JP3473123B2 - Brake fluid pressure control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake fluid pressure control device for a vehicle, and more particularly to improvement of an actuator capable of reducing operating noise generated when a pressure-increasing operation of an antilock brake is performed.

[0002]

2. Description of the Related Art In a vehicle brake fluid pressure control device,
For example, an anti-lock brake (anti-skid) is conventionally known as a device that controls a decrease and increase in wheel cylinder pressure including a gentle increase mode in order to prevent wheel lock during braking. 58-14195
No. 1).

[0003]

In increasing the wheel cylinder pressure of this type, an electromagnetic valve installed between the wheel cylinder for generating a braking force on the wheel and the master cylinder, which is a hydraulic pressure generating portion, is used for pressure reduction control. During the subsequent pressure increase control, it is possible to realize the slow pressure increase control by intermittently opening and closing.

Specifically, although FIG. 8 is also referred to later, as shown in FIG. 8, an opening / closing signal is repeatedly given to the solenoid valve when the wheel cylinder pressure is increased (see FIG. )), The pressure in the wheel cylinder rises and becomes constant by a certain step height, and thus the pressure in the wheel cylinder (FIG. (B)) can be gradually increased to gradually increase the pressure. In the device having such an anti-lock brake solenoid valve in the actuator, the required pressure increase gradient can be adjusted by the intermittent control by the control computer, however, on the other hand, on the other hand, the hydraulic pressure passage for the wheel cylinder is opened and closed. Since the pressure is changed stepwise, surge pressure is generated during the pressure increase control. That is, when the valve is closed, a pressure fluctuation occurs to shut off the flow from the high pressure master cylinder side oil passage to the low pressure wheel cylinder side oil passage (FIG. 8 (b)). Due to this pressure fluctuation, for example, from the solenoid valve to the wheel. The piping up to the cylinder is vibrated and noise is generated.

As described above, when the solenoid valve is provided in the fluid passage to the wheel cylinder and controls the degree of change of the wheel cylinder pressure by repeating the opening and closing of the solenoid valve, the solenoid valve vibrates the brake pipe or the like during its operation. It becomes a factor to generate an operating sound. As a countermeasure against such operating noise, if a special anti-vibration structure is applied around the pipes, it will lead to larger size and higher cost.In the conventional one, even the function of effectively reducing noise generated during operation Does not have.

In the present invention, in controlling the wheel cylinder pressure, even if the above-mentioned pressure fluctuation occurs due to the intermittent opening and closing of the used solenoid valve, the operating noise can be appropriately reduced. It is a thing.

Another object of the present invention is to provide a brake fluid pressure control device capable of ensuring the original control effectiveness and being able to deal with it in detail and realizing the above.

[0008]

According to the present invention, the following brake fluid pressure control device is provided. That is, a hydraulic pressure generation source capable of generating a pressure corresponding to a brake operating force, a wheel cylinder generating a braking force for a vehicle wheel, and a hydraulic pressure generation source provided between the hydraulic pressure generation source and the wheel cylinder are repeatedly opened and closed. a solenoid valve for controlling the degree of change in the wheel cylinder pressure, the obtained based on the running state of the vehicle
Calculates the solenoid valve closing time to achieve a slow boost curve
The solenoid valve closing time is generated when the solenoid valve is activated.
The pressure fluctuation level is not affected by the solenoid valve closing time.
It is compared with the boundary value according to the
This solenoid valve opening time control range is changed by changing the valve opening time control range.
Based on the above, the pressure fluctuation level is allowed as a noise level.
Slow boosting curve within a range that is below the allowable limit value
To control the opening and closing time of the solenoid valve so that
A brake fluid pressure control apparatus according to claim Rukoto equipped with.

Further, the control means is arranged to control the electromagnetic valve closing time.
Smaller than the boundary value, substantially the closing time value of the solenoid valve,
In the first area where both the open time values affect the pressure fluctuation level , the pressure fluctuation level becomes the noise level.
The solenoid valve opening / closing time is set by the combination of the closing time value and the opening time value selected within the allowable range, and / or the solenoid valve closing time is equal to or more than the boundary value , and the solenoid valve is closed substantially. time value is be difficult to affect the pressure fluctuation level in the second region, the pressure of the open time value
The brake fluid pressure control device is characterized in that the solenoid valve opening / closing time is set so that the fluctuation level is within an allowable range as a noise level .

Further, in one or both of the first area and the second area, the solenoid valve opening / closing time is controlled, and the number of repetitions of the solenoid valve opening / closing during the wheel cylinder pressure gentle pressure increase control is controlled to be changed. Opening and closing variable control means,
The brake fluid pressure control device further comprises:

[0011]

In the present invention, the pressure fluctuation level changes depending on the opening time and closing time of the solenoid valve, and this is utilized for suppressing noise generation due to the pressure fluctuation during the operation of the solenoid valve. This is a concrete example of the idea that the pressure fluctuation level can be reduced to noise.
By controlling the solenoid valve opening / closing time within a range where the level is below the allowable limit value, it is possible to control the pressure fluctuation level to fall within the allowable range.
Therefore, even in the case of a vehicle that produces an operating noise due to the vibration of the brake pipe or the like when the wheel cylinder pressure is increased, it is possible to easily and effectively reduce the noise level.

