JPH0958428A - Braking force maintaining device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a vehicle to start and stop through only the operation of a brake pedal by detecting the step-on quantity and time of a brake pedal, and releasing braking force when a state where the step-on quantity of the brake pedal is larger than fixed value continues longer than fixed time. SOLUTION: A brake sensor 6a is provided on a brake pedal 6 to detect the step-on quantity of the brake pedal 6 for outputting a signal corresponding to the step-on quantity to an electronic controller 10, and whether the brake pedal 6 is pressed down so as to generate braking force to check creeping force or not, and whether the counted value of a counter is more than set up value or not are checked on the signal outputted from the brake pedal sensor 6a. Namely, whether the brake pedal 6 has been stepped on again so as to generate the braking force to check the creeping force longer than a fixed time or not is judged. In this case, the above state is judged to be a short time stop during running on a jammed road and garaging a car, and a braking force maintaining device 4 is therefore released, and the running of a vehicle is made possible only by releasing the brake pedal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force holding device for holding a braking force of a vehicle.

[0002]

2. Description of the Related Art Conventionally, a fluid torque converter type automatic transmission for converting engine torque using a fluid has been widely used in vehicles. In a vehicle equipped with this type of fluid torque converter type automatic transmission, if the transmission is in the driving range even if the accelerator pedal is released, some power is transmitted to the wheels due to the action of the fluid of the torque converter. This causes a so-called creep phenomenon in which the vehicle starts to move. To prevent this creep phenomenon, Japanese Patent Publication No. 5-26704
The publication discloses a device for holding the braking force of a brake as shown in FIG. According to this document, an electromagnetic valve 4a is provided between the master cylinder 5 and the hydraulic brake 3a for the wheel,
A braking force holding device 4 including a check valve 4b is provided, and the solenoid valve 4a of the braking force control device 4 is controlled by the electronic control device 10 to hold the hydraulic pressure of the hydraulic brake 3a.
It is to cancel. That is, when the vehicle is temporarily stopped at an intersection where it is necessary to prevent the vehicle from starting to move due to the creep phenomenon, it is determined by the position of the select lever, the vehicle speed, the accelerator pedal depression amount, the engine speed, and the brake pedal depression / existence. The hydraulic pressure of the hydraulic brake 3a is held by operating the valve 4a, and the held hydraulic pressure is released depending on the engine speed, the vehicle speed, and the presence or absence of the accelerator pedal depression.

[0003]

In the technique disclosed in the above prior art, the hydraulic pressure held by the hydraulic brake 3a is released when the engine speed or the vehicle speed is equal to or higher than a set value and the accelerator pedal is depressed. Has been done. However, in a vehicle equipped with an automatic transmission, such as when traveling on a congested road or when entering a garage, it is necessary to stop the vehicle only by operating the brake pedal without depressing the accelerator pedal. is there. In the above-mentioned conventional one, the hydraulic pressure of the brake is still held even in such a case, and at that time, it is necessary to depress the accelerator pedal at the time of starting, and the brake operation and the accelerator operation are repeated, which means that the operation is complicated. There was a problem.

[0004]

In order to solve the above problems, according to the present invention, a hydraulic torque converter type automatic transmission is provided, which is caused by the depression of the brake pedal when the braking force holding condition is satisfied. In a braking force holding device for a vehicle that holds hydraulic pressure, a brake pedal sensor that detects a depression amount of the brake pedal and a timer that detects a depression time of the brake pedal are provided, and the depression amount of the brake pedal is a predetermined value or more. There is provided a braking force holding device that releases the braking force when the above state continues for a predetermined time or longer.

