Patent Application
20240217562
This application claims the benefit of Taiwan Patent Application No. 111150373, filed on 28 Dec. 2022, which is hereby incorporated by reference for all purposes as if fully set forth herein.
The present invention mainly relates to a safety mechanism and apparatus for a railcar, and in particular, to a method for preventing a railcar from overturning and an anti-overturning railcar.
A railcar (often referred to as a train for short) is a vehicle traveling on a railroad track. Because the railcar is prone to be affected by a centrifugal force and tilt outward when negotiating a curve, a driver must slow down when cornering, to avoid occurrence of a railcar overturning accident. The centrifugal force during cornering is generally referred to as lateral pressure. The lateral pressure divided by a weight of the railcar is a factor of safety for cornering, and an allowable value of the factor of safety should be less than 0.75. If the value is greater than 1, overturning is prone to occur.
In Taiwan, Taiwan Railway vehicles are classified into two vehicle models: an intercity express and a commuter electric multiple unit (EMU). Main vehicle models of the intercity express include a push-pull railcar (for example, Ziqiang Express) and a tilting railcar (for example, Taroko Express or Puyuma Express); and main vehicle models of the commuter electric multiple unit include EMU700 and EMU800.
A tilting control system for the tilting railcar uses a roller on a bogie to roll on a chute, so that a vehicle body can be tilted by 5 degrees to reduce a lateral acceleration and compensate cant deficiency in a curve section, so that a center of gravity of a vehicle can be lowered. In this way, the vehicle can negotiate a curve at a high speed while ensuring comfort of a passenger. Compared with a non-tilting railcar, a cornering speed can be increased by about 10-30 km/h for the tilting railcar.
Based on safety considerations, most railcars are currently equipped with an automatic train protection (ATP) to ensure that the railcar can stop in front of a parking point or have an actual speed less than a speed limit value in front of a speed limit point. However, unfortunately, in October 2018, because a driver turned off the ATP, a Puyuma Express in Taiwan sped through a curve and an overturning accident still occurred, causing many casualties.
In view of this, it is necessary to provide a safety mechanism and apparatus for the railcar, to resolve the foregoing problem.
An objective of the present invention is to provide a method for preventing a railcar from overturning. According to the method, when a railcar corners, an external force may be provided to the railcar to counteract a part of a centrifugal force, thereby assisting in guiding the railcar back to normal to avoid overturning.
A secondary objective of the present invention is to provide an anti-overturning railcar, and the anti-overturning railcar can implement the method for preventing a railcar from overturning.
To achieve the foregoing objectives, the present invention provides a method for preventing a railcar from overturning, comprising: enabling a side of a carriage of a vehicle body to comprise a side wing, so that airflow generates a centripetal force due to a difference in pressure on two surfaces of an airfoil of the side wing when the vehicle body travels through a curve portion of a track, to counteract a centrifugal force on the vehicle body by the centripetal force.
In some embodiments, two sides of the carriage may both comprise the side wing, so that a centripetal force is generated on each of the two sides of the carriage to counteract the centrifugal force on the vehicle body.
In some embodiments, the side wing is reversibly arranged on a side of the carriage, and the airflow may generate a downforce due to a difference in pressure on the two surfaces of the side wing when the vehicle body travels on a straight portion of the track.
In some embodiments, before the vehicle body is about to travel into the curve portion, the side wing may be controlled to be reversed, so that the downforce generated by the airflow may be converted into the centripetal force.
In addition, the present invention provides an anti-overturning railcar, comprising: a vehicle body, comprising a carriage, wherein when the vehicle body travels through a curve portion of a track, the carriage comprises an outer rail side surface facing an outer rail side of the curve portion, and the carriage comprises an inner rail side surface facing an inner rail side of the curve portion; and a side wing, located on a side of the carriage, wherein there is a fluid passage between the side wing and the carriage, the fluid passage comprises an inlet and an outlet, the side wing has a cross section in a shape of an airfoil and comprises a convex arc surface and a pressure surface opposite to the convex arc surface, a length of the convex arc surface is greater than a length of the pressure surface, and when the side wing is located on the outer rail side surface of the carriage, the convex arc surface of the side wing faces the outer rail side surface; and when the side wing is located on the inner rail side surface of the carriage, the pressure surface of the side wing faces the inner rail side surface.
In some embodiments, the convex arc surface may comprise a front arc segment gradually expanding from the inlet relative to the pressure surface, and the convex arc surface may comprise a rear arc segment extending from the front arc segment and gradually narrowing toward the outlet relative to the pressure surface.
