Patent Description:
The present invention relates to a snow-accumulation-preventing and flow guide device for a bogie, and a rail vehicle, which belong to the technical field of rail vehicle manufacturing.

When an urban rail transit train runs in a heavy snow weather in alpine regions, accumulated snow on the road will be rolled up due to the effect of flow disturbance in the region of a bogie, and accumulated on the bogie. Under the action of heating elements on the bogie, such as a motor, a gearbox and a disc brake, the accumulated snow will be melt into water and then ice will be formed, and after a reciprocating action, relatively large ice blocks will be finally formed on the bogie. The ice blocks change the dynamic characteristics of the bogie, deteriorate the curve negotiating capability of the urban rail vehicle, reduce the working stability of a braking system of the urban rail vehicle, and seriously threaten the running stability, safety and comfort of the urban rail transit train.

In patent document <CIT>, a snow-accumulation-preventing device for a bogie region of a train is provided, the device including a first actuator and a second actuator which determine a motion sequence according to a running direction of the train; the first actuator and the second actuator are respectively mounted on a front end plate and a rear end plate of a train chassis, and a bogie is located between the first actuator and the second actuator; the first actuator includes an extendable-retractable first flow guide plate, the second actuator includes an extendable-retractable second flow guide plate, and the first flow guide plate and the second flow guide plate are both driven by cylinders to extend and open or retract and close. When the train is running, the first flow guide plate close to the advancing direction of the train is in an extended and open state, and the second flow guide plate away from the advancing direction of the train is in a retracted and closed state, such that the amount of accumulated snow entering the front end region is reduced as much as possible, and the tail end guides air to flow out as much as possible, so as to reduce the occurrence of snow accumulation.

In the solution, the first flow guide plate and the second flow guide plate are respectively mounted on the front end plate and the rear end plate of the bogie region, the two flow guide plates are respectively provided at the bottoms of the two end plates, i.e., the front end plate and the rear end plate, and are both of cavity-type structures made of rubber capsules; mounting frames at one side of each cavity-type structure are mounted, in a fitting manner, on each of the front end plate and the rear end plate structures at the bottom of the train, and an end face on the other side thereof is connected to the cylinders, and the mounting frames are connected to the end faces by means of wrinkled extending-retracting portions, so as to achieve extending and retracting of the flow guide plates.

In this solution, the flow guide plates have wrinkled structures as a whole, and thus even if in an extended state, the lower surface (namely, a surface through which an airflow passes) of each flow guide plate still has wrinkles, and thus the flow guide plate cannot be completely extended, affecting flowing of airflow to a certain degree, and increasing the driving resistance, and snow is easily accumulated at the wrinkles, not facilitating complete retracting and closing. In addition, the flow guide plate away from the driving direction of the train is in a fully retracted and closed state, and abuts against the end plate. At this time, the gaps between the bogie and the end plates are in a fully open state, and there is a possibility that accumulated snow enters the upper part of the bogie. In addition, for rail vehicles having no front and rear end plate structures, the flow guide plates cannot completely close the gaps between the flow guide plates and the bogie, and cannot serve to block accumulated snow from entering the bogie region.

Other devices for preventing snow accumulation are known from <CIT> and <CIT>.

The main technical problems to be solved in some embodiments of the present invention are to provide a snow-accumulation-preventing and flow guide device for a bogie which has better flow guide and snow accumulation preventing effects, and can ensure stable and reliable working, and to provide a bogie and a rail vehicle each of which is mounted with the snow-accumulation-preventing and flow guide device.