Further, it is obtained based on the running condition of the vehicle.
Calculate the solenoid valve closing time to achieve a slow boost curve
The solenoid valve closing time is generated when the solenoid valve is activated.
The pressure fluctuation level is not affected by the solenoid valve closing time.
The present invention can be implemented as a configuration in which the electromagnetic valve opening time control range is changed according to the size relationship by the comparison, and the opening time and closing time depend on the magnitude of the electromagnetic valve closing time. Even when the control mode is changed depending on the magnitude of the closing time when the influence on the change occurs, it can be finely dealt with, and the above can be similarly performed.

Further, in particular, the electromagnetic valve closing time is the boundary.
In the first region where the pressure fluctuation level is smaller than the threshold value and both the closing time value and the opening time value of the solenoid valve substantially affect the pressure fluctuation level , the pressure fluctuation level is allowed as the noise level.
The solenoid valve opening / closing time is set by the combination of the closing time value and the opening time value selected within the range that can be set, and / or the electromagnetic valve closing time is equal to or more than the boundary value, and the closing time value of the electromagnetic valve is substantially set. In the second region where the pressure fluctuation level is less likely to be affected, the open time value is set to the pressure fluctuation level.
The present invention can be carried out by setting the solenoid valve opening / closing time so that the bell is within the allowable range of the noise level , and similarly, the above is enabled.

Further, in either one or both of the first area and the second area, the solenoid valve opening / closing time control and the number of repetitions of the solenoid valve opening / closing during the wheel cylinder pressure gentle pressure increase control are controlled. The present invention can be implemented by further including a control means for changing the number of times of opening and closing, and in this case, in addition to the above, by combining control for changing the number of times of slow pressure increase,
The demand can be easily met so as to realize the necessary gentle boosting curve, and more precise control can be performed while ensuring controllability, which makes it possible to be more effective.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram according to an embodiment of the present invention.
The case of a 4CH control type anti-skid (ABS) system of channel 4 sensor type is shown. In the figure, 1 is a brake pedal, 2 is a master cylinder (M / C), 3FL, 3
FR is the left and right front wheels of the vehicle, 3RL and 3RR are the same left and right rear wheels,
Reference numeral 4 indicates a wheel cylinder (W / C) of each wheel. Each wheel 3F from the master cylinder 2 that generates a braking fluid pressure (braking pressure) according to the depression of the brake pedal 1.
A brake actuator unit 10 is inserted in the brake hydraulic system that reaches the wheel cylinders 4 of L, 3FR, 3RL, and 3RR.

One liquid passage 15 from the master cylinder 2
The front wheel brake hydraulic system by the (oil passage) leads to the left and right front wheel cylinders 4, 4 via the fluid passages 16FL, 16FR (oil passage) individually via the actuator unit 10, and by the other fluid passage 15 (oil passage). The rear wheel brake hydraulic system individually passes through the actuator unit 10 and the hydraulic passage 16R.
The left and right rear wheel cylinders 4 and 4 are reached via L and 16RR (oil passage).

The actuator unit 10 constitutes an anti-skid control device together with the controller 20. For the hydraulic pressure control, each actuator of the brake hydraulic pressure supply system for the front, rear, left and right wheels can be used for ABS control. The solenoid valve (anti-lock brake solenoid valve) is equipped with each actuator to control the brake fluid pressure toward the wheel cylinder 4 of each wheel according to the control signal (command) from the controller 20 to adjust the wheel cylinder pressure. Eggplant As the actuator, one that can control depressurization, holding pressure (holding), and pressure increase can be used.

FIG. 2 shows only a brake fluid pressure control system relating to one wheel of the vehicle, and specifically shows only one system of a portion for performing a slow pressure increase. ,
The depressurization system is omitted. This is to make the explanation easy to understand. Therefore, for example, in the case of the 4CH control type as in the present embodiment, the same actuators according to the present embodiment are also applied to the other three wheels (other channels (systems)) of the vehicle. A configured brake pressure control system exists. That is, in the 4CH control type vehicle, there are a total of four systems including a front two systems and a rear two systems, that is, an anti-slock brake gradually increasing pressure system and a pressure reducing system for each system. It should be noted that the 3CH control type can be implemented by having three systems of front left and right and rear and a pressure reducing system.

