JPH0382659A - Brake hydraulic control device - Google Patents

Abstract

PURPOSE:To reduce vibration by feeding multiple split pressure change commands at such time interval that the vibration is made smaller than the vibration caused by the feeding of the normal pressure change command prior to the feeding of the normal pressure change command in a specific case when excessive vibration is judged to occur on a brake device. CONSTITUTION:In a system controlling a direction switching device 204 provided between a master cylinder 201 and a wheel cylinder 202 and a solenoid valve device 200 provided between a hydraulic source 206 and a reservoir 208 with the normal pressure change command (pressure increasing/decreasing command) from a normal feed control means A at a unit time for the variable continuous period, an excessive vibration judging means B judging whether excessive vibra tion caused by the normal pressure change command occurs on a brake device prior to the feeding of the normal pressure change command is provided. In a specific case when excessive vibration is judged to occur, multiple split pres sure change commands are fed from a specific feed control means C at such time interval that the vibration is made smaller than the vibration caused by the feeding of the normal pressure change command.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a brake fluid pressure control device that controls the fluid pressure of a wheel cylinder of a vehicle brake device using a solenoid valve device, and particularly to a solenoid valve device. This invention relates to technology for reducing vibrations that occur in a brake device due to switching.

[Conventional technology]

Anti-skid control,
BACKGROUND ART It is widely practiced to control the hydraulic pressure of a wheel cylinder (hereinafter referred to as hydraulic pressure Pw) using an electromagnetic valve device for the purpose of braking effect control, traction control, etc. Anti-skid control is a control that prevents the wheels from locking and skidding on the road surface due to excessive braking torque in relation to the coefficient of friction of the road surface when braking the vehicle. is a control that ensures that a braking effect commensurate with the brake operating force is always obtained during vehicle braking, regardless of the friction coefficient of the brake friction material or the magnitude of the load. In addition, traction control is used to prevent the wheels from slipping and preventing the vehicle from accelerating effectively due to the drive torque applied to the drive wheels being excessive in relation to the coefficient of friction of the road surface when the vehicle accelerates. control.

One of the brake fluid pressure control devices that can control these is
A solenoid valve device installed between a hydraulic pressure source of a brake device, a reservoir, and a wheel cylinder, and a solenoid valve device that sends a pressure change command, which is either a pressure increase command or a pressure decrease command, every unit time and for a variable duration. Some devices include a normal supply control means for supplying the same. In this type of brake fluid pressure control device, the fluid pressure P is controlled by changing the ratio of the duration of the pressure change command to the unit time. The amount of pressure increase or the amount of pressure decrease in each unit time is appropriately controlled. Note that, although the unit time is generally fixed, it can be made variable. Also, the solenoid valve device is always in the non-excited position, but if an excitation pulse is supplied to the solenoid, it switches to the excitation position, and as long as the excitation pulse is sustained, it remains in the excitation position. .

The solenoid valve device may take many forms. FIGS. 11 to 13 representatively show three examples of these aspects. Note that all three examples are suitable for a brake fluid pressure control device capable of traction control. Also,
The solenoid valve device F200 in each figure is the mask cylinder 2
It is provided between a direction switching device (ITM type or pilot type) 204 provided between the hydraulic pressure source 206 and the reservoir 208 . The direction switching device 204 is always connected to the wheel cylinder 202.
is shut off from the solenoid valve device 200 and the mask cylinder 201
However, if traction control is required, the wheel cylinder 202 is connected to the mask cylinder 2.
01 to a state where it is shut off and communicated with the electromagnetic valve device 200.

In FIG. 11, the electromagnetic valve device 200 is a three-position valve 210 that can be switched between a pressure increase position, a pressure holding position, and a pressure reduction position. This three-position valve 210 is in the reduced pressure position, which is the home position shown, when its solenoid is demagnetized;
If a weak excitation pulse (an excitation pulse with a small pulse amplitude) is supplied to the solenoid, the solenoid will switch to the pressure holding position, and if a strong excitation pulse (an excitation pulse with a large pulse amplitude) is supplied, it will switch to the pressure reduction position.

During pressure increase, strong excitation and weak excitation are performed once per unit time, and the 3-position valve 210 is switched to the pressure increase position and the pressure holding position once each. On the other hand, during pressure reduction, demagnetization and weak excitation are performed once per unit time, and the three-position valve 210 is switched to the pressure reduction position and the pressure holding position once each. That is, in this example, supplying a strong excitation pulse to the solenoid of the three-position valve 210 is a pressure increase command, and demagnetizing the solenoid is a pressure decrease command.

In FIG. 12, a hydraulic pressure source 206 and a directional switching device 20 are shown.
A normally open electromagnetic on/off valve 212 is provided between the reservoir 20B and the direction switching device 204, and a normally open electromagnetic on/off valve 214 is provided between the reservoir 20B and the direction switching device 204.
, 214 jointly constitute the solenoid valve device 200.

When the electromagnetic on-off valve 212 is not energized, it is in the pressure holding position, which is the original position shown in the figure, but when it is energized, it is switched to the pressure increasing position.

On the other hand, when the electromagnetic on-off valve 214 is not energized, it is in the pressure reducing position, which is the original position shown in the figure, but when it is energized, it is switched to the pressure holding position.

During pressure increase, the electromagnetic on-off valve 214 continues to be energized and maintained at the pressure holding position, while the electromagnetic on-off valve 212 is demagnetized and excited once per unit time to maintain the pressure holding position and the pressure increasing position. It switches once each. An example of the excitation pulse supplied to the electromagnetic on-off valve 212 is graphically shown in FIG. On the other hand, during pressure reduction, the electromagnetic on-off valve 212 continues to be demagnetized and maintained at the pressure holding position, while the electromagnetic on-off valve 214 is demagnetized and excited once each during a unit time, and is placed in the pressure reduction position and the pressure holding position. It switches once each. That is, in this example, supplying an excitation pulse to the solenoid of the electromagnetic on-off valve 212 is a pressure increase command, and demagnetizing the solenoid of the electromagnetic on-off valve 214 is a pressure reduction command.

