Brake control device for railway vehicles, brake control method for railway vehicles, and brake control program for railway vehicles

Abstract

This invention provides a technology that can reduce the impact of fluid leakage, even if fluid leakage occurs in the flow path leading to the brake cylinder in a railway vehicle brake. [Solution] The brake control device for railway vehicles comprises a brake control valve 14 controlled in response to a brake command, a flow sensor 80 provided in the flow path between the brake control valve 14 and a brake cylinder that operates in response to fluid pressure, an isolation valve 30 provided in the flow path between the brake control valve 14 and the brake cylinder, a determination unit 62 that determines fluid leakage based on the output value of the flow sensor 80, and an isolation control unit 64 that, when fluid leakage is determined, uses the isolation valve 30 to isolate and control the downstream side of the flow path from the upstream side of the isolation valve 30.

Description

Technical Field

[0001] The present invention relates to a brake control device for railway vehicles, a brake control method for railway vehicles, and a brake control program for railway vehicles.

Background Art

[0002] Patent Document 1 describes that in a pipe for supplying compressed air supplied from a tank to a brake device of a railway vehicle, the flow rate is adjusted using a plurality of regulating valves. In such a pipe, air leakage may occur. When air leakage occurs in the pipe, the flow of air is suppressed by an orifice provided in the pipe. Also, the flow path is isolated by manual cock operation or the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, even when the flow of air is suppressed by an orifice as in the prior art, it is inevitable that the pressure of the compressed air supplied to the brake cylinder decreases due to air leakage.

[0005] In view of the above problems, an object of the present invention is to provide a technology capable of reducing the influence of fluid leakage even when fluid leakage occurs in a flow path leading to a brake cylinder in a brake for railway vehicles.

Means for Solving the Problems

[0006] To solve the above problems, a brake control device for a railway vehicle according to one aspect of the present invention comprises: a brake control valve controlled in response to a brake command; a flow sensor provided in a flow path between the brake control valve and a brake cylinder that operates in response to fluid pressure; an isolation valve provided in the flow path between the brake control valve and the brake cylinder; a determination unit that determines fluid leakage based on the output value of the flow sensor; and, when fluid leakage is determined, an isolation control unit that uses the isolation valve to isolate and control the downstream side of the flow path from the upstream side of the isolation valve.

[0007] A brake control method for a railway vehicle according to one aspect of the present invention includes the steps of: determining fluid leakage based on the output value of a flow sensor provided in a flow path between a brake control valve controlled in response to a brake command and a brake cylinder that operates in response to fluid pressure; and, once fluid leakage is determined, isolating the downstream side of the flow path from the upstream side of the isolation valve using an isolation valve provided in the flow path between the brake control valve and the brake cylinder.

[0008] A brake control program for a railway vehicle according to one aspect of the present invention is a program that causes a computer to perform the following steps: determine fluid leakage based on the output value of a flow sensor provided in a flow path between a brake control valve controlled in response to a brake command and a brake cylinder that operates in response to fluid pressure; and, if fluid leakage is determined, isolate and control the downstream side of the flow path from the upstream side of the isolation valve using an isolation valve provided in the flow path between the brake control valve and the brake cylinder.

[0009] Furthermore, any combination of the above, or any substitution of the components or expressions of the present invention between methods, apparatus, programs, temporary or non-temporary storage media recording programs, systems, etc., are also valid embodiments of the present invention. [Effects of the Invention]

[0010] According to the present invention, even if fluid leakage occurs in the flow path leading to the brake cylinder in a railway vehicle brake, a technology is provided that can reduce the impact of fluid leakage. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic side view showing a railway vehicle to which a railway brake control device according to the first embodiment is applied. [Figure 2] Figure 1 is a block diagram showing the configuration of the brake control device. [Figure 3] This is a block diagram showing an example of a configuration related to the flow path of a railway vehicle. [Figure 4] This is a block diagram showing another example of a configuration related to the flow path of a railway vehicle. [Figure 5] This is a schematic diagram illustrating an example of the peripheral configuration of a sliding control valve. [Figure 6] This is a schematic diagram illustrating an example of the peripheral configuration of a sliding control valve. [Figure 7] This is a schematic diagram illustrating an example of the peripheral configuration of a sliding control valve. [Figure 8] This is a pneumatic circuit diagram schematically showing an example of an isolation valve. [Figure 9] This is a pneumatic circuit diagram schematically showing an example of an isolation valve. [Figure 10] This is a pneumatic circuit diagram schematically showing another example of an isolation valve. [Figure 11] This is a pneumatic circuit diagram schematically showing another example of an isolation valve. [Figure 12] This diagram schematically shows an example of the time change in brake pressure when a brake command is received. [Figure 13] This flowchart shows an example of isolation control using a brake control device. [Figure 14] This is a schematic side view showing a railway vehicle to which a railway brake control device according to the second embodiment is applied. [Figure 15] Figure 14 is a block diagram showing the configuration of the brake control device. [Figure 16]It is a block diagram showing an example of a configuration related to the flow path of a railway vehicle. [Embodiments for Carrying Out the Invention]

[0012] Among the embodiments disclosed in this specification, those composed of a plurality of objects may integrate the plurality of objects, and conversely, those composed of one object can be divided into a plurality of objects. Whether integrated or not, it only needs to be configured so that the object of the invention can be achieved.

