JP3573763B2 - Automotive brake fluid pressure control system - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a vehicle brake fluid pressure control device.
[0002]
[Prior art]
In Japanese Patent Publication No. 51-40816, a so-called break point of a proportioning valve for controlling the reduction in the brake fluid pressure applied to the rear wheel brake device by comparing the rotational speeds (corresponding to the rotational speeds) of the front and rear wheels is described. A configuration that can be changed by a pneumatic actuator, specifically, when the rotation speed of the rear wheel is higher than that of the front wheel, the turning point is increased, and when the rotation speed of the rear wheel is lower than that of the front wheel, A configuration for lowering the break point is disclosed.
[0003]
[Problems to be solved by the invention]
In the above-described conventional configuration, the distribution of the braking hydraulic pressure of the front and rear wheels cannot be made sufficiently equal to the distribution of the load of the front and rear wheels, and the distribution of the braking hydraulic pressure to the rear wheels decreases. That the vehicle deceleration cannot be sufficiently increased and that the front wheel brake device is overloaded, or that the distribution of brake fluid pressure to the rear wheels increases and the rear wheels tend to lock. Occurs.
The present invention has been made in order to address the above-described problems, and has as its object to improve braking performance by controlling brake fluid pressure to a rear wheel brake device and to improve durability of a front wheel brake device. To improve it.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a left and right front wheel speed sensor that detects each rotational speed of left and right front wheels, a left and right rear wheel speed sensor that detects each left and right rear wheel rotational speed, Based on the detection signals of the front wheel speed sensor and the left and right rear wheel speed sensors, the left front wheel rotation speed and the left rear wheel rotation speed are compared, and the right front wheel rotation speed and the right rear wheel rotation speed are compared. Comparing means, a first actuator for reducing, holding or restoring the brake fluid pressure applied to the left rear wheel brake device, and decreasing, holding or restoring the brake fluid pressure applied to the right rear wheel brake device. A second actuator to be driven, braking state determining means for determining that the vehicle is in a braking state, and left and right detected by the speed sensor in a state in which the braking state determining means determines that the vehicle is in a braking state. Front wheel The maximum wheel speed calculated based on each rotation speed and each rotation speed of the left and right rear wheels is greater than a predetermined value, and the rotation speed of the left rear wheel is smaller than the rotation speed of the left front wheel or the rotation of the right rear wheel by the comparing means. When it is determined that the speed is lower than the rotation speed of the right front wheel, the first actuator or the second actuator of the first actuator or the second actuator to reduce or maintain the braking fluid pressure applied to the left rear wheel brake device or the right rear wheel brake device . Controlling the operation of the brake device for the left rear wheel when the comparing means determines that the rotation speed of the left rear wheel is higher than the rotation speed of the left front wheel or the rotation speed of the right rear wheel is higher than the rotation speed of the right front wheel. or automotive brake fluid and control means for controlling operation of the first actuator or the second actuator so as to pressure restored the granted brake hydraulic pressure to the right rear wheel braking device There is provided a control device.
In practicing the present invention, in the brake fluid pressure control device for an automobile configured as described above, the left and right front speeds detected by the speed sensor in a state where the braking state is determined by the braking state determining means are determined. maximum wheel speed is greater with the determined the maximum wheel speed is the first predetermined value smaller than the second after than the first predetermined value which is calculated based on each rotational speed of the left and right rear wheels and the rotational speed of the wheel When it is determined by the comparing means that the rotation speed of the left rear wheel is smaller than the rotation speed of the left front wheel or the rotation speed of the right rear wheel is smaller than the rotation speed of the right front wheel before the comparison value becomes smaller than a predetermined value, actuation of the first actuator or the second actuator to vacuum or holding the granted brake hydraulic pressure to the left rear wheel brake device or the right rear wheel brake device under the control of the control means When the comparing means determines that the rotation speed of the left rear wheel is higher than the rotation speed of the left front wheel or that the rotation speed of the right rear wheel is higher than the rotation speed of the right front wheel, the left rear wheel braking device or the right It is desirable that the operation of the first actuator or the second actuator be controlled so as to restore the brake fluid pressure applied to the rear wheel brake device .