To achieve the described objects, the technical solution of some embodiments of the present invention is:
a snow-accumulation-preventing and flow guide device for a bogie, including a driving mechanism, and a first flow guide plate, a second flow guide plate and a third flow guide plate which are sequentially connected in a length direction of a vehicle body; two sides of the first flow guide plate, of the second flow guide plate and of the third flow guide plate are connected by means of extending-retracting portions, a top sealing plate is mounted on tops of the first flow guide plate and the third flow guide plate, the first flow guide plate, the second flow guide plate, the third flow guide plate, the extending-retracting portions at two sides and the top sealing plate together enclose a sealed cavity, top ends of the first flow guide plate and the third flow guide plate are configured to be rotatable around fixed points, the fixed points are provided on the top sealing plate or the vehicle body, a bottom end of the first flow guide plate is rotatably connected to the second flow guide plate, the second flow guide plate and the third flow guide plate can be connected to each other in a telescopic and slidable manner, and the driving mechanism drives the first flow guide plate and the second flow guide plate and a third flow guide plate to extend and open in a rail direction or retract and close in a direction of the vehicle body.

Further, the flow guide device is integrally mounted on a vehicle body chassis.

Further, a bottom end of the first flow guide plate is obliquely provided in a direction close to the bogie.

Further, in an extended and open state, an included angle α between the first flow guide plate and a horizontal plane ranges from <NUM>° to <NUM>°.

Further, in a retracted and closed state, an included angle β between the first flow guide plate and the horizontal plane is less than or equal to <NUM>°.

Further, the second flow guide plate and the third flow guide plate are two parallel flat plates, and the second flow guide plate and the third flow guide plate are connected by means of multiple sliding pairs.

Further, when the first flow guide plate is in the extended and open state, the height from the lowest point of the first flow guide plate to a rail surface is <NUM>/<NUM> to <NUM>/<NUM> of the height of wheels.

Further, the fixed point at the top end of the third flow guide plate is provided at a position close to the bogie.

Further, the driving mechanism is a cylinder-driving mechanism, a front end portion of the cylinder-driving mechanism is fixedly connected to the first flow guide plate, and the cylinder-driving mechanism drives the first flow guide plate to rotate upward or downward, so as to achieve extension and opening or retraction and closing; or the driving mechanism is an inflation mechanism, and the inflation mechanism inflates or deflates the cavity, so as to achieve extension and opening or retraction and closing.

Another technical solution of some embodiments of the present invention is:
a rail vehicle, mounted with a plurality of bogies; the flow guide devices as described above are mounted at a vehicle body chassis on a front end and a rear end of each bogie, two flow guide devices are mounted symmetrically relative to a central axis of the bogie, the two flow guide devices are configured such that when the flow guide device mounted at the front part in the running direction of the vehicle is in an extended and open state, the flow guide device away from the running direction of the vehicle is in a retracted and closed state.

In summary, compared with the prior art, the snow-accumulation-preventing and flow guide device for a bogie and the rail vehicle provided in some embodiments of the present invention have the following advantages:.

The described accompanying drawings include the following reference signs:
<NUM>. vehicle body chassis; <NUM>. flow guide device; <NUM>. bogie; <NUM>. wheel; <NUM>. first flow guide plate; <NUM>. second flow guide plate; <NUM>. third flow guide plate; <NUM>. extending-retracting portion; <NUM>. cavity; <NUM>. sliding groove; <NUM>. cylinder; <NUM>. air storage tank; <NUM>. solenoid valve; <NUM>. pin shaft; <NUM>. pin shaft; <NUM>. pin shaft; <NUM>. pin shaft; <NUM>: connecting base; <NUM>. mounting base; <NUM>. reinforcing rib frame; <NUM>. top sealing plate.

Hereinafter, some embodiments of the present invention are further described in detail with reference to the accompanying drawings and specific embodiments.

As shown in <FIG>, some embodiments of the present invention provide a snow-accumulation-preventing and flow guide device for a bogie, which is mounted in a region where a bogie <NUM> of a rail vehicle is located. In the present embodiment, the flow guide device is directly integrally mounted on a vehicle body chassis <NUM>. Two group of flow guide devices <NUM> are respectively mounted at a front end and a rear end of the bogie <NUM>. The front and rear two flow guide devices <NUM> have the same structure, and when being mounted, are symmetrically mounted relative to a central axis of the bogie <NUM>. The two flow guide devices <NUM> determine an action sequence according to a running direction of the vehicle, so as to achieve the effects of flow guide and snow accumulation preventing during bidirectional running of the rail vehicle. The cooperation relationship between the front and rear flow guide devices <NUM> is that when the vehicle moves forward, the flow guide device <NUM> located at the front end in the running direction extends toward the direction of a rail surface so as to be in an extended and open state, and at the same time, the flow guide device <NUM> away from the running direction of the vehicle gets close to the vehicle body chassis <NUM> so as to be in a retracted and closed state.

