JPH08104214A - Brake system - Google Patents

Abstract

(57) [Abstract] [Purpose] In a brake system that performs traction control by operating a pump to pump the brake fluid in the reservoir and supplying it to the brake cylinders of the driving wheels when the vehicle is driven, from the master cylinder during traction control. Make sure that the reservoir is not overfilled with brake fluid. A part of an auxiliary liquid passage 90 extending from the main liquid passage 54 to a reservoir 70 between a connecting position of the main liquid passage 54 and a connecting position of a relief liquid passage 94 having a relief valve 96 for a pump 76. An orifice 98 is provided in the. As a result, the surplus brake fluid from the pump 76 is pumped to the pump 7.
6, when the relief valve 96, the pilot type inflow control valve 92 and the reservoir 70 are circulated, the tendency of the brake fluid from the master cylinder 10 to flow into the circulation circuit is reduced, and the master cylinder 10 is controlled during the traction control. Brake fluid is not wasted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle brake system, and more particularly to a brake system for performing traction control for suppressing idling of driving wheels by operating a brake by using a pump as a pressure source when the vehicle is driven. It is a thing.

[0002]

2. Description of the Related Art A traction control is known which suppresses idling of a driving wheel by reducing excessive driving torque applied to the driving wheel by a brake when the vehicle is driven. As a method of applying a brake during this traction control, there is a method of using an accumulator that constantly accumulates brake fluid at high pressure, but if this method is adopted, an extra accumulator is required and the equipment cost increases. In addition, there is a drawback in that the weight of the device is increased. On the other hand, a brake system to which a traction control device is added usually also has an antilock control device, and the reflux pump in the antilock control device can function as a pressure source when the master cylinder is inactive. In view of this, there is also a system that uses a reflux pump as a system that applies a brake during traction control.

A conventional example of a brake system for performing traction control using a reflux pump is disclosed in Japanese Patent Laid-Open No. 5-116.
No. 556, gazette. This conventional example has the following configuration. That is, in the main fluid passage extending from the master cylinder to the brake cylinder of the drive wheel,
In the normal braking state, the brake cylinder communicates with the master cylinder.In the traction control state, the master cylinder cut valve shuts off the master cylinder, and at least brake fluid in the master cylinder is supplied to the brake cylinder to brake. An electromagnetic hydraulic pressure control device that switches between a pressure increasing state for increasing the pressure of the cylinder and a pressure reducing state for reducing the pressure of the brake cylinder by discharging the brake fluid in the brake cylinder to the reservoir, which is in the pressure increasing state in the normal braking state. Are provided in that order, the auxiliary fluid passage extends from the master cylinder, the pump fluid passage extends from a portion of the main fluid passage between the master cylinder cut valve and the electromagnetic fluid pressure control device, and the auxiliary fluid passage extends from the electromagnetic fluid pressure control device. The reservoir liquid passage extends, and these auxiliary liquid passages and pumps Both the liquid passage and the reservoir liquid passage reach the reservoir, and the auxiliary liquid passage has an inflow blocking state that blocks inflow from the master cylinder to the reservoir in the normal braking state, and an inflow permitted state that allows it in the traction control state. A pump is provided in the pump fluid passage to pump up the brake fluid in the reservoir and supply it to the main fluid passage. The pump extends from the discharge port of the pump and controls the connection position of the main fluid passage in the auxiliary fluid passage and the inflow control. A relief valve that prevents the discharge pressure of the pump from exceeding the set relief pressure is provided in the relief fluid passage that extends between the valve and the valve, and the controller operates the pump to control the electromagnetic fluid pressure control device. This is a braking system that performs traction control that suppresses idling of drive wheels when the vehicle is driven.

Here, the "master cylinder" is generally a device for mechanically generating a hydraulic pressure having a height corresponding to an operating force.

The "inflow control valve" can be electromagnetic. In this case, the inflow control valve is, for example, an electromagnetic on-off valve that is in the inflow blocking state in the normal braking state and is in the inflow allowing state in response to a signal from the controller in the traction control state. In a brake system using this electromagnetic inflow control valve, the electromagnetic inflow control valve is in an inflow blocking state in the normal braking state, and the master cylinder is cut off from the reservoir to enable boosting pressure, while in the traction control state Allowed to allow the pump to replenish the reservoir from the master cylinder with the brake fluid needed to boost the pressure of the brake cylinder. After that, when the discharge pressure of the pump is about to exceed the set relief pressure, the relief valve is opened and excess brake fluid is discharged to the relief fluid passage. Since the pressure in the reservoir chamber tends to be negative by the pump, the excess brake fluid discharged to the relief fluid passage passes through the portion of the auxiliary fluid passage between the relief fluid passage connection position and the reservoir. To reflux. That is, the surplus brake fluid is circulated in the circulation circuit in which the pump, the relief valve, the electromagnetic inflow control valve, and the reservoir are connected in series.