[0013] Among the embodiments disclosed in this specification, those in which a plurality of functions are provided dispersedly may provide some or all of the plurality of functions in an aggregated manner, and conversely, those in which a plurality of functions are provided in an aggregated manner can be provided such that some or all of the plurality of functions are dispersed. Whether the functions are aggregated or dispersed, it only needs to be configured so that the object of the invention can be achieved.

[0014] Also, for separate constituent elements having something in common, distinguish them by attaching "first", "second", etc. at the beginning of the name, and omit them when collectively referring to them. Also, terms including ordinals such as first and second are used to describe various constituent elements, but this term is only used for the purpose of distinguishing one constituent element from other constituent elements, and the constituent elements are not limited by this term.

[0015] Hereinafter, the present invention will be described based on preferred embodiments with reference to the respective drawings. In the embodiments and modification examples, the same or equivalent constituent elements and members are denoted by the same reference numerals, and repeated explanations are omitted as appropriate. Also, the dimensions of the members in each drawing are shown enlarged or reduced as appropriate for easy understanding. Also, a part of the members that are not important for explaining the embodiments in each drawing is omitted from the display.

[0016] [First Embodiment] The first embodiment will now be described with reference to the drawings. Figure 1 is a schematic side view of a railway vehicle 1 to which the railway brake control device (hereinafter referred to as "brake control device 50") according to the first embodiment is applied. First, an overview of the railway vehicle 1 will be described.

[0017] Each functional block shown in Figure 1 and other figures can be implemented in hardware terms using electronic elements, electronic circuits, and mechanical parts such as the CPU and memory of a computer, and in software terms using computer programs, etc. However, here we depict functional blocks that are realized through the coordination of these elements. Therefore, it will be understood by those skilled in the art that these functional blocks can be realized in various ways through combinations of hardware and software.

[0018] As shown in Figure 1, the railway vehicle 1 comprises a driver's cab 2, a first bogie 4, a second bogie 6, a braking mechanism 16, a compressed air supply source 8, and a brake control device 50. The driver's cab 2 is located at the front of the vehicle in the direction of travel. The first bogie 4 is located towards the front of the lower part of the vehicle. The second bogie 6 is located towards the rear of the lower part of the vehicle. The braking mechanism 16 is provided on both the first bogie 4 and the second bogie 6.

[0019] The brake control device 50 includes a control unit 52, a brake pressure adjustment mechanism 54 that adjusts the pressure of compressed air supplied to the brake mechanism 16 (hereinafter referred to as "brake pressure"), a flow sensor 80, and an isolation valve 30.

[0020] The compressed air supply source 8 is a tank that supplies compressed air, and the pressure inside the tank is maintained within a predetermined range by an air pump. The compressed air supply source 8 is connected to one end of the flow path 20 (see Figure 3) and functions as a supply source that supplies compressed air to the flow path 20. The compressed air supply source 8 is an example of a fluid supply source, and the pressurized fluid supplied by the fluid supply source may be a gas such as air, nitrogen, or an inert gas, or a liquid such as water or oil. In the following explanation, compressed air will be used as the pressurized fluid.

[0021] The first bogie 4 and the second bogie 6 each have two axles 10 spaced apart in the longitudinal direction. Wheels 12 are attached to both ends of the axles 10. The brake mechanism 16 operates in accordance with the brake pressure. The brake mechanism 16 has a friction material 16s that generates braking force on the wheels 12 and a brake cylinder 16t that drives the friction material 16s.

[0022] The friction material 16s is, for example, a brake pad. The brake cylinder 16t is connected to the other end of the flow path 20 (see Figure 3), that is, the end opposite to the end of the flow path 20 to which the compressed air supply source 8 is connected. Compressed air with brake pressure is supplied through the flow path 20, causing the brake cylinder pressure to rise and the brake cylinder 16t to operate. When the brake cylinder 16t operates, the friction material 16s is pressed against the tread surface of the wheel 12, generating a braking force on the wheel 12.

[0023] The details of the railway vehicle 1 will be described with reference to Figures 2 and 3. Figure 2 is a block diagram showing the configuration of the brake control device 50. As shown in Figure 2, the control unit 52 includes a receiving unit 56, a brake control unit 58, a sliding control unit 60, a determination unit 62, and an isolation control unit 64. The brake pressure adjustment mechanism 54 includes a brake control valve 14 and a sliding control valve 18.

[0024] Figure 3 is a block diagram showing an example of the configuration related to the flow path 20 of the railway vehicle 1. The flow path 20 is a supply path for supplying compressed air, partitioned by piping, etc. As described above, a compressed air supply source 8 is connected to one end of the flow path 20, and a brake cylinder 16t is connected to the other end. Hereinafter, in the flow path 20, the side to which the compressed air supply source 8 is connected will be referred to as the upstream side, and the side to which the brake cylinder 16t is connected will be referred to as the downstream side.

[0025] The brake control valve 14 is a valve mechanism located in the flow path 20 between the compressed air supply source 8 and the brake cylinder 16t, and adjusts the amount of compressed air supplied to the brake cylinder 16t. The brake control valve 14 is controlled in response to a brake command from the driver's cab 2. The brake control valve 14 may be a control valve for the service brake or a control valve for the emergency brake.

