JPH11348748A - Vehicle parking brake safety device - Google Patents

Abstract

(57) [Summary] [Problem] To prevent improper automatic stop due to shaking of a vehicle such as loading work, and to reliably perform a short distance even if the vehicle moves slowly due to a slope of a road surface or the like. Provided is a vehicle parking brake safety device that can be detected and automatically stopped. SOLUTION: A time interval ΔT of a pulse signal of a vehicle speed sensor.
If n + 1 is longer than the previous ΔTn (step S
55) The count value of the first counter is reset (step S60). When the generated pulse signal is due to the shaking of the vehicle caused by loading work, etc.,
Since the time interval of the pulse signal gradually increases with the decay of the fluctuation, the count value of the No. 1 counter is reset,
In other cases, the number of pulses continues to be accumulated without being reset, assuming that the vehicle has started moving.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for a parking brake for a vehicle.

[0002]

2. Description of the Related Art Conventionally, a parking brake safety device has been put to practical use that automatically stops a vehicle on the assumption that a parked vehicle starts moving naturally due to the inclination of a road surface due to insufficient operation of a parking brake or the like. I have. This type of safety device includes, for example, turning on a parking switch that detects an operation of a parking brake, detection of a vehicle speed by a vehicle speed sensor,
The automatic stop described above is executed when a preset condition such as detection of engine stop by a key switch is satisfied.

[0003] The presence or absence of the movement of the vehicle is determined based on the detection of the vehicle speed sensor. However, erroneous determination may occur due to the principle of the vehicle speed detection. That is, the vehicle speed sensor detects a change in the magnetic flux density of the magnet rotating plate that rotates together with the propeller shaft by the Hall element, shapes the output of the Hall element, and obtains a pulse signal having a period proportional to the vehicle speed. Then, the number of pulses from the vehicle speed sensor reaches a predetermined count value (the vehicle has moved by a corresponding distance).
When running an automatic stop. However, for example, even when the vehicle shakes during loading work or the like, the magnet rotating plate is slightly rotated and displaced together with the propeller shaft, so that the count value is accumulated even though the vehicle is not moving, and the automatic stop is performed. Was executed.

[0004] As a countermeasure, the present applicant has filed Japanese Patent Application No.
No. 021482 proposes a parking brake safety device. In this device, the number of pulses of the vehicle speed sensor is equal to a predetermined number (for example, 17, 6
0 cm), the automatic stop is executed at the time when the distance reaches 0 cm), and as shown in FIG. 3, the edge interval (time interval) ΔTn of the pulse signal is set to a predetermined value (for example, 3 sec) with the attenuation of the vehicle shake. (At time t1), the count value is reset on the assumption that the vehicle is shaking due to a loading operation or the like, and inappropriate automatic stop is prevented.

[0005]

However, in the above-mentioned determination focusing on the time interval of the pulse signal, as shown in FIG. 4, as long as the edge interval ΔTn exceeding 3 sec is continuous (that is, the moving speed of the vehicle is slow, As long as the vehicle is moving, there is a problem that the count is kept zero even if the vehicle is moving and the automatic stop is not executed. In the vehicle parking brake safety device of the earlier application, 3se
Another automatic stop condition is set so that automatic stop is executed when a predetermined number of counts are performed even if the edge interval ΔTn exceeds c. However, since this is an emergency measure, the count value is sufficiently large compared to the above-described normal setting (for example, 100;
cm) is set, and there is a problem that the vehicle cannot be stopped automatically unless it moves a considerable distance.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent an improper automatic stop due to shaking of a vehicle such as a loading operation from being performed, and to ensure a short distance even when the vehicle is slowly moving due to a slope of a road surface. It is an object of the present invention to provide a vehicle parking brake safety device that can be detected and automatically stopped.

[0007]

In order to achieve the above object, according to the present invention, when a time interval of a pulse signal of a vehicle speed sensor becomes longer than the previous time, a reset judgment is made by a signal judging means and the judgment is made. The reset means resets the cumulative value of the number of detected pulses. In other words, when the generated pulse signal is due to the sway of the vehicle caused by the loading operation or the like, the time interval of the pulse signal gradually increases with the decay of the sway,
When the accumulated value of the detected pulse number is reset and the change of the time interval of the pulse signal is other than that, the pulse number continues to be accumulated without being reset assuming that the vehicle starts moving, and the accumulated value reaches a predetermined value. Then, the braking force assisting means operates.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a safety device for a parking brake for a vehicle embodying the present invention will be described below.