In FIG. 13, a two-position valve 216 that can be switched between two positions, a pressure reduction position and a pressure increase position, is connected between the hydraulic pressure source 206, the reservoir 208, and the direction switching device 204. A normally open electromagnetic on-off valve 218 is connected between the position valve 216 and the direction switching device 204. That is, the two-position valve 216 and the one-magnetic on-off valve 218 constitute the solenoid valve device 200.

During pressure increase, the 2-position valve 216 continues to be energized and maintained at the pressure increase position, while the electromagnetic on-off valve 21B is demagnetized and energized once per unit time, and the electromagnetic on-off valve 218 is kept in the open position. and the closed position, that is, the pressure increasing position and the pressure holding position. On the other hand, during pressure reduction, the 2-position valve 216 is demagnetized and kept in the pressure reduction position, while the electromagnetic on-off valve 218 is demagnetized and energized once per unit time! The separation valve 218 is switched once between an open position and a closed position, that is, once between a pressure reducing position and a pressure holding position.

That is, in this example, demagnetizing the electromagnetic on-off valve 218 while energizing the 2-position valve 216 is a pressure increase command, and demagnetizing the electromagnetic on-off valve 218 while demagnetizing the 2-position valve 216 is a pressure reduction command.

In the above-mentioned brake fluid pressure control device, the switching of the solenoid valve device is performed instantaneously, so the fluid pressure between the solenoid valve device and the wheel cylinder (hereinafter referred to as brake fluid pressure) pulsates due to the switching. and change.

Fluid pressure P shows how brake fluid pressure changes. This will be explained based on FIG. 15, which shows an example of a change in pressure during pressure increase.

Note that FIG. 15 shows the electromagnetic on-off valve 212 in FIG.
As shown in FIG. 14, the unit time T. Hydraulic pressure P when one pressure increase command is supplied for a duration T, (<'r, ) every time. An example of a change in is shown.

As is clear from this figure, when the -pressure increase command is supplied, the hydraulic pressure P8 rapidly increases and then periodically fluctuates (pulsates) while attenuating over time.

Furthermore, in the brake fluid pressure control device, switching of the electromagnetic valve device is repeated approximately every unit time during brake fluid pressure control, so the above-mentioned fluctuation in brake fluid pressure is also repeated approximately every unit time.

Therefore, if the brake fluid pressure pulsates violently at each switching time, 1. There has been a problem in that it causes vibrations in the brake device, which in turn causes harsh noises and vibrations in the suspension adjacent to the wheel cylinder and cylinder.

In view of these circumstances, the applicant has previously developed the following brake fluid pressure control method. This brake fluid pressure control method is described in Japanese Patent Application Laid-Open No. 64-28057,
- Continuous pressure increase or decrease for a predetermined period of time is performed at the beginning of a unit time, and intermittent pressure increase or decrease is performed at the end of the unit time. If this brake fluid pressure control method is used, the pressure increases or decreases in each unit control are not performed continuously, that is, every time, but are divided into multiple times. Fluctuations in the brake fluid pressure at each time or when the pressure is reduced are reduced, and pulsations in the brake fluid pressure and thus vibrations of the brake device can be reduced.

[Problem to be solved by the invention]

However, subsequent research by the applicant revealed that the developed method may actually increase the vibration of the brake device. This will be explained below based on FIG. 16 and FIG. 17 showing the results of an experiment conducted by the applicant.

The experimental results shown in FIGS. 16 and 17 were both obtained using the brake device shown in FIG. 12. First, Fig. 16 shows the relationship between the duration T of a pressure change command, which is a pressure increase command or a pressure decrease command, at each pressure increase or decrease, and the maximum variation amount of brake fluid pressure (hereinafter referred to as pulsating pressure). It shows.

The pulsating pressure P in the wheel cylinder 202 when the pressure increases and when the pressure decreases. P-P and the boat on the wheel cylinder 202 side of the electromagnetic on-off valve 212 (hereinafter simply referred to as the electromagnetic on-off valve 2
It shows the pulsating pressure Pv□ at the time of pressure increase at the outlet of No. 12). As is clear from this figure, the duration is T when the pressure is increased.

The pulsating pressure PP-P (hereinafter simply referred to as pulsating pressure PP-P when pulsating pressure PWP-P and pulsating pressure Pv When the pressure is approximately 10 m5, the pulsating pressure is P8□.

is the highest.

On the other hand, in FIG. 17, 50 k is applied to the wheel cylinder 202.
Pulsating pressure PW when two pressure increase commands with a duration To of 4 ms are supplied at various time intervals T to the electromagnetic on-off valve 212 with an initial pressure P8° of gf /ci enclosed.
The relationship between F-P and its time interval T, - is shown. 2
The two pressure increase commands are the maximum pulsating pressure P during pressure increase in Figure 16.
The duration T indicating □2 is obtained by dividing one pressure increase command of 8 ms, and the hydraulic pressure P8 is almost the same when the -pressure increase command is supplied and when two divided pressure increase commands are supplied. The amount of pressure increase can be obtained. Note that the -pressure increase command will be referred to as a normal pressure increase command in relation to the divided pressure increase command.

As is clear from this figure, when the temperature of the brake fluid in the wheel cylinder 202 is, for example, 35°C,
If the time interval T is between 6 ms and 13 frames, it is true that the pulsating pressure PWP-P is the highest pulsating pressure P8□, which is about 11
kgf/C (value obtained from Fig. 16), the vibration reduction effect can be obtained, but the time interval T,
If it is between 13 and 24m5, the maximum pressure pulsation pressure will actually become higher than PWP-P, and no vibration reduction effect will be obtained. Incidentally, this situation is the same in the case of reduced pressure.