In FIG. 2, an oil passage 15 (piping) from the master cylinder 2 which generates hydraulic pressure in accordance with the operating force of the brake pedal 1 is a solenoid valve which is normally opened by spring force. It is possible to connect to the wheel cylinder 4 of the wheel 3 by an oil passage 16 (pipe) from the solenoid valve 11. This solenoid valve 11 installed between the wheel cylinder 4 that generates a braking force and the master cylinder 2 that is a hydraulic pressure generation unit controls the pressure inside the wheel cylinder by opening and closing it. It is in the first position shown when not energized, and when it is energized, the oil passage 1
5 is a 2-port 2-position solenoid valve (solenoid valve) that is controlled by the controller 20 so as to assume the second position that shuts off between 5 and the oil passage 16.

The master cylinder 2 is the brake pedal 1
When the master cylinder pressure corresponding to the pedal force of the brake pedal is output in conjunction with the brake operation by stepping on the wheel cylinders 4 and the wheel cylinders 4 arranged on each wheel are supplied as the wheel cylinder pressure Pw as it is. It is possible to brake each wheel by being actuated by the brake hydraulic pressure, causing each corresponding wheel to generate a braking force corresponding to the hydraulic pressure. The oil passage 16 connected to the wheel cylinder 4 is connected to the oil passage 15 on the master cylinder side via a branch oil passage (liquid passage) 17 and a return check valve 12 as shown in the figure. The check valve 12
Is arranged in a direction in which the pressure of the wheel cylinder 4 is released to the master cylinder 2 side, and serves to release the hydraulic pressure of the wheel cylinder 4 and return the hydraulic fluid (operating oil) to the master cylinder 2.

In this embodiment, as described above, the wheel cylinder 4 for generating the braking force and the master cylinder 2 for generating the braking pressure are provided in the pipe that communicates with each other, and the pressure in the wheel cylinder 4 is controlled by opening and closing the pipe. An anti-lock brake solenoid valve 11 is provided for each channel.

The solenoid valve 11 of each channel is controlled by the controller 20 including a control computer. Signals and the like from the wheel speed sensors 30 that detect the wheel speeds of the respective wheels are transmitted to the controller 20, and the controller 20 determines the solenoid valve 11 based on the input information.
The solenoid is controlled so that an opening / closing signal for controlling the opening / closing (ON / OFF) of the solenoid is given.

In the present embodiment, during normal braking (during normal braking), a braking force corresponding to the pedal pedal force is applied to each wheel 3FL, 3FR, 3RL, 3RR of the vehicle. Further, in the ABS operation, the brake control can be executed in the manner of reducing or increasing the wheel cylinder pressure for each channel. In this case, in the pressure increase control, basically, the solenoid valve 11 is opened and closed intermittently to gradually increase the pressure in the wheel cylinder 4 to execute the moderate pressure increase control so as to perform braking. In such a gradual pressure increase control, the controller 20 controls the opening / closing control of the solenoid valve 11 when the corresponding solenoid valve 11 is closed in order to reduce the operating noise during the gradual pressure increase operation of the antilock brake. Controls the opening / closing time within a range that keeps the pressure fluctuation level of the pressure fluctuation that occurs when the flow of hydraulic fluid from the master cylinder side oil path to the wheel cylinder side oil path is interrupted. By
To achieve this.

The opening / closing time can be controlled by controlling the opening and / or closing time, and the opening time control range is preferably changed according to the magnitude of the electromagnetic valve closing time. Preferably, in addition to this, it is also possible to combine control with respect to the number of times of gradually increasing pressure (the number of times of repeating opening and closing).

The operation of the present device during normal operation, during depressurization under ABS control, and during gradual pressure increase will be further described with reference to FIG.

During normal braking (during normal braking when the antilock brake does not operate) During normal braking when the antilock brake does not operate, no control signal is applied to the solenoid valve 11 (non-energized state), so the electromagnetic waves of each channel The valve 11 is always open by its own spring force. In such a state, the driver is braking and the brake pedal 1
When you step on the master cylinder 2
The master cylinder pressure generated in (1) passes through the oil passage 15 and, for each channel, the electromagnetic valve 11 in the open state,
It is transmitted via the oil passage 16 so as to act on the wheel cylinder 4 of each wheel as it is, and a braking force is generated.

During normal braking, it is possible to perform braking according to the driver's intention in this way. On the other hand, when the skid state of the wheels is detected by the controller 20 during braking on a low μ road such as an icy road, the brake fluid pressure control is performed by pressure reduction or pressure increase.

The basic operation of the antilock brake in this case will be described first as follows. When the wheels 3 are locked during braking, a pressure reducing system (not shown in FIG. 2) drains hydraulic oil from the wheel cylinders 4 and returns them to the master cylinder 2 or a reservoir tank (not shown) to bring them into a low pressure state. Loosen the braking force to remove the locked state. When the wheel speed increases due to the low hydraulic pressure in the wheel cylinder 4, the solenoid valve 11 is intermittently opened and closed to gradually increase the pressure in the wheel cylinder 4 for braking. That is, the pressure is gradually increased. Here, it is assumed that three types of control are performed, that is, the above-described pressure reduction and gentle pressure increase, and further, the holding state in which neither the pressure increase nor the pressure reduction is performed at the wheel speed.
Next, each braking operation will be specifically described.