[0005]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention.
In the figure, 1 is a well-known fluid torque converter including three types of impellers, a pump impeller 1a is attached to an input shaft 1b connected to a crankshaft of an engine (not shown), and a turbine liner 1c is attached to an output shaft 1d. The stator 1e is simplified and the stator 1e is fixed to the case.
Is attached via a one-way clutch 1g.
When the pump impeller 1a is driven by the rotation of the engine, the turbine liner 1c is driven by the action of the fluid due to the centrifugal force, and the torque is transmitted to the output shaft 1d. Reference numeral 2 is a transmission using a predetermined gear mechanism, and the rotational force of the output shaft 1d is changed by the gear mechanism and transmitted to the wheels 3. A vehicle speed sensor 2a detects a vehicle speed corresponding to the rotation speed of a predetermined gear of the transmission 2 and outputs the vehicle speed to an electronic control unit described later. Also, 3a
Is a wheel cylinder, which is provided in engagement with the wheels 3 and applies a braking force to the wheels 3 when hydraulic pressure is applied.

The braking force retaining device 4 includes a solenoid valve 4a and a check valve 4
b, and has a master cylinder 5 and a wheel cylinder 3a.
Is connected to the hydraulic path between the wheel cylinder 3a and the hydraulic pressure from the master cylinder 5 when the brake pedal 6 is depressed when the vehicle is braked, and the solenoid valve 4a
When is on, the hydraulic pressure of the wheel cylinders 3a is held to hold the braking force of the wheels 3. In addition, 6a
Is a brake sensor provided on the brake pedal 6, detects the amount of depression of the brake pedal 6, and outputs a signal corresponding to the amount of depression to the electronic control unit 10. 7a is an accelerator sensor that detects the amount of depression of the accelerator pedal 7,
Reference numeral 8a is a select sensor that detects the select position of the select lever 8, and 9 is an engine rotation sensor that detects the number of revolutions of the engine, and outputs the detected signals to the electronic control unit 10.

The electronic control unit 10 is composed of a microcomputer, a CPU for performing arithmetic processing, a ROM for storing an engine rotational speed map and the like preset corresponding to the accelerator pedal depression amount and the select lever position, and the arithmetic result. And a RAM for temporarily storing input signals and the like, and an input / output device. Then, the signals of the various sensors described above are calculated based on them, and a signal for controlling the solenoid valve 4a is output from the output device based on the calculation result to hold or release the hydraulic pressure of the wheel cylinder 3a. Has been done.

Next, the operation of the first embodiment of the present invention will be described with reference to the processing flow chart shown in FIG. The apparatus of the present embodiment is configured to be operated by turning on the power, that is, by turning on the key switch, and when the apparatus is operated, the initialization S is performed first.
1 is executed. In S1, initialization such as turning off the brake flag, clearing the counter, deactivating the output device, etc., which will be described later, is executed. Next, in S2, the operating state of the solenoid valve 4a is checked, and if the solenoid valve 4a is not operating, S3 to S9 are executed. If the solenoid valve 4a is operating, S10 is executed. Steps S3 to S9 are a flow for holding the braking force, the brake flag is turned off in S3, and steps S4 to S8 are performed.
Whether the select lever position is in the traveling range (S4), the vehicle speed is zero (S5), the accelerator pedal is released (S6), and the engine speed is equal to or higher than the set value (S7). Whether or not the brake pedal is depressed (S8) is checked, and only when all the conditions of S4 to S8 are satisfied, the solenoid valve 4a of the braking force holding device 4 is operated and the hydraulic pressure of the wheel cylinder 3a is held. S4
When the processes of to S9 are completed, the process returns to S2 and the operation of the solenoid valve 4a is checked again.

If it is determined in S2 that the solenoid valve 4a is activated, then the brake flag is checked in S10, and if the brake flag is off, S11 to S12 are executed,
When the brake flag is on, S13 to S21 are executed. In S11, it is checked whether or not the brake pedal is depressed. If not, the brake flag is turned on in S12, and if it is depressed, the process returns to S2 without doing anything. In this routine, since the solenoid valve 4a is operating in S2, it is determined whether the brake pedal is continuously depressed after being depressed or whether it is released after being depressed. Then, if the pedal is continuously depressed, the brake flag is kept off, and if it is released, the brake flag is turned on.

