JP3651554B2 - Vehicle parking brake safety device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a safety device for a parking brake for a vehicle.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a parking brake safety device that automatically stops a vehicle has been put into practical use, assuming that a parked vehicle starts to move naturally due to a slope of a road surface due to insufficient parking brake operation or the like. This type of safety device is, for example, when a preset condition such as turning on a parking switch that detects the operation of a parking brake, detecting a vehicle speed with a vehicle speed sensor, or detecting an engine stop with a key switch is satisfied. The automatic stop has been executed.
[0003]
Whether or not the vehicle starts to move is determined based on the detection of the vehicle speed sensor, but erroneous determination may occur due to the principle of 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 a Hall element, and forms a waveform of the output of the Hall element to obtain a pulse signal having a period proportional to the vehicle speed. When the number of pulses from the vehicle speed sensor reaches a predetermined count value (the vehicle has moved by a corresponding distance), automatic stop is executed. However, for example, even when the vehicle shakes during loading work etc., the magnet rotating plate moves slightly with the propeller shaft, so the count value is accumulated even if the vehicle has not started moving, and the automatic stop Has been executed.
[0004]
As a countermeasure, the present applicant has proposed a parking brake safety device described in Japanese Patent Application No. 10-021482. As shown in FIG. 3, this apparatus is configured to perform automatic stop when the number of pulses of the vehicle speed sensor reaches a predetermined number (for example, 17, converted to a distance of 60 cm) as in the above-described apparatus. In addition, when the edge interval (time interval) ΔTn of the pulse signal exceeds a predetermined value (for example, 3 seconds) due to the attenuation of the vehicle shake (at time t1), the count value is regarded as a vehicle shake due to loading work or the like. To prevent inappropriate automatic stop.
[0005]
[Problems to be solved by the invention]
However, in the determination focusing on the time interval of the pulse signal described above, as shown in FIG. 4, as long as the edge interval ΔTn exceeding 3 seconds continues (that is, as long as the moving speed of the vehicle is slow), the tailing vehicle moves. However, there is a problem that the count remains 0 and the automatic stop is not executed. In the vehicle parking brake safety device of the previous application, as a countermeasure, another automatic stop condition is set so that the automatic stop is executed when a predetermined number is counted even when the edge interval ΔTn exceeds 3 seconds. Yes. However, since this is only an emergency measure, a sufficiently large count value (for example, 100, 300 cm in terms of distance) is set compared to the normal setting described above, and the vehicle must move a considerable distance. There was a problem that it was not automatically stopped.
[0006]
The object of the present invention is to prevent an improper automatic stop due to vehicle shaking such as loading work, and to reliably detect even a slow movement of the vehicle due to road inclination, etc. in a short distance. It is an object of the present invention to provide a vehicle parking brake safety device that can be automatically stopped.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, when the time interval of the pulse signal of the vehicle speed sensor becomes longer than the previous time, the signal determination unit makes a reset determination, and based on the determination, the reset unit detects the number of detected pulses. It was configured to reset the cumulative value of. In other words, when the generated pulse signal is due to a vehicle shake caused by loading work or the like, the time interval of the pulse signal gradually increases with the attenuation of the shake, so the accumulated value of the number of detected pulses is reset. When the change in the time interval of the pulse signal is other than that, it is regarded that the vehicle starts to move, and the number of pulses continues to be accumulated without being reset. When the accumulated value reaches a predetermined value, the braking force assisting means is activated.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a vehicle parking brake safety device embodying the present invention will be described.
[0009]
As shown in the schematic block diagram of FIG. 1, the control system of the parking brake safety device according to the present embodiment includes an input unit 19, a control calculation unit 20, and braking force assisting means 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 unit 22 and the control condition setting unit 27 constitute a control unit.