As shown in the schematic block diagram of FIG.
The control system of the parking brake safety device according to the present embodiment includes an input unit 1
9, a control calculation unit 20, and a braking force assisting unit 33. The control calculation unit 20 includes a parking brake operation state detection unit 21, a counter unit 22, a signal determination unit 30, a reset unit 26, and a control condition setting unit 27.
The counter means 22 and the control condition setting section 27 constitute a control means.

From the input unit 19, required input signals, for example, a contact signal of the parking switch 10, a detection signal of the vehicle speed sensor 11, a contact signal for detecting that the shift position of the neutral switch 12 is in the neutral position, a stop lamp A contact signal indicating the state of the foot brake being depressed by the switch 13, a signal such as the on / off of the key switch 17, a computer start checked signal (not under initial check) required for other control systems, and a predetermined voltage of the battery power supply voltage 15, the signal 16 indicating that the lock brake is not operating, the signal 18 indicating that the clutch contact has been set, and the like, are input to the control calculation unit 20. The parking brake is stopped .

Next, it is confirmed by the detection means of the vehicle speed sensor 11 that the parking brake is moving despite the operation of the parking brake by the counter means 22, and the vehicle speed and the moving amount are calculated. The braking force assisting means 33 is appropriately operated to apply a braking force to wheels of the vehicle to stop the vehicle.

The operation of the braking force assisting means 33 is a combination of a plurality of setting elements to constitute two sets of operating mechanisms.
The setting element is the parking brake operating state detecting means 2.
According to 1, the setting element 28 that "the braking force assisting means 33 can be operated only during the parking brake operation" via the contact signal of the parking switch 10 of the input unit 19
Set.

Next, the counter means 22 incorporates a first counter 23, a second counter 24, and a timer 25. The detection signal of the vehicle speed sensor 11 of the input unit 19 is input to the first counter 23, To calculate the vehicle speed V,
Only when <0.2 km / h, the braking force assisting means 33 can be operated. "

Next, the first counter 2 of the counter means 22
3, the counter 23 does not satisfy the signal determination means 30 (for example, the edge interval ΔTn + 1 of the current pulse signal is a value obtained by multiplying the previous edge interval ΔTn by a constant C equal to or greater than 1). (A signal at the time of smaller value) is accumulated to obtain an accumulated signal S1 corresponding to the moving distance of the vehicle, and the operation of the braking force assisting means 33 is possible only when S1 reaches a predetermined value α (for example, 17). A setting element 31 is set to "Yes".

Next, the second counter 2 of the counter means 22
4, the counter 24 accumulates the detection signals from the vehicle speed sensor 11 irrespective of whether or not the signal determination means 30 is satisfied, and obtains an accumulated signal value S2 corresponding to the movement of the vehicle. The operation of the braking force assisting means 33 is possible only when the predetermined value β (for example, 100) is reached. "

As shown in FIG. 1, the above setting elements are combined, and when all of the setting elements 28, 29, and 32 are satisfied, and when all of the setting elements 28, 29, and 31 are satisfied, control is performed. The power assisting means 33 is operated to constitute a dual operation mechanism for stopping the movement of the vehicle.

Since the safety device for a parking brake for a vehicle according to the present invention shown in FIG. 1 is configured as described above, it operates as follows as shown in the flowchart of FIG.

First, in step S50, it is determined whether or not each condition for operating the parking brake safety device is satisfied while the vehicle is parked, based on the signals indicated by 10 to 18 above. If the determination in step S50 is NO (negative), the No. 2 counter 24 is reset in step S59,
In step S60, the first counter 23 is reset.
If the determination in step S50 is YES (Yes), the detection signal of the vehicle speed sensor 11 is input to the counter 22 of the control calculation unit 20 in step S51, and the flow proceeds to step S5.
At 2, it is determined whether or not a pulse edge of the detection signal has been detected. When an edge is detected and YES is determined,
In step S53, the first counter 23 and the second counter 2
1 is added to 4 and it is determined in step S54 whether or not the pulse is the first pulse. If NO is determined for the second and subsequent pulses, the process moves to step S55 to determine whether or not the following condition is satisfied.

ΔTn + 1> C × ΔTn where ΔTn + 1 is the edge interval of the current pulse signal, ΔTn + 1
Tn is the previous edge interval, and C is a constant of 1 or more. That is, the above equation means that the present edge interval ΔTn + 1 is increased with respect to the previous edge interval ΔTn, and the rate of increase is determined according to C. If the increase rate of the actual edge interval is equal to or less than the constant C (including the case where the edge interval is invariable and decreases) and the above condition is not satisfied, NO is determined in step S55, and the first counter is determined in step S56. It is determined in step S whether or not the count value of 23 has reached 17.
At 57, it is determined whether or not the count value of the second counter 24 has reached 100. Y in any step S
When it is determined as ES, the braking force assisting means 33 is operated in step S58.

