JPH05278585A - Braking hydraulic pressure controller for automobile - Google Patents

Abstract

PURPOSE:To improve the braking performance by providing a means of judging a controlled state, judging the rotation of each rear wheel by means of a comparing means, operating an actuator into decompression or vice versa. CONSTITUTION:At the time of braking, each rotational speed of both rear wheels RL, RR is compared with that of both front wheels FL, FR. When each rotational speed of these rear wheels RL, RR becomes large than that of respective front wheels FL, FR, a pulse number to be given to each of solenoid on-off valves 34a, 34b or 36a, 36b is decreased but the extent of hydraulic pressure to be given to a wheel cylinder 24 or 23 of each rear-wheel braking device grows larger, so each rotational speed of respective rear wheels RL, RR is decreased. In addition, when each rotational speed of the rear wheels RL, RR becomes smaller than that of the front wheels FL, FR, the pulse number to be given to the solenoid on-off valves 34a, 34b or 26a, 36b grows larger and thereby the braking hydraulic pressure being given to the wheel cylinder 24 or 23 of each rear wheel braking device is decreased, thus each rotational speed of respective rear wheels RL, RR is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking hydraulic pressure control device for an automobile.

[0002]

2. Description of the Related Art In Japanese Patent Publication No. 51-40816, a proportioning valve for comparing the rotational speeds of front and rear wheels (corresponding to the rotational speed) to control the braking fluid pressure applied to a rear wheel braking device is reduced. The configuration in which the so-called break point is variable by the pneumatically actuated actuator, specifically, if the number of revolutions of the rear wheel is higher than that of the front wheel, raise the above-mentioned breakpoint and make the number of revolutions of the rear wheel higher than that of the front wheel. A configuration is disclosed in which the above-mentioned break point is lowered when it is low.

[0003]

In the above-mentioned conventional structure, it is not possible to equalize the distribution of braking fluid pressure to the front and rear wheels to the distribution of load to the front and rear wheels, and the distribution of braking fluid pressure to the rear wheels is small. As a result, the problem that the vehicle deceleration cannot be increased sufficiently with respect to the increase in the brake pedal depression force, the problem that the front wheel braking device is overloaded, or the distribution of braking fluid pressure to the rear wheels increases. There is a problem that the rear wheels tend to lock. The present invention has been made to address the above-described problem, and an object thereof is to improve the braking performance by controlling the braking hydraulic pressure to the rear wheel braking device so that the front and rear wheels have substantially equal rotational speeds. And to improve the durability of the front wheel braking device.

[0004]

In order to achieve the above object, in the present invention, as shown in the outline of the configuration in FIG. Of the front wheel 1 and the rear wheel 3 based on the signals from the front wheel speed sensor 2 that detects the front wheel speed, the rear wheel speed sensor 4 that detects the rear wheel 3 rotation speed, and the sensors 2 and 4.
Comparing means 5 for comparing the rotational speeds of the two, an actuator 7 for reducing or maintaining the brake fluid pressure applied to the rear wheel braking device 6, and a return pressure, and a braking state for determining that the vehicle is in a braking state. The actuator 7 when the determination means 8 and the braking state determination means 8 determine that the vehicle is in the braking state and the comparison means 5 determines that the rotation speed of the rear wheel 3 is lower than the rotation speed of the front wheel 1.
And a drive means 9 for activating the actuator 7 in a decompressing or holding pressure mode and for activating the actuator 7 in a pressure-reducing manner when the rotational speed of the rear wheel 3 is determined to be higher than that of the front wheel 1.

[0005]

In the braking fluid pressure control device for a vehicle according to the present invention, when the rotation speed of the rear wheel 3 becomes lower than the rotation speed of the front wheel 1 during braking, this is determined by the braking state determination means 8 and the comparison means 5. Since it is determined that the driving means 9 operates the actuator 7 to reduce or hold pressure,
The braking hydraulic pressure applied to the rear wheel brake device 6 is reduced or held, and the rotational speed of the rear wheel 3 increases in relation to the front wheel speed. On the other hand, when the rotation speed of the rear wheel 3 becomes higher than the rotation speed of the front wheel 1 during braking, this is judged by the braking state judging means 8 and the comparing means 5 and the driving means 9 actuates the actuator 7 to repressurize the rear wheel. The braking fluid pressure applied to the brake device 6 increases and the rotational speed of the rear wheel 3 decreases. Therefore, the rotational speeds of the front and rear wheels during braking become substantially equal to each other, so that the tendency of the front wheels 3 to lock in advance is accurately prevented, and the vehicle deceleration is sufficiently increased with respect to the increase in the brake pedal depression force. As a result, the braking performance is improved, and the load on the front wheel braking device can be reduced, so that the durability of the front wheel braking device can be improved.