Next, when the brake flag is on in S10, the engine speed corresponding to the accelerator pedal depression amount for releasing the solenoid valve 4a is determined from the engine speed map stored in ROM in advance in S13. In S14, the current engine speed is compared with the engine speed obtained in S13. If the current engine speed is high, the process proceeds to S17, the solenoid valve 4a of the braking force retaining device 4 is deactivated, and the braking force of the wheels 3 is reduced. To release. If the current engine speed is low in S14, the process proceeds to S15 to check the vehicle speed. If the signal from the vehicle speed sensor 2a is larger than a predetermined set value, the signal from the accelerator pedal sensor 7a is further checked in S16 to check the accelerator pedal. When step 7 is depressed, the routine proceeds to step S17, where the solenoid valve 4a of the braking force retaining device 4 is deactivated and the wheel 3
The braking force of is released, the above-mentioned counter is cleared, and the process returns to S2. Here, as a result of the check in S15 or S16,
When the current vehicle speed is smaller than the set value or when the accelerator pedal is not depressed, S19 to S21 are executed. In S19, it is checked from the signal of the brake pedal sensor 6a whether or not the brake pedal is stepped on so as to generate a braking force that suppresses the creep force. If it is equal to or more than the creep force, the above-mentioned counter is counted up in S20, In S21, it is checked whether the count value of the counter is equal to or larger than the set value. This is because the brake pedal is depressed and the braking force holding device is activated (checked in S2), and then the brake pedal is released (S1).
It is checked whether or not the state in which the brake pedal is stepped on again is maintained so as to generate the braking force that suppresses the creep force for a certain period of time. If the count value of the counter is equal to or larger than the set value, S17 and S18 are executed and S2 is executed.
Return to. In other words, if the brake pedal is stepped on again to generate the braking force that suppresses the creep force for a certain period of time or more, it is judged that the vehicle is stopped for a short time, such as when traveling on a congested road or when entering the garage as described above. The vehicle can be driven only by releasing the power holding device and releasing the brake pedal (by the creep force). If the count value of the counter is less than or equal to the set value in S21, the process returns to S2 without clearing the counter. That is, it is determined that the brake pedal is stepped on again so as to generate the braking force that suppresses the creep force for a certain time or longer by executing the steps S2 to S21 multiple times. S1
At 9, if the brake pedal is not depressed to generate the braking force that suppresses the creep force, the above-mentioned counter is cleared and the process returns to S2.

Next, the operation of the second embodiment of the present invention will be described with reference to the processing flow chart shown in FIG. Since the device configuration of the second embodiment is the same as that of the first embodiment shown in FIG. 1, the description thereof is omitted here, and only the processing flow of the electronic control unit 10 different from that of the first embodiment is illustrated. This will be explained in Section 3. When the power is turned on, that is, the key switch is turned on, initialization S51 is first executed. In S51, initialization such as counter clear and output device non-operation described later is executed.
Next, in S52, the operating state of the solenoid valve 4a is checked,
If the solenoid valve 4a is not operating, S53 to S58 are executed. If the solenoid valve 4a is operating, S60 is executed. Steps S53 to S58 are a flow for executing holding of the braking force. Whether the select lever position is in the traveling range (S53), the vehicle speed is zero (S54), or the accelerator pedal is released (S55), Whether the engine speed is equal to or higher than a set value (S56) or whether the brake pedal is depressed (S57) is checked, and S53-
Only when all the conditions of S57 are satisfied, the solenoid valve 4a of the braking force retaining device 4 is activated and the hydraulic pressure of the wheel cylinder 3a is retained. When the processing of S53 to S58 is completed, S5
Returning to step 2, the operation of the solenoid valve 4a is checked again.