As is clear from the above explanation, in the development method described above, even if multiple divided voltage transformation commands are supplied in place of one normal pressure increase command or normal pressure reduction command (collectively referred to as normal pressure transformation commands), vibration is always reduced. The problem is that the effects are not necessarily achieved.

In addition, when supplying a plurality of divided voltage transformation commands, there is also a problem that the time it takes to finish supplying all of them becomes longer than when supplying a normal voltage transformation command.

By the way, as is clear from FIG. 16, the pulsating pressure PP-
P usually becomes high only when the duration T0 of the voltage transformation command is within a specific range, so if the duration T is outside of the duration T0 of the highest pulsation on the hour, for example, the higher the pulsation pressure PP-P becomes. Therefore, in such a case, there is no need to supply multiple divided transformation commands. Also,
According to experiments conducted by the applicant, the brake fluid pressure was approximately 2Q k
Pulsating pressure P that is so high even when lower than gf/cnl
It was found that P-P did not occur. In this way, there are cases in which even if a normal voltage transformation command is supplied, a very large vibration does not occur.

Therefore, if multiple divided pressure transformation commands are supplied regardless of these circumstances, the brake fluid pressure response time, that is, the time it takes for the brake fluid pressure to reach the target fluid pressure after the supply of the pressure transformation command is started. Time stretches out unnecessarily,
There is a problem in that the responsiveness of brake fluid pressure is reduced.

The present invention has been made based on the above findings, with the object of further reducing the vibrations of a brake device caused by switching of a solenoid valve device.

[Means to solve the problem]

The gist of the present invention is as shown in FIG.
In a brake fluid pressure control device including a valve device and a normal supply control means, (a) prior to supplying a normal pressure change command, an excessive vibration is determined to determine whether excessive vibration occurs in the brake device due to the normal pressure change command. (b) actuated at a specific time when excessive vibration is determined to occur by the excessive vibration determining means, and outputting a plurality of divided voltage transformation commands in place of the normal voltage transformation command, the vibration caused by supplying the plurality of divided voltage transformation commands is activated when excessive vibration is determined to occur; The present invention includes a specific time supply control means for supplying at a time interval that is smaller than the vibration caused by supplying the command.

[Effect]

In the device of the present invention, the split voltage transformation command is supplied only when excessive vibration occurs in the brake device when the normal voltage transformation command is supplied.

It can be seen from FIG. 17 that there is a certain relationship between the time interval T and the pulsating pressure PWP-F. For example, the temperature of the brake fluid in the wheel cylinder 202 in FIG.
℃, the time interval T.

The pulsating pressure PWP-P becomes the lowest when the time interval TP is about 9 m5, whereas the pulsating pressure PWP-P becomes the lowest when the time interval TP is about 18 m5.
The time interval T when P is the highest and the lowest pulsation on the hour,
It can be seen that the time interval T2 is half of the time interval T2 at the time of the maximum pulsating pressure. In the device of the present invention, a plurality of divided transformation commands are sent at a time interval T.

The pulse pressure is supplied at a time interval T determined in consideration of a certain relationship between the pulse pressure and the pulsation pressure PPF, and the time interval T is set to a value close to the time interval T at the hour of the lowest pulsation, for example.

18 to 20 show the results of an experiment to elucidate the mechanism of vibration reduction realized by the present invention, in which the wheel cylinder 202 shown in FIG.
The hydraulic pressure P and the outlet hydraulic pressure of the electromagnetic on-off valve 212 (hereinafter referred to as
It shows the change in hydraulic pressure (simply referred to as Pv).

First, in Fig. 18, a pressure increase command is given to the electromagnetic on-off valve 212 by 4 m.
The experimental results are shown when only s is supplied. Hydraulic pressure Pv
increases rapidly from the initial pressure P vo of 35 kgf/afl with the start of supply of the pressure increase command, rapidly decreases with the end of the pressure increase command, and then fluctuates periodically at a cycle of 22°5 ms. It also decreases over time. On the other hand, the hydraulic pressure Pw rises and falls from the initial pressure pwo, which is approximately the same height as the initial pressure pvo, at a slightly later time than the hydraulic pressure Pv, and then decreases to the hydraulic pressure P. It fluctuates periodically with the same period as the period of , and attenuates as time passes. In addition, in the figure, the initial pressure P. . is slightly higher than the initial pressure P vo, but this is thought to be due to measurement error. Hereinafter, the above-mentioned hydraulic pressure Pv and hydraulic pressure P. The period of is called the period of pulsating pressure P PP.

The reason why the hydraulic pressure Pw and the hydraulic pressure Pv change as shown in FIG. 18 is estimated as follows. When the electromagnetic on-off valve 212 switches from the closed position to the open position, a compression wave is generated from the electromagnetic on-off valve 212 toward the wheel cylinder 202, and the compression wave reaches the wheel cylinder 202 via the liquid passage, where it is reflected and returns to the same liquid passage. It reaches the electromagnetic on-off valve 212 through the. By the time the compression wave reaches the electromagnetic on-off valve 212, the electromagnetic on-off valve 2
12 has been switched from the open position to the closed position, it is presumed that the compression wave then reciprocates between the electromagnetic on-off valve 212 and the wheel cylinder 202 while attenuating.

FIG. 19 shows two pressure increase commands each having a duration T0 of 4 ms (the pressure increase command supplied earlier is the first pressure increase command,
The pressure increase command supplied later is referred to as the second pressure increase command), which is approximately equal to the period of pulsating pressure PP-P, 22°5 ms24.
The experimental results are shown when the gas is supplied after a time interval T of m5. Moreover, FIG. 20 shows the experimental results when the two pressure increase commands were supplied at a time interval T of 12 m5, which is approximately half the period of the pulsating pressure P PP.

