JP4491092B2 - Brake equipment for railway vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a railway vehicle brake device that prevents a small tire flat generated at a position on a wheel tread from redundantly becoming a large tire flat due to re-sliding in the tire flat portion.
[0002]
[Prior art and problems to be solved by the invention]
In a railway vehicle, when a brake is applied while the vehicle is running, a local decrease in adhesive strength may occur at the contact portion between the wheel and the rail. The decrease in adhesive strength is significant at the beginning of rain, during frost or snow. When the decrease in adhesion occurs and the braking force exceeds the adhesion, the wheel temporarily stops rotating and slides on the rail. At this time, depending on the situation, the wheel treads are locally flattened and tire flatness occurs. When the tire flat occurs, the wheel having an irregular shape rotates, so that noise and vibration are generated. For this reason, the ride comfort naturally decreases. The generation of noise and vibration becomes more conspicuous as the degree of wear increases, and in the worst case, it also causes track destruction and wheel shaft destruction.
[0003]
Even if a tire flat occurs, the corners of the flat portion are crushed by the rotation of the wheel, and noise and vibration tend to become minor. However, when a small tire flat 1x as shown in FIG. 5 (B) occurs from a normal state where no tire flat occurs on the wheel 1 as shown in FIG. The wheel is likely to stop, and there is a possibility that the tire flat 1y becomes large as shown in FIG.
[0004]
It has been confirmed that re-sliding during braking is likely to occur in the flat portion. This is because the braking force tends to exceed the adhesive force due to impact when the flat part comes into contact with the rail and temporary decrease in wheel load (the surface pressure of the flat part decreases; this is called wheel load loss). It is believed that there is. There is a tendency that re-sliding during braking tends to occur as the flat portion increases.
Actually, there are very few examples of tire flats occurring at a plurality of locations with one wheel. Therefore, it can be said from the actual example that re-sliding occurs at the time of braking in a small flat portion, and redundantly becomes a large tire flat.
[0005]
Continuing to use wheels with large tire flats will cause operational problems (such as noise / vibration, track destruction, wheel shaft destruction, reduced ride comfort, etc.). For this reason, conventionally, the wheel is sharply corrected. This wheel rectification is an operation for shaving and correcting a flat portion by using a wheel lathe, an existing milling cutter, a circumferential guide or the like provided in a train zone or the like.
[0006]
However, when a wheel lathe is used, a large work for once removing the wheel from the carriage is required.
On the other hand, when using an existing milling machine, it is not necessary to remove the wheel because the outer periphery of the wheel is cut into a circle with a diameter that is a dedicated milling machine. However, since the work of disassembling the end of the axle box has to be performed, a large work is also required in this case.
When the circumferential guide is used, the wheel tread is scraped while turning the wheel while receiving the outermost flange portion of the wheel. Therefore, it is difficult to ensure roundness when cutting a large flat. As described above, enormous labor and cost were required in both cases. Moreover, when wheel correction is performed, the larger the flat, the greater the amount of cut, which is uneconomical because the wheel life is shortened.
[0007]
On the other hand, as another measure for preventing tire flatness, there is a method of mounting a skid prevention mechanism or the like on the vehicle. However, the skid prevention mechanism is not installed in all vehicles. Moreover, even if the vehicle is mounted, tire flats may occur during unexpected sudden braking. Accordingly, there was no method other than performing the wheel grinding work. As described above, it is difficult to remove the tire flat once generated during traveling, and no measures have been taken to suppress the growth to a large flat.
[0008]
The present invention has been made in order to solve the above-described problem, and provides a completely new type railcar brake device that prevents re-running of a small tire flat portion and prevents a large tire flat. With the goal.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a brake device for a railway vehicle serving as a base of the present invention includes a detection means for detecting occurrence of local wear (tire flat) on a wheel tread, and a point when a tire flat portion of the wheel contacts a rail. in you it includes a brake force control means to weaken the braking force temporarily, the.
[0010]
The tire flat on the wheel tread is detected by the detecting means. This is performed, for example, by detecting the position of the tire flat from the vibration acceleration of the axle box and the rotation period of the wheels. Based on the detection result of the detection means, when the brake force control means releases the brake slightly to prevent re-sliding of the flat portion immediately before the flat portion matches the rail surface, and the flat portion moves away from the rail surface. Increase the brake again. The brake control is performed for each wheel shaft.
