JPH04163268A - Manual and electric two-system brake system - Google Patents

Abstract

PURPOSE:To reduce a device cost by providing a pilot type flow control device to effect both selection of a liquid pressure to a wheel cylinder of a master cylinder pressure and an electrode control pressure according to the propriety of the operation state of an electric control liquid pressure source and connection and disconnection between the master cylinder and a liquid absorber. CONSTITUTION:A pilot type flow control device 40 is connected between main liquid passages 14 and 16 through which a master cylinder pressure generated at a master cylinder 10 is transmitted to wheel cylinders 20 of front wheels on both sides. The flow control device 40 isolates a control port 56 from a liquid chamber 44 by a land 58 of a spool 42 through forward movement of the spool 42 when a liquid pressure in a liquid chamber 46 is increased to a value higher than that in a liquid chamber 44. A liquid absorber 60 is connected to the control port 56. An electric control liquid pressure source 80 is connected to a main liquid passage 18 and boosting is carried out when a pressure piston 84 is moved forward with the aid of an electric motor 82. A pressure chamber 86 is connected to a main liquid passage 18. Even during the occurrence of abnormality of an electric control system, a master cylinder pressure is transmittable to a wheel cylinder through the flow control device 40 by means of an electric liquid pressure source 80.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a manual/electric dual system braking system that selectively operates the brakes on the wheels of an automobile using a master cylinder and an electrically controlled hydraulic pressure source.
In particular, it relates to a technique for simplifying the configuration of the brake system.

An example of a conventional technical manual/electrical dual-system brake system is described as an example in Japanese Patent Application Laid-open No. 63-20256, which is filed by the present applicant or the applicant.

This consists of (a) a master cylinder that generates master cylinder pressure in response to the operation of a brake operating member such as a brake pedal, (b) a wheel cylinder that operates a brake that suppresses wheel rotation, and (C) these master cylinders. It is equipped with a control pressure chamber connected to the main fluid passage that connects the cylinder and wheel cylinder to each other, and has a predetermined height of electricity corresponding to the operating force of the brake operating member or the amount of brake operation determined by the operating stroke. An electrically controlled hydraulic pressure source that generates control pressure in a control pressure chamber by electrical control, and (d) connected to a portion of the main fluid passage upstream from the connection with the control royal chamber, and is discharged from the master cylinder when the brake is applied. A fluid absorber that temporarily stores brake fluid and returns it to the master cylinder when the brake is released is connected to the connection part between (e) the control pressure chamber of the main fluid passage, and connects the master cylinder pressure and electrical control pressure to each other. It is equipped with a control piston that operates by receiving pilot pressure in the opposite direction, and when the electric control hydraulic pressure source generates the electric control pressure at a normal level, the electric control pressure is transmitted to the wheel cylinder. A pilot type switching device that transmits the master cylinder pressure to the wheel cylinders when the control fluid pressure source does not generate an electrical control pressure of a normal height; A brake system including an electromagnetic on-off valve connected to the auxiliary fluid passage, which opens when the electrically controlled fluid pressure source produces a normal level of electrical control pressure, and closes when the electrically controlled fluid pressure source does not produce a normal level of electrical control pressure. It is.

Problems to be Solved by the Invention Using this brake system, the effectiveness of the brakes can be controlled electrically, and the car can be braked without any trouble even in the event of a failure of the electrical control system. To do this, an electrically controlled hydraulic pressure source, a pilot-operated switching device, as opposed to a manual brake system that generates brake pressure in the wheel cylinders only by the master cylinder.

A liquid absorber and electromagnetic on-off valve must be added.

As a result, the configuration of the brake system becomes complicated, resulting in a significant increase in equipment costs.Failures in the electrical control system must be electrically detected, resulting in a slight decrease in operational reliability. there were.

The present invention has been made with the object of solving these problems.

