Pantograph for railway vehicle

Abstract

Provided is a pantograph PG for a railway vehicle capable of stably bringing a collector shoe 1 into sliding contact with an overhead wire without using a sensor even when the speed of the railway vehicle changes.　This pantograph for a railway vehicle comprises: a collector shoe 1 that slidingly contacts an overhead wire and collects electricity; a framework 2 that supports the collector shoe 1 so as to be able to move up and down; and a drive means 3 that increases or decreases an upward force acting on the collector shoe 1 via the framework 2. On the basis of the lift change characteristic of the collector shoe 1 when the speed of the railway vehicle is changed, the drive means 3 is controlled so as to change, in accordance with the speed of the railway vehicle, the upward force acting on the collector shoe 1.

Description

Pantograph for railway vehicles

[0001] The present invention relates to a pantograph for a railway vehicle.

[0002] A known pantograph of this type includes a current collector shoe that collects current by sliding against the overhead wire, a frame that supports the current collector shoe so that it can be raised and lowered, and a drive mechanism that increases or decreases the lift force acting on the current collector shoe via the frame (see, for example, Patent Document 1). In this type of pantograph, when a railroad vehicle is traveling, the current collector shoe, which is pushed up into sliding contact with the overhead wire, is subjected to airflow generated by the vehicle's movement. As a result, a lift force or a negative lift force (downforce) acts on the current collector shoe depending on the speed of the railroad vehicle, in addition to the lift force from the drive mechanism. In this case, if the negative lift force acts on the current collector shoe and weakens its contact force with the overhead wire, the current collector shoe will not slide against the overhead wire stably, resulting in poor current collection efficiency. On the other hand, if the lift force acts on the current collector shoe and the contact force with the overhead wire becomes too strong, excessive force will be applied to the overhead wire, potentially damaging it.

[0003] In the conventional system described above, a sensor is provided on the collector shoe to measure the contact force between the collector shoe and the overhead wire, and the driving means is controlled to change the lifting force acting on the collector shoe based on the measurement value measured by the sensor. In this system, the sensor is provided on the collector shoe (i.e., the pantograph body), which is subject to high voltage. Therefore, devices such as a signal transmitter that converts the sensor measurement into a signal and transmits it, as well as communication wiring, must be installed insulated from the pantograph body. This complicates the pantograph installation process, and the use of a sensor increases the number of parts, resulting in increased costs. Furthermore, if the sensor or other components fail, it becomes difficult to control the driving means, potentially preventing the collector shoe from sliding stably against the overhead wire.

[0004] Japanese Patent No. 6420182

[0005] In view of the above, an object of the present invention is to provide a pantograph for a railway vehicle that can keep the current collector shoe in stable sliding contact with the overhead wire even when the speed of the railway vehicle changes, without using a sensor.

[0006] In order to solve the above problems, the present invention provides a pantograph for a railway vehicle, comprising a current collecting shoe that collects current by sliding contact with an overhead wire, a frame that supports the current collecting shoe so that it can be raised and lowered freely, and a drive means that increases or decreases the lift force acting on the current collecting shoe via the frame, characterized in that the drive means is controlled to change the lift force acting on the current collecting shoe in accordance with the speed of the railway vehicle, based on the lift change characteristics of the current collecting shoe when the speed of the railway vehicle is changed.

[0007] In the present invention, the lift change characteristic of the current shoe when the train speed of the railway vehicle is changed is calculated based on the lift change characteristic of the current shoe previously obtained through trial tests such as wind tunnel tests and on-board tests. Then, based on the lift change characteristic of the current shoe, when a negative lift force acts on the current shoe and the contact force with the overhead wire is weakened (in other words, the uplift force acting on the current shoe is insufficient), the drive unit is controlled to increase the uplift force acting on the current shoe. On the other hand, based on the lift change characteristic of the current shoe, when a lift force acts on the current shoe and the contact force with the overhead wire is strengthened (in other words, the uplift force acting on the current shoe is excessive), the drive unit is controlled to decrease the uplift force acting on the current shoe. This maintains a constant uplift force acting on the current shoe even when the train speed of the railway vehicle changes, allowing the current shoe to stably slide into contact with the overhead wire. Furthermore, in the present invention, the drive unit can be controlled without using a sensor to measure the contact force with the overhead wire. This eliminates the need for a sensor to measure the contact force with the overhead wire, which does not complicate the pantograph installation process and avoids cost increases due to an increase in the number of parts.It also avoids the risk of sensors or other components failing to ensure stable sliding contact between the current collector and the overhead wire.

