JPH0615320B2 - Break control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a brake control device used in an automobile or the like.

(Prior Art) As a conventional brake control device, for example, JP-A-60
-78847 (title of invention; brake booster)
Devices such as those described in US Pat.

This conventional device controls the output of the brake booster (brake booster) to keep the relationship between the brake pedal force and the braking deceleration constant, and detects the pedal force applied to the brake pedal. It has a pedaling force detecting means for outputting a pedaling force signal, a deceleration detecting means for detecting a deceleration of the vehicle due to braking and outputting a deceleration signal, a variable pressure chamber and a constant pressure chamber, and between the master cylinder and the brake pedal. A booster that is interposed, a fluid pressure supply source that communicates with a variable pressure chamber of the booster, and a valve device that is arranged in a communication conduit between the fluid pressure supply source and the variable pressure chamber and that is operated by a valve drive signal. A function generating means for outputting a target deceleration signal corresponding to the pedaling force signal, and the target deceleration signal and the deceleration signal are input, and the valve is driven so that the deceleration signal matches the target deceleration signal. Comparison that outputs a signal And, it was those with.

(Problems to be Solved by the Invention) However, in such a conventional device, although the relationship between the brake pedal force and the braking deceleration can be kept constant, the output from the brake booster device is converted into hydraulic pressure. Since there is a single hydraulic circuit from the master cylinder to the wheel cylinders, if the output hydraulic pressure is controlled based only on the difference between the target braking deceleration and the actual braking deceleration from the start of braking operation, Due to the system dynamics, etc., there is a time delay in the generation of vehicle deceleration with respect to the output from the booster, so the output overshoot becomes large, and as a result, the deceleration more than intended by the driver is generated. However, there is a problem in that the driver feels a sense of discomfort due to the occurrence or deterioration of the convergence to the target value.

(Means for Solving Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and in order to achieve this object, the present invention uses the following solving means.

The solution means of the present invention will be described with reference to the conceptual diagram of claims shown in FIG. 1. The master cylinder 2 for converting the pedaling force applied to the brake pedal 1 into hydraulic pressure, the master cylinder hydraulic pressure Pm, and the control load Fc are included in the signal load. An output hydraulic pressure control valve 6 for controlling the input hydraulic pressure Pp from the hydraulic pressure generating means 4 to an output hydraulic pressure Pw to the wheel cylinder 5, and a control load setting means 7 for setting the control load Fc according to a control signal. The deceleration sensor 8 and the pedaling force sensor are included in the 9-input sensor, and even if the difference between the target braking deceleration and the actual braking deceleration is equal to or greater than the pressure increase start set value, the rate of change of the target braking deceleration and the actual braking are reduced. If the difference from the rate of change in deceleration is equal to or greater than a predetermined value, the output hydraulic pressure is not increased, and a control signal for obtaining the target braking deceleration according to the pedal effort is output to the control load setting means 7. Control means 10, It was Eteiru means.

(Operation) Therefore, in the brake control device of the present invention, as described above, the hydraulic circuit from the master cylinder to the wheel cylinder is provided from the master cylinder to the hydraulic pressure generating means and from the hydraulic pressure generating means to the wheel cylinder. It is divided into systems, and the output hydraulic pressure control valve is installed in the other wheel cylinder hydraulic system,
By controlling this valve so that the braking deceleration corresponding to the pedal effort is obtained, the relationship between the brake pedal effort and the braking deceleration can be kept constant.

Furthermore, even if the difference between the target braking deceleration and the actual braking deceleration is greater than or equal to the pressure increase start set value, the difference between the target braking deceleration change rate and the actual braking deceleration change rate must be greater than or equal to a predetermined value. For example, by not performing the output hydraulic pressure increase control, the actual braking deceleration suddenly rises with a time delay after the start of the braking operation, and when there is a difference between the target and actual braking deceleration. The pressure increase control is not performed, the overshoot of the output hydraulic pressure is reduced, and the conformity with the target braking deceleration intended by the driver can be enhanced.

(Examples) Hereinafter, examples of the present invention will be described in detail with reference to the drawings. In describing this embodiment, a brake control device used in an automobile will be taken as an example.