Means for Solving the Problems And the gist of the present invention is to provide the dual manual/electric brake system with (a) the master cylinder, the wheel cylinder, and the liquid absorber; and (b) the master cylinder and the wheel cylinder. an electrically controlled hydraulic pressure source that generates hydraulic pressure in the control pressure chamber by electrical control; and (C) a connection with a liquid absorber in the main liquid passage. The control piston is connected to the control piston and operates by receiving the master cylinder pressure generated in the master cylinder and the electric control pressure generated in the electric control hydraulic pressure source as pilot pressure in opposite directions, respectively, and the electric control hydraulic pressure source When the electrical control pressure at a normal height is generated, the master cylinder is connected to the fluid absorber and the master cylinder pressure is not transmitted to the wheel cylinder, and the electrical control fluid pressure source generates the electrical control pressure at the normal height. It shall include a pilot type flow control device that isolates the master cylinder from the liquid absorber and transmits the master cylinder pressure to the wheel cylinder in a state where no pressure is generated, and an electrically controlled hydraulic pressure source of the control device. Even if the electric control system is abnormal, the master cylinder pressure can be transmitted to the wheel cylinders via the main fluid passage and the pilot type flow control device.

Note that the electrically controlled hydraulic pressure source may be of a type that electrically controls the correspondence between the brake operation amount and the brake pressure during brake operation, for example. Like the brake system described as an example in the above publication (hereinafter simply referred to as the conventional device), the height is such that a predetermined amount of deceleration is generated in the vehicle body in response to the amount of brake operation. An example of this is a type in which brake pressure is generated by electrical control, and an example is a type in which anti-lock control is performed, in which brake pressure is electrically controlled to prevent excessive slippage of the wheels.

All of the above examples electrically control the brake pressure used to brake a car.
Electrical control of brake pressure may also be used for other purposes. For example, acceleration slip control is used to electrically control brake pressure to prevent excessive wheel slip when the vehicle starts without brake operation, or brake pressure is controlled electrically to control the turning state of the vehicle. It can be electrically controlled.

Operation In the manual/electric dual-system brake system according to the present invention, the pilot type flow control device transmits either the master cylinder pressure or the electrical control pressure to the wheel cylinders depending on the operating condition of the electrically controlled hydraulic pressure source. selection of the hydraulic pressure of the
Both sides with blocking are done. The functions of the pilot type switching device and the electromagnetic on-off valve in the conventional device are realized by the pilot type flow control device.

In addition, in the conventional device, the communication/cutoff between the master cylinder and the liquid absorber was electrically performed using an electromagnetic on-off valve, but in the device of the present invention, the communication/cutoff is performed using a pilot type flow control valve. This is done mechanically by a control device.

Effects of the Invention Therefore, according to the present invention, the configuration of the manual/electric dual system brake system is simplified compared to the conventional device, and the device cost is reduced, and the number of electrically controlled parts is also reduced. The effect is that the operational reliability of the system is improved.

Embodiments Hereinafter, some embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 1, 10 is a master cylinder, and a brake pedal 12 as a brake operating member is connected to this master cylinder IO. The master cylinder 10 is a tandem type having two pressurizing pistons in series, and generates master cylinder pressures of approximately the same height in two independent pressurizing chambers in response to depression of the brake pedal 12. The master cylinder pressure generated in one pressurizing chamber is transferred to each of the left and right front wheel disc brakes (
This is an aspect of the brake in the present invention), and the master cylinder pressure generated in the other pressurizing chamber is transmitted to the wheel cylinders of each disc brake of the left and right rear wheels through main fluid passages 24, 26 and 28. 3
0.

Reference numeral 32 is a caliper of a disc brake, and 34 is a disc rotor. Note that since the front wheel brake system and the rear wheel brake system have the same configuration, the front wheel brake system will be described below as a representative example.

A pilot type flow control device (hereinafter simply referred to as flow control device) 40 is connected between the main liquid passages 14 and 16. The flow control device 40 has a spool 4 in the housing.
2 (this is one aspect of the control piston in the present invention) are fluid-tightly and slidably fitted. After spool 42.

Liquid chambers 44 and 46 are formed in the front (top and bottom in the figure), respectively.The liquid chamber 44 is connected to the master cylinder 10 through the main liquid passage 14, and the liquid chamber 46 is connected to the wheel cylinder through the main liquid passages 16 and 18. 20. Spool 4
An annular groove 50 is formed on the outer peripheral surface of 2, and this annular groove 50
A communication passage 52 communicating with the liquid chamber 44 is opened. The spool 42 is normally kept at the original position shown in the figure by a small elastic force of a spring 54, and the control port 56 is communicated with the liquid chamber 44 by the annular groove 50. When the liquid pressure becomes higher than the pressure in the chamber 44, it moves forward (moves downward in the figure), and the land 5 of the spool 42 moves forward (moves downward in the figure).
8 isolates the control port 56 from the liquid chamber 44. That is, the flow control device 40 has the control port 56 and the annular groove 5.
0 is achieved by a metal-to-metal seal between the land 58 and the cylinder bore into which the spool 42 is fitted.

