JP2008062756A - Vehicle brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle brake device capable of stopping the vehicle in accordance with a driver's brake operation at emergency braking in the brake device for reducing a brake pressure when the vehicle is transferred to the stopping state. <P>SOLUTION: A speed detection part 11 detects a traveling speed of the vehicle. A determination part 12 at emergency braking determines whether or not the vehicle condition when a brake pedal is stepped-in corresponds to that at emergency braking. A pressure reduction control part 13 performs pressure reduction control for reducing the pressure while gradually reducing the brake pressure to a predetermined pressure reduction target brake pressure when the traveling speed detected by the speed detection part 11 becomes a predetermined pressure reduction starting speed or less. Further, when it is determined by the determination part 12 at emergency braking that it corresponds to that at emergency braking, the pressure reduction control part 13 executed any one of the processing for forbidding the pressure reduction control, the processing for raising the pressure reduction target brake pressure and the processing for reducing the pressure reduction starting speed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle brake device.

In Patent Document 1 below, when the vehicle traveling speed decreases and the vehicle shifts to a stopped state, the brake pressure is reduced to reduce the longitudinal vibration of the vehicle body that occurs when the vehicle stops, and the vehicle body swings back. A vehicle brake device that suppresses the above is disclosed. In this vehicle brake device, the brake pressure is uniformly reduced regardless of the traveling state of the vehicle body.
JP-A-4-345565

  In the vehicle brake device described in Patent Document 1, since the brake pressure is reduced when the vehicle shifts to the stop state, the stop distance of the vehicle becomes longer than when the brake pressure is not reduced. On the other hand, for example, when a pedestrian jumps out into the travel lane or when the vehicle spins, it is necessary to stop the vehicle urgently. Even in such a case, if the brake pressure is reduced uniformly, a situation may occur in which the vehicle does not stop even when the stop position predicted by the driver is reached.

  Therefore, in order to solve the above-described problems, the present invention is a brake device that reduces the brake pressure when the vehicle shifts to a stop state, and can stop the vehicle in accordance with a driver's brake operation during emergency braking. An object of the present invention is to provide a vehicular brake device.

  The vehicle brake device according to the present invention includes a speed detection unit that detects a travel speed of the vehicle, and a brake pressure that is set to a predetermined pressure reduction target when the travel speed detected by the speed detection unit is less than or equal to a predetermined pressure reduction start speed. A pressure reduction control means for performing pressure reduction control for reducing the pressure to a brake pressure, and a determination means for determining whether or not the vehicle stabilization control is operating. The emergency braking time determination means is provided after the brake pedal is depressed. When it is determined by the determination means that the vehicle stabilization control is operating during the brake braking until the vehicle stops, a process for prohibiting the pressure reduction control and the pressure reduction target brake during the brake braking. At least one of a process for increasing the pressure and a process for decreasing the pressure reduction start speed is executed.

  According to the present invention, when it is determined that the vehicle stabilization control is operating during the brake braking, the process of prohibiting the pressure reduction control and the process of increasing the pressure reduction target brake pressure during the brake braking. Then, at least one of the processes for reducing the decompression start speed can be executed. Therefore, even in a brake device that reduces the brake pressure when the vehicle enters the stop state, the vehicle is adjusted in accordance with the driver's brake operation in the event of emergency braking where the vehicle stabilization control is activated. Can be stopped.

  The vehicle brake device according to the present invention includes a speed detection unit that detects a travel speed of the vehicle, and a brake pressure that is set to a predetermined pressure reduction target when the travel speed detected by the speed detection unit is less than or equal to a predetermined pressure reduction start speed. A pressure reduction control means for performing pressure reduction control for reducing the pressure to a brake pressure; and a determination means for determining whether or not the behavior of the vehicle is normal. The emergency braking time determination means includes a vehicle after the brake pedal is depressed. If the determination means determines that the vehicle behavior is abnormal during the brake braking until the vehicle stops, during the brake braking, a process for prohibiting the pressure reduction control and the pressure reduction target brake pressure are set. It is characterized in that at least one of a process for increasing and a process for decreasing the decompression start speed is executed.