[0011]
There is a concern that the braking distance may be increased by loosening the braking force. However, the brake distance is actually longer when tire flats occur (because of dynamic friction). For this reason, as a result, the braking distance can be shortened as compared with the case where sliding recurrence occurs in the flat portion. Note that the present invention is not intended to ensure forward stability (for example, an antilock brake system of an automobile), but is intended to ensure adhesive force between wheels and rails.
[0012]
As the brake for the brake device of the present invention, a non-pneumatic brake such as an electromagnetic brake having good responsiveness is most preferable because agile control is possible. However, a pneumatic or hydraulic brake can be used if the braking force can be increased or decreased instantaneously. In this case, control may be performed by providing a discharge valve in the vicinity of the brake cylinder, or control by hydraulic pressure. Furthermore, the present invention can be applied to a tread type or a brake disc type. By using a mechanical brake device with high responsiveness, it is possible to control to release the brake for a moment (when the flat portion rolls) for each rotation of the wheel, thereby preventing re-sliding of the flat portion.
[0013]
In the railcar brake device according to the present invention, the detection means includes a predetermined acceleration when the acceleration sensor that detects the acceleration of the axle box, the rotation angle sensor that detects the rotation angle of the wheel, and the wheel is at a certain rotation angle position. A tire flat determining unit that determines that a tire flat has occurred at the position by generating the above acceleration synchronously.
[0014]
When a tire flat occurs, a large vibration waveform is generated once per wheel rotation. A tire flat determination part determines with the tire flat having generate | occur | produced in the rotation angle position, when the acceleration more than predetermined has generate | occur | produced synchronously in the rotation angle position with a wheel. Then, immediately before the next large vibration waveform is generated, the brake force is slightly reduced by the brake force control means. As a result, the braking force in the flat portion can be prevented from becoming excessive (instantaneous reduction in wheel load), so that the flat portion can be prevented from growing. In order to distinguish between intermittent vibrations such as rail joints and periodic vibrations caused by tire flats, it can be determined by checking the waveform generation period of the acceleration sensor and the pulses of the rotation angle sensor.
[0015]
As described above, in the present invention, the braking force is controlled so that the tire flat generated when the adhesive force is reduced during rain or the like is not increased, so that vibration and along-line noise are prevented, or track destruction and wheel shaft destruction are avoided. can do. For this reason, the remarkable fall of riding comfort can also be prevented. If the flat portion does not become large, the amount of wheel correction is reduced, the life of the wheel can be extended, and the economy is improved. Furthermore, when the present invention is applied to an existing brake system, only a small amount of additional work is required, and no major modification or design change is required.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, it demonstrates, referring drawings.
{First Example}
1A and 1B are diagrams showing a railway vehicle brake device according to a first embodiment of the present invention. FIG. 1A is a schematic configuration diagram, and FIG. FIG. 2A is a diagram showing the railway vehicle brake device of FIG. 1 more specifically, and FIG. 2B is a detailed diagram of FIG. FIG. 3 is a conceptual diagram showing a configuration in the vicinity of a brake cylinder of the railcar brake device.
[0017]
As shown in FIG. 1, the railroad vehicle brake device of this example includes a restrictor 3 on both sides (only one side is shown in the figure) across the tread surface of the wheel 1. The restrictor 3 is a brake pad made of cast iron or the like. As shown in FIG. 3, the restrictor 3 is attached to the rod 5 a of the brake cylinder 5. The brake cylinder 5 is an electric actuator. A restoring spring 7 is provided inside the brake cylinder 5. The restoring spring 7 acts as a driving force for retracting the rod 5a.
[0018]
Note that there are two types of brake devices that press the control members against the wheel treads: a double-hold type (a method in which two control members are pressed from both sides) and a single-press type (a method in which one control member is pressed from one side). In the present embodiment, any of them can be applied. However, only one control device 3 will be described below.
[0019]
The brake cylinder 5 is connected to the control device 10. The control device 10 is connected with a reverse rotation handle (forward / reverse drive handle) 13 installed in the cab of the vehicle and a brake device 15. The reverse rotation handle 13 is a manual handle having three positions: a front position, a neutral position, and a rear position.
[0020]
On the other hand, the brake device 15 is a two-handle type electric command type brake device. In Japanese vehicles (trains and trains), it is generally installed on the right side of the cab and on the left side of Shinkansen and locomotives. The brake device 15 includes a handle 15a. The brake device 15 is operated by turning the handle 15a. A brake force according to the rotation angle of the handle 15a can be obtained, and the same applies to the one-handle type in which the mascon and the brake are integrated.
[0021]
As shown in FIGS. 1 and 2, an acceleration sensor (vibration accelerometer) 17 is attached to the axle box 2 of the wheel 1. The acceleration sensor 17 is attached to each axle (one axis) of the vehicle. Each acceleration sensor 17 is connected to the control device 10. The acceleration sensor 17 detects the acceleration of the axle box 2 that supports the axle, and sends the detection result to the control device 10.
[0022]
Further, a rotation angle sensor (wheel rotation pulse generator) 19 is also attached to the wheel 1. The rotation angle sensor 19 may be integrated with the vibration accelerometer 17 for each axle, or may be separate from the vibration accelerometer 17 (simple type). In the case of the simplified type, four are attached to each vehicle. The rotation angle sensor 19 detects the rotation angle of the wheel 1 and sends the detection result to the control device 10. The number of pulses corresponding to one wheel rotation (circumference about 3 m) is about 600 pulses. The rotation angle sensor 19 may be replaced by a tooth number sensor or an encoder with a built-in motor in the case of a geared axle having power.
[0023]
When the wheel 1 is at a certain rotation angle position (detected by the rotation angle sensor 19) and the acceleration of a predetermined level or more (detected by the acceleration sensor 17) is generated synchronously, the control device 10 It is determined that a tire flat has occurred. When the flat portion of the wheel 1 comes into contact with the rail surface, the electromagnetic force of the brake cylinder 5 is temporarily weakened, and control is performed so that the electromagnetic force of the brake cylinder 5 is increased again when the flat portion is separated from the rail surface. . Such electromagnetic force variable control of the brake cylinder 5 is performed individually for each wheel shaft.
[0024]
In the control device 10, by checking the waveform generation cycle of the acceleration sensor 17 and the pulse of the rotation angle sensor 19, intermittent vibrations such as rail joints (vibrations depending on the rail length of 25 m), and tires It can be distinguished from the periodic vibration (vibration proportional to the wheel circumference (radius)) caused by the flat (details will be described later).
[0025]
Next, an operation of the railway vehicle brake device having the above-described configuration will be described. When a tire flat occurs, a large vibration waveform α is generated once per wheel rotation. In the control device 10, the vibration waveform α is determined to be tire flat by checking the acceleration sensor 17 and the rotation angle sensor 19.
[0026]
That is, the control device 10 compares the detection value of the speed by the acceleration sensor 17 and the detection value of the wheel rotation number (wheel rotation angle position) by the rotation angle sensor 19 to make one rotation of the wheel (circumference about 3 m). When one vibration waveform is generated, it is determined that the tire is flat. Alternatively, it may be determined that a tire flat has occurred when the vibration waveform α is detected a plurality of times at a fixed interval.
[0027]
Here, when the acceleration sensor 17 and the rotation angle sensor 19 are installed for each axle, as shown in FIG. 2, from the number of pulses per one wheel rotation (for example, about 600 pulses), The arrival (vibration waveform α) is predicted in advance. Then, immediately before the flat portion α arrives, the control device 10 controls the brake cylinder 5 so that the electromagnetic force of the brake cylinder 5 is weakened and the pressing pressure of the brake control device 3 is reduced. This slightly relaxes the braking force. After passing through the flat portion α, the electromagnetic force of the brake cylinder 5 is instantly increased and control is performed so that the pressing pressure of the brake restrictor 3 is restored. This control is repeated until the vehicle stops as shown in FIG.
[0028]
On the other hand, in the case of a simple type (without a rotation angle sensor 19 for each axis), the waveform generation period based on the detection result of the vibration accelerometer 17 and the train speed (pulses on other axles) are checked. . In this case, when the wheel waveform almost coincides with the vibration waveform, the control device 10 stores the vibration waveform interval and immediately releases the brake immediately before the next vibration waveform appears. After passing through the vibration waveform, the electromagnetic force of the brake cylinder 5 is instantly increased and control is performed so that the pressing pressure of the brake control device 3 is restored.
[0029]
In the determination of the occurrence of tire flats, it is necessary to distinguish between intermittent vibrations such as rail joints and periodic vibrations caused by tire flats (that is, wheel rotation speed). This is determined by checking the speed detection value by the acceleration sensor 17 and the wheel rotation speed detection value by the rotation angle sensor 19. That is, as shown in FIG. 2A, the vibration waveform α corresponding to the flat portion is detected every rotation of the wheel, but the vibration waveform β corresponding to the rail joint is per rail length (for example, 25 m). Once detected. Such a vibration waveform β should not be regarded as a vibration waveform accompanying a tire flat.
[0030]
In addition, when considering the entire train organization, it is also effective to reduce (for example, 80%) the braking force of the wheel on which the tire flat has occurred, during the braking force control.
[0031]
{Second Example}
The second embodiment of the present invention will be described below.
FIG. 4 (A) is a block diagram of the vicinity of a brake cylinder of a railcar brake device according to a second embodiment of the present invention, FIG. 4 (B) is a detailed view of FIG. 4 (A), and FIG. C) is an operation explanatory diagram.
[0032]
In the second embodiment, the brake cylinder is a hydraulic brake system. This brake system includes a hydraulic cylinder 23 connected to a hydraulic source 21 via a pipe 22. A small pressure increase / decrease cylinder 25 is incorporated in a part of the side wall of the hydraulic cylinder 23. A brake control 3 is attached to the tip of the rod 23a of the hydraulic cylinder 23.
[0033]
Such a hydraulic cylinder 23 can finely adjust the internal hydraulic pressure as shown in FIG. 4C by the pressure increasing / decreasing cylinder 25 operating frequently. Therefore, since the braking force can be slightly increased / decreased instantaneously in particular, it is possible to perform control such as releasing the brake only for a moment (when the flat portion rolls) for each rotation of the wheel, as in the first embodiment. Such a hydraulic cylinder 23 can also be applied to a disc brake system.
As this type of brake system, a system proposed in Japanese Patent Application No. 9-92791 filed earlier by the present applicant may be used.
[0034]
【The invention's effect】
As is clear from the above description, according to the present invention, it is possible to prevent re-sliding of a small tire flat portion and to prevent a large tire flat. For this reason, the following effects can be acquired especially.
(1) Vibration and along-line noise can be prevented, or track destruction and wheel shaft destruction can be avoided.
(2) A significant decrease in ride comfort can be prevented.
(3) Since the wheel correction amount of the flat portion is reduced and the life of the wheel can be extended, the economy is improved.
(4) When applied to an existing brake system, only a small amount of additional work is required, and no major modification or design change is required.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams showing a railway vehicle brake device according to a first embodiment of the present invention, in which FIG. 1A is a schematic configuration diagram and FIG.
FIG. 2 (A) is a diagram more specifically showing the railcar brake device of FIG. 1, and FIG. 2 (B) is a detailed diagram of FIG. 2 (A).
FIG. 3 is a conceptual diagram showing a configuration in the vicinity of a brake cylinder of the railcar brake device.
FIG. 4 (A) is a block diagram of the vicinity of a brake cylinder of a railway vehicle brake device according to a second embodiment of the present invention, and FIG. 4 (B) is a detailed view of FIG. 4 (A). FIG. 4C is an operation explanatory view.
FIGS. 5A and 5B are diagrams illustrating a process of generating tire flats, where FIG. 5A is a diagram when normal, FIG. 5B is a diagram when small flats are generated, and FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wheel 2 Shaft box 3 Control wheel 5 Brake cylinder 10 Control apparatus 13 Reverse rotation handle 15 Brake apparatus 17 Acceleration sensor 19 Rotation angle sensor 21 Hydraulic source 23 Hydraulic cylinder 25 Pressure increase / decrease cylinder

Claims (2)

Detection means for detecting the occurrence of local wear (tire flat) of the wheel tread;
Braking force control means for temporarily reducing the braking force when the tire flat portion of the wheel contacts the rail;
Comprising
With the brake force control means, just before the flat portion matches the rail surface, the brake is loosened to an extent that prevents the flat portion from re-sliding, and when the flat portion moves away from the rail surface, the brake control is performed to reinforce the brake. A railcar brake device, which is performed for each shaft. The detection means is
An acceleration sensor for detecting the acceleration of the axle box;
A rotation angle sensor for detecting the rotation angle of the wheel;
When the wheel is at a certain rotational angle position, a tire flat determination unit that determines that a tire flat has occurred at the position by synchronously generating a predetermined acceleration or more,
The railcar brake device according to claim 1, comprising:

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