First, the configuration of the embodiment will be described.

The brake control device A of the embodiment, as shown in FIG.
As the master cylinder hydraulic system, the brake pedal 20, the master cylinder 21, the master cylinder hydraulic oil passages 22, 2
2. Accumulator (stroke absorbing means) 23, 23
As a wheel cylinder hydraulic system, a hydraulic pump (hydraulic pressure generating means) 24, input hydraulic oil passages 25, 25, output hydraulic pressure control valves 26, 26, wheel cylinder hydraulic oil passages 27, 27, wheels Cylinders 28 and 28 'are provided, a first solenoid valve 51 and a second solenoid valve 52 are provided as control load setting means, and a deceleration sensor 32 and a master cylinder hydraulic pressure sensor (pedal force sensor) 33 are provided as input sensors. A control unit 34 including a microcomputer is provided as control means.

The master cylinder 21 is a means for converting the pedal effort on the brake pedal 20 into hydraulic pressure.

The master cylinder hydraulic oil passages 22 and 22 are oil passages for flowing oil of the master cylinder hydraulic pressure Pm generated in the master cylinder 21, one is a front master cylinder hydraulic oil passage, and the other is a rear side. It is a master cylinder hydraulic oil passage.

Note that the hydraulic oil passage includes the oil passage formed in the pipe and the oil passage formed in the valve body 35.

The accumulators 23, 23 are provided in the master cylinder hydraulic pressure oil passages 22, 22 to store the oil of the master cylinder hydraulic pressure Pm at the time of brake operation, and to change the pedal stroke with respect to the brake pedal force to the brake pedal 20 to the master cylinder hydraulic pressure. Is supplied to the wheel cylinder as it is to perform a braking operation, and the accumulators 23, 23 are means for maintaining a constant relationship.
Is formed inside.

The hydraulic pump 24 serves as a hydraulic pressure source that creates a hydraulic pressure to the wheel cylinders 28, 28 during brake operation. The suction oil passages 36, 36 of the hydraulic pump 24 are reserved via one-way valves 37, 37. Connected to the tank 38, the discharge oil passages 39, 39 have one-way valves 40, 40
Are connected to the output hydraulic pressure control valves 26, 26 (input hydraulic pressure oil passages 25, 25) and the first solenoid valve 51 (input hydraulic pressure oil passage 41).

Incidentally, accumulators 42, 42 are provided in the discharge oil passages 39, 39 in order to reduce fluctuations in hydraulic pressure.

The output hydraulic pressure control valves 26, 26 are the same as the hydraulic pump 24.
Is a valve for controlling the input hydraulic pressure Pp from P to the output hydraulic pressure Pw to the wheel cylinders 28, 28 ', and valves having the same structure are provided in parallel in the valve body 35.

Structurally, a valve hole 126 having ports 126a to 126d and a land 226a corresponding to the valve hole 126.
~ 226b and axially movable spool 226,
The stepped piston hole 326 formed in the left side of the spool 226 in the drawing having the ports 326a and 326b, the stepped piston hole 426 capable of reciprocating in the stepped piston hole 326 and contacting the spool 226, and the spool 226 are shown. And a spring 526 for biasing to the left.

The port 126a is in contact with the drain oil passage 43.
The port 126c is connected to the input hydraulic oil passage 25.
The ports 126b and 126d are connected to the output hydraulic oil passage 27.

Further, the port 326 a is connected to the master cylinder hydraulic oil passage 22. The port 326b is a control signal hydraulic oil passage 4
4 is connected.

The wheel cylinders 28, 28 are provided in front and rear wheel braking devices (disc brakes, drum brakes, etc.),
A member that applies a braking force to the wheels by the output hydraulic pressure Pw, one of which is a front wheel side wheel cylinder and the other of which is a rear wheel side wheel cylinder.

First solenoid valve 51 and second solenoid valve 5
2 is a control signal hydraulic pressure P to the output hydraulic pressure control valve 26.
The hydraulic pressure control valve c is generated in response to a control signal from the control unit 34, and is provided in the valve body 35.