If it is determined in S52 that the solenoid valve 4a is in operation, then it is checked in S60 whether the brake pedal is continuously depressed or once released. If the brake pedal is continuously depressed, this process ends. Becomes S60
If it is determined that the brake pedal has been released once,
In S61, the engine rotation speed for releasing the solenoid valve 4a is obtained according to the depression amount of the accelerator pedal, and in S62, it is checked whether or not the current engine rotation speed is higher than the engine rotation speed for releasing the solenoid valve 4a. If the engine speed is higher, S70 is executed, the solenoid valve 4a is released, and this processing ends. If the current engine speed is lower than the engine speed at which the solenoid valve 4a is released, S63
If the signal from the vehicle speed sensor 2a is larger than a predetermined set value by checking the vehicle speed, the signal of the accelerator pedal sensor 7a is further checked in S64, and if the accelerator pedal 7 is depressed, the process proceeds to S70 and the braking force holding device is operated. Then, the solenoid valve 4a of No. 4 is released to release the braking force of the wheel 3, and this processing is ended. Here, as a result of the check in S63 or S64, if the current vehicle speed is smaller than the set value or if the accelerator pedal is not depressed, S65 to S69 are executed. In S65, it is checked from the signal of the brake pedal sensor 6a whether or not the brake pedal is stepped on so as to generate a braking force that suppresses the creep force. If it is equal to or more than the creep force, the counting of the counter described above is started in S66. Then, in S67, it is checked again whether or not the brake pedal is depressed, and the process waits in S67 until the brake pedal is released. In the meantime, the counter continues counting, that is, measures the time when the brake pedal is depressed. When the brake pedal is released, it is checked in S68 whether or not the value of the counter is equal to or more than the set value. The braking force of is released, and this processing ends. If the value of the counter is less than or equal to the set value in S68, the process is terminated without releasing the solenoid valve 4a. If the brake pedal is released in S65, the counter is cleared in S69 and the process ends. Although the present invention has been described with reference to the above-described embodiments, various modifications and applications are possible within the scope of the gist of the present invention, and these modifications and applications are not excluded from the scope of the present invention.

[0013]

According to the present invention, after the vehicle is stopped by braking, the braking force holding device is operated to hold the braking force of the wheels, and the vehicle is stopped even if the brake pedal is released. , The braking force holding device is released when the brake pedal is stepped on again to generate the braking force that suppresses the creep force for a certain period of time, so the vehicle can be started without increasing the engine rotation by the accelerator pedal. Thus, it is possible to easily perform the starting operation when there is a vehicle, a wall, or the like immediately before, such as a traffic jam or a garage.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a processing flow chart of the first embodiment of the present invention.

FIG. 3 is a processing flowchart of the second embodiment of the present invention.

[Explanation of symbols]

 1 ... Fluid torque converter 2 ... Transmission 2a ... Vehicle speed sensor 3 ... Wheel 3a ... Wheel cylinder 4 ... Braking force control device 4a ... Solenoid valve 4b ... Check valve 5 ... Master cylinder 6 ... Brake pedal 6a ... Brake sensor 7 ... Accelerator Pedal 7a ... Accelerator sensor 8 ... Select lever 8a ... Select sensor 9 ... Engine rotation sensor 10 ... Electronic control device

(72) Inventor Masao Morimoto 5-8-14 Minami Ikuta, Tama-ku, Kawasaki-shi, Kanagawa Sunyotsu Masahiro 201 (72) Inventor Katsuhiro Suga 2-6-4 Kamisueyoshi, Tsurumi-ku, Yokohama-shi, Kanagawa

Claims (1)

[Claims] 1. A braking force holding device for a vehicle, comprising a fluid torque converter type automatic transmission, which holds hydraulic pressure generated by depression of a brake pedal when a braking force holding condition is satisfied. A brake pedal sensor for detecting the depression amount and a timer for detecting the depression time of the brake pedal are provided, and the braking force is released when the depression amount of the brake pedal is equal to or more than a predetermined value for a predetermined time or more. A braking force holding device for a vehicle characterized by the above.