At the time of ABS control pressure reduction At this time, the following operation is performed. Now, when the braking force acts on the wheels 3 through the brake fluid pressure path as described in the normal braking described above, the controller 20 that receives a signal from the wheel speed sensor 30 or the like detects the vehicle speed and the detected wheels of each wheel. When the skid state of the wheel is detected based on the speed, pressure reduction control of the wheel in the skid state is started. This can be done as follows.

That is, the controller 20 closes the solenoid valve 11 of the corresponding channel from the state of FIG. 2 to block the inflow of the hydraulic fluid from the master cylinder 2 into the corresponding wheel cylinder 4, and also the above-mentioned. As described above, a decompression system (not shown) is used to control the hydraulic oil in the wheel cylinder 4 to be drained. As described above, the wheel cylinder 4 of the corresponding wheel
Is reduced.

At the time of the ABS control slowly increasing pressure At this time (that is, when the antilock brake operates as described above to perform the gradually increasing pressure), basically, the following operation is performed, and the pressure reducing wheel cylinder pressure is increased. Slow pressure increase control of Pw is performed (see FIG. 8). When the restraining force of the corresponding wheel 3 is weakened by reducing the pressure of the wheel cylinder 4 of the corresponding channel as described above, the rotation of the wheel 3 is restored.
When the rotation is sufficiently recovered and the slip ratio of the road surface and the wheel is reduced, the controller 20 judges this and starts the pressure increase control.

That is, the controller 20 determines the solenoid valve 11 based on the signal from the wheel speed sensor 30 when a slow pressure increase is required.
Give an open / close signal to. Here, since the holding state is maintained before the start of slowly increasing pressure, the solenoid valve 11 is closed (solenoid ON signal).
Is given (current is given to the solenoid valve 11), and the oil passage 1
Cut off 5,16. Therefore, the wheel cylinder pressure Pw is maintained at a constant low value controlled by the pressure reduction control (for example, before time t1 in FIG. 8).

Therefore, when increasing the pressure, an open signal (solenoid OFF signal) is given to the solenoid valve 11 (time t).
1-t2). That is, the current to the solenoid valve 11 is cut off, and the state is switched to the normal open state. In this way, the oil passages 15 and 16 are opened by the spring force, and high-pressure hydraulic fluid is supplied to the wheel cylinder 4 to increase its pressure.
Then, the pressure Pw of the wheel cylinder 4 suddenly rises,
A closing signal is given to the solenoid valve 1 so as not to be locked again, and the pressure Pw of the wheel cylinder 4 increases by a certain step height and becomes constant. Slow pressure increase is realized by repeating the above pressure increase and pressure retention (time t1 to t2, t2 to t).
3, t3 to t4, etc.).

The gradual pressure increase control is basically performed in this manner, but in this embodiment, in this case, the controller 20
Executes control of the solenoid valve 11 according to a control program whose example is shown in FIGS. This is based on the following ideas based on the following consideration results.

In FIG. 3, when the open time Ton and the close time Toff (see FIG. 8) of the solenoid valve 11 are changed, the pressure fluctuation level Pp (from the high pressure master cylinder side oil passage 15 to the low pressure level) shown in FIG. 2 shows how the pressure fluctuation level (caused by shutting off the flow to the wheel cylinder side oil passage 16) changes. The opening time Ton
Is used as a parameter, the vertical axis represents the magnitude of the pressure fluctuation level Pp, and the horizontal axis represents the magnitude of the closing time Toff.

Open time Ton and close time Tof in FIG.
To see the relationship between f and the pressure fluctuation level Pp, the open time Ton
When the closing time Toff is changed while keeping constant (for example, Ton1, Ton2, Ton3, etc.), a region of approximately Toff <Toffc (region (A) in the figure) with respect to a certain predetermined value Toffc illustrated in the drawing for the closing time Toff. Then, as shown in the figure, it can be seen that the pressure fluctuation level Pp increases as the open time Ton and the close time Toff increase. In the region of Toff> Toffc (region (B) in the figure), the pressure fluctuation level Pp does not change (substantially does not change) even if the closing time Toff is changed, and only the change of the opening time Ton is the pressure. The fluctuation level Pp is affected. From the above, it can be said that the value Toffc is substantially the boundary at which the pressure fluctuation level Pp is not affected by the closing time.

On the other hand, the pressure fluctuation Pp in the pipe through which the hydraulic fluid is passed.
Generates vibrations by vibrating the piping system and the like, so that there is a limit pressure fluctuation level Pc within which the noise level is within an allowable range. When the solenoid valve 11 is closed, a pressure fluctuation Pp is generated to shut off the flow from the high pressure master cylinder side oil passage to the low pressure wheel cylinder side oil passage. Due to this pressure fluctuation, piping from the solenoid valve 11 to the wheel cylinder 4 is generated. Is one of the factors that cause noise to be excited, but with regard to such pressure fluctuations, even if fluctuations occur, there is an upper limit value that the noise level is acceptable if it does not exceed a certain value and is not large. is there.