Each flow guide device <NUM> includes a first flow guide plate <NUM>, a second flow guide plate <NUM> and a third flow guide plate <NUM> which are sequentially connected in the length direction of the vehicle body. The first flow guide plate <NUM> is mounted on the side away from the bogie <NUM>, and the second flow guide plate <NUM> and the third flow guide plate <NUM> are mounted on the side facing the bogie <NUM>. In the flow guide device mounted at the front end in the running direction of the vehicle, the first flow guide plate <NUM> is located at one side of a windward surface (namely, a plane functioning to guide an airflow), and the second flow guide plate <NUM> and the third flow guide plate <NUM> are located at one side of a leeward surface. The whole length of the first flow guide plate <NUM>, of the second flow guide plate <NUM> and of the third flow guide plate <NUM> are all provided along the transverse width of the vehicle body. In order to achieve the optimal blocking effect, the lengths of the first flow guide plate <NUM>, the second flow guide plate <NUM> and the third flow guide plate <NUM> in the transverse direction of the vehicle body match the width of the bogie <NUM>, and the lengths of the flow guide plates are at least greater than or equal to the wheel distance between two wheels <NUM> on the bogie <NUM>, thereby ensuring to reduce the possibility of snow and sand entering the bogie <NUM> to the greatest extent.

In this embodiment, two sides of the first flow guide plate <NUM>, of the second flow guide plate <NUM>, and of the third flow guide plate <NUM> are respectively connected by means of extending-retracting portions <NUM>, and a top sealing plate <NUM> is further mounted on top ends of the first flow guide plate <NUM> and the third flow guide plate <NUM>. The first flow guide plate <NUM>, the second flow guide plate <NUM>, the third flow guide plate <NUM>, the extending-retracting portions <NUM> at two sides and the top sealing plate <NUM> together enclose a sealed cavity <NUM>, the cavity <NUM> is substantially in the shape of a triangular prism, thereby effectively preventing snowflakes from being suctioned into the interior of the cavity <NUM> when the vehicle moves, ensuring stable and reliable operation of the flow guide device. In order to further improve the sealing performance of the cavity <NUM>, sealed connection structures may be further mounted between the first flow guide plate <NUM>, the third flow guide plate <NUM>, the extending-retracting portions <NUM> at two sides and the top sealing plate <NUM>, so that the cavity forms a completely sealed structure.

In this embodiment, each of the extending-retracting portions <NUM> is of a wrinkled structure made of a soft material, so as to facilitate the extension and retraction of the three flow guide plates. Preferably, the extending-retracting portions <NUM> are composed of a rubber material or a fiber material which is high cold-resistant, impact-resistant, light-weight and highly elastic, which can ensure that the flow guide device reaches a predetermined angle when the extending-retracting portion is extended and that the flow guide device can be retracted to a predetermined position when the extending-retracting portion is retracted.

The flow guide device further includes a driving mechanism, and the driving mechanism drives the flow guide device to automatically extend and retract according to a change of the running direction of the vehicle, i.e. switching between two states of extending and opening or retracting and closing. The flow guide device being in an extended and opened state specifically means that the driving mechanism drives the flow guide device to rotate in the direction of the rail surface, so that the distance between the lowest point of the flow guide device and the rail surface is reduced; and the flow guide device being in a retracted and closed state specifically means that the driving mechanism drives the whole flow guide device to rotate and close upward, so that the whole flow guide device gets close to the vehicle body chassis <NUM> and closely abuts against the bottom of the vehicle body.