[0026] The flow path 20 branches into two first branch flow paths 22a and 22b downstream of the brake control valve 14. Downstream of one of the first branch flow paths 22a, the flow path 20 further branches into two second branch flow paths 24a and 24b, and downstream of the other first branch flow path 22b, it further branches into two second branch flow paths 24c and 24d. The four second branch flow paths 24a to 24d correspond to the first to fourth axles, respectively. Downstream of each of the four second branch flow paths 24a to 24d, the flow path 20 branches further, with each branch connected to one brake cylinder 16t. The flow path 20 is partitioned, for example, by piping made of metal or the like that partitions most of the flow path 20, and by an air hose made of flexible resin or the like that that connects the piping to the brake cylinder 16t. Of these, damage to the air hose in particular may cause air leakage from the flow path 20.

[0027] The slip control valve 18 is installed in the flow path 20 between the brake control valve 14 and the brake cylinder 16t. The slip control valve 18 is a valve mechanism that eliminates slippage by reducing the brake pressure when the wheels 12 slip while the railway vehicle 1 is being braked by the brake mechanism 16, by discharging air to the outside of the flow path 20. Multiple slip control valves 18 are provided, corresponding to each of the multiple axles 10 of the railway vehicle 1. Specifically, a total of four slip control valves 18 are provided, one for each of the four axles 10 of the railway vehicle 1. In other words, one slip control valve 18 is provided in each of the four second branch flow paths 24a to 24d. Details of the operation of the slip control valve 18 will be described later.

[0028] The isolation valve 30 is installed in the flow path 20 between the brake control valve 14 and the brake cylinder 16t. The isolation valve 30 is composed of a solenoid valve. When no power is supplied and the system is not energized, the isolation valve 30 connects the upstream and downstream sides of the location where the isolation valve 30 is installed in the flow path 20. When power is supplied and the system is energized, the isolation valve 30 isolates the downstream side of the location where the isolation valve 30 is installed in the flow path 20 from the upstream side. In the example shown in Figure 3, one isolation valve 30 is installed in each of the second branch flow paths 24a to 24d. Details of the operation of the isolation valve 30 will be described later.

[0029] The flow sensor 80 is installed in the flow path 20 between the brake control valve 14 and the brake cylinder 16t. Specifically, the flow sensor 80 is installed between the isolation valve 30 and the brake cylinder 16t. The flow sensor 80 detects the flow rate of compressed air flowing through the flow path 20 and outputs it to the receiving unit 56 of the control unit 52. In the example shown in Figure 3, one flow sensor 80 is installed in each of the second branch flow paths 24a to 24d.

[0030] As described above, with the configuration shown in Figure 3, compressed air supplied from the compressed air supply source 8 is supplied to the brake control valve 14 through the flow path 20. The amount of compressed air supplied to the brake control valve 14 is adjusted by the brake control valve 14 and supplied to each of the four sliding control valves 18. The amount of compressed air supplied to each of the four sliding control valves 18 is adjusted by each of the four sliding control valves 18 and supplied to the brake cylinder 16t. However, compressed air is supplied to the brake cylinder 16t only when there is no air leakage from the flow path 20 and the isolation valve 30 is not energized.

[0031] As shown in Figure 2, the receiving unit 56 receives brake commands from the driver's cab 2 and input signals from other devices. The brake command includes a brake command that commands the braking state of the brake mechanism 16 and a release command that commands the release state of the brake mechanism 16. The brake command is a command to operate the brake mechanism 16 to generate a specified target braking force in response to the brake operation.

[0032] The receiving unit 56 further receives the value of the flow rate in the flow path 20, which is the output value of the flow sensor 80.

[0033] The brake control unit 58 controls the brake control valve 14 based on the brake command. The brake control unit 58 starts or increases the supply of compressed air from the brake control valve 14 in response to the braking command. The brake control unit 58 stops or decreases the supply of compressed air from the brake control valve 14 in response to the release command.

[0034] The slip control unit 60 determines whether or not slippage is occurring in the wheel 12 while controlling the brake mechanism 16. The slip control unit 60 may detect wheel slippage using various known methods. For example, the slip control unit 60 can determine whether or not slippage is occurring based on a comparison of the rotational speed of the axle 10 and the translational speed of the railway vehicle 1. If the slip control unit 60 determines that slippage is occurring in the wheel 12, it controls the slip control valve 18 to reduce the brake pressure and eliminate the slippage.

[0035] The determination unit 62 determines air leakage based on the output value of the flow sensor 80 received by the receiving unit 56. The determination unit 62 individually determines air leakage at the location of each flow sensor 80 based on the output values ​​of the multiple flow sensors 80. Details of the determination by the determination unit 62 will be described later.

[0036] When the determination unit 62 determines that an air leak has occurred, the isolation control unit 64 uses an isolation valve 30, which is located in the same branch channel as the flow sensor 80 used to determine the air leak, to isolate the downstream side of the channel 20 from the upstream side of the isolation valve 30. Specifically, the isolation control unit 64 isolates the downstream side of the isolation valve 30 from the upstream side of the isolation valve 30 by energizing the isolation valve 30. This isolates the downstream side of the isolation valve 30 in the channel 20 where a fluid leak has been determined, so that even if a fluid leak occurs from the channel 20 while the railway vehicle 1 is running, it can still move using other brakes. Therefore, the impact of the fluid leak can be reduced.