Therefore, paying attention to the above, since the pressure fluctuation level Pp changes depending on the opening time and closing time of the solenoid valve 11, the opening / closing time is controlled within a range such that the pressure fluctuation level Pp is below a certain value. This is the basic of the control of the present embodiment, and the pressure fluctuation level Pp becomes the allowable limit Pc of the noise level according to FIG. 3 in the opening / closing control of the solenoid valve 11 during the slow pressure increasing operation. Open time To
If a combination of n and closing time Toff is obtained and control is performed within the range of this combination, the pressure fluctuation level Pp is always the value Pc or less, and the noise level can be kept within an allowable range. For example, if the opening time is the value Ton1, the closing time is set to a value smaller than the Toff value corresponding to the intersection of the characteristic line of the opening time Ton1 and the broken line representing the value Pc in the figure, and the opening / closing is performed. Will be controlled.

Also, the opening time To can be changed depending on the size of Toff.
n, the influence of the closing time Toff on the pressure fluctuation level Pp changes, so it is necessary to change the control method depending on the magnitude of the closing time Toff. It is a further desirable mode to set the control in consideration of this also, and the opening time control range is changed according to the magnitude of the electromagnetic valve closing time.

4 and 5 show examples of control modes according to this embodiment. First, in FIG. 4, the closing time Toff <
The control range in the case of Toffc, that is, the control target range in the case of the region corresponding to the (A) side in FIG. 3 is shown. The horizontal axis represents the open time Ton, and the vertical axis represents the closed time Toff. Ton
0 and Toff0 are the lower limit values in terms of the followability of the used solenoid valve with respect to the opening / closing time, and the applicable solenoid valve 11 cannot follow and cannot control in each control uncontrollable region, that is, in the range of opening time Ton <Ton0. Became,
Further, in the range of the closing time Toff <Toff0, it also means that the control becomes impossible.

On the other hand, the boundary line L in the figure is the pressure fluctuation level P.
p is the limit pressure fluctuation level Pc at which the noise level is allowable
A combination of the open time Ton and the close time Toff is shown. Therefore, as shown, Ton0 and Ton
off 0 and the pressure fluctuation level Pp is a permissible limit pressure Pc. The line L below the line L where the combination of Ton and Toff is satisfied, that is, the noise level is allowable. In a region where a possible combination of Ton and Toff can be established, the noise level can always be kept within the allowable range by controlling the opening time Ton and the closing time Toff. Therefore, in this case, control is performed within this range.

FIG. 5 shows the control range in the case where the closing time Toff ≧ Toffc, that is, the control target range in the region corresponding to the side (B) in FIG. The vertical axis represents the pressure fluctuation level Pp, and the horizontal axis represents the opening time Ton. This figure means the following.
In the range of Toff> Toffc, the pressure fluctuation level Pp is not affected by the closing time Toff as described above (FIG. 3). On the other hand, the characteristic line in FIG. 5 indicates the open time Ton.
Shows the state of change in the pressure fluctuation level Pp when the pressure change level changes. Therefore, when the open time when the noise level reaches the allowable limit pressure fluctuation Pc is Tonc,
By controlling the opening time Ton> Tonc, the noise level can always be kept within the allowable range even in the region of Toff ≧ Toffc. Here, as shown in the figure, for the open time Ton, Ton0 <Ton <
Tonc corresponds to an unacceptable range of noise levels, but Ton> Tonc is in an acceptable range of noise levels.

An example of the control method in the case of performing the control according to FIGS. 4 and 5 is as shown in Table 1 below, and it is more effective to implement any of them.

[0044]

[Table 1]

In Table 1, the left column side corresponds to the control in the area (A) of FIG. 3, and the right column side corresponds to the control in the area (B) of FIG. It can be executed in a mode in which the opening time Ton and the closing time Toff of the solenoid valve 11 are selected within a range in which the noise level is allowable based on FIG. 4, and a mode in which the opening time Ton> Tonc is selected in accordance with FIG.

Further, in the case of Table 1 above, in addition to the solenoid valve opening / closing time control, control for ensuring controllability can be performed. That is, in the case of Toff <Toffc, if the opening time Ton and the closing time Toff must be set in a region outside the control range from the vehicle state, the opening time Ton on the boundary line L in FIG. By setting the closing time Toff and changing the number of times the pressure boosting is repeated, the same pressure boosting line can be realized. In this way, when the control to get out of the range of FIG. 4 is required, the controllability is ensured by increasing / decreasing the number of slow pressure increases (lower left column in the table).

In the case of Toff> Toffc, the opening time T is set in a region smaller than the value Tonc in FIG. 5 from the vehicle state.
When it is necessary to set on (Ton <Tonc)
Corresponds to the case where the slow pressure-increasing line is desired to be gradual. Therefore, the same slow pressure-increasing line can be realized by setting the open time Ton to Tonc, increasing the closing time Toff, and reducing the number of repeated times of the slow pressure-increasing. Thus, when control of Ton <Tonc is required (when the gentle pressure increase gradient is reduced), To
Controllability is secured by increasing ff (lower right column of the same).