[0006]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 schematically shows a braking fluid pressure control device for an automobile according to the present invention. In this device, a braking fluid pressure generation device including a master cylinder 11, a booster 12 and a reservoir 13 is operated by depressing a brake pedal 14. 10 and wheel cylinders 21 and 2 of each brake device arranged on each wheel FR, FL, RR, and RL.
Pumps 31a and 31b and reservoirs 32a and 3 are provided in two systems of diagonal hydraulic circuits to which 2, 23 and 24 are connected.
A publicly known ABS control actuator 30 which is constituted by 2b and electromagnetic switching valves 33a to 36a and 33b to 36b and whose operation is controlled by an electronic control unit 40 is interposed.
Both pumps 31a and 31b are a single electric motor 37.
Is configured to be driven by.

The electronic control unit 40 includes wheels FR, FL,
Each wheel speed sensor 41, 4 arranged in RR and RL
2, 43, 44 are connected, and the electromagnetic opening / closing valves 33a to 36a and 33b to 36b of the actuator 30 are connected to the electric motor 37.
To control. Further, the electronic control unit 40
Is a CPU 47b, a ROM 47c, a RAM 47d, which are commonly connected to a bus 47a, as shown in FIG.
A wheel speed sensor 41, 42, 42 is provided with a microcomputer 47 including a timer 47e, an input interface circuit 47f, and an output interface circuit 47g.
The output signals of 43 and 44 are input to the input interface circuit 47f via the amplifier circuits 48a to 48d, and the output signals from the microcomputer 47 are input to the electromagnetic on-off valves 33a to 36a via the drive circuits 49a to 49i.
33b to 36b and the electric motor 37. Each solenoid on-off valve 33a-36a, 33b-
The output signal to 36b is a pulse signal, and when the number of pulses given to each electromagnetic on-off valve 33a to 36a increases, the master cylinder 11 and each wheel cylinder 21 are correspondingly increased.
Each passage that connects ~ 24 is narrowed down, and each solenoid on-off valve 3
When the number of pulses applied to 3b to 36b decreases, the wheel cylinders 21 to 24 and the reservoirs 32 are correspondingly decreased.
Each passage connecting a and 32b is opened.

ROM 47c of the microcomputer 47
Stores a program corresponding to each of the flowcharts shown in FIGS. 4 to 7, and the CPU 47b starts executing the program in response to the closing of an ignition switch (not shown), and the program during the closing of the switch. The RAM 47d temporarily stores the variable data necessary for executing the program.

In the present embodiment configured as described above, a series of processing is performed in the electronic control unit 40,
The operation of the actuator 30 is controlled. The operation will be described below with reference to the flowcharts of FIGS.
The CPU 47b of the microcomputer 47 in the electronic control unit 40 starts executing the program corresponding to the flowchart of FIG. 4 in step 100 in response to the closing of the ignition switch. In the execution of such a program, both the left control in-progress flag LF and the right control in-progress flag RF which are initialized in step 101 and will be described later are set to "
0 ", the elapsed time t is cleared, and various calculated values are cleared. Further, if it is determined in step 102 whether ABS control is necessary, and if" YES "is determined, the process proceeds to step 103. Well-known ABS control routine is executed, and when it is determined to be "NO", the normal brake control routine is executed in step 110.

In the normal brake control routine, as shown in FIG. 5, each wheel speed sensor 4 is detected in step 111.
From the output signals of 1 to 44, the wheel speeds VwFL and Vw of the respective wheels
FR, VwRL, VwRR are calculated, the maximum wheel speed VwMAX is calculated from the wheel speed in step 112, and the acceleration DVwMAX of the maximum wheel speed is calculated in step 113. Further, the left rear wheel control routine is executed in step 200, and the right rear wheel control routine is executed in step 300. In step 114, the elapsed time t is counted and t> T1 (calculation cycle setting time T1: 3 to 5 mse
It is determined whether or not c), and when it is determined to be "NO", step 114 is repeatedly executed, and when it is determined to be "YES", the routine proceeds to step 115 and the elapsed time t is cleared.