In addition, the anti-overturning railcar may further comprise a support assembly and a reversion module, wherein the support assembly may connect the side wing and the carriage, and the reversion module may be connected with the support assembly to reverse the side wing.
In some embodiments, the support assembly may comprise at least one support connected with the carriage, and a pivoting shaft. The pivoting shaft may be combined with the side wing and may be arranged on the support.
In some embodiments, the reversion module may comprise a first gear combined with an end of the pivoting shaft, and a second gear. The second gear may be arranged on the support and engaged with the first gear, and the second gear may be connected with a driver, to be driven to rotate by the driver.
In some embodiments, when the vehicle body travels on a straight portion of the track, the convex arc surface of the side wing may face a ground.
The method for preventing a railcar from overturning and the anti-overturning railcar according to the present invention have the following features. By arranging the side wing, when the railcar corners, an aerodynamic force generated by the side wing forms the centripetal force, to counteract a part of the centrifugal force by the centripetal force, thereby indeed assisting in guiding the railcar back to normal even if a vehicle speed fails to drop below a speed limit value, thereby avoiding occurrence of an overturning accident. In this way, the method for preventing a railcar from overturning and the anti-overturning railcar according to the present invention have the effect of improving safety.
Embodiments of the present invention are described in detail below with reference to accompanying drawings. The accompanying drawings are mainly simplified schematic diagrams, and only exemplify the basic structure of the present invention schematically. Therefore, only the components related to the present invention are shown in the drawings, and are not drawn according to the quantity, shape, and size of the components during actual implementation. During actual implementation, the specification and size of the components are actually an optional design, and the layout of the components may be more complicated.
The following description of various embodiments is provided to exemplify the specific embodiments for implementation of the present invention with reference to the accompanying drawings. Direction terms mentioned in the present invention such as “upper”, “lower”, “front”, and “rear” are only directions with reference to the accompany drawings. Therefore, the used direction terms are intended to describe and understand the present invention but are not intended to limit the present invention. In addition, in the specification, unless explicitly described as contrary, the word “comprise” is understood as comprising the component, but does not exclude any other components.
The present invention provides a method for preventing a railcar from overturning, including: enabling a side of a carriage of a vehicle body to include a side wing, so that airflow generates a centripetal force due to a difference in pressure on two surfaces of an airfoil of the side wing when the vehicle body travels through a curve portion of a track, to counteract a centrifugal force on the vehicle body by the centripetal force. Therefore, in the present invention, an aerodynamic force generated by the airflow may be used to keep the railcar in a state of not tilting excessively when cornering, thereby effectively preventing the railcar from overturning. It is worth mentioning that the railcar described in the present invention may include transportation such as a train, rapid transit, or a light rail, and may include a similar item such as a train toy or a display model.
Referring to
A form of the vehicle body 1 and a driving manner of the vehicle body 1 are not limited in the present invention. The vehicle body 1 may travel on a track R, and a traveling direction for the vehicle body 1 is guided by the track R. The track R may extend in a plane or a three-dimensional shape, and a structure of the track R is well known, so that details are not described herein again. The track R includes at least one curve portion R1. Two sides of the curve portion R1 are an outer rail side S1 and an inner rail side S2 respectively. The vehicle body 1 includes at least one carriage 11, and the carriage 11 is prone to tilt toward the outer rail side S1 when negotiating the curve portion R1.
Additionally, when the vehicle body 1 travels through the curve portion R1, the carriage 11 includes an outer rail side surface 111 facing the outer rail side S1 of the curve portion R1, and includes an inner rail side surface 112 facing the inner rail side S2 of the curve portion R1. It should be particularly noted that the outer rail side surface 111 and the inner rail side surface 112 of the carriage 11 are not fixed on a left or right side (depending on a direction facing a vehicle front) of the carriage 11, but are relative to a vehicle driving direction D and the curve portion R1. This can be understood by those of ordinary skill in the art.
In addition, referring to
Referring to
Specifically, referring to
In this way, the airflow may form bypass flows when flowing through a head end of the side wing 2. A part of the airflow passes through the fluid passage T and flows along a surface of the side wing 2 toward the outlet T2 of the fluid passage T. Another part of the airflow may flow along another surface of the side wing 2, and two bypass flows merge at an end of the side wing 2. Because a path of the convex arc surface 21 of the side wing 2 is longer than a path of the pressure surface 22, a flow speed of the airflow on a side of the convex arc surface 21 is higher and a flow speed on a side of the pressure surface 22 is lower. According to Bernoulli's principle, pressure is low where a flow speed is high, and the pressure is high where the flow speed is low. Therefore, pressure of the airflow on the side of the convex arc surface 21 is lower, and pressure on the side of the pressure surface 22 is higher.