[0037] Figure 4 is a block diagram showing another example of the configuration related to the flow path 20 of the railway vehicle 1. In the example shown in Figure 4, the positions where the isolation valves 30 and flow sensors 80 are provided differ from those in the example shown in Figure 3. Specifically, in the example shown in Figure 3, four isolation valves 30 and flow sensors 80 are provided, one each in the second branch flow paths 24a to 24d, whereas in the example shown in Figure 4, two isolation valves 30 and flow sensors 80 are provided, one each in the first branch flow paths 22a and 22b. In the example shown in Figure 3, only the downstream side of one of the second branch flow paths 24a to 24d corresponding to the location of the fluid leak is isolated, thus minimizing the number of brake cylinders 16t that stop operation. In the example shown in Figure 4, the number of isolation valves 30 and flow sensors 80 can be reduced compared to the example shown in Figure 3.

[0038] The operation of the skid control valve 18 will be explained with reference to Figures 5 to 7. Figures 5 to 7 are schematic diagrams illustrating an example of the surrounding configuration of the skid control valve 18. Figure 5 shows the supply state for generating normal braking force in the brake mechanism 16. Figure 6 shows the holding state for maintaining braking force in skid control. Figure 7 shows the discharge state for reducing braking force in skid control. In Figures 5 to 7, the brake mechanism 16 is arranged adjacent to the downstream side of the skid control valve 18 for illustrative purposes, but the configuration is not limited to this.

[0039] The sliding control valve 18 includes a supply valve HV, a discharge valve RV, an inlet 18p, an outlet 18s, and an external discharge 18g. The supply valve HV controls the supply of compressed air Ap to the downstream side of the flow path 20. The supply valve HV includes a drive unit 17a, a valve body 17c, and a valve section 17e. The discharge valve RV controls the discharge of compressed air Ap to the outside of the flow path 20. The discharge valve RV includes a drive unit 17b, a valve body 17c, and a valve section 17f. When the sliding control unit 60 energizes and drives the drive units 17a and 17b, they move the valve body 17c back and forth in the opening and closing direction (left and right direction in the figure) by electromagnetic action. The valve body 17c closes or opens the valve sections 17e and 17f by moving its central part back and forth.

[0040] In the supply state shown in Figure 5, both the supply valve HV and the discharge valve RV are de-energized. At this time, the valve portion 17e of the supply valve HV is open, and the valve portion 17f of the discharge valve RV is closed. When the valve portion 17e of the supply valve HV is open, compressed air Apr is supplied from the sliding control valve 18 to the inlet 18p and then supplied to the brake mechanism 16 from the outlet 18s. Since the valve portion 17f of the discharge valve RV is closed, there is no inflow or outflow of compressed air Apr at the external discharge section 18g.

[0041] When compressed air Ap flows into the brake mechanism 16, the brake pressure increases, causing a piston rod (not shown) to extend and press the friction material 16s against the tread surface of the wheel 12. This action applies the brakes to the wheel 12.

[0042] In the holding state shown in Figure 6, the supply valve HV is energized and the discharge valve RV is deconductive. At this time, the supply valve HV and the discharge valve RV are closed, there is no inflow or outflow of compressed air Ap at the inlet 18p and the external discharge 18g, the amount of compressed air Ap inside the brake mechanism 16 does not increase or decrease, and the brake pressure is maintained.

[0043] In the discharge state shown in Figure 7, both the supply valve HV and the discharge valve RV are in a conductive state. At this time, the valve portion 17e of the supply valve HV is closed, and the valve portion 17f of the discharge valve RV is open. Since the valve portion 17e of the supply valve HV is closed, there is no inflow or outflow of compressed air Apr at the inlet portion 18p. During the period when the valve portion 17f of the discharge valve RV is open, a portion of the compressed air Apr inside the brake mechanism 16 escapes from the outlet portion 18s through the discharge valve RV and out to the outside from the external discharge portion 18g.

[0044] When some of the compressed air Ap inside the brake mechanism 16 escapes, the brake pressure decreases accordingly, reducing the pressure of the friction material 16s on the wheel tread 12, and thus reducing the braking force. Therefore, the longer the discharge valve RV remains open, the greater the decrease in braking force.

[0045] The operation of the isolation valve 30 will be explained with reference to Figures 8 to 11. Figures 8 and 9 are schematic pneumatic circuit diagrams showing an example of the isolation valve 30, namely isolation valve 30A. In Figures 8 and 9, the inlet IN is connected to the upstream side of the flow path 20, and the outlet OUT is connected to the downstream side of the flow path 20. The isolation valve 30A includes a solenoid valve 32A and a pneumatic valve 34A. The isolation valve 30A and the pneumatic valve 34A each function as flow path switching valves having different flow paths in the left and right directions of the figure. The solenoid valve 32A is biased towards the left in the figure by a biasing member 36A such as an elastic spring. The pneumatic valve 34A is biased towards the left in the figure by a biasing member 38A such as an elastic spring. In the isolation valve 30A, the flow path from the inlet IN branches, one branch is connected to the solenoid valve 32A, and the other branch is connected to the pneumatic valve 34A.