[0005]
[Action and Effect of the Invention]
In automotive brake fluid pressure control apparatus of the present invention constructed as described above, the braking by the state determining means left and right rear wheel brake device is determined to be operated, the left and right rear wheels and the rotational speeds of the left and right front wheels The rotation speed of the left rear wheel becomes smaller than the rotation speed of the left front wheel or the rotation speed of the right rear wheel becomes smaller than the rotation speed of the right front wheel in a state where the maximum wheel speed calculated based on the respective rotation speeds becomes larger than a predetermined value. When the speed is lower than the speed, the brake fluid pressure applied to the left rear wheel brake device or the right rear wheel brake device is reduced or held, and the rotation speed of the left rear wheel becomes higher than the rotation speed of the left front wheel or the rear right speed. When the rotation speed of the wheel becomes higher than the rotation speed of the right front wheel, the brake fluid pressure applied to the left rear wheel brake device or the right rear wheel brake device is restored . Therefore, when the maximum wheel speed is smaller than the predetermined value, the braking of the left and right rear wheels is accurately secured without reducing the brake fluid pressure applied to the left and right rear wheel brake devices, and the maximum wheel speed is reduced. When the pressure is larger than the predetermined value, the brake fluid pressures applied to the left and right rear wheel brake devices are maintained without being reduced or increased, so that the leading lock tendency of the left and right rear wheels is properly prevented, and the vehicle is braked. Performance is improved.
[0006]
【Example】
An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 schematically shows a brake fluid pressure control device for a motor vehicle according to the present invention. In this device, a brake fluid pressure control device comprising a master cylinder 11, a booster 12, and a reservoir 13 and operated by depressing a brake pedal 14 is shown. 10 and two systems of diagonal hydraulic circuits in which the wheel cylinders 21, 22, 23, and 24 of the brake devices arranged on the wheels FR, FL, RR, and RL are connected. A known ABS control actuator 30, which includes 32a and 32b and electromagnetic on-off valves 33a to 36a and 33b to 36b and whose operation is controlled by the electronic control unit 40, is provided. The two pumps 31a and 31b are configured to be driven by a single electric motor 37.
[0007]
The electronic control unit 40 is connected to each of the wheel speed sensors 41, 42, 43, and 44 disposed on each of the wheels FR, FL, RR, and RL, and each of the electromagnetic on-off valves 33a to 36a, 33b to 36b and the electric motor 37 are connected to control the actuator 30. As shown in FIG. 3, the electronic control device 40 includes a microcomputer 47 including a CPU 47b, a ROM 47c, a RAM 47d, a timer 47e, an input interface circuit 47f, and an output interface circuit 47g, which are commonly connected to a bus 47a. The output signals of the wheel speed sensors 41, 42, 43, and 44 are input to the input interface circuit 47f via the amplifier circuits 48a to 48d, and the output signal from the microcomputer 47 is output to the drive circuits 49a to 49i. Each of the electromagnetic switching valves 33 a to 36 a and 33 b to 36 b is output to the electric motor 37. The output signal to each of the solenoid on-off valves 33a to 36a and 33b to 36b is a pulse signal. When the number of pulses applied to each of the solenoid on-off valves 33a to 36a increases, the master cylinder 11 and each of the wheel cylinders 21 to 24 are correspondingly increased. Are narrowed, and when the number of pulses applied to each of the electromagnetic on-off valves 33b to 36b increases, each passage connecting each of the wheel cylinders 21 to 24 and each of the reservoirs 32a and 32b is opened.
[0008]
The 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 closing of an ignition switch (not shown), and executes the program. During the closing, the program is continuously executed, and the RAM 47d temporarily stores variable data necessary for executing the program.