Therefore, the convex arc surface 21 and the pressure surface 22 of the side wing 2 can generate an aerodynamic force F by using a pressure difference, and a direction of the aerodynamic force F needs to be opposite to a direction of a centrifugal force causing the carriage 11 to tilt toward the outer rail side S1 (with reference to
In addition, to stably arrange the side wing 2 and respond to the curve portion R1 of the track R bending in different directions, the anti-overturning railcar according to this embodiment may further include a support assembly 3 and a reversion module 4. The support assembly 3 may connect the side wing 2 and the carriage 11, and the reversion module 4 is connected with the support assembly 3 and reverses the side wing 2 according to a direction of the curve portion R1 about to be entered by the vehicle body 1, so that the side wing 2 can generate the aerodynamic force F (a centripetal force) in a correct direction, to counteract the centrifugal force causing the carriage 11 to tilt.
Specifically, the support assembly 3 according to this embodiment may include a pivoting shaft 31, and the pivoting shaft 31 may be combined with the side wing 2, to drive the side wing 2 to synchronously pivot with the pivoting shaft 31. It should be particularly noted that the pivoting shaft 31 according to this embodiment is not limited to a single component, but can constitute a concept of a rotating shaft. For example, the pivoting shaft 31 may be in a shape of a long rod and entirely pass through a head and tail of the side wing 2. Alternatively, a short rod may be arranged on and protrude from each of the head and tail of the side wing 2, and two short rods may be coaxially arranged, to jointly form the pivoting shaft 31. The support assembly 3 may further include at least one support 32. The present invention does not limit a form of the support 32, and use the following as a principle: the pivoting shaft 31 can be arranged, the side wing 2 does not collide with the carriage 11 during pivoting, and a fluid passage T is kept between the side wing and the carriage 11. In this embodiment, two supports 32 may be respectively connected with the carriage 11. A bearing 33 may be arranged on each of the two supports 32, so that the pivoting shaft 31 can pass through two bearings 33, to pivot smoothly relative to the two supports 32.
The reversion module 4 according to this embodiment may include a first gear 41, where the first gear 41 is combined with an end of the pivoting shaft 31; and a second gear 42 arranged on the support 32 and engaged with the first gear 41, where the second gear 42 is connected with a driver 43, to be driven to rotate by the driver 43. In this way, when the side wing 2 needs to be reversed, the driver 43 may be controlled to operate, and the second gear 42 is driven to rotate by the driver 43, thereby linking the first gear 41 to rotate, to drive the pivoting shaft 31 and the side wing 2 to synchronously pivot.
In this way, referring to
Referring to
A lift (L) is calculated by using the following formula:
For example, when an air density is approximately 1.225 kg/m3, a vehicle speed is approximately 19.03 m/s (68.5 km/hr), and a surface area of the side wing 2 is approximately 10 m*2 m, an angle of attack of the side wing 2 is assumed to be approximately 10 degrees, and it may be learned by table lookup that a corresponding lift coefficient is approximately 1.5. In this case, the lift (namely, the foregoing aerodynamic force F) generated by the side wing 2 on a single side=½ *1.225 kg/m3*(19.03 m/s)2*(10 m*2 m)*1.5≈6653 N≈6.65 kN, and the lift on both sides may reach 13.31 kN, to counteract 26.61% of a maximum lateral force 50 kN between a wheel and a track when the vehicle body 1 travels on the curve portion R1 with a radius of 287 m. The maximum lateral force is an actual measured value of Chengdu-Chongqing Line in China when negotiating the curve portion R1 with a radius of 287 m at a speed of 68.5 km/hr. It may be learned from this that the anti-overturning railcar according to the present invention can indeed effectively prevent the vehicle body 1 from overturning.
In conclusion, according to the method for preventing a railcar from overturning and the anti-overturning railcar for implementing the method, by arranging the side wing, when the railcar corners, the aerodynamic force generated by the side wing forms the centripetal force, to counteract a part of the centrifugal force by the centripetal force, thereby indeed assisting in guiding the railcar back to normal even if a vehicle speed fails to drop below a speed limit value, thereby avoiding occurrence of an overturning accident.
The foregoing disclosed embodiments merely exemplify the principles, features, and effects of the present invention, but are not intended to limit the implementation scope of the present invention. A person skilled in the art can modify or change the foregoing embodiments without departing from the spirit and scope of the present invention. Any equivalent change or modification made using the content disclosed by the present invention shall fall within the scope of the claims below.
| Number | Date | Country | Kind |
|---|---|---|---|
| 111150373 | Dec 2022 | TW | national |