[0008] In the present invention, the lift change characteristic of the current collecting shoe is preferably expressed by a broken line function divided into a plurality of vehicle speed ranges. This allows the relationship between the vehicle speed of the railway vehicle and the lift force acting on the current collecting shoe to be expressed by a superposition of linear characteristics. As a result, quadratic calculations or programming for controlling the drive means are not required, which is advantageous in that control of the drive means can be simplified compared to the above-mentioned conventional example in which the drive means is controlled based on measurements taken by a sensor.

[0009] The present invention relates to a pantograph, a pantograph lifting device, and a power train.

[0010] Hereinafter, an embodiment of a pantograph of the present invention that is mounted on the roof of a railway vehicle and collects power from an overhead line will be described with reference to the drawings. In the following, the vehicle length direction is the x-axis direction, the vehicle width direction is the y-axis direction, and the vehicle height direction is the z-axis direction, and terms indicating directions such as "up" and "down" are based on Figure 2, which shows the mounting position of the pantograph on the vehicle roof.

[0011] 1 and 2, the pantograph PG is a so-called single-arm type pantograph. The pantograph PG includes a current collector shoe 1 having a slider 11 and a collector head 12, with the upper surface of the slider 11 in sliding contact with the overhead wire to collect current, a frame 2 supporting the current collector shoe 1 so that it can move up and down and having an upper frame 21 and a lower frame 22 connected to each other so that they can bend and stretch in the z-axis direction, and an actuator 3 as a driving means for increasing or decreasing the upward force acting on the current collector shoe 1 via the frame 2.

[0012] An underframe 4 is installed on the roof of the vehicle. Main shaft support portions 41, 41 extending upward in the z-axis direction are provided at both ends of the underframe 4, on one side (the front side of the paper in FIG. 1 ) and the other side (the rear side of the paper in FIG. 1 ) in the y-axis direction, and a main shaft 42 extending in the y-axis direction is journaled by these main shaft support portions 41, 41.

[0013] The current collecting shoe 1 is supported on the upper end of the upper frame 21 via a shoe support 13. The lower end of the upper frame 21 and the upper end of the lower frame 22 are connected to each other so as to be flexible and stretchable by a hinge having a shaft 24. The lower end of the lower frame 22 is pivotally attached to the underframe 4 by a main shaft 42, and the upper frame 21 swings in conjunction with the swing of the lower frame 22 accompanying the rotation of the main shaft 42. Note that known components of the pantograph PG, such as the current collecting shoe 1 and the frame 2, can be used, and therefore further detailed description thereof will be omitted.

[0014] The underframe 4 is also provided with an air spring 31 serving as the actuator 3 that receives compressed air from a compressed air flow path 51 (described later) to generate a driving force in the x-axis direction, a chain 32 that transmits the biasing force of the air spring 31, which is the driving force of the actuator 3, in the x-axis direction, and a cam 33 that is connected to the main shaft 42 and the chain 32 and converts the biasing force transmitted from the chain 32 into torque that rotates the main shaft 42.

[0015] The air spring 31 expands and contracts in the x-axis direction as compressed air is supplied and discharged, with the direction toward the main shaft 42 (upper side in FIG. 1) being the x-axis positive (+) direction and the direction away from the main shaft 42 (lower side in FIG. 1) being the x-axis negative (-) direction. A mounting plate 31a is attached to the end of the air spring 31 facing the x-axis negative direction, and multiple rods 31b are fixed to this mounting plate 31a and extend in the x-axis positive direction. The ends of the rods 31b facing the x-axis positive direction are connected to the chain 32 via arms 31c.