  According to the present invention, when it is determined that the behavior of the vehicle is abnormal during brake braking, a process of prohibiting the pressure reduction control during the brake braking, a process of increasing the pressure reduction target brake pressure, At least one of the processes for reducing the decompression start speed can be executed. Therefore, even if the brake device reduces the brake pressure when the vehicle shifts to the stop state, the vehicle is adapted to the driver's brake operation in the event of emergency braking where the vehicle behavior is abnormal. Can be stopped.

  According to the vehicle brake device of the present invention, the brake pressure can be reduced when the vehicle shifts to the stop state, and the vehicle can be stopped in accordance with the driver's brake operation during emergency braking. .

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a vehicle brake device according to the present invention will be described with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted.

  FIG. 1 is a diagram illustrating a functional configuration of a vehicle brake device according to an embodiment. As shown in FIG. 1, the vehicle brake device 1 includes a speed detection unit 11 (speed detection unit), an emergency braking determination unit 12 (determination unit), and a pressure reduction control unit 13 (pressure reduction control unit).

  The speed detector 11 detects the traveling speed of the vehicle. For example, the speed detector 11 calculates the wheel speed of each wheel using signals from the rear wheel speed sensor and the front wheel speed sensor, and detects the fastest wheel speed among the calculated wheel speeds as the traveling speed. .

  The emergency braking determination unit 12 determines whether or not the vehicle situation when the brake pedal is depressed corresponds to the emergency braking. For emergency braking, for example, when vehicle stabilization control such as ABS (Antilock Brake System), VSC (Vehicle Stability Control) is activated, or when vehicle behavior is not normal, such as when the vehicle spins, This applies when the brake operation amount (depression amount) is large, or when the brake assist is activated.

  Specifically, the emergency braking time determination unit 12 controls any one of ABS, VSC, and brake assist by, for example, an ABS operation detection unit, a VSC operation detection unit, and a brake assist operation detection unit. When it is detected that is operating, it is determined that the emergency braking is applicable. Further, the emergency braking determination unit 12 determines that the behavior of the vehicle is abnormal when the turning radius calculated from the steering wheel angle based on the driver's steering wheel operation and the vehicle speed is equal to or less than a predetermined threshold, It is determined that it is applicable during braking. Further, the emergency braking time determination unit 12 determines that the brake operation amount is large and corresponds to emergency braking when the brake operation amount detected by the brake operation amount detection unit is equal to or greater than a predetermined threshold, for example. Note that these determination conditions may be employed alone or in appropriate combination. However, when determining according to the amount of brake operation and whether or not the brake assist is activated, it is determined whether or not emergency braking is taking into account only the driver's operation, whereas vehicle stabilization When determining according to whether or not the control is activated and whether the vehicle behavior is correct or not, it is determined whether it is emergency braking in consideration of not only the driver's operation but also the road surface condition. It is possible to accurately determine whether emergency braking is in progress.

  The depressurization control unit 13 performs depressurization control for depressurization while gradually decreasing the brake pressure to a predetermined depressurization target brake pressure when the traveling speed detected by the speed detection unit 11 is equal to or lower than a predetermined depressurization start speed. . Here, the pressure reduction start speed refers to a travel speed that becomes a threshold value when starting to reduce the brake pressure. The decompression start speed corresponds to a speed at which the traveling speed of the vehicle decreases and the vehicle shifts to a stop state, specifically, for example, about 5 km / h to 10 km / h. The reduced pressure target brake pressure is the final brake pressure after the brake pressure is gradually reduced. As this decompression target brake pressure, for example, a pressure corresponding to about 50% of the brake pressure at the start of decompression corresponds. By performing the pressure reduction control described above, the vehicle can be stopped while the brake pressure is gradually reduced (so-called smooth stop control) at a low speed when the vehicle shifts to the stop state. Vibration can be reduced and the vehicle body can be prevented from shaking back. In addition, about the detail of smooth stop control, the well-known technique described in the patent document 1 mentioned above is employable, for example.

  The depressurization control unit 13 includes a process of prohibiting the depressurization control, a process of increasing the depressurization target brake pressure, and a process of decreasing the depressurization start speed when the emergency braking time determination unit 12 determines that the emergency braking is applicable. Execute one of the processes. Note that these processes may be employed alone or in appropriate combination.