A liquid absorber 60 is connected to the control port 56. The fluid absorber 60 is of a spring type biased in the forward direction by a piston 64 or a spring 66 that is fluid-tightly and slidably fitted into the housing, and absorbs an amount of brake fluid proportional to the fluid pressure. It is something. Further, a normally open electromagnetic on-off valve 70 is connected between the main liquid passages 16 and 18.

An electrically controlled hydraulic pressure source 80 is connected to the main liquid passage 18 . An electrically controlled hydraulic pressure source 80 is connected to the electric motor 8 within the housing.
The pressurizing piston 84, which is moved forward and backward by the pressure piston 2, is of an electric motor type and is fluid-tightly and slidably fitted therein. A pressurizing chamber 86 (this is one aspect of the control chamber in the present invention) is formed in front of the pressurizing piston 84, and the pressurizing chamber 86 is connected to the main liquid passage 18. A ball screw 88 is engaged with the rear end surface of the pressurizing piston 84 . The ball screw 88 is held by a fixing member (not shown) so as to be non-rotatable around the axis and movable in the axial direction. This ball screw 88 is screwed into a nut 90. The nut 90 is held by a fixing member (not shown) so as to be rotatable around the axis and immovable in the axial direction.

A large diameter gear 92 is formed on the outer peripheral surface of the nut 90, and a small diameter gear 94 is meshed with this large diameter gear 92.

The small diameter gear 94 is connected to the electric motor 8 via a clutch 98.
It is connected to the second rotating shaft. The clutch 98 is a one-way type that transmits the rotation on the electric motor 82 side to the small diameter gear 94, but does not transmit the rotation on the small diameter gear 94 side to the electric motor 82.

In the electrically controlled hydraulic pressure source 80 configured as described above, when the electric motor 82 is rotated in the forward direction, the small diameter gear 94. Since the large diameter gear 92° nut 90 and the ball screw 88 are also rotated in the forward direction, the ball screw 88 moves forward together with the pressurizing piston 84 (moves to the right in the figure), thereby opening the pressurizing chamber 86. The volume decreases and the electrical control pressure increases. On the other hand, the electric motor 82
If you rotate it in the opposite direction, the ball hitter 88
etc. are also rotated in the opposite direction, so the ball screw 88 retreats together with the pressurizing piston 84, and as a result, the pressurizing chamber 8
6 increases and the electrical control pressure decreases. Further, when the electric motor 82 is in a stopped state, the electric control pressure is held constant by the clutch 98.

The pedal force applied to the brake pedal 12 is detected by a pedal force sensor 130, and the wheel speed of each wheel is detected by each wheel speed sensor 132. Those sensors 13
The output signal from 0,132 is sent to the electronic control unit (hereinafter referred to as
It is simply expressed as ECU.

140 (the same applies in the figure), and the ECUI 40 controls the electromagnetic on-off valve 70 and the electric motor 82 based on these output signals. ECUI40 is C (not shown)
It is mainly a computer in which a PU, ROM, and RAM are connected to each other via a bus. The ROM's program memory always applies a deceleration to the vehicle body that is commensurate with the pedal force, regardless of the friction coefficient of the brake friction material of the disc brake, the slope of the road surface, the load, etc. Various control programs are stored therein, including a control program that performs control that can be called braking effect control, and a control program that performs anti-lock control that prevents excessive slip from occurring in each wheel during vehicle braking.

The ROM also stores an FG map that defines the correspondence between pedal force F and deceleration G.

Next, the operation will be explained.

When the brake pedal 12 is not depressed, the flow side (discharge device 40, liquid absorber 60, electromagnetic on-off valve 70, and electrically controlled hydraulic pressure source 80 are in their original state as shown in the figure. At this time, the pressurizing chamber 86 is also No hydraulic pressure is generated in the wheel cylinders 20 and 30 either.