The first flow guide plate <NUM> and the third flow guide plate <NUM> are configured as structures capable of rotating around fixed points, the fixed points can be provided on the vehicle body chassis <NUM>, and can also be provided on the top sealing plate <NUM>, and then the top sealing plate <NUM> is fixed on the vehicle body chassis <NUM>. As shown in <FIG>, in this embodiment, the top end of the first flow guide plate <NUM> is rotatably connected to the vehicle body chassis <NUM> by a pin <NUM>, the top end of the third flow guide plate <NUM> is rotatably connected to the vehicle body chassis <NUM> by a pin <NUM>, and the top sealing plate <NUM> is fixedly connected to the fixed points on the vehicle body chassis <NUM>. The bottom end of the first flow guide plate <NUM> is rotatably connected to one end of the second flow guide plate <NUM> by a pin <NUM>, the second flow guide plate <NUM> and the third flow guide plate <NUM> are two parallel plates, and the second flow guide plate <NUM> and the third flow guide plate <NUM> can be unfolded or overlapped relative to each other, and the two are connected by means of a telescopic sliding mechanism. The top ends of the first flow guide plate <NUM> and the third flow guide plate <NUM> are mounted on corresponding crossbeams (not shown in the figures) of the vehicle body chassis.

The telescopic sliding mechanism includes multiple sliding pairs provided between the second flow guide plate <NUM> and the third flow guide plate <NUM>. As shown in <FIG>, a plurality of sliding grooves <NUM> are provided on the upper surface of the third flow guide plate <NUM>, the plurality of sliding grooves <NUM> are provided in parallel, and three sliding grooves <NUM> can be provided and are respectively provided at two sides and the middle of the third flow guide plate <NUM>, so as to ensure that the extension and retraction are stable and do not deflect. Corresponding to the three sliding grooves <NUM>, three sliding blocks (not shown in the figures) are provided on the lower surface of the second flow guide plate <NUM>, and the sliding blocks slide inside the sliding grooves. When the flow guide device needs to be extended and opened, the second flow guide plate <NUM> and the third flow guide plate <NUM> slide in a direction facing away from each other, and the second flow guide plate <NUM> and the third flow guide plate <NUM> are in a state of extending relative to each other as shown in <FIG>; and when the flow guide device needs to be retracted and closed, the second flow guide plate <NUM> and the third flow guide plate <NUM> slide in a direction facing each other, and the second flow guide plate <NUM> and the third flow guide plate <NUM> are in a mutually overlapping state as shown in <FIG>.

As shown in <FIG>, the driving mechanisms are cylinder-type driving mechanisms, and include cylinders <NUM>, an air storage tank <NUM> and solenoid valves <NUM>. In this embodiment, the cylinders <NUM> are double-acting cylinders, the air storage tank <NUM> is in communication with the cylinders <NUM>, and double-acting solenoid valves <NUM> are mounted on air paths between the cylinders <NUM> and the air storage tank <NUM>, so as to adapt to the movements of the vehicle in a forward direction and a backward direction. Driving mechanisms of two flow guide devices mounted on one bogie <NUM> share one air storage tank <NUM>.

The cylinders <NUM> are integrally mounted inside the cavity <NUM>, the tops of the cylinders <NUM> are mounted on the top sealing plate <NUM>, and the front end parts of cylinder rods are fixedly connected to the first flow guide plate <NUM>; or the cylinders <NUM> are mounted above the top sealing plate <NUM>, and the cylinder rods thereof pass through the top sealing plate <NUM> and are fixedly connected to the first flow guide plate <NUM>. The cylinders <NUM> are used to drive the first flow guide plate <NUM> to move, so as to extend and open or retract and close the flow guide device. In this embodiment, the first flow guide plate <NUM> is mounted with a reinforcing rib frame <NUM>. One end of each of the cylinders <NUM> is rotatably connected to the vehicle body chassis <NUM> by means of a mounting base <NUM> and a pin shaft <NUM>, the front end part of the cylinder rod of each cylinder <NUM> is fixedly connected to the reinforcing rib frame <NUM> by a connecting base <NUM>, and in this way it can be better ensured that an airflow guide surface of the first flow guide plate <NUM> is not deformed under the action of the driving mechanism, and the other surface can be deformed rapidly, so as to achieve extension and opening or retraction and closing. In order to ensure a smooth movement of the first flow guide plate <NUM> as a whole, at least three cylinders <NUM> are mounted on the first flow guide plate <NUM>. When the driving mechanism drives the first flow guide plate <NUM> to move in the direction of the rail surface, the extension and opening of the flow guide device is achieved; and when the driving mechanism drives the first flow guide plate <NUM> to move in the direction of the vehicle body, the retraction and closing of the flow guide device is achieved.