  The process for prohibiting the pressure reduction control is a process for prohibiting the pressure reduction control for reducing the brake pressure to the pressure reduction target brake pressure. When the process for prohibiting the decompression control is executed, the decompression control unit 13 does not perform the decompression control even when the traveling speed detected by the speed detection unit 11 is equal to or lower than the decompression start speed.

  The process for increasing the pressure reduction target brake pressure is a process for setting the pressure reduction target brake pressure to a pressure higher than the pressure during normal braking. More specifically, for example, when the target pressure for decompression at the time of normal braking is 50% of the brake pressure at the start of decompression, the target brake pressure at the time of emergency braking is reduced to the brake pressure at the time of start of decompression. This corresponds to setting the pressure to 75%. When the process of increasing the pressure reduction target brake pressure is executed, the brake pressure is not reduced compared with that during normal braking, so that the braking force increases and can be made closer to the braking force according to the driver's brake operation.

  The process of reducing the pressure reduction start speed is a process of setting the traveling speed when starting to reduce the brake pressure to a speed slower than the speed during normal braking. More specifically, for example, when the decompression start speed during normal braking is 10 km / h, this corresponds to setting the decompression start speed during emergency braking to 5 km / h. When the process for reducing the pressure reduction start speed is executed, the pressure reduction control is started at a speed slower than that during normal braking, so that the braking force can be made closer to the driver's braking operation.

  Next, a brake control process of the vehicle brake device 1 will be described with reference to FIGS. 2 is a flowchart showing a brake control process when a process for prohibiting the pressure reduction control is performed, FIG. 3 is a flowchart showing a brake control process when a process for increasing the pressure reduction target brake pressure is performed, and FIG. FIG. 6 is a flowchart showing a brake control process in a case where a process for reducing the pressure reduction start speed is performed. These brake control processes start when the brake pedal is depressed, and end when the brake pedal is released or the vehicle stops.

  With reference to FIG. 2, the brake control process in the case of performing the process which prohibits pressure reduction control is demonstrated. First, the emergency braking determination unit 12 of the vehicle brake device 1 determines whether or not the vehicle situation when the brake pedal is depressed corresponds to emergency braking (step S1). When this determination is YES (step S1; YES), a process for prohibiting the pressure reduction control is executed (step S6). As a result, a normal brake control process that does not perform the smooth stop control by the pressure reduction control is executed.

  On the other hand, if it is determined in step S1 that the vehicle does not correspond to emergency braking (step S1; NO), the decompression control unit 13 of the vehicle brake device 1 detects the vehicle traveling speed detected by the speed detection unit 11. Is determined to be 10 km / h or less (step S2). If this determination is NO (step S2; NO), the determination in step S2 is repeated.

  On the other hand, when it is determined in step S2 that the traveling speed is 10 km / h or less (step S2; YES), the pressure reduction control unit 13 of the vehicle brake device 1 starts the pressure reduction control (step S3). ). As a result, the smooth stop control is performed while the brake pressure is gradually lowered to the reduced pressure target brake pressure.

  Next, the decompression control unit 13 of the vehicle brake device 1 determines whether or not the vehicle has stopped (step S4). If this determination is NO (step S4; NO), the determination in step S4 is repeated.

  On the other hand, when it is determined in step S4 that the vehicle has stopped (step S4; YES), the pressure reduction control unit 13 of the vehicle brake device 1 ends the pressure reduction control (step S5).

  With reference to FIG. 3, the brake control process in the case of performing the process which raises pressure reduction target brake pressure is demonstrated. Note that the processing from step S12 to S15 shown in FIG. 3 has the same processing contents as the processing from step S2 to S5 shown in FIG.

  First, the emergency braking determination unit 12 of the vehicle brake device 1 determines whether or not the vehicle situation when the brake pedal is depressed corresponds to the emergency braking (step S11). If this determination is NO (step S11; NO), the process proceeds to step S12.

  On the other hand, if it is determined in step S11 that the emergency braking is applied (step S11; YES), the pressure reduction control unit 13 of the vehicle brake device 1 uses the pressure reduction target brake pressure as the pressure reduction target brake during normal braking. A pressure higher than the pressure is set (step S16). Thereby, when the pressure reduction control is started thereafter, the smooth stop control is performed while the brake pressure is gradually lowered to the pressure reduction target brake pressure after the setting change.