If the brake pedal 12 is depressed from this state, E
The CU I 40 reads the pedal force from the pedal force sensor 130, determines the deceleration corresponding to the pedal force as the target deceleration using the FG map, and also determines the deceleration corresponding to the pedal force as the target deceleration.
Based on the output signal of 32, the actual deceleration actually occurring in the vehicle body is calculated.

Furthermore, the ECU 140 calculates the control amount of the electric motor 82 for the front wheel brake system and the rear wheel brake system based on the actual deceleration and the target deceleration, respectively, and then
Each electric motor 82 is controlled by each control amount. In this brake system, when the electrically controlled hydraulic pressure source 80 is operating normally, the electrically controlled pressure generated in the pressurizing chamber 86 or the master cylinder 10 is generated, except when anti-lock control is being performed. The master cylinder pressure is set to be higher than the master cylinder pressure. Therefore, assuming that the electrically controlled hydraulic pressure source 80 is currently in a normal operating state, when the brake pedal 12 is depressed, the flow control device 40 detects that the hydraulic pressure in the liquid chamber 46 is higher than that in the liquid chamber 44. , the spool 42 is still held in its original position as shown, allowing the master cylinder 10 to communicate with the liquid absorber 60 and not transmitting master cylinder pressure to the wheel cylinders 20, 30, i.e. The wheel cylinder pressure is under control by the electrically controlled hydraulic pressure source 80. Therefore, this time, hydraulic pressure equal in height to the electric control pressure of each electric control hydraulic pressure source 80 is generated in each wheel cylinder 20.30, and the automobile is braked with a deceleration of a magnitude commensurate with the pedal force. .

Currently, the master cylinder 10 is communicated with the liquid absorber 60 by the flow control device 40, so as the brake pedal 12 is depressed more or less, the master cylinder 10
The brake fluid discharged from the brake fluid absorber 60 is absorbed into the fluid absorber 60, and as the depression is weakened, the brake fluid in the fluid absorber 60 is returned to the master cylinder 10.

Therefore, even when the wheel cylinder pressure is electrically controlled, an appropriate pedal stroke can be obtained in accordance with the pedal force, and the brake operation feeling is improved.

Although the wheel cylinder pressure is actually controlled by the electrically controlled hydraulic pressure source 80, the brake operation can be performed as if it were controlled by the master cylinder 10. The brake absorption characteristics of the liquid absorber 60, that is, the correspondence between the pedal force and the pedal stroke, can be changed by, for example, changing the initial length or spring constant of the spring 66 of the liquid absorber 60.

During the braking operation, the ECU 140 also determines whether the front or rear wheels are being braked because the current pedal force applied to the brake pedal 12 is excessive in relation to the coefficient of friction of the road surface, based on the output signal of each wheel speed sensor 132. It is periodically determined whether a locking tendency has occurred or not. If it is determined that a locking tendency has occurred, the braking effect control is interrupted and anti-lock control is started for the front wheel brake system and the rear wheel brake system to which the wheel determined to have a locking tendency belongs. do.

If it is determined that the wheels have a tendency to lock, the ECU
140 closes the electromagnetic on-off valve 70 belonging to the brake system including the wheel determined to have a tendency to lock prior to the anti-lock control, thereby communicating with the wheel cylinder 20.30 and the electrically controlled hydraulic pressure source 80. The control device 40 and the master cylinder 10 are also isolated from each other.

Thereafter, the ECU 140 controls the electric motor 82 of the electrically controlled hydraulic pressure source 80 to generate a high hydraulic pressure in the wheel cylinder 20.30 to maintain the slip ratio of the wheel determined to have a tendency to lock within an appropriate range. Control.

During anti-lock control, the electrical control pressure may be reduced to a level lower than the master cylinder pressure, but since the wheel cylinders 20 and 30 are cut off from the flow control device 40 by the electromagnetic on-off valve 70, the flow control The spool 42 of the device 40 is not unintentionally advanced from its home position as shown, and the wheel cylinder pressure remains controlled by the electrically controlled hydraulic pressure source 80. And E.C.
If the UI 40 determines that anti-lock control is no longer necessary, it ends the anti-lock control, opens the electromagnetic on-off valve 70, and then resumes braking effect control.