[0046] In the state shown in Figure 8, the solenoid valve 32A is de-energized. At this time, the solenoid valve 32A and the pneumatic valve 34A are biased to the left in the figure by the biasing force of the biasing member 36A. In this state, the flow path connecting the inlet IN to the solenoid valve 32A is closed inside the solenoid valve 32A, so the compressed air Ap entering from the inlet IN passes through the pneumatic valve 34A and is supplied to the downstream side of the flow path 20 from the outlet OUT.

[0047] In the state shown in Figure 9, the solenoid valve 32A is energized. At this time, the solenoid valve 32A moves to the right in the figure due to the energization. In this state, the flow path connected from the inlet IN to the solenoid valve 32A passes through the solenoid valve 32A and reaches the end of the pneumatic valve 34A (the left end in the figure). As a result, the compressed air Ap entering from the inlet IN passes through the solenoid valve 32A and biases the pneumatic valve 34A to the right in the figure, causing the pneumatic valve 34A to move to the right in the figure. At this time, the flow path connected from the inlet IN to the pneumatic valve 34A closes inside the pneumatic valve 34A, so the compressed air Ap entering from the inlet IN is not supplied from the outlet OUT. Furthermore, the flow path connected from the outlet OUT to the pneumatic valve 34A reaches the exhaust port of the pneumatic valve 34A, so the flow path 20 downstream of the isolation valve 30A is exhausted.

[0048] Figures 10 and 11 are pneumatic circuit diagrams schematically showing isolation valve 30B, another example of isolation valve 30. In Figures 10 and 11, the inlet IN is connected to the upstream side of the flow path 20, and the outlet OUT is connected to the downstream side of the flow path 20. Isolation valve 30B includes a solenoid valve 32B and a pneumatic valve 34B. Isolation valve 30B and pneumatic valve 34B each function as flow path switching valves having different flow paths in the left and right directions of the figure. Solenoid valve 32B is biased to the left in the figure by a biasing member 36B such as an elastic spring. In isolation valve 30B, the flow path from the inlet IN branches, one branch is connected to solenoid valve 32B, and the other branch is connected to pneumatic valve 34B.

[0049] In the state shown in Figure 10, the solenoid valve 32B is de-energized. At this time, the solenoid valve 32B is biased to the left in the figure by the biasing force of the biasing member 36B. In this state, the flow path connected from the inlet IN to the solenoid valve 32B passes through the solenoid valve 32B and reaches the end of the pneumatic valve 34B (right end in the figure). As a result, the compressed air Ap entering from the inlet IN passes through the solenoid valve 32B and biases the pneumatic valve 34B to the left in the figure, causing the pneumatic valve 34B to move to the left in the figure. At this time, the flow path connected from the inlet IN to the pneumatic valve 34B reaches the outlet OUT, so the compressed air Ap entering from the outlet IN passes through the pneumatic valve 34B and is supplied to the downstream side of the flow path 20 from the outlet OUT.

[0050] In the state shown in Figure 11, the solenoid valve 32B is energized. At this time, the solenoid valve 32B moves to the right in the figure due to the energization. In this state, the flow path connected from the inlet IN to the solenoid valve 32B passes through the solenoid valve 32B and reaches the end of the pneumatic valve 34B (left side in the figure). As a result, the compressed air Ap entering from the inlet IN passes through the solenoid valve 32B and biases the pneumatic valve 34B to the right in the figure, causing the pneumatic valve 34B to move to the right in the figure. At this time, the flow path connected from the inlet IN to the pneumatic valve 34B closes inside the pneumatic valve 34B, so the compressed air Ap entering from the inlet IN is not supplied from the outlet OUT. Furthermore, the flow path connected from the outlet OUT to the pneumatic valve 34B reaches the exhaust port of the pneumatic valve 34B, so the flow path 20 downstream of the isolation valve 30B is exhausted.

[0051] Figure 12 schematically shows an example of the change in brake pressure over time when a brake command is received. Figure 12 shows a graph of brake pressure with time on the horizontal axis and pressure on the vertical axis. Figure 12 shows the brake pressure 92 when no air leak occurs and the brake pressure 94 when air leak occurs.

[0052] First, let's explain the brake pressure 92 when no air leak is occurring. Between timings t0 and t1, no brake command is input. At this time, no brake pressure 92 is generated, and the flow rate value output from the flow sensor 80 is also zero.

[0053] At timing t1, a brake command is input, and the brake command continues thereafter. The brake control unit 58 controls the brake control valve 14 so that the brake pressure corresponds to the input brake command. As a result, the brake pressure 92 increases. When the brake pressure 92 starts to rise, the flow rate value output from the flow sensor 80 increases sharply.