[0009]
In the present embodiment configured as described above, a series of processes are performed in the electronic control unit 40, and the operation of the actuator 30 is controlled. The operation will be described below with reference to the flowcharts of FIGS. CPU47b the microcomputer 47 starts executing a program corresponding to the flowchart of FIG. 4 in response to the closing of the ignition switch at step 100 in the electronic control unit 40. In the execution of this program, initialization is performed in step 101, a left control flag LF and a right control flag RF described later are both set to "0", the elapsed time t is cleared, and various calculated values are cleared. Is done. Also, it is determined whether or not the ABS control is necessary in step 102, and if "YES" is determined, the well-known ABS control routine is executed in step 103. If "NO" is determined, the routine proceeds to step 110. A brake control routine is executed.
[0010]
In the normal brake control routine, as shown in FIG. 5, the wheel speeds VwFL, VwFR, VwRL, VwRR of each wheel are calculated from the output signals of the wheel speed sensors 41 to 44 at step 111, and at step 112 A maximum wheel speed VwMAX is calculated from the wheel speed, and an acceleration DVwMAX of the maximum wheel speed is calculated in step 113. In step 200, a left rear wheel control routine is executed, and in step 300, a right rear wheel control routine is executed. In step 114, the elapsed time t is counted, and it is determined whether or not t> T1 (calculation cycle setting time T1: 3 to 5 msec). If “NO” is determined, step 114 is repeatedly executed, and “YES” When it is determined that the time has elapsed, the routine proceeds to step 115, where the elapsed time t is cleared.
[0011]
In the left rear wheel control routine, as shown in FIG. 6, whether or not the left control flag LF is "1" is determined in step 201, and when it is determined to be "NO" (the control is not being performed). ), Steps 202, 203, and 204, which are control start conditions, are executed. If "YES" is determined (when control is being performed), steps 205 and 206, which are control end conditions, are executed. In step 202, it is determined whether or not the maximum wheel speed VwMAX> K1 (K1: 10 Km / h). In step 203, it is determined whether or not the maximum wheel speed acceleration DVwMAX <K2 (K2: -0.25G). At 204, it is determined whether 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 VwRL <VwFL + K3 (K3: 1 Km / h), and any one of the steps 202, 203, and 204 is determined. If "NO" is determined in step, the left rear wheel control routine ends and the routine proceeds to step 300 in FIG. 5 , and if all "YES" are determined in steps 202, 203 and 204, step 207 is performed. The left control flag LF is set to “1”, and the routine proceeds to step 210.
[0012]
On the other hand, in step 205, it is determined whether or not the maximum wheel speed VwMAX <K4 (K4: 5Km / h). In step 206, it is determined whether or not the acceleration of the maximum wheel speed DVwMAX> K5 (K5: -0.15G). If “NO” is determined in both steps 205 and 206, the process proceeds to step 210. If “YES” is determined in any of steps 205 and 206, the left control flag LF is set in step 208. is "0", both solenoid valves 34a at step 209, the number of pulses applied to 34b becomes zero after being sequentially reduced setting time, the left rear wheel control routine to step 300 of FIG. 5 ends move on.
[0013]
In step 210, it is determined whether or not 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 VwRL> VwFL + K6 (K6: 1 km / h). In step 211, VwRL <VwFL-K7 ( K7: 1 Km / h) is determined, and if “YES” is determined in step 210, step 212 is executed and the left rear wheel control routine ends, and “NO” is determined in step 210. When the determination is made and "YES" is determined in step 211, step 213 is executed and the left rear wheel control routine ends, and when both are determined to be "NO" in both steps 210 and 211, the left rear wheel is left as it is. wheel control routine continues to step 300 of FIG. 5 ends. Thus, in the execution of step 212, the number of pulses applied to the two solenoid on-off valves 34a and 34b is reduced by the set amount, and the brake fluid pressure applied to the wheel cylinder 24 is increased (restored) by the set amount. Is executed, the number of pulses applied to the two electromagnetic on-off valves 34a and 34b is increased by a set amount, the brake fluid pressure applied to the wheel cylinder 24 is reduced by the set amount, and each state is maintained. On the other hand, if both steps 210 and 211 determine “NO”, the brake fluid pressure applied to the wheel cylinder 24 is maintained while the number of pulses applied to the electromagnetic on-off valves 34a and 34b is maintained. .