The first solenoid valve 51 is a valve which is normally closed and outputs a high control signal pressure Pc by the valve opening operation, and the second solenoid valve 52 is a valve which is normally opened and drains the control signal pressure Pc in the valve opened state. Each solenoid valve 5
1, 52 are ports 151a, 151b and 152a,
Valve holes 151 and 152 having 152b, and port 1
Valve members 251 and 252 for opening and closing 51a and 152a
And the spring 3 for urging the valve members 251, 252
51, 352 and solenoids 451 and 452 for applying electromagnetic force to the valve members 251, 252.

The ports 151a and 152a are connected to the control signal hydraulic oil passage 44, the port 151b is connected to the input hydraulic oil passage 41, and the port 152b is connected to the reserve tank 38.

The deceleration sensor 32 is a sensor that detects the source speed of the vehicle and outputs a deceleration signal according to the deceleration.

The master cylinder hydraulic pressure sensor 33 is a sensor that detects the master cylinder hydraulic pressure Pm and outputs a hydraulic pressure signal corresponding to the brake pedal force.

The control unit 34 includes a deceleration signal from the deceleration sensor 32 and the master cylinder hydraulic pressure sensor 33.
The hydraulic pressure signal from the above is input and processed according to a predetermined processing condition, and the difference Δα between the target braking deceleration αi and the actual braking deceleration αr is increased with respect to the first solenoid valve 51 and the second solenoid valve 52. Even if the pressure start set value ε ₁ or more, if the difference Δ between the rate of change i of the target braking deceleration αi and the rate of change of the actual braking deceleration αr is not more than a predetermined value −δ (error is not less than δ). , Δα is the limit set value ε ₂ (> ε
₁ ) Control means for holding the output pressure reduction Pw on condition that it is equal to or less than the above and outputting a control signal for obtaining a target braking deceleration αi according to the brake pedal force.
(Random access memory) 234, ROM (Read only memory) 334, CPU (Central.
Processing. Unit) 434, clock circuit 53
4 and an output circuit 634.

The input circuit 134 is used to amplify the input signal and
A circuit for converting into a signal that can be processed by the RAM 34, a RAM
Reference numeral 234 denotes a write / read memory circuit for temporarily writing an input signal or temporarily writing information during processing, and the ROM 334 is a memory circuit for preliminarily storing information necessary for control processing. C
PU 434 is a central arithmetic processing circuit that performs comparison and arithmetic processing according to a predetermined processing means, clock circuit 534 is a circuit that sets a control processing time, and output circuit 634 outputs a control signal based on a result signal from CPU 434. It is a circuit to do.

In the ROM 334, an arithmetic expression for calculating the target braking deceleration αi from the hydraulic pressure signal, an arithmetic expression for the change rate i of the target braking deceleration αi (dαi / dt), and a change rate of the actual braking deceleration αr. The calculation formula (dαr / dt) of r and the braking deceleration difference Δα between the target braking deceleration αi and the actual braking deceleration αr.
And a change rate difference Δ between the change rates i and r
The calculation formula for obtaining, the change rate difference set value −δ, the pressure increase start set value ε ₁ , the limit set value ε ₂ (> ε ₁ ), the depressurization start set value −ε _{3, and the} like are stored in advance.

The set values ε ₁ , ε ₂ , ε ₃ and δ are positive values.

Next, the operation of the embodiment will be described.

First, the control operation of the control unit 34 of the embodiment will be described with reference to the flow chart shown in FIG.

(B) When the braking deceleration difference Δα is Δα> ε ₁ , the flow of control operation at this time is Δα> ε ₁ and Δ ≧ −δ, and Δ ≦ −δ, Δα ≧ ε ₂ (> ε ₁ ). Case and Δ ≦
-Δ differs from ε ₁ <Δ <ε ₂ .

If Δα> ε ₁ and Δ> −δ, the flow proceeds to step 200 → step 201 → step 202 → step 203 → step 204 → step 205 → step 206 → step 207 → step 208, and Δ ≦
If Δα ≧ ε ₂ (> ε ₁ ) at −δ, step 200
→ Step 201 → Step 202 → Step 203 →
The flow proceeds from step 204 → step 205 → step 206 → step 207 → step 209 → step 208. In either case, the first solenoid valve 51 is opened (ON signal) and the second solenoid valve 52 is closed (ON). Signal) to increase the pressure.