The case where the electrically controlled hydraulic pressure source 80 operates normally has been described above, but the case where the electrically controlled hydraulic pressure source 80 is in a state where it does not generate an electrically controlled pressure of a normal height will be described.

In this case, even if the brake pedal 12 is depressed and the master cylinder pressure increases, the electrical control pressure does not increase (this time it is assumed that no electrical control pressure is generated), so the flow control device 40 The hydraulic pressure inside the spring 54
When the spool 42 is raised to a height that overcomes the elastic force of the fluid and the fluid pressure (this time zero) in the fluid chamber 46, the spool 42 advances from its original position as shown, thereby isolating the master cylinder 10 from the fluid absorber 60. Ru. Therefore, this time, the brake fluid in the master cylinder 10 is discharged only to the wheel cylinders 20, 30 and not to the fluid absorber 60, and as a result, the pedal stroke is abnormally long in relation to the pedal force.
This prevents this from happening and ensures a good brake operation feeling.

Further, the pressurizing piston 84 of the electrically controlled hydraulic pressure source 80 can maintain the pressurizing chamber 86 even when its electrical control system (for example, the electric motor 82, means for supplying an electric signal to the electric motor 82, etc.) fails. Since the clutch 98 prevents the retreat to increase the volume, the pressurizing chamber 86 is in a state where the pressure can be increased.

Therefore, in this state, the spool 42 of the flow control device 40 can function as a mere movable partition wall, and a liquid pressure approximately equal to the master cylinder pressure is applied to the liquid chamber 4.
6. This occurs within the pressurized chamber 86 and the wheel cylinder 20.30. Therefore, even when the electrically controlled hydraulic pressure source 80 fails, the vehicle can be braked without any problem.

Another embodiment of the flow control device is shown in FIGS. 2 and 3, respectively.

The flow control device 160 shown in FIG. 2 includes a cylindrical housing 162 with a bottom. The inner peripheral surface of this housing 162 is defined as a cylinder bore 164, into which a control piston 166 is fitted in a fluid-tight and slidable manner. A plug 170 is liquid-tightly fixed to the open end of the housing 162 by screwing. Code 172 is 0 ring, 174
is a backup ring. By fitting the control piston 166 into the housing 162, the control piston 1
A liquid chamber 180 and a liquid chamber 182 are formed at the rear (upper side in the figure) of 66 and the liquid chamber 182 at the front (lower side in the figure). The fluid chamber 180 communicates with the master cylinder 10 through a port 186, and the fluid chamber 182 communicates with the electrically controlled fluid pressure source 80 and the wheel cylinders 20, 30 through a port 188.

Control piston 166 is always held in the home position shown by the small elastic force of spring 190.

An annular groove 192 is formed on the outer peripheral surface of the control piston 166, and cup seals 194, 1 are provided before and after the annular groove 192.
96 is attached. cup seal 194.19
6 are respectively connected to the liquid chambers 180 and 182 from the annular groove 192 side.
This prevents brake fluid from flowing toward the side. Note that the control piston 166 further includes a liquid chamber 180.18.
Cup seals 198 and 200 are also attached to prevent the flow of brake fluid from the annular groove 192 toward the annular groove 192.

Further, the annular groove 192 is always connected to the liquid chamber 1 by the communication path 202.
80.

The housing 162 also has a control port 204 connected to the liquid absorber 60 .

The control port 204 is connected to the cup seal 1 of the cylinder bore 164 with the control piston 166 in the home position shown.
It is opened at a portion between 94 and 196. That is, in this state, the control port 204 is communicated with the liquid chamber 180 through the annular groove 192 and the communication path 202.

Therefore, when the electrically controlled hydraulic pressure source 80 is operating normally, the hydraulic pressure in the liquid chamber 182, that is, the electrically controlled pressure is
Since the hydraulic pressure in 80 is higher than the master cylinder pressure,
The control piston 166 is in the home position shown in which the master cylinder 10 is connected to the liquid absorber 60 and no master cylinder pressure is transmitted to the wheel cylinders 20,30.