[0014]
After the execution of the left rear wheel control routine described above, the right rear wheel control routine shown in FIG. 7 is executed to control the brake fluid pressure applied to the wheel cylinder 23 of the right rear wheel RR. Since the right rear wheel control routine is substantially the same as the left rear wheel control routine described above as is apparent from FIG. 7, similar steps are denoted by similar reference numerals and description thereof will be omitted.
[0015]
In short, in the present embodiment, the rotation speed of each rear wheel RL, RR is compared with the rotation speed of each front wheel FL, FR during braking (steps 210 and 211 in FIG. 6 and steps 310 and 311 in FIG. 7). If the rotation speed of each rear wheel RL, RR is greater than the rotation speed of each front wheel FL, FR (more precisely, the rotation speed of the front wheel +1 Km / h), it is applied to each of the solenoid valves 34a, 34b or 36a, 36b. The number of applied pulses decreases, the braking fluid pressure applied to the wheel cylinder 24 or 23 of each rear wheel brake device increases (restoring pressure), and the rotation speed of each rear wheel RL, RR decreases. When the rotation speed of the wheels RL, RR is lower than the rotation speed of each of the front wheels FL, FR (more precisely, the rotation speed of the front wheel -1 Km / h), the rotation is given to each of the solenoid valves 34a, 34b or 36a, 36b. The number of pulses increases, the braking fluid pressure applied to the wheel cylinder 24 or 23 of each rear wheel brake device decreases, the rotation speed of each rear wheel RL, RR increases, and the rotation of each rear wheel RL, RR When the speed is equal to the rotation speed of each front wheel FL, FR (more precisely, within the rotation speed of the front wheel ± 1 Km / h), the number of pulses given to each of the electromagnetic on-off valves 34a, 34b or 36a, 36b is held and The brake fluid pressure applied to the wheel cylinder 24 or 23 of the rear wheel brake device is maintained.
[0016]
Therefore, in the present embodiment, the rotational speeds of the front and rear wheels FL, RL or FR, RR during the normal brake braking are substantially equal, and the tendency of the rear wheels RL, RR to lock in advance is of course properly prevented. In addition to the increase in brake pedal depression force, the vehicle deceleration can be sufficiently increased to improve braking performance, and the burden on each front wheel brake device can be reduced, improving the durability of each front wheel brake device. Can be done.
[0017]
In the above embodiment, the example in which the ABS control actuator 30 is used also as the actuator of the present invention has been described. However, the present invention can be implemented by employing the dedicated actuator 130 shown in FIG. The actuator 130 shown in FIG. 8 includes reservoirs 132a and 132b, and electromagnetic switching valves 134a and 134b and 136a and 136b. Each of the electromagnetic switching valves does not include the steps 102 and 103 in FIG. The operation is controlled by 140. Incidentally, the operation of this embodiment because it seems to be easily understood from the above configuration and operation described in the above embodiment, a description thereof will be If omitted.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an outline of an automotive brake fluid pressure control device according to the present invention.
FIG. 2 is an overall configuration diagram showing an embodiment of an automotive brake fluid pressure control device according to the present invention.
FIG. 3 is a block diagram illustrating a configuration of the electronic control device of FIG. 2;
FIG. 4 is a flowchart of a program executed by the microcomputer of FIG. 3;
FIG. 5 is a flowchart of a program executed by the microcomputer of FIG. 3;
FIG. 6 is a flowchart of a program executed by the microcomputer of FIG. 3;
FIG. 7 is a flowchart of a program executed by the microcomputer of FIG. 3;
FIG. 8 is an overall configuration diagram showing another embodiment of the vehicle brake fluid 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, 40: Electronic control device, 41, 42: Front wheel speed sensor , 43, 44: rear wheel speed sensor, FL, FR: front wheel, FR, RR: rear wheel.