Step 200 is a step of reading a hydraulic signal corresponding to the brake pedal force.

Step 201 is a calculation step for calculating the target braking deceleration αi based on the hydraulic pressure signal (master cylinder hydraulic pressure Pm) read in step 200.

In step 202, the target braking deceleration αi calculated in step 201 is differentiated with respect to time to obtain a change rate i (dαi
This is a calculation step for calculating / dt).

Step 203 is a reading step for reading the deceleration signal actual braking deceleration αr from the deceleration sensor 32.

In step 204, the actual deceleration αr read in in step 203 is differentiated with respect to time, and the change rate r (dαr /
This is a calculation step for calculating dt).

Step 205 is a calculation step for calculating a braking deceleration difference Δα (= αi−αr) from the target braking deceleration αi and the actual braking deceleration αr.

Step 206 is the braking deceleration difference Δα at 205.
And a pressure increase start set value ε ₁ and a pressure decrease start set value −ε ₃ are compared.

Step 207 is the step 202 and the step 2
This is a determination step for comparing the change rate Δ obtained from the change rates i and r in 04 with the change rate difference set value −δ.

Step 208 is a pressure increase output step in which the first solenoid valve 51 is opened and the second solenoid valve 52 is closed.

In step 209, the braking deceleration difference Δα and the limit set value ε ₂
This is a determination step for comparing with.

Further, when Δ ≦ −δ and ε ₁ <Δα <ε ₂ , step 200 → step 201 → step 202 → step 203 → step 204 → step 205 → step 2
06 → step 207 → step 209 → step 21
At step 210, the second solenoid valve 51 is closed (OFF signal), the second solenoid valve 52 is closed (ON signal), and pressure holding control is performed to maintain the output hydraulic pressure Pw.

(B) When the braking deceleration difference Δα is −ε ₃ ≦ Δα ≦ ε ₁ , the braking operation flow at this time is as follows: Step 200 → Step 201 → Step 202 → Step 203 → Step 2
04 → step 205 → step 206 → step 21
The flow proceeds to 0, and the holding pressure control for holding the output hydraulic pressure Pw is performed.

(C) When the braking deceleration difference Δα is Δα <−ε ₃ , the flow of the braking operation at this time is as follows: Step 200 → Step 201 → Step 202 → Step 203 → Step 2
04 → step 205 → step 206 → step 21
In step 211, the first solenoid valve 51 is closed (OFF signal), the second solenoid valve 52 is opened (OFF signal), and pressure reduction control is performed to reduce the output hydraulic pressure Pw.

The output hydraulic pressure Pw is controlled by the above-described control operation, which will be described with reference to the time chart shown in FIG.

In this time chart, αr ₀ is the braking deceleration difference Δ
This is the actual braking deceleration when the output hydraulic pressure Pw ₀ is controlled based only on α, and Δα ₀ is the braking deceleration difference at this time.

First, looking at the output hydraulic pressure characteristic Pw ₀ in which the output hydraulic pressure is controlled only based on this braking deceleration difference Δα, when the braking deceleration difference Δα is equal to or greater than the pressure increase start set value ε _{1, the} pressure increase control is always performed. As a result, the actual braking deceleration αr ₀ overshoots due to the delay in the generation of the braking deceleration, and even after the pressure reduction control for holding pressure and pressure reduction is performed thereafter, the actual braking deceleration αr ₀ is generated more than necessary. However, the convergence to the target braking deceleration αi is poor, and the closeness to the target output hydraulic pressure characteristic Pw ^* is low.

On the other hand, as in the embodiment, when a predetermined condition is satisfied (Δ ≦
-Δ, Δα ≧ ε ₂ ), the braking deceleration difference Δα is Δα> ε ₁
Even when the actual braking deceleration αr is increased, the holding pressure is controlled when the actual braking deceleration αr suddenly rises due to the overshoot. Is suppressed, the convergence to the target braking deceleration αi is improved, and the closeness to the target output hydraulic pressure characteristic Pw ^* is also improved.