On the other hand, if the electrically controlled hydraulic pressure source 80 fails, the hydraulic pressure in the liquid chamber 180, that is, the master cylinder pressure, will change from the hydraulic pressure in the liquid chamber 182, that is, the electric control pressure (assumed to be 0 again this time). When the control piston 166 is raised by a certain amount or more, the control piston 166 starts moving forward (downward movement in the figure), and the control piston 166 moves forward by a certain distance or more from its original position.
When the control port 204 is disengaged from the cup seal 196 to its rearward side (upper side in the figure), the flow of brake fluid from the fluid chamber 180 side to the control port 204 side is blocked by the cup seal 196, thereby preventing the fluid from flowing. Room 180
That is, the master cylinder 10 is cut off from the liquid absorber 60. In addition, in this state, since movement of the control piston 166 is allowed, the master cylinder pressure
66 to the liquid chamber 182 or wheel cylinder 20
As a result, a hydraulic pressure approximately equal in height to the master cylinder pressure is generated in the wheel cylinder 20°30.

The flow control device 220 shown in FIG.
It is fluid-tightly closed.

An O-ring 226 and a backup ring 228 are also attached to this plug 224. /) Uzing 2
22 is formed with a stepped cylinder bore 230 into which a stepped control piston 232 is fluid-tightly and slidably fitted.

The space inside the housing 222 is partitioned into three by the control piston 232: a space behind the control piston 232 (the upper space in the figure), a space in front of the control piston 232 (the lower space in the figure), and a stage of the control piston 232. The annular spaces between the attached portion and the stepped portion of the cylinder bore 230 are liquid chambers 240, 242 and 244, respectively. The liquid chamber 240 is connected to the master cylinder 10 through a port 246.
゜The liquid chamber 242 is connected to the liquid absorber 60 via the control port 248.
The fluid chamber 244 is connected via a port 250 to the electrically controlled fluid pressure source 80 and the wheel cylinder 20.30. The liquid chambers 240 and 242 are constantly communicated with each other through a communication path 251. Additionally, cup seals 252, 254, 256 and 258 are attached to the control piston 232. Further, the control piston 232 is always maintained at the original position shown by the small elastic force of the spring 260.

An on-off valve 262 for opening and closing the control port 248 is provided within the liquid chamber 242 . The on-off valve 262 is formed on the bottom surface of the cylinder bore 230 and is connected to the control port 24.
It is equipped with a valve seat 264 that opens 8 times. The on-off valve 262 is further seated on its valve seat 264 and has control ports 1 to 248.
A rubber valve 266 that shuts off the valve 266 and a direction perpendicular to the plane of the valve seat 264, that is, a control piston 232.
The holding member 270 is slidably held in a direction parallel to the axial direction of the holding member 270. Note that the spring 260 is disposed between its holding member 270 and a spring retainer 272 of the control screws 1 to 232. The valve 266 is always placed between the holding member 270 and the valve 266 on the valve seat 2.
A spring 274 is provided that biases toward the 64 side.

The valve element 266 is normally separated from the valve seat 264 by the valve opening member 278.

Therefore, when the brake pedal 12 is depressed, if the electrically controlled fluid pressure source 80 is in a normal operating state, the fluid pressure in the fluid chamber 244, that is, the electrically controlled pressure is higher than the fluid pressure in the fluid chamber 244.
40 and the hydraulic pressure in the liquid chamber 242, that is, the master cylinder pressure, a retraction force (an upward force in the figure) is applied to the control piston 232, and the control piston 232 is still maintained at its original position. Therefore, the valve 266 is also kept in its original position and the master cylinder 10 is connected to the port 246. Liquid chamber 240. Communication path 251. It is communicated with liquid absorber 60 via liquid chamber 242 and control ports 1-248.

On the other hand, if the electrically controlled hydraulic pressure source 80 fails, either the hydraulic pressure in the liquid chamber 240 or the liquid chamber 242
4 (again, assumed to be O), the control piston 232 moves forward (moves downward in the figure) while compressing the spring 260. At this time, the valve 266 is moved from the control piston 232 by the spring 274.
The valve moves forward integrally with the valve seat 264, and eventually seats on the valve seat 264. This blocks the control port 248 and blocks the master cylinder 10 from the liquid absorber 60. Also, since the control piston 232 can be moved, the master cylinder pressure can be changed from the liquid chamber 240. is transmitted to the wheel cylinder 20°30 via the control piston 232 and the fluid chamber 244, so that
A hydraulic pressure approximately equal to the master cylinder pressure will be generated in the wheel cylinders 20 and 30.