[0054] As the brake pressure 92 rises and approaches the brake pressure P1 indicated by the brake command, the brake control unit 58 controls the brake control valve 14 so that the change in brake pressure 92 becomes gradual. Then, the brake pressure 92 becomes almost constant near the brake pressure P1 indicated by the brake command, and the brake pressure 92 stabilizes. At this time, the value of the flow rate output from the flow sensor 80 also decreases. At timing t2 when the brake pressure 92 stabilizes, the value of the flow rate output from the flow sensor 80 is less than or equal to a predetermined threshold α. Note that during the period between timing t and t2 when the brake pressure 92 is rising, the value of the flow rate output from the flow sensor 80 is sufficiently larger than the threshold α. Here, the time required from timing t1 when the brake command is input to timing t2 when the brake pressure 92 stabilizes is, for example, 2 to 3 seconds.

[0055] Next, we will explain the brake pressure 94 when an air leak is occurring. Between timings t0 and t1, no brake command is input, so no brake pressure 94 is generated, and the flow rate value output from the flow sensor 80 is also zero.

[0056] At timing t1, a brake command is input, and the brake command continues thereafter. The brake control unit 58 controls the brake control valve 14 so that the brake pressure corresponds to the input brake command. As a result, the brake pressure 94 increases. When the brake pressure 94 starts to rise, the flow rate value output from the flow sensor 80 increases sharply.

[0057] The brake pressure 94 increases and approaches the brake pressure P1 indicated by the brake command. However, because an air leak is occurring, the brake pressure 94 does not reach brake pressure P1. At this time, compressed air continues to be supplied due to the air leak, so the flow rate value output from the flow sensor 80 remains higher than when there is no air leak. Subsequently, even when the brake pressure 94 appears to stabilize at timing t2, the flow rate value output from the flow sensor 80 remains higher than when there is no air leak. At timing t2, the flow rate value output from the flow sensor 80 is greater than the threshold α.

[0058] Figure 12 shows an example where the brake pressure 94, when air leakage occurs, stabilizes at a pressure lower than the brake pressure P1. However, the brake pressure 94 when air leakage occurs may be controlled to stabilize near the brake pressure P1. Alternatively, the brake pressure 94 when air leakage occurs may not stabilize even after timing t2. In either of these cases, since compressed air continues to be supplied due to the air leakage, the flow rate value output from the flow sensor 80 at timing t2 is greater than the threshold α.

[0059] As described above, if the output value of the flow sensor 80 is greater than the threshold α after the same brake command has been applied for a predetermined period of time, it is considered that an air leak has occurred. Therefore, the determination unit 62 of this embodiment determines that an air leak has occurred if the output value of the flow sensor 80 is greater than the threshold α after the same brake command has been applied for a predetermined period of time. The predetermined period here is the time required from timing t1 to timing t2 as described above, and is, for example, 2 to 3 seconds.

[0060] The threshold value α mentioned above may vary depending on the brake pressure indicated by the brake command. Since the flow rate of compressed air is expected to increase as the brake pressure indicated by the brake command increases, this configuration allows for the use of an appropriate threshold value α according to the brake command.

[0061] Figure 13 is a flowchart showing an example of isolation control by the brake control device 50. The process shown in Figure 13 is executed, for example, while the railway vehicle 1 is in motion.

[0062] If the brake control device 50 is performing sliding control by the sliding control unit 60 (Y in S10), it returns to step S10. In other words, the brake control device 50 does not perform isolation control in subsequent steps while sliding control is in progress. This is to improve the accuracy of fluid leakage detection by eliminating the influence of sliding control of the sliding control valve 18 on the output value of the flow sensor 80.

[0063] If the brake control device 50 is not performing skidding control by the skidding control unit 60 (N in S10), it acquires the output values ​​of each flow sensor 80 via the receiving unit 56 (S12). The determination unit 62 determines whether or not there is an air leak at the location of each flow sensor 80 based on the output values ​​of each flow sensor 80 (S14). If the determination unit 62 determines that there is no air leak (N in S14), the process returns to step S10. If the determination unit 62 determines that there is an air leak (Y in S14), the process proceeds to step S16.

[0064] The isolation control unit 64 uses an isolation valve 30 located in the same branch channel as the flow sensor 80 at the location where an air leak is detected, and isolates the downstream side of the isolation valve 30 from the upstream side (S16). The brake control device 50 repeatedly executes steps S10 to S16 to monitor air leaks in the flow channel 20 while the railway vehicle 1 is running.

[0065] The brake control device 50 may perform step S10 at a timing between step S12 and step S14, or at a timing between step S14 and step S16. In other words, the brake control device 50 does not need to perform isolation control during skidding control, may acquire the output value of the flow sensor 80 during skidding control, or may determine if there is an air leak during skidding control.

[0066] As described above, the brake control device 50 of this embodiment includes a flow sensor 80 provided in the flow path between a brake control valve 14 controlled in response to a brake command and a brake cylinder 16t that operates in response to fluid pressure, an isolation valve 30 provided in the flow path 20 between the brake control valve 14 and the brake cylinder 16t, a determination unit 62 that determines fluid leakage based on the output value of the flow sensor 80, and an isolation control unit 64 that, when fluid leakage is determined, uses the isolation valve 30 to isolate and control the downstream side of the flow path 20 from the upstream side of the isolation valve 30. As a result, the downstream side of the isolation valve 30 in the flow path 20 where fluid leakage has been determined can be isolated, so that even if fluid leakage occurs from the flow path 20 while the railway vehicle 1 is running, for example, it is possible to propel the vehicle using other brakes. Therefore, the impact of fluid leakage can be reduced.