[0010]
From the input unit 19, 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, and a stop lamp switch 13. A contact signal indicating the foot brake depression state, a key switch 17 on / off signal, etc., and a computer start check signal 14 (not under initial check) required for other control systems, and the status of holding the battery power supply voltage at a predetermined voltage. A signal 15 indicating that the lock brake is not operating, a clutch contact set signal 18 and the like are input to the control arithmetic unit 20. First, the parking brake operating state detecting means 21 causes the vehicle to park the parking brake via the parking switch 10. Confirm that the machine is in a stopped state.
[0011]
Next, the counter means 22 confirms that the parking brake is moving despite the operation, based on the detection signal of the vehicle speed sensor 11, calculates the vehicle speed and the moving amount, and assists the braking force by collecting the respective setting elements. The means 33 is actuated as appropriate to apply a braking force to the vehicle wheel to stop the vehicle.
[0012]
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, and the setting elements are
The setting element 28 is set by the parking brake operating state detecting means 21 through the contact signal of the parking switch 10 of the input unit 19 so that “the braking force assisting means 33 can be operated only while the parking brake is operating”. To do.
[0013]
Next, the counter means 22 includes a No. 1 counter 23, a No. 2 counter 24, and a timer 25. The detection signal of the vehicle speed sensor 11 of the input unit 19 is input to the No. 1 counter 23, and the vehicle speed V is passed through the timer 25. Is set, and a setting element 29 is set that “the braking force assisting means 33 can be operated only when V <0.2 km / h”.
[0014]
Next, the No. 1 counter 23 of the counter means 22 is used, and the counter 23 does not satisfy the signal determination means 30 (for example, the edge interval ΔTn + 1 of the current pulse signal is the previous edge interval ΔTn). And a cumulative signal S1 corresponding to the moving distance of the vehicle is obtained, and “only when S1 reaches a predetermined value α (for example, 17)” is accumulated. The setting element 31 is set to “the operation of the braking force assisting means 33 is possible”.
[0015]
Next, the No. 2 counter 24 of the counter means 22 is used, and the detection signals from the vehicle speed sensor 11 are accumulated regardless of whether or not the signal determination means 30 is satisfied by the counter 24, and the accumulation corresponds to the movement of the vehicle. After obtaining the signal value S2, the setting element 32 is set such that the braking force assisting means 33 can be operated only when S2 reaches another predetermined value β (for example, 100).
[0016]
Combining the above setting elements, as shown in FIG.
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, the braking force assisting means 33 is activated to stop the movement of the vehicle. Constructs a heavy operating mechanism.
[0017]
Since the vehicle parking brake safety device of the present invention shown in FIG. 1 is configured as described above, it operates as follows as shown in the flowchart of FIG.
[0018]
First, in step S50, based on the signals shown in the above 10 to 18, it is determined whether or not each condition for operating the parking brake safety device is established while the vehicle is parked. When the determination in step S50 is NO (No), the number 2 counter 24 is reset in step S59, and the number 1 counter 23 is reset in step S60. When the determination in step S50 is YES (positive), the detection signal of the vehicle speed sensor 11 is input to the counter means 22 of the control calculation unit 20 in step S51, and whether or not the pulse edge of the detection signal is detected in step S52. Determine. When the edge is detected and it is determined YES, 1 is added to the No. 1 counter 23 and the No. 2 counter 24 in Step S53, and it is determined whether or not it is the first pulse in Step S54. When it is determined NO in the second and subsequent pulses, the process proceeds to step S55 and it is determined whether or not the condition of the following equation is satisfied.
[0019]
ΔTn + 1> C × ΔTn
Here, ΔTn + 1 is the edge interval of the current pulse signal, ΔTn is the previous edge interval, and C is a constant of 1 or more. That is, the above equation means that the current edge interval ΔTn + 1 is increased with respect to the previous edge interval ΔTn, and the increase rate is determined according to C. When the actual increase rate of the edge interval is equal to or less than the constant C (including the case where the edge interval is unchanged and decreased), it is determined NO in step S55, and the No. 1 counter is determined in step S56. In step S57, it is determined whether the count value of No. 2 counter 24 has reached 100 or not. If YES is determined in any step S, the braking force assisting means 33 is operated in step S58.