  With reference to FIG. 4, the brake control process in the case of performing the process of reducing the pressure reduction start speed will be described. Note that the processing from step S22 to S25 shown in FIG. 4 has the same processing contents as the processing from step S2 to S5 shown in FIG.

  First, the emergency braking determination unit 12 of the vehicle brake device 1 determines whether or not the vehicle situation when the brake pedal is depressed corresponds to the emergency braking (step S21). If this determination is NO (step S21; NO), the process proceeds to step S22.

  On the other hand, if it is determined in step S21 that the emergency braking is applied (step S21; YES), the decompression control unit 13 of the vehicle brake device 1 sets the decompression start speed from the decompression start speed during normal braking. Is set to a slow speed (step S26).

  Next, the decompression control unit 13 of the vehicle brake device 1 determines whether or not the traveling speed of the vehicle detected by the speed detection unit 11 is 5 km / h or less (step S27). If this determination is NO (step S27; NO), the determination in step S27 is repeated.

  On the other hand, when it is determined in step S27 that the traveling speed is 5 km / h or less (step S27; YES), the pressure reduction control unit 13 of the vehicle brake device 1 starts the pressure reduction control (step S23). ). As a result, the smooth stop control is performed while the brake pressure is gradually lowered to the reduced pressure target brake pressure.

  As described above, according to the vehicle brake device 1 of the present embodiment, when it is determined that the vehicle situation when the brake pedal is depressed corresponds to the time of emergency braking, the process of prohibiting the pressure reduction control and the pressure reduction Either of the process of increasing the target brake pressure and the process of decreasing the pressure reduction start speed can be executed. Therefore, even if the brake device performs pressure reduction control for reducing the brake pressure when the vehicle shifts to the stop state, the vehicle can be stopped in accordance with the driver's brake operation in the case of emergency braking. .

  In the above-described embodiment, when the vehicle situation when the brake pedal is depressed corresponds to emergency braking, processing for prohibiting pressure reduction control, processing for increasing the pressure reduction target brake pressure, and processing for decreasing the pressure reduction start speed However, the condition for executing each process is not limited to this. For example, each of the above processes can be executed even when the vehicle situation corresponds to emergency braking after the brake pedal is depressed. Therefore, in consideration of these, when it is determined that the vehicle situation corresponds to emergency braking during the period from when the brake pedal is depressed until the vehicle stops (during braking), the above processing is performed during braking. Can be executed.

It is a figure which illustrates functional composition of a brake device for vehicles in an embodiment of an invention. It is a flowchart for demonstrating the brake control process in the case of performing the process which prohibits pressure reduction control. It is a flowchart for demonstrating the brake control process in the case of performing the process which raises pressure reduction target brake pressure. It is a flowchart for demonstrating the brake control process in the case of performing the process which reduces pressure reduction start speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle brake device, 11 ... Speed detection part, 12 ... Emergency braking time determination part, 13 ... Decompression control part.

Claims (2)

Speed detecting means for detecting the traveling speed of the vehicle;
Pressure reduction control means for performing pressure reduction control for reducing the brake pressure to a predetermined pressure reduction target brake pressure when the traveling speed detected by the speed detection means is equal to or lower than a predetermined pressure reduction start speed;
Determining means for determining whether or not the vehicle stabilization control is operating,
The emergency braking time determination means, when it is determined by the determination means that the vehicle stabilization control is operating during the brake braking from when the brake pedal is depressed until the vehicle stops. During braking, at least one of a process for prohibiting the pressure reduction control, a process for increasing the pressure reduction target brake pressure, and a process for reducing the pressure reduction start speed is executed. apparatus. Speed detecting means for detecting the traveling speed of the vehicle;
Pressure reduction control means for performing pressure reduction control for reducing the brake pressure to a predetermined pressure reduction target brake pressure when the traveling speed detected by the speed detection means is equal to or lower than a predetermined pressure reduction start speed;
Determination means for determining whether or not the behavior of the vehicle is normal,
The emergency braking time determination means determines that the brake is applied when the determination means determines that the behavior of the vehicle is abnormal during brake braking from when the brake pedal is depressed until the vehicle stops. During braking, at least one of a process for prohibiting the pressure reduction control, a process for increasing the pressure reduction target brake pressure, and a process for reducing the pressure reduction start speed is executed. .

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