[0067] In the brake control device 50, the flow path 20 may branch between the brake control valve 14 and the multiple brake cylinders 16t, and the multiple brake cylinders 16t may each be connected to a branch flow path at the end of the branch of the flow path 20, and the flow sensor 80 and the isolation valve 30 may each be provided in the branch flow path. This makes it possible to selectively isolate the downstream side of the isolation valve 30 in the branch flow path to which the multiple brake cylinders 16t corresponding to one brake control valve 14 are connected, and which is determined to have a fluid leak. As a result, only the brake cylinders 16t affected by the fluid leak can be shut off, further reducing the impact of the fluid leak.

[0068] In the brake control device 50, the determination unit 62 may determine fluid leakage if the output value of the flow sensor 80 is greater than a threshold value after the same brake command has been applied for a predetermined period of time. This allows the determination that the flow rate remains above the threshold due to fluid leakage, even at a point when the brake pressure stabilizes and the flow rate of the fluid flowing through the flow path 20 falls below the threshold value due to the continued application of the same brake command, if no fluid leakage has occurred. This improves the accuracy of fluid leakage detection.

[0069] In the brake control device 50, the threshold value may differ depending on the brake pressure indicated by the brake command. This allows for the use of an appropriate threshold value corresponding to the brake command, since the fluid flow rate is expected to increase as the brake pressure indicated by the brake command increases.

[0070] In the brake control device 50, the flow sensor 80 may be provided between the isolation valve 30 and the brake cylinder 16t. This allows the flow sensor 80 to be provided downstream of the isolation valve 30, thereby more reliably isolating the location of fluid leakage.

[0071] In the brake control device 50, the isolation valve 30 is separate from the sliding control valve 18. This allows for a highly flexible design of the isolation valve 30's operation control, without being constrained by certification requirements for the sliding control valve 18.

[0072] In the brake control device 50, the isolation control unit 64 may perform isolation control when a fluid leak is detected while the sliding control valve 18 is in a non-sliding control state. This eliminates the influence of sliding control of the sliding control valve 18 on the output value of the flow sensor 80, thereby further improving the accuracy of fluid leak detection.

[0073] In the brake control device 50, the isolation valve 30 may include a solenoid valve, and the isolation control unit 64 energizes the isolation valve 30 when a fluid leak is detected, and the isolation valve 30 may connect its upstream and downstream sides when de-energized, and isolate its downstream side from its upstream side when energized. This allows the brake cylinder 16t to operate normally even if power supply to the isolation valve 30 becomes impossible for any reason such as a malfunction.

[0074] In the brake control device 50, the isolation valve 30 may exhaust the downstream side of the isolation valve 30 when energized. This allows the downstream side of the isolation valve 30 to be isolated and exhausted when a fluid leak is detected, thereby more reliably stopping the operation of the brake cylinder 16t located downstream of the location of the fluid leak.

[0075] [Second Embodiment] Next, a second embodiment will be described. In the drawings and description of the second embodiment, the same or equivalent components and members as in the first embodiment are denoted by the same reference numerals. Descriptions that overlap with the first embodiment will be omitted as appropriate, and the differences from the first embodiment will be described in detail. This embodiment is an example in which the sliding control valve 18 is also used as the isolation valve 30 in the first embodiment.

[0076] Figure 14 is a schematic side view showing a railway vehicle 1 to which the railway brake control device according to the second embodiment (hereinafter referred to as "brake control device 50A") is applied. The brake control device 50A comprises a control unit 52A, a brake pressure adjustment mechanism 54, and a flow sensor 80. The brake control device 50A of this embodiment differs from the brake control device 50 of the first embodiment in that it has a control unit 52A instead of a control unit 52, and does not have an isolation valve 30.

[0077] Figure 15 is a block diagram showing the configuration of the brake control device 50A. As shown in Figure 15, the control unit 52A includes a receiving unit 56, a brake control unit 58, a sliding control unit 60, a determination unit 62, and an isolation control unit 64A. The brake control device 50A of this embodiment differs from the brake control device 50 of the first embodiment in that it includes an isolation control unit 64A instead of an isolation control unit 64.

[0078] Figure 16 is a block diagram showing an example of a configuration related to the flow path 20 of the railway vehicle 1. As shown in Figure 16, in this embodiment, the function of the isolation valve 30 in the first embodiment is realized using the sliding control valve 18, so no isolation valve separate from the sliding control valve 18 is provided. The flow sensor 80 is provided between the sliding control valve 18 and the brake cylinder 16t. One flow sensor 80 is provided in each of the second branch flow paths 24a to 24d.

[0079] Returning to Figure 15, when the determination unit 62 determines that there is an air leak, the isolation control unit 64A uses a sliding control valve 18, which is located in the same branch channel as the flow sensor 80 used to determine the air leak, to isolate the downstream side of the sliding control valve 18 in the flow channel 20 from the upstream side of the sliding control valve 18.

[0080] As described above, in the brake control device 50A of this embodiment, the isolation valve is the sliding control valve 18. As a result, the sliding control valve 18 can be used as an isolation valve, and there is no need to provide an isolation valve 30 separately from the sliding control valve 18. In this embodiment, the same effects as in the first embodiment can be obtained for the configurations that are common with the first embodiment.