Claims (5)

The left and right front wheel speed sensors that detect the left and right front wheel rotation speeds , the left and right rear wheel speed sensors that detect the left and right rear wheel rotation speeds , the left and right front wheel speed sensors, and the left and right rear wheel speed sensors comparing means for comparing the rotational speeds of the right rear wheel of the right front wheel as well as comparing the rotational speeds of the left rear wheel of the left front wheel on the basis of the detection signal is applied to the brake device for the rear left wheel that the brake fluid reduced the pressure pressure, a first actuator for pressure retention or recovery, reduced pressure brake fluid pressure applied to the right rear wheel brake device, and a second actuator for pressure retention or recovery, the vehicle is in a braking state Braking state determining means for determining that the vehicle is in the braking state; and a rotational speed of each of the left and right front wheels and a rotational speed of each of the left and right rear wheels detected by the speed sensor in a state where the braking state is determined by the braking state determining means. Based on speed When the maximum wheel speed calculated rotational speed of the left rear wheel is determined as the rotation speed of the rotation speed is less than or the right rear wheel of the left front wheel is smaller than the rotational speed of the right front wheel by said comparing means greater than a predetermined value The operation of the first actuator or the second actuator is controlled so as to reduce or maintain the braking fluid pressure applied to the left rear wheel brake device or the right rear wheel brake device . When it is determined that the rotation speed is greater than the rotation speed of the left front wheel or the rotation speed of the right rear wheel is greater than the rotation speed of the right front wheel, the brake fluid applied to the left rear wheel brake device or the right rear wheel brake device And a control means for controlling the operation of the first actuator or the second actuator so as to restore the pressure . Left and right front wheel speed sensors that detect the left and right front wheel rotation speeds, left and right rear wheel speed sensors that detect the left and right rear wheel rotation speeds, the left and right front wheel speed sensors, and the left and right rear wheel speed sensors Comparison means for comparing the rotation speed of the left front wheel with the rotation speed of the left rear wheel based on each detection signal and comparing the rotation speed of the right front wheel with the rotation speed of the right rear wheel; To reduce, hold or restore the brake fluid pressure One An actuator for reducing, holding or restoring the brake fluid pressure applied to the right rear wheel brake device; Two An actuator, braking state determining means for determining that the vehicle is in a braking state, and left and right front wheels detected by the speed sensor in a state in which the braking state determining means determines that the vehicle is in a braking state. After it is determined that the maximum wheel speed calculated based on the rotation speed and the respective rotation speeds of the left and right rear wheels is larger than a first predetermined value, the maximum wheel speed is smaller than the first predetermined value. Two When it is determined by the comparing means that the rotation speed of the left rear wheel is smaller than the rotation speed of the left front wheel or the rotation speed of the right rear wheel is smaller than the rotation speed of the right front wheel before the comparison value becomes smaller than the predetermined value. The above-mentioned first or second brake fluid pressure applied to the left rear wheel brake device or the right rear wheel brake device is reduced or maintained. One Controlling the operation of the actuator or the second actuator, and when it is determined by the comparing means that the rotation speed of the left rear wheel is greater than the rotation speed of the left front wheel or that the rotation speed of the right rear wheel is greater than the rotation speed of the right front wheel, The above-mentioned second control is performed so as to restore the brake fluid pressure applied to the left rear wheel brake device or the right rear wheel brake device. One And a control means for controlling the operation of the actuator or the second actuator. Left and right front wheel speed sensors that detect the left and right front wheel rotation speeds, left and right rear wheel speed sensors that detect the left and right rear wheel rotation speeds, the left and right front wheel speed sensors, and the left and right rear wheel speed sensors Comparison means for comparing the rotation speed of the left front wheel with the rotation speed of the left rear wheel based on each detection signal and comparing the rotation speed of the right front wheel with the rotation speed of the right rear