In the embodiment described above, the driver or the brake pedal
2, but it may also be read from the height of the master cylinder pressure, for example.

Further, in those embodiments, the wheel speed sensor 132
Although the actual deceleration of the vehicle body was detected using a deceleration sensor, it is also possible to provide a deceleration sensor and read the actual deceleration from that sensor.

In addition, in these embodiments, the brake system for the four wheels is divided into two, a front wheel brake system and a rear wheel brake system, and common hydraulic pressure control is performed for the left and right front wheels and the left and right rear wheels. It looked like this,
For example, the brake system may be divided into three parts: a front left brake system, a front right brake system, and a rear brake system, each with an electrically controlled hydraulic pressure source. The system may be divided into four parts: a brake system and a right rear wheel brake system, and each may be provided with an electrically controlled hydraulic pressure source.

Furthermore, in those embodiments, the electrically controlled hydraulic pressure source 80 is of a type that generates electrically controlled pressure by operating the pressurizing piston 86 based on the rotation of the electric motor 82; A type in which electric control pressure is generated by the operation of a pressurizing piston 86 based on the base, or a type in which electric control pressure is generated by controlling the accumulator pressure generated in an accumulator by a pump to an appropriate height with an electromagnetic proportional control valve. You can also use it as An example of the latter format is Japanese Patent Application Laid-Open No.
It is described in the publication No.-278874. Note that when using a piezoelectric element, even if the electrical control system of the piezoelectric element fails, the main liquid passage 16 does not need to be provided with any special means.
Normally, I6 and 18 can be pressurized, but if an electromagnetic proportional control valve is used, if the electrical control system fails, the main liquid passages I6 and 18 will be connected to the reservoir via the electromagnetic proportional control valve. There are cases where the main liquid passages 16 and 18 cannot be pressurized due to communication. Therefore, when using this type, when the electrical control system is normal, the main liquid passage 16
A cut valve is required which connects 18 and the electromagnetic proportional control valve to each other and shuts off the valve in the event of a failure.

Although several embodiments of the present invention have been described above in detail based on the drawings, the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art. can.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a manual/electric brake system and a front sectional view of a pilot type flow control device, which is an embodiment of the present invention. FIG. 2 is a front sectional view showing another embodiment of the pilot type flow control device. FIG. 3 is a front sectional view showing still another embodiment of the pilot type flow control device. 10, Master cylinder 20.30: Wheel cylinder 40, '160. 220: Pilot type flow control device 60: Liquid absorber 80: Electrically controlled liquid pressure source Applicant 1 ~ Yota Jidosha Co., Ltd.

Claims (1)

[Scope of Claims] A master cylinder that generates hydraulic pressure in response to the operation of a brake operating member, a wheel cylinder that operates a brake that suppresses rotation of the wheels, and a main fluid that connects the master cylinder and the wheel cylinder to each other. a control pressure chamber connected to the passage, an electrically controlled hydraulic pressure source that generates hydraulic pressure in the control pressure chamber by electrical control; a fluid absorber that temporarily stores brake fluid discharged from the master cylinder when the brake is applied and returns it to the master cylinder when the brake is released; and a fluid absorber that is connected to the connection portion of the main fluid passage with the fluid absorber. , a control piston that operates by receiving master cylinder pressure generated in the master cylinder and electric control pressure generated in the electrically controlled hydraulic pressure source as pilot pressures in opposite directions, and the electrically controlled hydraulic pressure source is normally operated. In the state where the electric control pressure of the height is generated, the master cylinder is connected to the liquid absorption table and the master cylinder pressure is not transmitted to the wheel cylinder, and the electric control hydraulic pressure source is in the state where the electric control pressure of the normal height is generated. a pilot-type flow control device that isolates the master cylinder from the liquid absorber and transmits the master cylinder pressure to the wheel cylinder in a state where the electrically controlled fluid pressure source A dual manual/electric system, characterized in that even if the control system is abnormal, the master cylinder pressure can be transmitted to the wheel cylinders via the main fluid passage and the pilot type flow control device. brake system.