FIG. 19 shows a case where the first compression wave caused by the supply of the first pressure increase command and the second compression wave caused by the supply of the second pressure increase command overlap in the same phase, and FIG. This shows a case where the first compression wave and the second compression wave overlap with a phase shift of half a period. As is clear from those two figures: - pulsating pressure P; , 7 and the pulsating pressure Pv□ in FIG. 20 are significantly lower than in FIG. 19. In this way, it is better to supply two pressure increase commands for a time @TP that is half the period of the pulsating pressure P, -1.
The pulsating pressure PP is supplied at the same time interval T as the period of p.
-P decreases because if the phases of the first compression wave and the second compression wave are shifted by half a cycle, the two compression waves weaken each other, whereas if the phases match, the two compression waves weaken each other. It is presumed that this is because they strengthen each other.

Note that the hydraulic pressure is P when the pressure is reduced. and the change in hydraulic pressure Pv is the first
This corresponds to the changes shown in FIGS. 8 to 20. When the electromagnetic on-off valve 214 in FIG. 12 is switched from the closed position to the open position, an expansion wave is generated from the electromagnetic on-off valve 214 toward the wheel cylinder 202, and the expansion wave reaches the wheel cylinder 202 through the liquid passage, where it reaches the wheel cylinder 202. It is reflected and reaches the electromagnetic on-off valve 214 via the same liquid path. If the electromagnetic on-off valve 214 has been switched from the open position to the closed position by the time the expansion wave reaches the electromagnetic on-off valve 214, the expansion wave will attenuate after that and the electromagnetic on-off valve 214 and the wheel cylinder 20 will be attenuated.
This is because you will have to go back and forth between 2 and 2. Therefore, even in the case of pressure reduction, the two pressure reduction commands are pulsating pressure P P-P
It is better to supply the pulsating pressure P at a time interval T, which is half the period of
-2 period and the same time interval T, the pulsation is reduced.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, a plurality of divided voltage transformation commands are supplied only when excessive vibration occurs in the brake device when a normal voltage transformation command is supplied.
The time required for supplying the pressure change command is not extended unnecessarily, and a decrease in the responsiveness of the brake fluid pressure can be suppressed to a small level.

Furthermore, according to the present invention, the divided voltage transformation command is the pulsating pressure P
Since the brake fluid pressure is supplied at a time interval T based on a fixed relationship between P-P and the time interval T, the pulsation of brake fluid pressure is less than when multiple divided pressure transformation commands are supplied at a time interval TP that is unrelated to that relationship. As a result, the effect of reducing the vibration of the brake device can also be obtained.

FIG. 21 and FIG. 22 show experimental results for confirming the reduction effect. FIG. 21 shows how two divided pressure increase commands are supplied to the electromagnetic on-off valve 212 in FIG. 12 during one unit time T0 at a time interval T that is half the period of the pulsating pressure PP-P; FIG. 22 shows changes in the hydraulic pressure P8 due to the supply of the two divided pressure increase commands. As is clear from FIG. 22, the hydraulic pressure P during each unit time T0. When a change in normally supplies a pressure increase command (the first
(shown in Figure 5), it is smoother, and the pulsation of the brake fluid pressure and the vibration of the brake system are reduced.

〔supplementary explanation〕

According to experiments by the applicant, the period of the pulsating pressure PP-P is equal to the initial pressures PVO and P. . It was found that it changes depending on When one pressure increase command having a duration T of 4 ms is supplied to the electromagnetic on-off valve 212, as shown in FIG.
In the lower region the initial pressures PV11 and P. . The higher the value, the shorter the period, but the period remains almost constant in the region of approximately 60 kgf/c+f1 or higher. Further, when a pressure reduction command having a duration To of 4 ms is supplied to the electromagnetic on-off valve 214, as shown in FIG. 24, the initial pressure P v
In the range where o and P8° are lower than about 20 kgf/ci, the period becomes shorter as the initial pressures P vo and P, 1° are higher, but in the range above about 20 kgf/d, the cycle is kept almost constant.

Therefore, in order to more effectively suppress the vibrations occurring in the brake device by utilizing the fixed relationship between the pulsating pressure PP-P and the time interval T, the specific time supply control means should be controlled in accordance with a plurality of divided voltage transformation commands. It is desirable to include time interval changing means for changing the time interval T to a value suitable for the initial pressure PV6 or pwo.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a traction control device in a traction type hydraulic brake device for a rear-wheel drive four-wheel vehicle will be described in detail below with reference to the drawings.

This trough cylinder control device uses a hydraulic brake device and an output torque reduction means that reduces the output torque of the engine in order to suppress the rotation of the rear wheels, which are the driving wheels. Descriptions using text and figures are omitted because they are not essential for understanding the present invention.

In FIG. 2, reference numeral 10 indicates a brake pedal. The brake pedal 10 is connected to a tandem brake mask cylinder (hereinafter simply referred to as a mask cylinder) 14 via a booster 12. Mask cylinder 14
generates equal height hydraulic pressure in two independent pressurizing chambers in response to the operating force of the brake pedal 10. The hydraulic pressure generated in one pressurizing chamber passes through the liquid passage 18 to the left and right front wheels 20.2.
The brake wheel cylinders 2 each provided in 2
4.26, and the hydraulic pressure generated in the other pressurizing chamber is transmitted via the liquid passage 28 to the wheel cylinders 34, 36 of the brakes provided on the left and right rear wheels 30, 32, respectively. Note that the rear wheels 30 and 32 are connected to the engine via a power transmission mechanism (not shown), and are driven by this.

A normally open electromagnetic on-off valve 40 is provided in the middle of the liquid passage 28 . The electromagnetic on-off valve 40 is continuously switched to the closed position when traction control is required under the control of a control device 42 mainly composed of a computer. The electromagnetic on-off valve 40 shuts off the wheel cylinder side from the mask cylinder side when traction control is required. The liquid passage 28 is divided into a mask cylinder side passage 44 and a wheel cylinder side passage 46 by an electromagnetic on-off valve 40. A bypass passage 48 that bypasses the electromagnetic on-off valve 40 is provided between the mask cylinder side passage 44 and the wheel cylinder side passage 46. A check valve 50 is provided that allows brake fluid to flow in one direction but prevents the flow in the opposite direction.