As described above, the controller 20
At the time of intermittent opening / closing control of the solenoid valve 11 required at the time of gradual pressure increase, the opening / closing time is controlled within a range such that the pressure fluctuation level Pp is equal to or less than the value Pc. When the valve is repeatedly closed, the flow from the high-pressure oil passage 15 to the low-pressure oil passage 16 is shut off. As a result, even if a pressure fluctuation occurs and the piping system is vibrated by the pressure fluctuation, the noise caused by the pressure fluctuation is appropriately adjusted. It suppresses and reduces the operation noise generated during the gradual pressure increase operation.

FIGS. 6 and 7 are flowcharts showing an example of a control program including processing for ensuring controllability for any of the above areas. This corresponds to the slowly increasing pressure control portion of the ABS control program, and this program is executed by the microcomputer in the controller 20. It should be noted that the data and the like used in the processing of the determination step described later are stored in advance in the memory as a table or map data, and the necessary arithmetic processing is executed by the table or map search based on these.

During ABS operation, as described above, A
After the BS pressure reduction control, the rotation of the wheels is sufficiently restored, the slip ratio is reduced, and the controller 20 determines that the timing corresponds to the pressure increase control start timing, and the pressure increase control by the solenoid valve 11 is started.

That is, in FIG. 6 , when the ABS is operating, this control is started (step 100). Step 101
Is a step of determining whether or not the slow pressure increase is necessary. If it is determined here that the slow pressure increase is not necessary, the process returns to step 101 upstream, while it is determined that the slow pressure increase is necessary. If so, steps 102 and subsequent steps are executed. First, a required slow pressure increasing curve is obtained from the wheel speed data obtained from the wheel speed sensor (step 102), and the valve opening time Ton and closing time Tof required to realize the slow pressure increasing curve are obtained.
f, the number N of slow pressure increases is calculated (step 103).

Next, it is judged whether or not the value Toff (calculated value) obtained above is smaller than the value Toffc (FIG. 3) at which the pressure fluctuation level Pp is not affected by the closing time Toff of the solenoid valve 11. (Step 104). Then,
If Toff <Toffc is established as a result of the determination,
Since both the opening time Ton and the closing time Toff of the solenoid valve 11 affect the pressure fluctuation level Pp (FIG. 3 (A), FIG. 4, left column of Table 1), the process proceeds to step 105 (FIG. 7),
The value Toff is larger than the value Toffc and Toff ≧
When Toffc is satisfied, only the open time Ton affects the pressure fluctuation level Pp (FIG. 3 (B), FIG. 5, right column of Table 1), and therefore the process proceeds to step 110 (FIG. 7) and later described below. .

Step 105 judges whether or not the combination of the calculated value Ton and the value Toff obtained by the above calculation is within the allowable range of the noise level of the allowable limit line L in FIG. It is a step. Here, it is determined whether the point obtained by the above values Ton and Toff is within the allowable range of the noise level from the allowable limit line L in FIG. Proceeding to the output process of step 120, the Ton value of the calculation result of the calculation step 103,
In this step, a signal is directly output to the solenoid valve 11 according to the Toff value and the N value. As a result, the pressure of the wheel cylinder 4 of the corresponding wheel 3 is pressure-controlled in the manner of the electromagnetic valve opening time Ton, the closing time Toff, and the number N of slow pressure increases.

On the other hand, if the result of the determination in step 105 is not within the allowable range, the pressure increase control output process (step 120) for the solenoid valve 11 is executed through the processes of steps 106 and 107. That is, in step 106,
Value T as open and closed time values to be applied to output processing
On, the value Toff is set to a value corresponding to the allowable limit line L in FIG. 4 (lower left column in Table 1), and then in step 107, the slow increase curve required by the Ton value and the Toff value on the allowable limit line L. To obtain the number N of slow pressure increases for realizing
The process proceeds to step 120 to give a signal to the solenoid valve 11. Therefore, in this case, the solenoid valve opening time and closing time are replaced by the set values in step 106 instead of the calculated values in step 103, and the number of slow pressure increases is replaced by the calculated values in step 103. Step 106
The value N obtained in 1 is applied to the drive of each solenoid valve 11, the controllability is ensured, and both are achieved.

On the other hand, when the process proceeds from step 104 to step 110, the calculated value Ton in step 110 is the value Tonc which is the lower limit of the noise.
It is determined whether or not it is smaller than (FIG. 5). As a result of the determination, if the value Ton is large (Ton ≧ Tonc), the noise level is regarded as an allowable range, and the process directly proceeds to step 120. As in the case of the process from step 105 to step 120, the solenoid valve 11 is directly operated. Output a signal to. Thereby, the wheel cylinder 4 of the corresponding wheel 3
In this region, the pressure is controlled to increase in the manner of the electromagnetic valve opening time Ton, closing time Toff, and the gradual pressure increase number N obtained in step 103, and noise can be reduced.