In the left rear wheel control routine, as shown in FIG. 6, the left control in-progress flag LF is set to "" in step 201.
When it is determined "1" or not, and when "NO" is determined (when control is not in progress), steps 202, 203 and 204 which are control start conditions are executed, and when "YES" is determined When the control is in progress, steps 205 and 206, which are control end conditions, are executed. Step 20
2, the maximum wheel speed VwMAX> K1 (K1: 10Km /
h), it is determined in step 203 whether or not the maximum wheel speed acceleration DVwMAX <K2 (K2: -0.25G), and in step 204, the wheel speed VwRL of the left rear wheel RL and the left front wheel FL. The relationship between the wheel speed VwFL and Vw
It is determined whether or not RL <VwFL + K3 (K3: 1 Km / h), and if it is determined to be "NO" in any one of steps 202, 203, 204, the left rear wheel control routine ends and the routine shown in FIG. Step 300 of each, and each Step 202, 2
If it is determined YES at 03 and 204, the left control in-progress flag LF is set to "1" at step 207 and the routine proceeds to step 210.

On the other hand, in step 205, the maximum wheel speed V
It is determined whether wMAX <K4 (K4: 5 Km / h),
In step 206, the maximum wheel speed acceleration DVwMAX>
Whether or not it is K5 (K5: -0.15G) is determined, and if "NO" is determined in both steps 205 and 206, the process proceeds to step 210, and "YES" is determined in either of the steps 205 and 206. When the determination is made, the left control in-progress flag LF is set to "0" in step 208, the number of pulses applied to both the electromagnetic on-off valves 34a and 34b is sequentially reduced in step 209, and becomes zero after the set time, The left rear wheel control routine ends and the routine proceeds to step 300 in FIG.

In step 210, the relationship between the wheel speed VwRL of the left rear wheel RL and the wheel speed VwFL of the left front wheel FL is V.
It is determined whether or not wRL> VwFL + K6 (K6: 1Km / h), and in step 211 VwRL <VwFL-K7 (K
7: 1 Km / h), and if "YES" in step 210, step 212 is executed and the left rear wheel control routine ends, and step 210
Is determined as “NO” in step 211 and “YES in step 211.
If it is determined to be "S", step 213 is executed and the left rear wheel control routine ends, and if it is determined to be "NO" at both steps 210 and 211, the left rear wheel control routine ends and the routine ends. Go to step 300 of 3. Therefore, in the execution of step 212, both the solenoid on-off valves 34a, 3
The number of pulses applied to 4b decreases by a set amount, and the braking hydraulic pressure applied to the wheel cylinders 24 increases by a set amount (return pressure).
In step 213, both solenoid on-off valves 34
The number of pulses applied to a and 34b is increased by a set amount, the braking hydraulic pressure applied to the wheel cylinder 24 is decreased by a set amount, and the respective states are maintained. On the other hand, both steps 21
When both 0 and 211 are determined to be “NO”, the braking fluid pressure applied to the wheel cylinder 24 is held while the number of pulses applied to both the electromagnetic opening / closing valves 34a and 34b is held.

After the above-mentioned left rear wheel control routine is executed, the right rear wheel control routine shown in FIG. 7 is executed to control the braking hydraulic pressure applied to the wheel cylinder 23 of the right rear wheel RR. .. The left rear wheel control routine is shown in FIG.
As is clear from the above, since it is substantially the same as the above-mentioned left rear wheel control routine, similar steps are designated by similar reference numerals, and description thereof will be omitted.

In summary, in this embodiment, the rotational speeds of the rear wheels RL and RR and the front wheels FL and RL are reduced during braking.
The rotational speeds of the FRs are compared (step 210 of FIG. 6,
211 and steps 310 and 311 in FIG. 7), when the rotational speed of each rear wheel RL, RR becomes greater than the rotational speed of each front wheel FL, FR (more accurately, the rotational speed of the front wheel +1 Km / h), each electromagnetic on-off valve 34a, 34b or 36a, 3
The number of pulses applied to 6b decreases, the braking fluid pressure applied to the wheel cylinder 24 or 23 of each rear wheel braking device increases (restore pressure), and the rotational speed of each rear wheel RL, RR decreases, Further, the rotation speed of each rear wheel RL, RR is equal to that of each front wheel F.
Rotational speed of L and FR (To be exact, the rotational speed of the front wheel-1 km
/ H), the electromagnetic on-off valves 34a, 34b
Alternatively, the number of pulses applied to 36a, 36b increases and the wheel cylinder 24 or 23 of each rear wheel braking device is increased.
The braking fluid pressure applied to the rear wheels RL and RR increases, and the rotation speeds of the rear wheels RL and RR are the same as those of the front wheels FL and FR. Speed ±
(Within 1 Km / h), each electromagnetic on-off valve 34a, 3
The number of pulses applied to 4b or 36a, 36b is held, and the braking hydraulic pressure applied to the wheel cylinder 24 or 23 of each rear wheel brake device is held.

Therefore, in this embodiment, each of the front and rear wheels FL, RL or FR at the time of normal brake braking,
The rotation speeds of the RRs become substantially equal to each other, and the preceding locking tendency of the rear wheels RL, RR is properly prevented, and the vehicle deceleration is sufficiently increased with respect to the increase of the brake pedal depression force to perform braking. The performance is improved, and the load on each front wheel braking device can be reduced, and the durability of each front wheel braking device can be improved.

In the above embodiment, an example in which the ABS control actuator 30 is also used as the actuator of the present invention has been described, but the present invention can also be implemented by using the dedicated actuator 130 shown in FIG. Is. The actuator 130 shown in FIG.
32a, 132b and electromagnetic on-off valves 134a, 134b and 136a, 136b, and the operation of each electromagnetic on-off valve is controlled by the electronic control unit 140 which does not include steps 102 and 103 of FIG. ing. It should be noted that the operation of this embodiment can be easily understood from the above-mentioned configuration and the operation description of the embodiment,
The description is omitted. The present invention also relates to the reservoir 1 of FIG.
32a and 132b and electromagnetic on-off valves 134b and 136b are omitted, and the program of the electronic control unit is changed,
The braking fluid pressure is reduced only by the operation of the electromagnetic on-off valves 134a and 136a (the pressure is reduced during pressure increase, and cannot be reduced after pressure increase),
It is also possible to re-pressurize and carry out. Further, in each of the above-described embodiments, the fact that the vehicle is in the braking state is determined by the acceleration of the wheels, but it may be determined by determining the master cylinder hydraulic pressure, the operation of the brake switch, or the like. It is possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a vehicle braking fluid pressure control device according to the present invention.

FIG. 2 is an overall configuration diagram showing an embodiment of a vehicle braking hydraulic pressure control device according to the present invention.

FIG. 3 is a block diagram showing a configuration of the electronic control device of FIG.

4 is a flowchart of a program executed by the microcomputer of FIG.

5 is a flowchart of a program executed by the microcomputer of FIG.

6 is a flowchart of a program executed by the microcomputer of FIG.

7 is a flowchart of a program executed by the microcomputer of FIG.

FIG. 8 is an overall configuration diagram showing another embodiment of the vehicle braking hydraulic pressure control device according to the present invention.

[Explanation of symbols]

21 to 24 ... Wheel cylinder (rear wheel brake device), 30 ... Actuator, 32a, 32b ... Reservoir, 34a, 34b, 36a, 36b ... Electromagnetic on-off valve, 4
0 ... Electronic control device, 41, 42 ... Front wheel speed sensor, 4
3, 44 ... Rear wheel speed sensor, FL, FR ... Front wheel, F
R, RR ... rear wheels.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noriaki Hattori 2-1, Asahi-cho, Kariya city, Aichi Aisin Seiki Co., Ltd. (72) Kenji Totsu 2-1-1, Asahi-cho, Kariya city, Aichi prefecture Aisin Seiki Co., Ltd. (72) Inventor Kenji Asano 2-1-1 Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd. (72) In-house Hiroaki Kawai 2-1-1 Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd. (72) Inventor Masakazu Sugizawa, Aisin Seiki Co., Ltd., 2-chome, Asahi-cho, Kariya city, Aichi prefecture (72) Inventor Kyosuke Hata 2-chome, Asahi-cho, Kariya, Aichi prefecture, Aisin Seiki Co., Ltd. (72) Inventor Noboru Noguchi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd.

Claims (1)

[Claims] 1. A front wheel speed sensor for detecting a front wheel rotation speed, a rear wheel speed sensor for detecting a rear wheel rotation speed, and a front wheel rotation speed and a rear wheel rotation based on signals from the both sensors. Comparing means for comparing speeds, an actuator for reducing or maintaining the brake fluid pressure applied to the rear wheel brake device, and a return pressure, and a braking state determining means for determining that the vehicle is in a braking state, When the braking state determination means determines that the vehicle is in the braking state and the comparison means determines that the rotation speed of the rear wheels is lower than the rotation speed of the front wheels, the actuator is operated to reduce pressure or hold pressure and the rotation speed of the rear wheels. Is a rotational speed of the front wheels, the braking fluid pressure control device for a vehicle comprises: a drive unit that operates the actuator to return pressure.