The operation of the output hydraulic pressure control valve 26 at the time of controlling the output hydraulic pressure Pw will be described.

The output hydraulic pressure control valve 26 has a generally well-known hydraulic spool valve structure. When the axial position of the spool 226 is at the left side position in FIG. 2, the output hydraulic pressure port 126b and the drain port 126a are not connected. Communication, the output hydraulic pressure Pw becomes the drain pressure which is the lowest pressure, and the spool 2
When the axial position of 26 is at the right side position in FIG. 2, the output hydraulic pressure port 126b and the input hydraulic pressure port 126c communicate with each other, and the output hydraulic pressure Pw becomes the maximum input hydraulic pressure Pp,
The output hydraulic pressure Pw is controlled to a hydraulic pressure within the range of the drain pressure to the input hydraulic pressure Pp by controlling the axial position of the spool 226 to any position between the left and right end positions.

That is, the axial position control of the spool 226 is the output hydraulic pressure control as it is, and the axial position of the spool 226 is determined by the relationship between the forces acting on both ends of the spool 226 as described below.

Spool 226 in the right direction in FIG. 2 (direction to increase pressure)
The pushing force is the force obtained by multiplying the control signal hydraulic pressure Pc by the pressure receiving area of the stepped piston 426 where this hydraulic pressure acts, and the master cylinder hydraulic pressure Pm and the pressure receiving area of the stepped piston 426 where this hydraulic pressure acts. It is the sum of the power multiplied by. On the other hand, the force that pushes the spool 226 to the left (the direction of reducing pressure) in the drawing of FIG. 2 is the force of the spring 526 and the force obtained by multiplying the output hydraulic pressure Pw and the pressure receiving area of the spool 226 on which this hydraulic pressure acts. Become.

Therefore, the axial position of the spool 226 is controlled so that the force in the right direction of the drawing and the force in the left direction of the drawing are balanced, and when the output hydraulic pressure Pw is increased, it is created by both solenoid valves 51 and 52. When the control signal hydraulic pressure Pc is increased, the spool 226 moves to the right in the drawing of FIG. 2 to increase the output hydraulic pressure Pw, and when the output hydraulic pressure Pw is reduced, both solenoid valves 51,
By reducing the control signal hydraulic pressure Pc generated by 52, the spool 226 moves to the left in the drawing of FIG. 2 to achieve the reduction of the output hydraulic pressure Pw, and when the output hydraulic pressure Pw is maintained, both solenoid valves are operated. By maintaining the control signal hydraulic pressure Pc generated by 51 and 52, the spool 22
6 is maintained and the output hydraulic pressure Pw is maintained.

As described above, the brake control device A of the embodiment
In this case, the hydraulic circuit from the master cylinder 21 to the wheel cylinder 28 is divided into two systems, a master cylinder hydraulic system and a wheel cylinder hydraulic system, and one of the master cylinder hydraulic systems has a brake pedal 20. Since the accumulator 23 that absorbs the pedal stroke is provided, the relationship between the brake pedal force and the brake stroke is kept constant, and the brake feeling is not deteriorated.

Further, an output hydraulic pressure control valve 26 is provided in another wheel cylinder hydraulic system so that a target braking deceleration αi corresponding to the master cylinder hydraulic pressure Pm (corresponding to the brake pedal force) can be obtained by this valve 26. Since the brake is applied, the relationship between the brake pedal force and the braking deceleration can be kept constant.

Even if the difference Δα between the target braking deceleration αi and the actual braking deceleration αr is equal to or larger than the pressure increase start set value ε ₁ , the rate of change i of the target braking deceleration αi and the rate of change r of the actual braking deceleration αr. If the difference Δ from the output pressure P is less than or equal to the set value −δ, the output hydraulic pressure P is set on condition that Δα is less than or equal to the limit set value ε ₂ (> ε ₁ ).
Since the pressure increase control of w is not performed, the actual braking deceleration αr suddenly rises with a time delay after the start of the brake operation, and a difference between the target and the actual braking deceleration Δα occurs (ε _The pressure increase control is not performed for ₁ <Δα <ε ₂ ), the overshoot of the actual braking deceleration αr and the output pressure reduction Pw becomes small, and the matching with the target braking deceleration αi intended by the driver is enhanced. be able to.