When the determination in step S55 is YES, that is, when the rate of increase in the edge interval exceeds the constant C and satisfies the above equation, the process proceeds to step S60 to reset the first counter 23. Therefore, the first counter 23
Will be accumulated again from 0.

FIGS. 3 and 4 show the processing status of the above counter.
When a pulse signal is generated due to the shaking of the vehicle due to a loading operation or the like, as shown in FIG. 3, the interval between the pulse edges gradually increases as the shaking attenuates. Since the increase rate of the edge interval at this time exceeds the constant C in the above equation, the condition in the above equation is continuously satisfied for each pulse edge, and the first counter 23 is maintained at 0 without being accumulated. You. In other words, the value of the constant C is determined so that the above equation is satisfied by the increase rate of the edge interval caused by the vehicle shake. Therefore, even when the vehicle shakes due to the loading operation or the like, it is possible to prevent a situation in which the automatic stop is inappropriately executed.

On the other hand, the movement of the vehicle originally assumed by the parking brake safety device is caused by the inclination of the road surface when the parking brake operation is insufficient or the like. Therefore, the moving speed generally shows a tendency to gradually increase from 0 in the stopped state, and it is not considered that a significant deceleration occurs. The edge interval at this time indicates any state of decrease, invariance, or slight increase irrespective of the level of the moving speed, and there is no possibility that the increase rate exceeds the constant C (satisfies the above equation). . As a result, as shown in FIG. 4, even if the movement of the vehicle is slow, the first counter 23 continues to be accumulated and a predetermined number (for example, 17, which is much smaller than the second counter 24, 60 cm in distance). ), The automatic stop is performed immediately at the time of T2, and the vehicle can be reliably stopped at a very short distance.

Although the description of the embodiments has been completed above, embodiments of the present invention are not limited to these embodiments. For example,
In the above embodiment, the second counter 2 that is unconditionally accumulated is separate from the first counter 23 that is accumulated based on the above equation.
4 were provided. This No. 2 counter 24 is based on the assumption that the No. 1 counter 23 is not accumulated assuming that the increase rate of the edge interval does not satisfy the above equation, although the vehicle actually starts moving. If the value of the constant C is appropriately set as described above, it is possible to reliably accumulate the No. 1 counter 23 as the vehicle starts moving.
The processing relating to the second counter 24 may be omitted.

[0024]

As described above, according to the vehicle parking brake safety device of the present invention, when the time interval of the pulse signal of the vehicle speed sensor is longer than the previous time, that is, when the generated pulse signal is used for loading work or the like. When it is caused by the shaking of the vehicle caused by the above, the accumulated value of the number of detected pulses is reset, so that inappropriate execution of the automatic stop can be prevented. Since the detection pulse signal continues to be accumulated without resetting assuming that the vehicle has started to move, even if the vehicle moves slowly, the automatic stop is executed immediately when the accumulated value reaches the predetermined value, and the The vehicle can be reliably stopped at a distance.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a control system of a safety device for a vehicle parking brake according to an embodiment.

FIG. 2 is a flowchart executed by a control calculation unit of a safety device for a vehicle parking brake.

FIG. 3 is a time chart showing the accumulated state of the first counter of the conventional example and the embodiment when the vehicle shakes.

FIG. 4 is a time chart showing the accumulated state of the first counter of the conventional example and the embodiment when the moving speed of the vehicle is slow.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Vehicle speed sensor 21 Parking brake operation state detection means 22 Counter means as control means 26 Reset means 27 Control condition setting part as control means 30 Signal determination means 33 Braking force assisting means

Claims (1)

[Claims] 1. A vehicle speed sensor for detecting the rotation of a rotating body that rotates in accordance with a vehicle speed as a pulse signal, a parking brake operating state detecting means for detecting an operating state of a parking brake, and independent of a braking operation by a driver. Braking force assisting means provided so as to be able to apply a braking force to the vehicle, and detecting the number of pulses detected by the vehicle speed sensor when the parking brake is being operated by the parking brake operating state detecting means. Control means for activating the braking force assisting means when the accumulated value reaches a predetermined value; and the parking brake is being operated, and the time interval of the pulse signal detected from the vehicle speed sensor is the same as the previous time interval. A signal determination means for making a reset determination when the signal time interval becomes longer, and when a reset determination is made by the signal determination means,
And a reset means for resetting the cumulative value of the number of pulses detected by the control means.