The wheel cylinder side passage 46 is connected in parallel to an accumulator 56 and a reservoir 58 via a slave cylinder 54. The slave cylinder 54 is connected to the housing 62
The piston 64 is fluid-tightly and slidably fitted in the piston 64, and the piston 64 is urged by a spring 66 to the rearward end position, which is the original position shown in the figure. Liquid chamber 6 formed on the right side)
8 is connected to a wheel cylinder side passage 46, and an accumulator 56 and a reservoir 58 are connected to a liquid chamber 70 formed at the rear.

The slave cylinder 54 and the accumulator 56 are connected via a normally open electromagnetic on-off valve 74, while the slave cylinder 54 and the reservoir 58 are connected via a normally open electromagnetic on-off valve 76. The electromagnetic on-off valves 74 and 76 operate between the accumulator 56 and the reservoir 5 under the control of the control device 42.
8 is alternatively communicated with the slave cylinder 54, and the brake fluid supplied from the slave cylinder 54 to the wheel cylinder 34, 36 causes the wheel cylinder 34.
In other words, the hydraulic pressure P, , 4 is increased or decreased. The electromagnetic opening/closing valve 74 switches the voltage from the accumulator 56 to the slave cylinder 5 by changing the duty ratio of the solenoid excitation current supplied from the control device 42.
The amount of increase in the hydraulic pressure P8 can be changed by changing the flow rate of the hydraulic fluid toward the pump 4, and the hydraulic pressure P8 can be kept constant by continuous demagnetization. On the other hand, the electromagnetic on-off valve 76 is a control bag? By changing the duty ratio of the solenoid excitation current supplied from f42, the slave cylinder 5
The hydraulic pressure P is determined by changing the flow rate of the hydraulic fluid from 4 to the reservoir 58. It is possible to change the amount of pressure reduction and to maintain the hydraulic pressure P8 constant by continuous excitation. That is, B
The on-off valves 74 and 76 constitute the electromagnetic valve device 78.

The hydraulic fluid pumped up by the pump 80 from the reservoir 58 is accumulated in the accumulator 56.
The hydraulic pressure of the accumulator 56 is detected by a hydraulic pressure sensor (not shown), and based on the detection result, the control device 42 controls starting and stopping of the motor 82 that drives the pump 80, so that the accumulator 56 always operates within a constant hydraulic pressure range. It is designed to store liquid. A check valve 84 prevents the hydraulic fluid from flowing from the pump 80 to the reservoir 58 , and a check valve 86 prevents the hydraulic fluid from flowing from the accumulator 56 to the pump 80 . That is, accumulator 56. Pump 80. Motor 82, check valves 84, 86. The hydraulic pressure sensor and the motor control portion of the control device 42 constitute the hydraulic pressure source 90.

The rotational speeds of the left and right front wheels 20.22 are detected by left and right front wheel speed sensors 94, 96, respectively, and the rotational speeds of the left and right rear wheels 30.32 are detected by a rear wheel speed sensor 98. The rear wheel speed sensor 98 connects the engine and the rear wheels 30.
The rotational speed of the rear wheels 30 and 32 is detected based on the rotational speed of the output shaft of the transmission provided between the rear wheels 30 and 32.

These speed sensors 94-98 are connected to the control device 42.

A hydraulic pressure sensor 100 for detecting hydraulic pressure P8 is provided in the wheel cylinders 34 and 36 of the left and right rear wheels 30 and 32. This hydraulic pressure sensor 100 is also connected to the control device 42.

The ROM of the control device 42 stores various control programs including the brake control routine shown in the flowcharts of FIGS. 3 and 4.

Control of drive wheel slip by the traction control device configured as described above will be schematically explained.

If the opening degree of the main throttle valve provided in the intake manifold of the engine is increased by depressing the accelerator pedal (not shown), the vehicle body speed Vf (front wheel 20
．． In this case, the reference speed v0 is determined to be larger than the vehicle speed Vf by a predetermined value. The driving wheel speed, that is, the rear wheel speed V1 is the reference speed ■. If it exceeds the hydraulic pressure P. By increasing the pressure, decreasing the pressure, or maintaining the pressure, the rotation of the left and right rear wheels 30, 32 is suppressed. Specifically, for each cycle time Tc as a unit time, the hydraulic pressure P- is increased, decreased, or kept at the same level based on the rear wheel speed ■1 and the rear wheel acceleration G. In the case of pressure increase and pressure reduction, the time TX is also determined, and the hydraulic pressure P is determined based on the determination result. is controlled.

Hydraulic pressure P. When it is determined to increase the pressure, the electromagnetic on-off valve 76 continues to be excited, and a pressure increase command is supplied to the electromagnetic on-off valve 74. In this example, the time TX is 41
IIS shorter or longer than 12IIS or hydraulic pressure P. is lower than 20 kgf/cTM, one excitation pulse is supplied to the solenoid of the electromagnetic on-off valve 74 for a duration TD equal to the time TX, as shown in FIG. and the hydraulic pressure P. is 20kgf/crA or more, the 6th
As shown, - the excitation pulse is divided into two sub-excitation pulses each having a duration T0 of half the time TX, which sub-excitation pulses are applied at an interval of time Tp; In other words, when the time TX is between 4 ms and 12 m5 and the hydraulic pressure P is 20 kgf,/ci or more, it is a specific time for pressure increase, and at that specific time, the split pressure increase command is issued as a split pressure increase command. Two excitation pulses are supplied, but in other cases one excitation pulse is normally supplied as a pressure increase command.

For the sake of explanation, as shown in FIG. 6, supplying the first divided excitation pulse of the two divided excitation pulses is referred to as the first pressure increase, and supplying the latter divided excitation pulse is referred to as the second pressure increase. ,
The demagnetization performed between the first pressure increase and the second pressure increase will be referred to as the first holding pressure, and the demagnetization performed after the second pressure increase will be referred to as the second holding pressure.

The state of hydraulic pressure control during pressure increase will be explained based on the schematic flowchart shown in FIG. 7. During pressure increase, a command is first determined at every cycle time Tc, and then the first pressure increase is performed regardless of whether or not the excitation pulse needs to be divided this time, and at the end of the first pressure increase, the excitation pulse is A determination is made as to whether division is necessary, and when it is determined that it is not necessary, a second pressure increase is immediately performed, and upon completion of the second pressure increase, a second pressure holding is performed. By performing the first pressure increase and the second pressure increase successively, it becomes the same as continuously supplying the -pressure increase command at the time Tx. On the other hand, when it is determined that division is necessary, first pressure holding is performed, and after that, second pressure increase and second pressure holding are performed in order.

On the other hand, the hydraulic pressure P. When it is determined to reduce the pressure, the electromagnetic on-off valve 74 continues to be demagnetized, while a pressure reduction command is supplied to the electromagnetic on-off valve 76.

Since the electromagnetic on-off valve 76 is in a demagnetized state and in a pressure reducing position, it is necessary to keep energizing it in order to maintain it in a pressure holding position.

In this embodiment, the pressure reduction command is to shift the electromagnetic on-off valve 76 in the energized state to the demagnetized state for a time TX. Hereinafter, for purposes of explanation, the pressure increase command supplied to the electromagnetic on-off valve 74 during pressure increase will be referred to as an excitation pulse, and the pressure reduction command supplied to the electromagnetic on-off valve 76 during pressure reduction will be referred to as a demagnetization pulse.

If the time T8 is shorter than 6 ras or longer than 14 m5, or if the hydraulic pressure P8 is lower than 20 kgf/d, a degaussing pulse is supplied with a duration equal to the time TX, as shown in FIG. , time TX is 6ms and 14
m5 and the hydraulic pressure P.

is greater than or equal to 20 kgf/ctA, as shown in FIG. divided into two divided degaussing pulses with
These divided demagnetizing pulses are supplied at intervals of time T. In other words, when the time TX is between 6 ms and 14 m5 and the hydraulic pressure P is 20 kgf/d or more, this is a specific time for depressurization, and at that specific time, the divided degaussing pulse as a divided depressurization command is issued. The degaussing pulse is supplied after two times T, but in other cases, one degaussing pulse is normally supplied as a pressure reduction command.

For the purpose of explanation, as shown in FIG. 9, supplying the first divided demagnetizing pulse of the two divided demagnetizing pulses is referred to as the first depressurization, and supplying the later divided demagnetizing pulse is referred to as the second depressurizing.
The excitation performed between the first and second pressure reductions will be referred to as the first holding pressure, and the excitation performed after the second pressure reduction will be referred to as the second holding pressure.

Since the hydraulic pressure control during pressure reduction is almost the same as the hydraulic pressure control during pressure increase, it is shown in parentheses in FIG. 7 and detailed explanation will be omitted.

As shown in FIGS. 5, 6, 8, and 9, there is a pressure holding period from the start time t1 of cycle time T to the start time L2 of the first pressure increase or decrease. but,
In the brake fluid pressure control routine, after measuring time t, calculations and commands for rear wheel speed and rear wheel acceleration G, and determination of time TX are performed.
, it is not possible to start supplying excitation pulses and demagnetization pulses from .

The time T2 is determined by the hydraulic pressure P8 according to the experimental results shown in FIG.
The length is determined to be suitable for the height. The hydraulic pressure sensor 100 is provided to determine this time T. The 17th point is that the appropriate value of the time TP changes not only depending on the height of the hydraulic pressure P8 but also depending on the temperature of the brake fluid.
This is clear from the experimental results shown in the figure. However, in this example, assuming that the temperature is constant at 35°C, the time T
The appropriate value of , is determined. However, when the pressure is reduced, as is clear from the experimental results shown in Figure 24, the initial pressure PWO of the wheel cylinder 34.36 is 20 kgf.
/ci or more, the period of the pulsating pressure PP-P is constant at 20 m5, so the time TP is equal to the hydraulic pressure P as in the case of pressure increase. It does not change depending on the height of the building, but is always half the period of 10 buildings.

Furthermore, in this embodiment, the cycle time T.

is assumed to remain unchanged, and when the voltage transformation command is issued continuously over multiple control cycles, the time TP between two adjacent excitation pulses or demagnetization pulses spanning two control cycles is the pulsating pressure PP. -P is determined so as not to match the period, and in this embodiment, it is set to 25 m5.

In this way, in this embodiment, the time T of two excitation pulses or demagnetization pulses in one control cycle is made equal to half the period of the pulsating pressure PP-P, and
The time T of two excitation pulses or demagnetization pulses in the preceding and succeeding control cycles is made not to coincide with the cycle of the pulsating pressure P, -2, but to be equal to half of the cycle as much as possible.

Also, the hydraulic pressure P. If it is determined that the pressure is to be maintained, the electromagnetic on-off valve 74 continues to be demagnetized, while the electromagnetic on-off valve 76 continues to be energized.

Hereinafter, control of the hydraulic pressure P8 will be explained in detail based on the flowcharts of FIGS. 3 and 4.

At the same time as the control device 42 is powered on, step 5100
Initial settings are performed in (hereinafter simply referred to as 3100; the same applies to other steps), and the necessity of traction control is waited for by repeating the execution of 5IIO. It is determined whether the accelerator pedal is depressed and the rear wheel speed Vr exceeds the reference speed v0. The rear wheel speed ■ is calculated based on the output signal of the rear wheel speed sensor 98, and is the reference speed V. is the front wheel speed sensor 94.
It is calculated as the sum of the vehicle body speed vr based on the output signal of 96 and the predetermined value. If traction control is required, the determination result at 3110 becomes YES.

As a result, the electromagnetic on-off valve 40 is energized and closed at 5120, and the mask cylinder side and the wheel cylinder side are cut off. After that, at 5130, the electromagnetic on-off valve 7
6 is energized and closed, thereby isolating the slave cylinder 54 from the reservoir 58. Solenoid on-off valve 40
and 76 are both closed, so that the hydraulic pressure P,1 can be increased by the accumulator 56.

Subsequently, in 5140, the time L1 of the built-in timer is read and stored in the RAM, and in 3140, the rear wheel speed (2) and the rear wheel acceleration G are calculated based on the output signal of the rear wheel speed sensor 98.

After that, in 3160, it is determined whether the pressure should be increased based on the rear wheel speed V and the rear wheel acceleration G obtained in 5150.
It is determined whether the pressure should be reduced or maintained, and the time TX is also determined. Then, at 5170, 51
A determination is made at 60 as to what the determined command is.

If the determined command is a pressure increase command, in 3180, half of the time T8 determined in 5160 is calculated, and the result is the time T. After the time Lz is stored in the RAM, the time Lz of the timer is read at 5190.

Thereafter, in 5200, the electromagnetic on-off valve 74 is energized and opened, and then, in 5210, the time t of the timer is read, and in 5220, the first energization time of the electromagnetic on-off valve 74 is subtracted from time t, time 11. is calculated, and waits until the initial excitation time reaches time T.

The first excitation time has expired and the judgment result of 5220 is YES.
Then, at 5230, the time T is 41'as and 1
It is determined whether the time is between 2 μs or not.

Assuming that this is the case now, the current determination result at 5230 is YES, and at 5240, the hydraulic pressure sensor 1
Hydraulic pressure P based on the output signal of 00.

is read and at 5250 its hydraulic pressure P. is 20
It is determined whether or not kgf/c111 or more. Assuming that this is the case at present, the current determination result at 5250 is YES, and the time T is determined at 5260. In this embodiment, the hydraulic pressure P8 and the time T,
The relationship ' with is stored in the ROM, and the hydraulic pressure P is determined based on the relationship. The time T corresponding to is determined.

As a result, after the electromagnetic on-off valve 74 is demagnetized and closed at 5270, time t4 of the timer is read at 3280, and at 5290, the first demagnetization time of the electromagnetic on-off valve 74 is subtracted from time t4. The target time for the first demagnetization is calculated by subtracting the time TD from the time TP, and it is waited for the first demagnetization time to reach the target time.

The first degaussing time has expired and the judgment result of 5290 is YES.
Then, at 5300, the electromagnetic on-off valve 74 is energized again and opened, the time t of the timer is read at 3310, and the second energization time of the electromagnetic on-off valve 74 is clocked at 5320.

It is calculated by subtracting time t4 from t4, and waits until the second excitation time reaches time T0. When the second excitation time has expired and the determination result at 5320 is YES, the electromagnetic on-off valve 74 is demagnetized and closed at 5330, the time t of the timer is read at 5340, and the electromagnetic on-off valve 74 is turned off at 5350. Valve 7
4, the second demagnetization time is calculated by subtracting the time t5 from the time t, and the target time for the second demagnetization is calculated by subtracting the difference between the cycle time Tc and the time tl, The second degaussing time is waited for to reach the target time.

The second degaussing time has expired and the judgment result of 5350 is YE.
If S, it is determined in 5360 whether or not traction control should be ended.

Assuming that is not the case this time, the process returns to 5140.

In the above description, the time TX is between 4 ms and 12 μs, and the hydraulic pressure P. is assumed to be 20 kgf/c4 or more, but if the time Tx deviates from between 4 ms and 12 frames, the determination result of 5230 will be N
o, and instead of bypassing the execution of 3240-3300, the steps after 5310 are executed after the latest value of time t, :l read at 3210 is stored in RAM as time t4 at 5370. This time, the second pressure increase is at time T from time t3 at the end of the first pressure increase.

Therefore, the first pressure increase and the second pressure increase are performed consecutively, that is, without the first pressure holding.

Also, although the time TX is between 4ms and 12m5,
If the hydraulic pressure P1 is lower than 20 kgf/ct, 3
The determination result at 230 is YES, and at 5240 the hydraulic pressure is P. is read, the determination result at 5250 becomes NO, and the steps after 3370 are executed in the same way as in the above case.

The case where the command determined in 5I60 is a pressure increase command has been described above, but if it is a pressure decrease command, steps 5390 to 3560 in FIG. 4 are executed. These steps are executed when the pressure is increased.
, and the demagnetization and excitation are reversed, so a detailed explanation will be omitted. However, during depressurization, the time T is fixed as Ioms, so 326
The step corresponding to 0 is omitted, and the step corresponding to 5230 is when the time TX is 6 ms or more and 14 Ils.
3440 to determine whether or not it is less than or equal to 5290
The step corresponding to changes the initial excitation time of the electromagnetic on-off valve 76 from time t4 to time t.

Calculate by subtracting , and wait for the initial excitation time to reach 10 m5 as the target time 54
It is said to be 90.

The cases in which the command determined in 5160 was a pressure increase command and the case in which it was a pressure reduction command were explained above, but if it was a pressure hold command, in 5380, the latest value of time t is After being stored in RAM as t, 334
Steps after 0 are executed. The determination at 5350 ultimately determines whether L6-tl ≧Tc holds.
In other words, the demagnetization time of the electromagnetic on-off valve 74 is the cycle time T
It is judged whether or not c has been reached, and this time the cycle time is T, medium! The separation valve 74 will continue to be demagnetized.

As a result of pressure increase, pressure reduction, or pressure holding as described above, if it is determined in 3360 that traction control should be terminated, then in 3580 the electromagnetic on-off valve 4
After 0 is demagnetized and opened, the electromagnetic on-off valve 76 is demagnetized and opened at 3590. As a result, the hydraulic pressure P. is lowered to O, and the hydraulic pressure Pw returns to a state in which it can be increased by the mask cylinder 14. After that, 5
The process returns to step 110 and waits until traction control is required.

As is clear from the above explanation, in this example,
3100-2 of the computer of the control device 42 in FIG.
20,3310-5380. 5390-543 in Figure 4
0,5510-3590 constitutes a normal supply control means, and the part that executes 5230-5250 in FIG. 3 and 5440-5460 in FIG. 4 of the hydraulic pressure sensor 100 and the computer of the control device 42. 5180 and 5260 to 5290 in FIG. 3 and 5390 and 54 in FIG.
70 to 5490 constitutes a specific time supply control means, and among the specific time supply control means, the hydraulic pressure sensor 100 and the part of the computer that executes 5240 and 5260 serve as a time interval changing means. It consists of

Although one embodiment of the present invention has been described above in detail based on the drawings, the present invention can be implemented in other embodiments.

For example, in this embodiment, pulse division is possible both when increasing the pressure and when decreasing the pressure, but it can be made possible only during either one of them.

Furthermore, in this embodiment, when the normal voltage transformation command is divided, the duration is divided into halves, but it is possible to make them different. For example, it is possible to set the duration of the first divided pressure transformation command of the two divided pressure transformation commands to be longer than the duration of the second divided pressure transformation command, so that the division mode emphasizes the responsiveness of the hydraulic pressure P8.

In addition, in this embodiment, when a normal voltage transformation command is divided, it is always divided into two parts, but it can be divided into three or more parts, or the number of divisions can be changed as necessary. be able to.

In addition, in this embodiment, after determining the necessity of dividing the normal voltage transformation command, the time TX of the normal voltage transformation command is determined.
However, values related to the length of time Tx, such as rear wheel speed ■1. This can be done based on the rear wheel acceleration G7 or the like. In this way, it is no longer essential to determine the duration T to determine whether division is necessary, so if it is determined from the above-mentioned related values that division is not necessary, the time TX is determined, but if it is necessary, Once determined, the time TD can be determined immediately without determining the time TX.

In addition, in this embodiment, as shown in FIG. 7, the determination is made after the first pressure increase (depressurization) is performed, regardless of the determination result of the necessity of division, and the determination result determines the hydraulic pressure. Although the mode of control was different, for example, as shown in the flowchart in Fig. 10, after the command is determined, it is determined whether or not division is necessary, and if it is determined that it is not necessary, the pressure is increased (fJli pressure) and the process is completed. Pressure holding is performed later, but if it is determined that it is necessary, the first pressure increase (pressure reduction), the first pressure hold, the second pressure increase (pressure reduction), and the second pressure hold can be performed in sequence.

Further, although this embodiment is an example in which the present invention is applied to a traction control device, the present invention can be applied to other brake fluid pressure control devices such as an anti-skid control device and a braking effect control device. .

In addition to these, the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art, although they will not be illustrated individually.

[Brief explanation of drawings]

FIG. 1 is a block diagram conceptually showing the configuration of the present invention. FIG. 2 is a system diagram of a traction type hydraulic brake system which is an embodiment of the present invention, FIGS. 3 and 4 are flow charts showing a brake control routine stored in the computer of the brake system, and FIG. and FIG. 6 are diagrams showing one excitation pulse and two divided excitation pulses for pressure increase, respectively. FIG. 7 is a schematic flowchart schematically showing how the brake control routine is executed.
9 and 9 are diagrams showing one degaussing pulse and two divided degaussing pulses for pressure reduction, respectively. FIG. 10 is a schematic flowchart schematically explaining hydraulic pressure control of a wheel cylinder in a traction type hydraulic brake device according to another embodiment. FIGS. 11 to 13 are system diagrams representatively showing three embodiments of electromagnetic valve devices suitable for traction control. FIG. 14 is a graph showing an example of an excitation pulse for pressure increase in a conventional brake fluid pressure control device, and FIG. . 16th
The figure is a graph showing the results of an experiment to determine the relationship between the duration TD of the voltage transformation command and the pulsating pressure P, -2. FIG. 17 shows the time interval T2 between two pressure increase commands and the pulsating pressure P in the wheel cylinder. , , is a graph showing experimental results for determining the relationship between , , and . Figures 18 to 20 are each
Fluid pressure changes in the wheel cylinder and solenoid valve device
3 is a graph for explaining the relationship with the time interval T between two pressure increase commands. FIG. 21 is a graph showing an example of a divided excitation pulse for increasing pressure by the device of the present invention, and FIG. 22 is a graph showing the hydraulic pressure P accompanying the supply of the divided excitation pulse. 2 is a graph showing an example of a change in . FIG. 23 shows the initial pressure P in the wheel cylinder and electromagnetic valve device during pressure increase. . FIG. 24 is a graph showing the experimental results for determining the relationship between P vo and the period of the pulsating pressure P2-1, and FIG. 24 is a graph showing the experimental results for determining the relationship during pressure reduction. 34.36: Wheel cylinder two control device 58: Reservoir 8: Solenoid valve device 90: Hydraulic pressure source

Claims (1)

[Claims] An electromagnetic valve device provided between a hydraulic pressure source, a reservoir, and a wheel cylinder of a brake device, and a normal pressure change command, which is either a pressure increase command or a pressure decrease command, can be made variable every unit time. In the brake fluid pressure control device, the brake fluid pressure control device includes a normal supply control means for supplying the solenoid valve device with a normal pressure supply control means for a period of time, and prior to the supply of the normal pressure transformation command, does excessive vibration occur in the brake device due to this? excessive vibration determining means for determining whether excessive vibration occurs; A brake fluid pressure control device comprising: specific time supply control means for supplying vibration at time intervals of a length such that vibration is smaller than vibration caused by supply of the normal pressure change command.