As shown in <FIG>, the top end of the first flow guide plate <NUM> is fixedly connected to the vehicle body chassis <NUM>, and the bottom end thereof is obliquely provided in a direction close to the bogie <NUM>. In an extended and open state of the first flow guide plate <NUM>, an included angle α between the outer surface of the first flow guide plate and a horizontal plane ranges from <NUM>° to <NUM>°, preferably <NUM>° to <NUM>°, and the optimum value is selected to be <NUM>°, and this inclined plane is used to guide air at the bottom of the vehicle body to deviate toward the rail surface. In a retracted and closed state of the first flow guide plate <NUM>, an included angle β between the first flow guide plate and the horizontal plane is less than or equal to <NUM>°, preferably less than or equal to <NUM>°, and the optimal value is selected to be <NUM>°, so that the flow guide device is as close as possible to the vehicle body chassis <NUM>, and the inclined plane formed by the first flow guide plate <NUM> in a retracted and closed state can guide air entering the rear region of the bogie <NUM> to flow out to the rear of the bogie <NUM>. According to a large number of experiments or simulation calculations, preferably, when the first flow guide plate <NUM> is in an extended and open state, the height from the lowest point of the first flow guide plate <NUM> to the rail surface is <NUM>/<NUM> to <NUM>/<NUM>, preferably <NUM>/<NUM> to <NUM>/<NUM> of the height of wheels. The snow-accumulation-preventing device of the present embodiment can guide air at the bottom of an urban rail train in a more targeted manner. On the one hand, in the front end region of the bogie, the amount of accumulated snow entering the region where the bogie <NUM> is located is reduced as much as possible; and on the other hand, at the tail end of the region where the bogie <NUM> is located, air is guided out as much as possible, so as to prevent airflow at the rear of the region where the bogie <NUM> is located from flowing back to the region where the bogie <NUM> is located, reducing the occurrence of snow accumulation. Furthermore, as the first flow guide plate <NUM>, the second flow guide plate <NUM> and the third flow guide plate <NUM> are all flat plate structures, when the vehicle runs, surfaces through which airflow flows are all smooth surfaces, so that the flow guide plates, while guiding airflow, also facilitate the airflow to flow more smoothly through the surfaces of the flow guide plates, thereby further reducing the running resistance, and also facilitating prevention of accumulation of ice and snow, and facilitating the falling off of ice and snow from the surfaces of the flow guide plates. In order to increase the structural strength and rigidity of the flow guide plates, a plurality of concave ribs (not shown in the figures) may also be provided on the flow guide plates, the concave ribs extend along the length direction of the vehicle body, and of course, structures such as reinforcing ribs may also be provided only on the inner surfaces of the flow guide plates.

In the present embodiment, a connection point between the top end of the third flow guide plate <NUM> and the vehicle body chassis <NUM> is close to the position of the bogie <NUM>, so that the upper region of the bogie <NUM> can be effectively blocked whether in an extended and open state or in a retracted and closed state, thereby preventing accumulated snow from entering the upper region of the bogie <NUM>.