On the other hand, when the calculated value Ton is smaller than the value Tonc, it is assumed that the control of Ton <Tonc is necessary and the gentle pressure-increasing gradient is made small, and the processing is switched to the steps 111 and 112 side as follows ( (Table 1, lower right column), open time value T
On is a value Tonc, and is changed so that the closing time Toff is increased and the number of times of gradual pressure increase is reduced.

That is, in step 111, the applied opening time value T
On is set to the value Tonc, which is the limit at which the noise level is acceptable. Next, at step 112, the closing time To for realizing the slow pressure increase curve necessary for the value Tonc
The ff value and the number N of slow pressure increases are calculated, and the solenoid valve 1
A signal is given to 1 to execute the pressure increasing control output processing (step 120). Thus, in this case, the solenoid valve opening time, the closing time, and the number of times the pressure is gradually increased are determined in step 103
In place of the respective calculated values of
12, the open time Tonc value and the close time T of the above embodiment obtained
The off value and the gradual pressure increase number value N are applied to drive the solenoid valve 11, and similarly, the noise level is reduced, the conventional problem is solved, and the controllability is secured.

When the ABS control is gradually increased, the pressure of the wheel cylinder 4 of the corresponding wheel 3 is gradually increased as described above.

In the control of this embodiment, A as described above is used.
By repeating the pressure reduction control during BS operation and the slow pressure increase control described so far with reference to FIG. 3 and subsequent figures, brake fluid pressure control is performed on a low μ road to prevent wheel lock,
In addition, in the slow pressure increase control, when opening / closing the solenoid valve 11, the opening / closing time can be controlled within a range such that the pressure fluctuation level Pp is equal to or less than the Pc value. Therefore, when the solenoid valve 11 is operated, The pressure fluctuation level can be controlled to fall within the allowable range, and the noise level can be reduced.

In this case, the solenoid valve 11 and its surroundings such as the piping can be achieved by using a known one which is intermittently controlled to be opened and closed as it is. Therefore, a special noise prevention mechanism is added. Without doing so, the actuator is not increased in size, and it is possible to realize antilock brake control that is small in size, low in cost, and can appropriately suppress noise. According to the conventional configuration, it is possible to easily and effectively reduce the operating noise even in the case of a vehicle in which the operating noise is generated by the vibration of the brake pipe when increasing the wheel cylinder pressure. It is possible.

Further, in the present embodiment, by combining the control for changing the number of times of gentle pressure increase, the above can be realized at the same time while easily meeting the demand to realize a necessary curve of moderate pressure increase. Therefore, even when the pressure increasing speed is relatively fast, or when the pressure increasing speed is slow and the pressure increasing control is slow, it is possible to perform more detailed control and to realize such correspondence. Then, a more effective one can be obtained.

The present invention is not limited to the above embodiments. For example, as mentioned above, it goes without saying that the present invention can be applied not only to the case of 4-channel ABS but also to 3-channel ABS and others. Further, in a brake system in which a hydraulic pressure generation source that generates a brake operation force corresponding pressure according to the brake operation force is provided in place of the master cylinder, and the pressure from the pressure source is used as the original pressure,
The present invention can be implemented. Further, in FIG. 2, the configuration of the 2-port / 2-position solenoid valve and the like is shown, but the configuration is not limited to the illustrated configuration, and the hydraulic pressure generation source and the wheel that generate the pressure corresponding to the brake operating force may be provided. The present invention is widely applicable as long as it is provided in a pipe communicating with a wheel cylinder that generates a braking force and the wheel cylinder pressure is controlled by opening / closing control of the wheel cylinder.

[0063]

According to the present invention, when the degree of change in wheel cylinder pressure is controlled by repeatedly opening and closing the solenoid valve between the hydraulic pressure source and the wheel cylinder, the pressure fluctuation level is allowed as a noise level. It is possible to control the solenoid valve opening / closing time within a range such that it is less than or equal to the limit value that is possible, and therefore, it is possible to control so that the pressure fluctuation level falls within the allowable range, even when the wheel cylinder pressure is increased. Even in the case of a vehicle that emits an operating noise due to vibration of the brake pipe or the like, the noise level can be easily and effectively reduced, and the operating noise can be appropriately reduced.

Further, it is obtained based on the running condition of the vehicle.
Calculate the solenoid valve closing time to achieve a slow boost curve
The solenoid valve closing time is generated when the solenoid valve is activated.
The pressure fluctuation level is not affected by the solenoid valve closing time.
It can be implemented as a configuration in which the solenoid valve opening time control range is changed according to the size relation by the comparison, and the influence of the opening time and closing time on the pressure fluctuation level depends on the size of the electromagnetic valve closing time. When the control mode is changed according to the magnitude of the closing time when is changed, it is possible to finely respond to this, and the above can be similarly realized.