[0020]
If the determination in step S55 is YES, that is, if the increase rate of the edge interval exceeds the constant C and satisfies the above equation, the process proceeds to step S60 and the No. 1 counter 23 is reset. Accordingly, the No. 1 counter 23 is accumulated from 0 again.
[0021]
The processing status of the counter described above will be described with reference to the time charts of FIGS. 3 and 4. 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. Edge spacing increases gradually. Since the increase rate of the edge interval at this time exceeds the constant C of the above equation, the condition of the above equation continues to be satisfied for each pulse edge, and the No. 1 counter 23 is kept at 0 without being accumulated. The In other words, the value of the constant C is determined so that the above equation is satisfied by the increasing rate of the edge interval caused by the vehicle shake. Therefore, even when the vehicle shakes due to the loading operation or the like as described above, it is possible to prevent the situation where the automatic stop is improperly performed.
[0022]
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 there is an insufficient operation of the parking brake. Accordingly, the movement speed generally shows a tendency to gradually increase from 0 in the stop state, and a significant deceleration is not conceivable, and if it is such a deceleration, it is not necessary to automatically stop. At this time, the edge interval shows either a decrease, no change, or a slight increase regardless of the movement speed, and there is no possibility of showing an increase rate exceeding the constant C (satisfying the above equation). . As a result, as shown in FIG. 4, even if the moving vehicle is slow, the No. 1 counter 23 continues to be accumulated, for example, 17 which is much smaller than the No. 2 counter 24, 60 cm in terms of distance. The automatic stop is promptly executed at the time T2 when reaching (2), and the vehicle can be surely stopped at a very short distance.
[0023]
This is the end of the description of the embodiment. However, the embodiment of the present invention is not limited to this embodiment. For example, in the above-described embodiment, the No. 2 counter 24 that is accumulated unconditionally is provided separately from the No. 1 counter 23 that is accumulated based on the above equation. This No. 2 counter 24 assumes that the No. 1 counter 23 is not accumulated because the rate of increase in the edge interval does not satisfy the above equation even though the vehicle is actually moving. If the value of the constant C is appropriately set as described above, the No. 1 counter 23 can be accumulated reliably as the vehicle starts to move, and therefore the processing relating to the No. 2 counter 24 may be omitted.
[0024]
【The invention's effect】
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, the generated pulse signal of the vehicle generated during loading work or the like. If it is caused by shaking, the accumulated value of the number of detected pulses is reset, so that inappropriate automatic stop can be prevented, and if the change in the time interval of the pulse signal is other than that, it is regarded as the start of vehicle movement. Since the detection pulse signal continues to be accumulated without resetting, even if the vehicle moves slowly, the vehicle automatically stops immediately when the accumulated value reaches a predetermined value, and the vehicle is surely secured in a very short distance. Can be stopped.
[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 the vehicle parking brake safety device.
FIG. 3 is a time chart showing a cumulative state of the No. 1 counter of the conventional example and the example when the vehicle shakes.
FIG. 4 is a time chart showing a cumulative state of the No. 1 counter of the conventional example and the example 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 26 as control means Reset means 27 Control condition setting part 30 as control means Signal determination means 33 Braking force auxiliary means

Claims (1)

A vehicle speed sensor that detects the rotation of the rotating body that rotates in accordance with the vehicle speed as a pulse signal;
Parking brake operating state detecting means for detecting the operating state of the parking brake;
Braking force assisting means provided so as to be able to apply braking force to the vehicle independently of the braking operation by the driver;
When the parking brake operating state detecting means detects that the parking brake is operating, the number of detected pulses of the vehicle speed sensor is accumulated, and when the accumulated value reaches a predetermined value, the braking force assist Control means for actuating the means;
Signal determination means for making a reset determination when the parking brake is in operation and the time interval of the pulse signal detected from the vehicle speed sensor is longer than the previous signal time interval;
A safety device for a parking brake for a vehicle, comprising: reset means for resetting a cumulative value of the number of detected pulses by the control means when a reset judgment is made by the signal judgment means.

Images