As shown in <FIG>, when the vehicle is running to the left, high-pressure air in the air storage tank <NUM> flows through a <NUM>-position end of the double-acting solenoid valve <NUM> at the right side, and inflates <NUM>-position ends of double-acting cylinders <NUM> at the rear end (the right side) of the region where the bogie <NUM> is located, which drives the three double-acting cylinders <NUM> at the rear end to retract and to jointly push the first flow guide plate <NUM> to rotate in the direction of the vehicle body chassis <NUM>; and during the rotation, the second flow guide plate <NUM> and the third flow guide plate <NUM> overlap each other under the constraint of the telescopic sliding mechanism, and the flow guide device is retracted and closed and in a retracted and closed state, and is closely attached to the vehicle body chassis <NUM>. Meanwhile, the high-pressure air in the air storage tank <NUM> flows through a <NUM>-position end of the double-acting solenoid valve <NUM> at the left side, and inflates <NUM>-position ends of double-acting cylinders <NUM> at the front end (left side) of the region where the bogie <NUM> is located, and the three double-acting cylinders <NUM> at the front end of the region where the bogie <NUM> is located are extended, and jointly push the first flow guide plate <NUM> to rotate in the direction of the rail surface; and during the rotation, the second flow guide plate <NUM> and the third flow guide plate <NUM> extend from each other under the constraint of the telescopic sliding mechanism, reducing the distance between the first flow guide plate <NUM> and the front end of the rail surface, and thus the flow guide device is in an extended and open state, and the inclined plane formed by extending and opening of the first flow guide plate <NUM> in the flow guide device at the left side forces the airflow at the front bottom part to deviate toward the rail surface, preventing the airflow from entering the region where the bogie <NUM> is located. As the airflow entrains snowflakes, the amount of snow entering the region where the bogie <NUM> is located is also reduced. Then, the first flow guide plate <NUM> of the flow guide device at the right side is in a retracted and closed state, and the inclined plane formed thereby enables the airflow to still move rearward when the bottom airflow flushes the first flow guide plate <NUM> at the rear part, thereby preventing the airflow from flowing back to the region where the bogie <NUM> is located. As the airflow entrains snowflakes, the amount of snowflakes entering, from the rear part, the region where the bogie <NUM> is located is also reduced. By means of combined action of the first flow guide plates <NUM> at the a front end and a rear end of the bogie, snow accumulation in the region where the bogie <NUM> is located is greatly reduced, and the operation safety of the train can be ensured to the greatest extent without reducing the running speed.

When the train travels to the right, the double-acting solenoid valve <NUM> at the right side is switched to the <NUM>-position end, and the double-acting solenoid valve <NUM> at the left side is switched to the <NUM>-position end, so that the double-acting cylinders <NUM> on the two sides of the bogie <NUM> have opposite actions; however, the working principle is completely the same as that when the train travels to the left, so that the occurrence of snow accumulation can also be reduced. When the train enters a garage or stops for a long time, the first flow guide plates <NUM> on the sides of the bogie <NUM> are both retracted under the action of the respective double-acting cylinders <NUM>, so that the first flow guide plates can return to a non-operating state.

<FIG> and <FIG> show numerical simulation results of the flow guide devices.

A model is solved by using a computational fluid dynamics (CFD) method, and the following comparison result between an optimization model to which the flow guide devices are added and an original model without the flow guide devices is obtained:.

The accumulation amount of snow particles in the optimization solution is far less than the accumulation amount of snow particles in the original working condition, in which the accumulation amount of snow particles in a first bogie in the optimization solution only accounts for <NUM>% of that in the original working condition, the accumulation amount of snow particles in a second bogie only accounts for <NUM>% of that in the original working condition, and the number of accumulated particles in the optimization solution is <NUM>% of that in the original working condition. Therefore, the snow accumulation situation in the region where a bogie <NUM> of an urban rail train is located in the optimization solution is far better than that in the original working condition, and the optimization is effective.

Regardless of the accumulation amount in the first bogie, the accumulation amount in the second bogie or the total number, the optimization solution has great advantages over the original working condition. The amount of accumulation snow in the braking device of the first bogie is reduced by <NUM>%, and the amount of accumulation snow in the braking device of the second bogie is reduced by <NUM>%, and the total amount is reduced by <NUM>%.

It can be determined from the described simulation results that the mounting of the flow guide devices effectively improves the flow field characteristics of the region where the first bogie <NUM> located at the front end of the running direction of the train is located. Sufficiently guiding airflow downward makes a majority of high-velocity airflow entrained with snow particles flows out from the bottom of the first bogie <NUM>, particularly in positions of some key components such as a motor, a gearbox and a braking device, the reduction of accumulation snow is particularly obvious. The airflow continues to flow backwards, and is blocked by vehicle bottom apparatuses, etc., and then is located at a low position, and when the airflow comes to the front of the second bogie <NUM>, the speed is greatly reduced, so that the accumulation snow on the upper surface of the second bogie <NUM> is more completely reduced, and the amount of accumulation snow on the upper surface of the second bogie is substantially zero.

This embodiment differs from Embodiment I in that: in this embodiment, the driving mechanisms are inflation mechanisms, the cylinders <NUM> in Embodiment I are replaced with inflation/deflation dual-purposed air pumps, one end of each inflation/deflation dual-purposed air pump is in communication with the air storage tank <NUM>, or is directly connected to an air source on the vehicle, and the other end thereof is in communication with the cavity <NUM> in the flow guide device by an air pipe. The inflation/deflation dual-purposed air pumps are controlled by a controller, so as to achieve switching between an inflation operation and a deflation operation. In order to shorten the inflation and deflation time, a plurality of inflation/deflation dual-purposed air pumps can be mounted at the same time.

When the flow guide device needs to be extended and opened, the controller is used to control the inflation/deflation dual-purposed air pumps to start an inflation action, so as to inflate into the cavity <NUM> of the flow guide device; and along with the flowing of air, the first flow guide plate <NUM> can rotate downward around the fixed point at the top end, and at this time, the second flow guide plate <NUM> and the third flow guide plate <NUM> slide in a direction facing away from each other until extended, and the extending-retracting portions <NUM> are gradually extended, and by controlling the inflation time, the first flow guide plate <NUM> can be controlled to rotate to a preset angle.

When the flow guide device needs to be retracted and closed, the controller is used to control the inflation/deflation dual-purposed air pumps to start an air extraction operation, so as to extract air in the cavity <NUM> of the flow guide device; and along with the flowing out of air, the first flow guide plate <NUM> can rotate upward around the fixed point at the top end, and at this time, the second flow guide plate <NUM> and the third flow guide plate <NUM> slide in a direction facing each other until overlapped, and the extending-retracting portions <NUM> are gradually closed, and by controlling the extraction time, the first flow guide plate <NUM> can be controlled to rotate to a preset angle.

Claim 1:
A snow-accumulation-preventing and flow guide device for a bogie, comprising a driving mechanism, and a first flow guide plate (<NUM>), a second flow guide plate (<NUM>) and a third flow guide plate (<NUM>) which are sequentially connected in a length direction of a vehicle body; two sides of the first flow guide plate (<NUM>), of the second flow guide plate (<NUM>) and of the third flow guide plate (<NUM>) are connected by means of extending-retracting portions (<NUM>), a top sealing plate (<NUM>) is mounted on tops of the first flow guide plate (<NUM>) and the third flow guide plate (<NUM>), the first flow guide plate (<NUM>), the second flow guide plate (<NUM>), the third flow guide plate (<NUM>), the extending-retracting portions (<NUM>) at two sides and the top sealing plate (<NUM>) together enclose a sealed cavity, top ends of the first flow guide plate (<NUM>) and the third flow guide plate (<NUM>) are configured to be rotatable around fixed points, the fixed points are provided on the top sealing plate (<NUM>) or the vehicle body, a bottom end of the first flow guide plate (<NUM>) is rotatably connected to the second flow guide plate (<NUM>), the second flow guide plate (<NUM>) and the third flow guide plate (<NUM>) can be connected to each other in a telescopic and slidable manner, and the driving mechanism drives the first flow guide plate (<NUM>) and the second flow guide plate (<NUM>) and a third flow guide plate (<NUM>) to extend and open in a rail direction or retract and close in a direction of the vehicle body.