wheel; To reduce or restore the brake fluid pressure One An actuator for reducing or restoring the brake fluid pressure applied to the right rear wheel brake device; Two An actuator, braking state determining means for determining that the vehicle is in a braking state, and a rotational speed of the left rear wheel being left by the comparing means in a state in which the braking state determining means determines that the vehicle is in a braking state. When it is determined that the rotation speed of the front wheel is lower than the rotation speed of the right rear wheel, or the rotation speed of the right rear wheel is lower than the rotation speed of the right rear wheel, the brake fluid pressure applied to the left rear wheel brake device or the right rear wheel brake device is reduced. So the said One And a control means for controlling the operation of the actuator or the second actuator. Left and right front wheel speed sensors detecting left and right front wheel rotation speeds, left and right rear wheel speed sensors detecting left and right rear wheel rotation speeds, left and right front wheel speed sensors and left and right rear Comparing means for comparing the rotation speed of the left front wheel with the rotation speed of the left rear wheel based on each detection signal of the wheel speed sensor and comparing the rotation speed of the right front wheel with the rotation speed of the right rear wheel; The second for reducing or restoring the brake fluid pressure applied to the brake device One An actuator for reducing or restoring the brake fluid pressure applied to the right rear wheel brake device; Two An actuator, braking state determining means for determining that the vehicle is in a braking state, and a rotational speed of the left rear wheel being left by the comparing means in a state in which the braking state determining means determines that the vehicle is in a braking state. When it is determined that the rotation speed of the front wheel is lower than the rotation speed of the right rear wheel, or the rotation speed of the right rear wheel is lower than the rotation speed of the right rear wheel, the brake fluid pressure applied to the left rear wheel brake device or the right rear wheel brake device is reduced. So the said One Controlling the operation of the actuator or the second actuator, and when it is determined by the comparing means that the rotation speed of the left rear wheel is greater than the rotation speed of the left front wheel or that the rotation speed of the right rear wheel is greater than the rotation speed of the right front wheel, The above-mentioned second control is performed so as to restore the brake fluid pressure applied to the left rear wheel brake device or the right rear wheel brake device. One And a control means for controlling the operation of the actuator or the second actuator. Left and right front wheel speed sensors that detect the left and right front wheel rotation speeds, left and right rear wheel speed sensors that detect the left and right rear wheel rotation speeds, the left and right front wheel speed sensors, and the left and right rear wheel speed sensors Comparison means for comparing the rotation speed of the left front wheel with the rotation speed of the left rear wheel based on each detection signal and comparing the rotation speed of the right front wheel with the rotation speed of the right rear wheel; To reduce or restore the brake fluid pressure One An actuator for reducing or restoring the brake fluid pressure applied to the right rear wheel brake device; Two An actuator, braking state determining means for determining that the vehicle is in a braking state, and left and right front wheels detected by the speed sensor in a state in which the braking state determining means determines that the vehicle is in a braking state. Until the rotation speed and the maximum wheel speed calculated based on each rotation speed of the left and right rear wheels become smaller than a predetermined value, the rotation speed of the left rear wheel is smaller than the rotation speed of the left front wheel or right by the comparison means. When it is determined that the rotation speed of the rear wheel is smaller than the rotation speed of the right front wheel, the second control is performed so as to reduce the brake fluid pressure applied to the left rear wheel brake device or the right rear wheel brake device. One Controlling the operation of the actuator or the second actuator, and when it is determined by the comparing means that the rotation speed of the left rear wheel is greater than the rotation speed of the left front wheel or that the rotation speed of the right rear wheel is greater than the rotation speed of the right front wheel, The above-mentioned second control is performed so as to restore the brake fluid pressure applied to the left rear wheel brake device or the right rear wheel brake device. One And a control means for controlling the operation of the actuator or the second actuator.

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