Further, in particular, the electromagnetic valve closing time is set to the boundary.
In the first region where the pressure fluctuation level is smaller than the threshold value and both the closing time value and the opening time value of the solenoid valve substantially affect the pressure fluctuation level , the pressure fluctuation level is allowed as the noise level.
The solenoid valve opening / closing time is set by the combination of the closing time value and the opening time value selected within the range that can be set, and / or the electromagnetic valve closing time is equal to or more than the boundary value, and the closing time value of the electromagnetic valve is substantially set. In the second region where the pressure fluctuation level is less likely to be affected, the open time value is set to the pressure fluctuation level.
The present invention can be implemented by setting the solenoid valve opening / closing time so that the bell is within the allowable range of the noise level , and the above can be similarly realized.

Further, in one or both of the first area and the second area, the solenoid valve opening / closing time is controlled, and the number of times of repeating the solenoid valve opening / closing during the wheel cylinder pressure gentle pressure increase control is controlled to be changed. The present invention can be implemented by further providing a control means for changing the number of times of opening and closing, and in this case, in addition to the above-mentioned point, it is required to realize a necessary slow pressure increasing curve by also combining control for changing the number of times of slow pressure increasing. It is possible to easily deal with the above, and more precise control can be achieved while ensuring controllability, and it is possible to achieve even more effective control.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a configuration relating to a slow pressure increasing system for anti-lock brake hydraulic pressure control for one wheel in the actuator in the same example.

FIG. 3 is a diagram for explaining the principle of the present control, and is a diagram showing changes in pressure fluctuation level due to opening time and closing time of a solenoid valve.

FIG. 4 is a diagram for explaining a control range in the embodiment control,
It is a figure which shows an example at the time of solenoid valve closing time Toff <Toffc.

FIG. 5 is a diagram similarly showing an example of a control range in the case of closing time Toff> Toffc.

FIG. 6 shows an example of a suitable control program for a controller, and is a partial flowchart thereof.

FIG. 7 is a flowchart of another part of the same.

FIG. 8 is a diagram showing a typical control signal and pressure change in the case of wheel cylinder pressure increase by intermittent opening / closing of an electromagnetic valve in anti-lock brake hydraulic pressure control.

[Explanation of symbols]

1 Brake Pedal 2 Master Cylinder 3, 3FL, 3FR, 3RL, 3RR Wheel 4 Wheel Cylinder 10 Actuator Unit 11 Solenoid Valve 12 Return Check Valve 15 Liquid Channel (Oil Channel) 16, 16FL, 16FR, 16RL, 16RR Liquid Channel (Oil) 17) Liquid path (oil path) 20 Controller 30 Wheel speed sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A 64-28057 (JP, A) JP-A 2-70566 (JP, A) JP-A 3-82659 (JP, A) JP-A 5- 4573 (JP, A) JP 5-50909 (JP, A) JP 5-97026 (JP, A) Actual opening 1-167954 (JP, U) Actual opening 5-26701 (JP, U) 5-54138 (JP, U) 5-49242 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60T 8/58

Claims (3)

(57) [Claims] 1. A hydraulic pressure generation source capable of generating a pressure corresponding to a brake operation force, a wheel cylinder generating a braking force for a vehicle wheel, and a hydraulic pressure generation source provided between the hydraulic pressure generation source and the wheel cylinder. A solenoid valve that controls the degree of change in wheel cylinder pressure by repeating opening and closing, and a slow pressure increase curve obtained based on the running state of the vehicle are implemented.
When the solenoid valve closing time to calculate is calculated,
The pressure fluctuation level generated during the operation of the solenoid valve is
Compared with the boundary value that is not affected by the solenoid valve closing time,
The solenoid valve opening time control range can be changed according to the magnitude relation by the comparison.
Change the pressure based on the solenoid valve open time control range.
Below the limit value where the force fluctuation level is acceptable as the noise level
In order to achieve a slow boost curve within the range
A brake fluid pressure control device comprising: a control unit that controls a magnetic valve opening / closing time . 2. The control means is characterized in that the electromagnetic valve closing time is shorter than the boundary value, and both the closing time value and the opening time value of the electromagnetic valve substantially affect the pressure fluctuation level. In the area of 1, the pressure fluctuation level
The solenoid valve opening / closing time is set based on the combination of the closing time value and the opening time value selected within the range where the bell is acceptable as the noise level , and / or the electromagnetic valve closing time is set.
In the second region where the closing time value of the solenoid valve is substantially less likely to affect the pressure fluctuation level above the boundary value , the opening time value is allowed as the noise fluctuation level.
2. The brake fluid pressure control device according to claim 1, wherein the solenoid valve opening / closing time is set so as to be within an acceptable range. 3. A control for changing the number of repetitions of opening / closing of the solenoid valve during wheel cylinder pressure slow pressure increase control together with solenoid valve opening / closing time control in one or both of the first region and the second region. Opening and closing frequency variable control means,
The brake fluid pressure control device according to claim 2, further comprising: