JP2006069317A - Adhesion preventing method in skid readhesion control - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve responsivity of braking while suppressing adhesion of a wheel, when the wheel skids during traveling of a vehicle. <P>SOLUTION: When the skid of a wheel is detected, an RV valve of a brake device of the wheel is opened to decrease brake cylinder pressure P1. When a slip rate η of an axle of the wheel exceeds 50%, the brake cylinder pressure P1 is further decreased. However, acceleration α of the wheel changes to be increased, and if α exceeds 2 km/h/s, the RV valve is closed to keep the brake cylinder inner pressure P1. When it is confirmed that the wheel readheres, the brake cylinder inner pressure P1 is raised. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sticking prevention method in sliding re-adhesion control of a vehicle.

While running a train or other vehicle, the coefficient of friction between the wheel and the rail decreases due to rain or oil on the rail, and the wheel slides against the rail when the brake is applied. Sometimes. When such a sliding occurs, the braking distance increases or the wheels and rails are damaged, and it is known to perform sliding re-adhesion control to prevent the sliding.
The sliding re-adhesion control means that when sliding is detected by β detection or speed difference detection, a sliding prevention valve (RV valve (exhaust valve), HV valve ( This is a control in which the brake cylinder pressure is exhausted stepwise by operating the supply valve)) stepwise so that the wheel does not stick to the rail and is quickly re-adhered. Here, in order to detect sliding, the speed of each wheel may be detected by a speed detector. The speed detector is attached to each wheel, and outputs a frequency signal corresponding to the speed of the wheel. Therefore, this frequency signal is monitored for each axle, and if there is an axis that has a speed difference with respect to the reference axis speed (four maximum axis speeds or simulated speeds) during braking, the axle is sliding. It will be. And if sliding is detected, braking force is reduced so that it may not fall into the sticking phenomenon which the wheel of the axle stops (for example, refer to patent documents 1).

A conventional example of such sliding re-adhesion control will be specifically described with reference to FIG.
(1) When sliding is detected at point A in FIG. 1, the brake cylinder pressure is exhausted for t1 hours. After reducing the brake cylinder pressure, the pressure is held for t2 hours. After the time t2 has elapsed, if the detection condition at point A continues, the brake cylinder pressure is exhausted again for t1 time and held at that pressure for t2 hours. If the detection condition at point A is maintained, this operation is repeated.
(2) After sliding is detected at point A, if the condition at point B is satisfied without satisfying the detection condition, the control of (1) is stopped, and the brake cylinder pressure at that time Hold. Note that when the brake cylinder pressure is maintained based on the point B condition and the detection condition for the point A is satisfied again, the control is switched to the control (1).
(3) After sliding is detected at point A, the speed of the sliding shaft changes, and when the condition at point C is satisfied, the brake cylinder pressure is restored.

In an actual vehicle, even if the above-mentioned sliding re-adhesion control is performed, the sliding shaft has a high deceleration rate, which may result in stuck wheels. In order to prevent such sticking, sticking prevention control is performed in which the brake cylinder pressure is continuously exhausted to reduce the braking force. A conventional example of such sticking prevention control is shown in FIG.
(1) When the reference shaft speed is 10 km / h or more and the slip rate η of the sliding shaft is 50% or more, the brake cylinder pressure is continuously exhausted.
(2) Until the point C is detected, the brake cylinder pressure is continuously exhausted.
(3) When point C is detected, the anti-skid valve (RV valve, HV valve) is turned off to return the brake cylinder pressure.
JP-A-5-319242

However, in the conventional anti-sticking control, the brake cylinder pressure is continuously exhausted until the condition of the point C is satisfied. Therefore, when the sliding shaft is re-adhered, the brake cylinder pressure is almost reduced to 0 kPa. Therefore, even if the brake cylinder pressure is increased again from there, it takes time to return to the brake cylinder pressure that generates an effective braking force. Therefore, the braking distance of the vehicle cannot be shortened.
Further, when the reference shaft speed is less than 10 km / h, the sticking prevention control is not performed, so that there is a possibility that the sliding just before the stop results in the sticking.
The present invention has been made in view of such circumstances, and an object of the present invention is to improve braking responsiveness while suppressing the sticking of the wheel when the wheel slides while the vehicle is running. It is to let you.