Further, in the embodiment, the accumulators 23, 23, the hydraulic pump 24, the output hydraulic pressure control valves 26, 26, the control signal hydraulic valve 29, the oil passage, etc. are contained in one valve body 35, so that the apparatus is made compact. Can be achieved.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and the present invention can be applied even if there is a design change or the like within a range not departing from the gist of the present invention. included.

For example, in the embodiments, the spool valve type is shown as the output hydraulic pressure control valve, but a control valve of other structure such as a ball valve type control valve may be used.

Further, although the control pressure setting valve of the solenoid valve structure is shown as the control load setting means in the embodiment, a valve operated by a motor actuator or an actuator directly generating a control load may be used.

Further, in the embodiment, the master cylinder hydraulic pressure sensor that indirectly detects the brake pedal force is shown as the pedal force sensor.
The brake pedal force may be directly detected, or the brake pedal force may be indirectly detected by a master cylinder stroke, an accumulator stroke, or the like.

Further, in the embodiment, as the deceleration sensor, a sensor which directly detects the deceleration is shown, but like the vehicle speed sensor (the deceleration can be obtained by calculation), the wheel load sensor, or the like,
It may be a sensor that indirectly detects the deceleration.

(Effects of the Invention) As described above, in the brake control device of the present invention, the pressure reducing circuit from the master cylinder to the wheel cylinder includes the master cylinder to the pressure reducing generating means.
The system is divided into two systems from the pressure reduction generating means to the wheel cylinder, and the other wheel cylinder hydraulic system is provided with an output hydraulic pressure control valve, and this valve is controlled so as to obtain a control deceleration according to the pedaling force. The effect that the relationship between the brake pedal force and the braking deceleration can be kept constant is obtained.

Even if the difference between the target braking deceleration and the actual braking deceleration is greater than or equal to the pressure increase start set value, the difference between the target braking deceleration change rate and the actual braking deceleration change rate must be greater than or equal to a predetermined value. For example, by not performing the output hydraulic pressure increase control, the actual braking deceleration suddenly rises with a time delay after the start of the braking operation, and when there is a difference between the target and actual braking deceleration. The pressure increase control is not performed, the overshoot of the output hydraulic pressure is reduced, and the effect of being able to improve the conformity with the target braking deceleration intended by the driver is obtained.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a brake control device of the present invention, FIG. 2 is a diagram showing a brake control device of an embodiment, and FIG.
FIG. 4 is a flow chart showing the flow of control operation in the control unit of the embodiment apparatus, and FIG. 4 is a time chart diagram when the embodiment apparatus is in the correct state. 1 …… Brake pedal 2 …… Master cylinder 3 …… Master cylinder Hydraulic oil passage 4 …… Hydraulic pressure generating means 5 …… Wheel cylinder 6 …… Output hydraulic pressure control valve 7 …… Control load setting means 8 …… Decrease Speed sensor 9 ... pedal force sensor 10 ... control means

Claims (1)

[Claims] 1. A master cylinder for converting a pedaling force applied to a brake pedal into a hydraulic pressure, a master cylinder hydraulic pressure and a control load included in a signal load, and an input hydraulic pressure from a hydraulic pressure generating means to an output hydraulic pressure to a wheel cylinder. An output hydraulic pressure control valve for controlling the control load, a control load setting means for setting the control load according to a control signal, a deceleration sensor and a pedaling force sensor are included in the input sensor, and the target braking deceleration and the actual braking deceleration are Even if the difference is equal to or higher than the pressure increase start set value, if the difference between the change rate of the target braking deceleration and the change rate of the actual braking deceleration is equal to or more than a predetermined value, the output hydraulic pressure increase control is not performed. A brake control device comprising: a control unit that outputs a control signal for obtaining a target braking deceleration corresponding to a pedaling force to the control load setting unit.