[0016] In this embodiment, when compressed air is supplied to the air spring 31 from the compressed air flow path 51, the air spring 31 expands in the negative x-axis direction, and the rod 31b and arm 31c translate in the negative x-axis direction, causing the chain 32 to also translate in the negative x-axis direction. This translational movement of the chain 32 is converted via the cam 33 into torque that rotates the main shaft 42. As the main shaft 42 rotates clockwise, the lower frame 22 also swings clockwise, and in conjunction with this swing, the upper frame 21 swings counterclockwise. As a result, the upward force acting on the current shoe 1 via the framework 2 increases, and the current shoe 1 is lifted. Meanwhile, when the compressed air filled in the air spring 31 is released, the air spring 31 contracts, causing the upper frame 21 to swing clockwise due to the weight of the current shoe 1, causing the main shaft 42 to rotate counterclockwise, and causing the lower frame 22 to swing counterclockwise. As a result, the upward force acting on the current collector shoe 1 through the framework 2 is reduced and the pantograph PG is folded.

[0017] One end (downstream side) of a compressed air flow path 51 that supplies compressed air to the air spring 31 is connected to the air spring 31 via a porcelain tube In installed on the roof of the vehicle, and the other end (upstream side) of the compressed air flow path 51 is connected to a compressor Cm that serves as a compressed air supply source installed inside the vehicle. Also, a solenoid valve 52 that starts and stops the supply of compressed air to the air spring 31 is provided on the upstream side of the compressed air flow path 51. In this embodiment, when a pantograph lift-lowering signal is input to a control board Cb installed inside the vehicle, the solenoid valve 52 opens in response to the signal, and compressed air is supplied to the air spring 31 via the compressed air flow path 51.

[0018] An electro-pneumatic regulator 53 is provided downstream of the solenoid valve 52. In this embodiment, the control board Cb controls the opening degree of the electro-pneumatic regulator 53 in accordance with input signals (a control pattern selection signal and a vehicle speed signal, which will be described later) input to the control board Cb. This allows the compressed air downstream of the electro-pneumatic regulator 53 (in other words, the compressed air supplied to the air springs 31) to be adjusted to a predetermined pressure. In this embodiment, a pressure sensor 54 is provided to measure the pressure of the compressed air downstream of the electro-pneumatic regulator 53, and the measured value of the pressure of the compressed air downstream of the electro-pneumatic regulator 53 measured by the pressure sensor 54 is sent to the control board Cb. Note that, although this embodiment will be described taking an example in which the pressure sensor 54 is provided, the pressure sensor 54 may be omitted.

[0019] When a pantograph lift signal is input to the control board Cb, the solenoid valve 52 opens and compressed air is supplied to the air spring 31, which pushes up the current collector shoe 1 so that it comes into sliding contact with the overhead wire via the frame 2. At this time, the pressure of the compressed air supplied to the air spring 31 through the compressed air flow path 51 is maintained at a predetermined constant pressure by the electro-pneumatic regulator 53.

[0020] When a railway vehicle is traveling, the current collector shoe 1 is pushed up so as to come into sliding contact with the overhead wire, and in addition to the upward force from the actuator 3, a lift force or a negative lift force acts on the current collector shoe 1 depending on the vehicle speed of the railway vehicle, so the contact force with the overhead wire changes. Below, with reference to Figure 3 as well, we will explain the control method for the pantograph PG of this embodiment, which controls the amount of contact between the current collector shoe 1 and the overhead wire (in other words, the upward force of the current collector shoe 1) depending on the vehicle speed of the railway vehicle.

[0021] 3(a) shows a control method for the pantograph PG when a negative lift acts on the current shoe 1, weakening its contact force with the overhead line (i.e., when the lifting force of the current shoe 1 is insufficient), and FIG. 3(b) shows a control method for the pantograph PG when a lift acts on the current shoe 1, strengthening its contact force with the overhead line (i.e., when the lifting force of the current shoe 1 is excessive). In FIGS. 3(a) and 3(b), the target characteristics indicated by the dashed dotted lines are target values ​​for the contact force with the overhead line (the lifting force of the current shoe 1) relative to the train speed of the railway vehicle. These target characteristics are set arbitrarily based on the running conditions of the railway vehicle, etc., within a range of the lifting force of the current shoe 1 that allows the current shoe 1 to stably contact the overhead line in accordance with the train speed while the train is running, without applying excessive contact force to the overhead line. In addition, in Figures 3(a) and 3(b), the pre-correction characteristic indicated by the two-dot chain line shows the contact force of the current shoe 1 with the overhead wire when the train speed of the railway vehicle is changed while the current shoe 1 is pushed up so as to make sliding contact with the overhead wire. This pre-correction characteristic is determined by the shape of the current shoe 1, etc., and is obtained in advance through trial tests such as wind tunnel tests and on-board tests. Furthermore, the dashed lines shown in Figures 3(a) and 3(b) show the lift change characteristic of the current shoe 1 when the train speed of the railway vehicle is changed. This lift change characteristic can be calculated based on the difference between the target characteristic and the pre-correction characteristic. In this embodiment, the lift change characteristic is expressed by a broken line function divided into two train speed ranges based on a train speed of approximately 200 km / h. The lift change characteristic is stored in the control board Cb.