The invention according to claim 1 of the present invention that solves the above-mentioned problems opens the discharge valve of the brake cylinder that brakes the wheel when the sliding of the wheel is detected while the vehicle is running, and reduces its internal pressure. Therefore, when the vehicle is re-adhered to the rail, the speed of the wheel is controlled by controlling the internal pressure of the brake cylinder to prevent the wheel from sticking. When detecting that the wheel has slipped, the discharge valve of the brake cylinder is closed and the internal pressure of the brake cylinder is maintained. This is a sticking prevention method in sliding re-adhesion control.
In the sticking prevention method in the sliding re-adhesion control, the internal pressure of the brake cylinder is lowered to re-adhere the wheel, the braking force is reduced, and the wheel speed is temporarily reduced. Then, the discharge valve is controlled so that the cylinder internal pressure of the wheel brake is maintained at a higher value than in the prior art. For example, the discharge valve is switched when it is detected that the acceleration of the axle has started to increase.

According to a second aspect of the present invention, in the sticking prevention method in the sliding re-adhesion control according to the first aspect, the brake is applied even when the speed of the vehicle is equal to or lower than a constant speed while the sliding of the wheel is detected. The discharge valve of the cylinder is closed, and the internal pressure of the brake cylinder is maintained.
In this sticking prevention method in sliding re-adhesion control, re-adhesion control is performed even in a low-speed region where sticking prevention control is conventionally performed, and the internal pressure of the brake cylinder is maintained to prevent the wheels from sticking.

According to the present invention, when prevention of sticking of the wheel is performed in the re-adhesion control at the time of sliding, only a minimum pressure is exhausted from the brake cylinder. Therefore, it is possible to quickly secure the pressure required for the brake after the wheels are re-adhered, and the braking distance can be shortened as compared with the conventional control.
Even when the speed of the vehicle is low, if the re-adhesion control is being performed, the control is continued until the release condition is satisfied, so that sticking in the low speed region (before stopping) can be suppressed.

The best mode for carrying out the invention will be described in detail with reference to the drawings.
FIG. 1 shows a control state diagram when the sticking prevention method in the re-adhesion control in the present embodiment is applied.
In FIG. 1, the horizontal axis indicates the passage of time, and the standard vehicle travel speed Vs of the vehicle is shown at the top in the figure. The vehicle travel speed Vs corresponds to the reference shaft speed of each axle when no activity is occurring. FIG. 1 shows the vehicle travel speed Vs during braking, and the vehicle travel speed Vs decreases linearly with time. On the other hand, the wheel rotation speed Vn indicates the speed of the wheel when the wheel slides. The wheel rotation speed Vn coincides with the vehicle travel speed Vs in the initial stage, and then decreases more than the vehicle travel speed Vs. It has changed.

  Below the wheel rotation speed Vn, the operation of the RV valve (discharge valve) and the HV valve (supply valve) and the change of the brake cylinder pressure (BC pressure) P1 are associated with the changes of the respective speeds Vs and Vn. It is shown in the figure. The RV valve is operated in accordance with the discharge signal S1 output from the control device. When the discharge signal S1 is High, the RV valve discharges fluid from the brake cylinder, performs a discharge operation to reduce the internal pressure, and releases the brake. The HV valve is operated in accordance with a supply stop signal S2 output from the control device. When the supply stop signal S2 is Low, a fluid is supplied to the brake cylinder and a supply operation is performed to increase its internal pressure, and the brake force is increased. Hold. The brake cylinder pressure P1 is a cylinder pressure of a brake device that applies a braking force to the axle, and changes according to the operation of the RV valve and the HV valve. Note that the RV valve, HV valve, and brake cylinder pressure P1 shown in FIG. 1 are shown for a brake cylinder of a sliding wheel that rotates at a wheel rotation speed Vn.

Next, sticking prevention control in this embodiment will be described.
First, when the wheel rotational speed Vn of a predetermined axle decreases with respect to the vehicle travel speed Vs and satisfies the condition indicated by point A, the discharge signal S1 becomes High, the RV valve opens, and the brake cylinder starts to exhaust. Is done. At the same time, the supply stop signal S2 becomes High, the HV valve is closed, and the supply of fluid to the brake cylinder is stopped. As a result, the brake cylinder pressure P1 decreases. The RV valve is maintained for the holding time t3, after which the discharge signal S1 becomes low. As a result, both supply and exhaust of fluid to the brake cylinder are stopped, and the brake cylinder pressure P1 is maintained at a constant value. The brake cylinder pressure P1 at this time is a pressure that suppresses the exhaust amount from the brake cylinder and can be promptly restored.

