Pantograph for railway vehicle

Abstract

To provide a pantograph PG for a railway vehicle capable of keeping a collector shoe 1 in stable sliding contact with an overhead wire even when the vehicle speed of a railway vehicle is changed, without using a sensor.SOLUTION: In a pantograph for a railway vehicle which comprises: a collector shoe 1 that is brought into sliding contact with an overhead wire to collect current; a frame 2 that supports the collector shoe 1 in a vertically movable manner; and drive means 3 that increases or decreases an upward pressing force applied to the collector shoe 1 via the frame 2, the drive means 3 is controlled such that the upward pressing force applied to the collector shoe 1 is changed according to the vehicle speed of the railway vehicle on the basis of the lift variation characteristics of the collector shoe 1 when the vehicle speed of the railway vehicle is changed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventionally, 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 upward force acting on the current collector shoe via the frame (see, for example, Patent Document 1). With this type of pantograph, when a railroad vehicle is traveling, the current collector shoe, which is pushed up so as to be in sliding contact with the overhead wire, is subjected to airflow generated by the traveling vehicle. 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 upward force from the drive mechanism. In this case, if the negative lift force acts on the current collector shoe and weakens the contact force with the overhead wire, the current collector shoe will not be in stable sliding contact with the overhead wire, resulting in a decrease in 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, which may be damaged.

[0003] Therefore, in the above-mentioned conventional system, a sensor is provided on the current collector shoe to measure the contact force between the current collector shoe and the overhead wire, and the driving means is controlled to change the lifting force acting on the current collector shoe based on the measurement value measured by the sensor. In this system, the sensor is provided on the current collector shoe (i.e., the pantograph body), which is subject to high voltage, and devices such as a signal transmitter that converts the measurement value measured by the sensor 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 device fails, it becomes difficult to control the driving means, and there is a risk that the current collector shoe will not be able to slide stably against the overhead wire. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6420182 Summary of the Invention [Problem to be solved by the invention]

[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. [Means for solving the problem]

[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 obtained in advance 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. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic partial front view of the pantograph according to the embodiment of the present invention. [Figure 2] FIG. 3 is a schematic diagram showing an air circuit of a pantograph lifting device. [Figure 3]10 is a graph showing the change in lift force of a current collector when the vehicle speed of a railway vehicle is changed. DETAILED DESCRIPTION OF THE INVENTION

[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 wire 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, PG is a so-called single-arm pantograph. The pantograph PG includes a current collector shoe 1 having a slider 11 and a pantograph body 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 parts 41, 41 extending upward in the z-axis direction are provided at both ends of the underframe 4, on one side in the y-axis direction (the front side of the paper in FIG. 1) and the other side (the back side of the paper in FIG. 1), and a main shaft 42 extending in the y-axis direction is journaled by these main shaft support parts 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 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 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] Air spring 31 expands and contracts in the x-axis direction as compressed air is supplied and discharged, with the direction toward main shaft 42 (upper side in FIG. 1) being the x-axis plus (+) direction and the direction away from main shaft 42 (lower side in FIG. 1) being the x-axis minus (-) direction. Attached to the end of air spring 31 facing the x-axis minus (-) direction is mounting plate 31a, and multiple rods 31b are fixed to mounting plate 31a and extend in the x-axis plus direction. The ends of rods 31b facing the x-axis plus direction are connected to 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 translate in the negative x-axis direction as well. 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-down 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. As a result, the compressed air downstream of the electro-pneumatic regulator 53 (in other words, the compressed air supplied to the air springs 31) is adjusted to a predetermined pressure. Also, in this embodiment, a pressure sensor 54 is provided that measures 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, pushing 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 Fig. 3 as well, we will explain the control method of 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] Figure 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 Figure 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 Figures 3(a) and 3(b), the target characteristics indicated by the dashed dotted lines are the target values ​​of 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, within a range of the lifting force of the current shoe 1 that allows the current shoe 1 to stably contact the overhead line according to 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 represents 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 slide against 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. In addition, the dashed line shown in Figures 3(a) and 3(b) represents 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 (patterns shown in FIG. 3(a)) that results in insufficient lift force (pattern shown in FIG. 3(b)) based on the lift force change characteristics and a speed signal indicating the vehicle speed while the vehicle is running are input to the control board Cb, the control board Cb controls the opening of the electro-pneumatic regulator 53 based on the lift force change characteristics to increase the lift force acting on the current shoe 1 according to 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 according to the speed signal if the lift force acting on the current shoe 1 is excessive. The actuator 3 is controlled so that the lift force acting on the current shoe 1 is changed by adjusting the compressed air supplied to the air spring 31 to a predetermined pressure. Through this control, the contact force between the current shoe 1 and the overhead wire while the vehicle is running is corrected to the corrected characteristics shown by the solid lines 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 in a stable manner. 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 in a stable manner due to a failure of the 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 collecting 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 embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications are possible without departing from the spirit of the present invention. In the above embodiments, 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, but is not limited to this. The criterion for dividing the vehicle speed ranges is not limited to the vehicle speed (approximately 200 km / h) but may be any 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 embodiments, a single-arm pantograph PG is used as an example, but the present invention can also be applied to a double-arm pantograph. [Explanation of symbols]

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

Claims

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

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

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