[0022] When a control pattern selection signal for selecting one of the control patterns resulting in an insufficient lift force (pattern shown in FIG. 3( a)) or an excessive lift force (pattern shown in FIG. 3( b)) based on the above-mentioned lift force change characteristic and a speed signal indicating the vehicle speed while the vehicle is traveling are input to the control board Cb, the control board Cb controls the opening of the electro-pneumatic regulator 53 based on the above-mentioned lift force change characteristic so as to increase the lift force acting on the current shoe 1 in accordance with the speed signal if the lift force acting on the current shoe 1 is insufficient, or to decrease the lift force acting on the current shoe 1 in accordance with the speed signal if the lift force acting on the current shoe 1 is excessive. The actuator 3 is controlled so that the compressed air supplied to the air spring 31 is adjusted to a predetermined pressure, thereby changing the lift force acting on the current shoe 1. Through this control, the contact force between the current shoe 1 and the overhead wire while the vehicle is traveling is corrected to the corrected characteristic shown by the solid line in FIGS. 3( a) and 3(b).

[0023] According to the above embodiment, even if the speed of the railway vehicle changes, the upward force acting on the current collecting shoe 1 is maintained constant, allowing the current collecting shoe 1 to slidably contact the overhead wire stably. Furthermore, since a sensor for measuring the contact force with the overhead wire is not required, the installation process of the pantograph PG is not complicated and costs due to an increase in the number of parts can be avoided. Furthermore, the risk that the current collecting shoe 1 cannot slidably contact the overhead wire stably due to a failure of a sensor or the like can be avoided.

[0024] In the above embodiment, the lift force change characteristics are expressed by a broken line function divided into two sections of vehicle speed range, and the relationship between the vehicle speed of the railway vehicle and the lift force acting on the current collector shoe 1 can be expressed by a superposition of linear characteristics. This eliminates the need for quadratic calculations or programming to control the actuator 3, and simplifies the control of the control board Cb.

[0025] Although the present invention has been described above with reference to an embodiment, it is not limited to the above embodiment, and various modifications are possible without departing from the spirit and scope of the present invention. In the above embodiment, the lift force change characteristic is expressed by a broken line function divided into two vehicle speed ranges based on a vehicle speed of approximately 200 km / h. However, this is not limiting. The vehicle speed ranges may be divided not only by the vehicle speed (approximately 200 km / h) but also by any other vehicle speed. Furthermore, the lift force change characteristic may be a broken line function divided into, for example, three or more vehicle speed ranges. Furthermore, the lift force change characteristic is not limited to a broken line function but may be, for example, a quadratic curve. Furthermore, in the above embodiment, a single-arm pantograph PG is used as an example. However, the present invention can also be applied to a double-arm pantograph.

[0026] PG...pantograph, 1...collector shoe, 2...frame, 3...actuator (driving means).

Claims

1. A pantograph for a railway vehicle comprising a current collecting shoe that collects current by sliding against an overhead wire, a framework that supports the current collecting shoe so that it can be raised and lowered freely, and a drive means that increases or decreases the lifting force acting on the current collecting shoe via the framework, wherein the drive means is controlled to change the lifting force acting on the current collecting shoe in accordance with the speed of the railway vehicle, based on the lift change characteristics of the current collecting shoe when the speed of the railway vehicle is changed.

2. A pantograph for a railway vehicle according to claim 1, wherein the lift change characteristics of said current collector are expressed by a broken line function divided into a plurality of vehicle speed ranges.

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