Further, when the wheel rotation speed Vn of the sliding shaft decreases and the point B1, that is, the sliding rate η of the sliding shaft becomes 50% or more, the discharge signal S1 is set to High again, the RV valve is opened, and the brake cylinder pressure P1 is set. Are exhausted continuously. Thereby, the wheel rotational speed Vn of the sliding shaft decreases.
Thereafter, the wheel rotation speed Vn starts to increase through a minimum value, and at this time, the acceleration α of the sliding shaft also starts to increase. Then, as indicated by point B2, when a sensor (not shown) detects α> 2 km / h / s as the acceleration α of the sliding shaft, the discharge signal S1 becomes low and the RV valve is closed. As a result, the brake cylinder pressure P1 is maintained at a constant value that is sufficiently larger than 0 kPa. In addition, even after the acceleration α once exceeds 2 km / h / s, the control device exhausts the brake cylinder pressure P1 again when the point A is detected again to detect sliding.

  When the wheel rotation speed Vn further increases and the control device detects the point C, the supply signal S2 is set to low, the HV valve is opened, and the brake cylinder pressure P1 is set to the value before starting the re-adhesion control. To the pressure at which the necessary braking force can be applied to the wheels. Then, a braking force is applied to the re-adhered wheel to stop the vehicle. In this case, the brake is applied more quickly than before, and the vehicle stops.

  Here, even if the reference shaft speed (vehicle traveling speed Vs) is 10 km / h or less, the control device determines that the detection cancellation condition is satisfied when the sliding detection from point A to point C continues. The sticking prevention control described above is performed until the state of point C is established.

In this embodiment, when a wheel slides, when controlling the pressure P1 of the brake cylinder that applies the brake to the wheel to prevent re-adhesion and sticking, the acceleration α of the sliding shaft is detected and the acceleration α When the engine pressure exceeds a predetermined value, the brake cylinder internal pressure P1 is maintained at a constant value by closing the RV valve. Therefore, the brake cylinder internal pressure P1 when the wheel is re-adhered is higher than the conventional value. Become. Therefore, it is possible to prevent the internal pressure of the brake cylinder from approaching zero and taking time to return from the time when the wheel slides to the time of re-adhesion, as in the prior art. For this reason, it is possible to improve the responsiveness of the brake after re-adhesion is performed while preventing sticking to the sliding wheel.
Furthermore, since the above-described sticking prevention control is performed while sliding is detected even when the vehicle speed, that is, the reference shaft speed is 10 km / h or less, sticking can be suppressed even in a low speed range.

The present invention is not limited to the above-described embodiments, and can be widely applied without departing from the spirit of the present invention.
For example, the acceleration α at the time of switching the RV valve may be a value that can detect that the sliding shaft has changed from deceleration to acceleration, and varies depending on the type of vehicle, the running state, the volume of the brake cylinder, and the like. Can be set.
The above embodiment is also applied to a braking system including a brake device including a brake cylinder, an RV valve, and an HV valve, a control device that outputs signals S1 and S2, and detection means that detects the brake cylinder pressure P1 and the like. The same action and effect can be obtained.

It is a state figure explaining the sticking prevention method of re-adhesion control in an embodiment of the invention. It is a state figure for demonstrating the conventional re-adhesion control. It is a state figure for demonstrating the conventional sticking prevention control.

Explanation of symbols

P1 Brake cylinder pressure (Brake cylinder internal pressure)
S1 Discharge signal S2 Supply signal α Acceleration

Claims (2)

When the sliding of a wheel is detected while the vehicle is running, the brake cylinder that brakes the wheel is opened and the internal pressure is reduced to reduce the internal pressure. A method for preventing sticking in sliding re-adhesion control that controls the speed of the wheel by controlling the internal pressure of the wheel and prevents sticking of the wheel,
While detecting the sliding of the wheel, when it is detected that the axle of the wheel has changed from deceleration to acceleration, the discharge valve of the brake cylinder is closed and the internal pressure of the brake cylinder is maintained. A method for preventing sticking in sliding re-adhesion control. 2. While the wheel sliding is detected, the discharge valve of the brake cylinder is closed and the internal pressure of the brake cylinder is maintained even when the speed of the vehicle is equal to or lower than a constant speed. The sticking prevention method in the sliding re-adhesion control as described in 1.

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