that is fitted to bogie 10 will now be described initially with reference to figures 5 to 9. The roll control arrangement 34 includes an anti-roll bar 36. Each end of anti-roll bar 36 is connected via a splined fitting to interconnecting link arms 38 and 40. The interconnecting link arms are, in turn, attached via bushes to car body links in the form of first arm 42 and a second arm 44. The first
arm 42 and second arm 44 are bush mounted in respective housings 46, 48. Housings 46, 48 are then attached to the railway car body.
Figure 9 shows the attachment of the upper end of arm 42 to housing 46. In particular, the upper end of arm 42 is fitted with a bush 50. Bush 50 may be press fitted or shrink fitted to the upper end of arm 42. Bush 50 has a hole passing therethrough and connecting pin 52 is inserted through the hole in the bush and tlirough complementary holes 54, 56 in the outer wall of housing 46. Appropriate bolts and nuts 58, 60 are used to hold the pin 52 in place.
The second arm 44 is connected to housing 48 in a similar fashion. The attachment of the interconnecting arms to the anti-roll bars is shown in figure
8. As shown in figure 8, the end of anti-roll bar 36 has a splined end 62. Interconnecting arm 38 is formed with a splined opening 64 (best shown in figure 6) which is fitted on to splined end 62 of anti-roll bar 36. Due to the splined fitting between arm 38 and anti-roll bar 36, relative rotation between the end of arm 38 and splined end 62 of anti-roll bar 36 is not possible.
Figure 8 also shows some details of the connection of the arm 42 to the interconnecting link arm 38. In particular, arm 42 is provided with a bush 66. A bolt and appropriate nuts and washers 68 are used to secure the bush 66 in position between arms 70 and 72 formed on the end of interconnecting link arm 38. This connection between first arm 42 and interconnecting link arm 38 allows for a hinging motion between the two arms.
The roll control arrangement 34 is attached to the bottom of the bogie frame 12 by use of bearings in permanently fixed brackets forming part of the bogie frame. As shown in figure 7, bracket 74 is permanently attached to the underside of bogie frame 12. A thrust pad and bush arrangement 76 is then used to secure the anti-roll bar to the bracket 74. Both ends of the roll control arrangement 34 are affixed to the bogie frame 12 in this fashion.
The housing 46 is bolted around its flange to the car body to react to the vertical loads that are transmitted through the anti-roll bar mechanism 34 during roll of the car. A damper 78 is also connected between the bogie frame and housing 46. This is best shown
in Figure 1. Damper 78 provides damping for the vertical motion of the car/bogie during roll and vertical bounce. Housing 48 is similarly connected to the car body.
In use of the bogie shown in figures 1 to 9, the bogie is attached to the railway car. The central air spring 32 provides the primary vertical support to the railway car and also controls the vertical movement of the car. However, the central air spring 32 plays only a small part in controlling the roll of the car. Consequently, central air spring 32 can be optimised to provide a comfortable ride by providing appropriate control of the vertical movement of the car relative to the bogie.
Primary control of the roll motion of the railway car is provided by the roll control arrangement 34. When the railway car rolls, it causes opposite movement of arms 42 and 44. For example, roll of the railway car may cause arm 42 to move downwardly and arm 44 to move upwardly. As arm 42 moves downwardly, it lowers end 80 of first interconnecting link arm 38. This rolling motion also causes arm 44 to move upwardly, which raises the corresponding end of second link arm 40. This causes link arms 38, 40 to apply a torque or moment to the anti-roll bar 36 by virtue of the splined connection of those link arms to the anti-roll bar 36. hi particular, the downward motion of arm 42 causes an anti-clockwise torque or moment to be applied to the anti-roll bar 36 whilst the corresponding upward motion of second arm 44 results in a clockwise torque or moment being applied to anti-roll bar 36. Thus, roll of the railway car causes a torsion force to be applied to the anti-roll bar. By virtue of the dimensions and materials of the anti-roll bar, the anti-roll bar acts as a torsion bar to control the roll motion of the railway car. Thus, it can be seen that vertical control and roll control of the railway car have effectively been separated in the bogie of the present invention. This enables a comfortable ride to be provided to the railway car whilst controlling roll to an extent sufficient to ensure that the railway car does not move beyond its kinematic window during operation.
Lateral stiffness is provided by the air spring 32 in combination with the lateral force component generated due to the geometry of the roll control arrangement 34. The lateral motion of the car is damped by a dual rate hydraulic damper 82 and the maximum movement is cushioned by progressive rate rubber bump stops 83.
The top of arms 42 and 44 are inclined towards each other as shown in Fig 9. This has the effect that as the car moves laterally the top end of arm 42 will move upwards through an arc pivoted about the bottom of the attachment of arm 42 to link arm 38 and conversely arm 44 will move downwards through an arc pivoted about the attachment of arm 44 to link arm 40. This movement produces torsional forces in the anti-roll bar, which then reduces the amount of roll of the car during curving without affecting the vertical suspension stiffness.
Traction and braking forces are transmitted between the railway car body and the bogie through a traction link system that includes traction links 84 and 86. In the embodiment shown in figures 1 to 9, the traction link system applies the loads at the approximate height of the bogie pitching centre so that bogie pitching will minimise longitudinal forces on the car body.
Another feature of preferred embodiments of the present invention is that trailer and motor bogies can use a common frame design and, where possible, common components. A motor bogie is shown in figure 10. The bogie design is essentially similar to that shown in figure 1 and like parts have been given like reference numerals. However, the motor bogie also includes a power pack/traction motor 90 and a gear box 92 that has been press fitted to the axle 24 of wheel set 20.
The railway bogie shown in figures 1 to 10 has the following advantageous characteristics: a) excellent capability for handling twisted track with little variation in wheel unloading performance; b) optimised vertical ride characteristics; c) improved lateral suspension characteristics; and d) improved bogie yaw performance as the single air spring bogie provides an optimal amount of yaw stiffness when compared to twin air spring bogies.
The railway bogie of the present invention allows the vertical stiffness to be optimised independently of the roll stiffness, thus providing comfortable ride characteristics whilst ensuring that the train does not exceed its kinematic envelope
during use. In addition, the system provides the ability to handle rough or poor track without exceeding wheel unloading parameters. The bogie of the present invention provides a compliant suspension for comfortable ride, appropriate wheel unloading characteristics on rough or twisted track and appropriate control of roll to maintain the car within the required kinematic envelope. In addition, the bogie is expected to be especially robust to provide a long term, trouble free life.
It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.
The foregoing describes embodiments of the present invention and modifications, obvious to those skilled in the art can be made thereto, without departing from the scope of the present invention.