[0081] The embodiments of the present invention have been described in detail above. The embodiments described above are merely examples of how to implement the present invention. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes, such as changes, additions, and deletions of components, are possible as long as they do not depart from the spirit of the invention as defined in the claims. In the embodiments described above, such design changes are described with notations such as "of the embodiments" or "in the embodiments," but design changes may also be permitted in contents without such notations.

[0082] [Differentiation] The following describes modified examples. In the drawings and descriptions of the modified examples, components and parts that are the same as or equivalent to those in the embodiments are denoted by the same reference numerals. Descriptions that overlap with those in the embodiments will be omitted as appropriate, and the descriptions will focus on the configurations that differ from those in the embodiments.

[0083] In the description of the embodiment, an example was shown in which one brake control device 50, 50A is provided for each railway vehicle 1, but the invention is not limited to this. For example, multiple brake control devices 50, 50A may be provided for each railway vehicle 1.

[0084] When the control unit 52 is isolating a predetermined branch channel with a predetermined isolation valve, the brake control valve 14 may be controlled to increase the brake pressure in other branch channels compared to the state where isolation control is not in place. This allows the brake pressure acting on other brake mechanisms 16 to be increased even if a brake mechanism 16 fails to operate due to isolation control, thereby preventing a decrease in the overall braking force of the railway vehicle 1.

[0085] The modifications described above produce the same functions and effects as each embodiment.

[0086] Any combination of the embodiments and modifications described above is also useful as an embodiment of the present invention. The new embodiments resulting from these combinations possess the combined effects of the respective embodiments and modifications.

[0087] In the embodiments disclosed herein, those in which multiple functions are provided in a distributed manner may have some or all of those multiple functions integrated into a single unit, and conversely, those in which multiple functions are integrated may have some or all of those functions provided in a distributed manner. Whether the functions are integrated or distributed, the configuration should be such that the objective of the invention can be achieved. [Explanation of Symbols]

[0088] 1 Railway vehicle, 8 Compressed air supply source, 14 Brake control valve, 16 Brake mechanism, 16t Brake cylinder, 18 Sliding control valve, 20 Flow path, 30, 30A, 30B Isolation valves, 32A, 32B Solenoid valves, 50 Brake control device, 52 Control unit, 54 Brake pressure adjustment mechanism, 58 Brake control unit, 60 Sliding control unit, 62 Judgment unit, 64 Isolation control unit, 80 Flow sensor.

Claims

1. A flow sensor is provided in the flow path between a brake control valve, which is controlled in response to a brake command, and a brake cylinder, which operates in response to fluid pressure. An isolation valve provided in the flow path between the brake control valve and the brake cylinder, A determination unit that determines fluid leakage based on the output value of the flow sensor, When a fluid leak is detected, the isolation control unit controls the isolation of the flow path downstream of the isolation valve from the upstream side of the isolation valve, A brake control device for railway vehicles equipped with the following features.

2. The aforementioned flow path branches between the brake control valve and the plurality of brake cylinders, The plurality of brake cylinders are each connected to a branch passage at the end of the flow path, The flow sensor and the isolation valve are each provided in the branch channel, The brake control device for a railway vehicle according to claim 1.

3. The determination unit determines fluid leakage if the output value of the flow sensor after a predetermined period of time of the same brake command is greater than a threshold value. The brake control device for a railway vehicle according to claim 1.

4. The threshold value varies depending on the brake pressure indicated by the brake command. The brake control device for a railway vehicle according to claim 3.

5. The flow sensor is provided between the isolation valve and the brake cylinder. The brake control device for a railway vehicle according to claim 1.

6. The isolation valve is a sliding control valve. The brake control device for a railway vehicle according to claim 1.

7. The isolation valve is separate from the sliding control valve. The brake control device for a railway vehicle according to claim 1.

8. The isolation control unit performs the isolation control when it determines that there is fluid leakage while the sliding control valve is in a non-sliding control state. A brake control device for a railway vehicle according to claim 6 or 7.

9. The isolation valve includes a solenoid valve, When the isolation control unit detects the fluid leak, it energizes the isolation valve. The isolation valve connects the upstream side and the downstream side when de-energized, and isolates the downstream side from the upstream side when energized. The brake control device for a railway vehicle according to claim 1.

10. The isolation valve, when energized, exhausts the downstream side. The brake control device for a railway vehicle according to claim 9.

11. A step of determining fluid leakage based on the output value of a flow sensor installed in the flow path between a brake control valve controlled in response to a brake command and a brake cylinder that operates in response to fluid pressure, When a fluid leak is detected, the process involves isolating the downstream side of the flow path from the upstream side of the isolation valve by an isolation valve provided in the flow path between the brake control valve and the brake cylinder, A brake control method for railway vehicles, including the following.

12. A step of determining fluid leakage based on the output value of a flow sensor installed in the flow path between a brake control valve controlled in response to a brake command and a brake cylinder that operates in response to fluid pressure, When a fluid leak is detected, the process involves isolating the downstream side of the flow path from the upstream side of the isolation valve by an isolation valve provided in the flow path between the brake control valve and the brake cylinder, A brake control program for railway vehicles, designed to be executed by a computer.

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