The "inflow control valve" may also be pilot operated. In this case, as described in the above publication, the reservoir is formed in the housing such that the reservoir piston is substantially airtight and slidably fitted into the housing to form a reservoir chamber for containing the reservoir liquid. When the volume of the reservoir chamber increases from the normal value, the reservoir piston is displaced from the normal position to the volume increasing position, and when the volume decreases from the normal value, the reservoir piston is displaced from the normal position to the volume decreasing position. The inflow control valve is actuated by the reservoir piston,
The pilot type inflow control valve is in an inflow blocking state when the reservoir piston is in the volume increasing position, and is in an inflow allowing state when the reservoir piston is in the volume reducing position.

In the brake system using the pilot type inflow control valve, when the traction control is started, the pump is operated so that the reservoir chamber has a negative pressure and the reservoir piston is displaced to the volume reduction position. Type inflow control valve is in the inflow allowable state,
The brake fluid in the master cylinder flows into the reservoir via the pilot type inflow control valve, which is pumped up to increase the pressure in the brake cylinder of the drive wheel.
After that, when the discharge pressure of the pump is about to exceed the set relief pressure, as in the case of using the electromagnetic inflow control valve, the relief valve is opened and excess brake fluid is discharged to the relief fluid passage, A pump, a relief valve, a pilot type inflow control valve and a reservoir are circulated in a circulation circuit connected in series with each other.

[0008]

However, no matter which type of inflow control valve is used, in the conventional brake system, the brake fluid in the master cylinder is replenished to the reservoir more than necessary during the traction control. There is a problem.

During traction control, it is sufficient that the required amount of brake fluid is replenished from the master cylinder to the reservoir. For example, since the brake fluid in the reservoir is generally insufficient at the start of traction control, it is necessary to replenish the brake fluid from the master cylinder. However, after the traction control is started and after the excess brake fluid is discharged from the pump, it is no longer necessary to replenish the brake fluid from the master cylinder, and the brake fluid circulated in the circulation circuit is no longer necessary. Is generally sufficient to be supplied to the brake cylinder as needed.

The phenomenon that the brake fluid is replenished to the reservoir more than necessary from the master cylinder during the traction control causes the following phenomenon when the inflow control valve is of the pilot type, for example.

In a brake system using a pilot type inflow control valve, if only the excess brake fluid from the pump can be circulated in the circulation circuit, the pressure in the reservoir chamber can be kept substantially constant and the reservoir piston The position is also kept almost constant, and the pilot type inflow control valve is kept in the inflow permitted state as planned. Therefore, in this case, when the driver operates the brake operating member such as the brake pedal during the traction control, the pilot type inflow control valve is in the inflow allowable state, so that the brake fluid in the direction from the master cylinder to the reservoir is Flow is allowed and braking can be performed as in normal braking conditions.

However, since the master cylinder is also connected to the circulation circuit, and the pressure in the reservoir chamber is negative and the pressure in the master cylinder is atmospheric pressure, the master cylinder moves to the reservoir even after the traction control is started. The inflow of the brake fluid is permitted. In this case, the brake fluid from the master cylinder is supplied to the reservoir together with the surplus brake fluid from the pump, the volume of the reservoir chamber increases, the reservoir piston is displaced to the volume increasing position, and the pilot type The inflow control valve becomes more likely to enter the inflow blocking state. When the pilot type inflow control valve is in the inflow blocking state during the traction control, even if the driver operates the brake operating member, the discharge of the brake fluid from the master cylinder is blocked and the displacement of the brake operating member is also blocked.

Traction control is usually designed to end when the operation of an acceleration operating member such as an accelerator pedal is released, or when the operation of a brake operating member such as a brake pedal is started. Further, the start of the brake operation is usually detected when the brake operation member is displaced to some extent and the brake switch is switched from the OFF state to the ON state or from the ON state to the OFF state. Therefore, if the brake operation is started before the traction control is completed because the release of the acceleration operation cannot be detected for some reason or the detection is delayed, the driver operates the brake operation member. Even if the brake operation member is not displaced, the brake switch cannot detect the brake operation even if the brake operation is actually performed, and the traction control does not end immediately.

If the brake operating member is not immediately displaced during the traction control, the traction control does not end immediately, so that the master cylinder cut valve is kept in the closed state and the master cylinder is kept disconnected from the brake cylinder. Therefore, there is a time when the vehicle deceleration does not increase even though the operation feeling of the brake operation member is hard, and the operation feeling of the brake operation member becomes a plate brake feeling.

Further, if the brake fluid is not discharged from the master cylinder even though the brake operating member is operated during the traction control, the pressure of the master cylinder suddenly rises due to the brake operation, and the master cylinder is used. High pressure may suddenly act on the rubber seal, which may reduce the durability of the seal.

In view of these circumstances, the invention of claim 1 is
An object of the invention is to prevent the master cylinder from replenishing the brake fluid more than necessary during the traction control. This invention also
In a brake system where the inflow control valve is a pilot type, by ensuring that the pilot type inflow control valve is kept in the inflow allowable state as much as possible during traction control, even when a brake operation is performed during traction control. It was also made as a task to ensure that the brake operation is performed as usual.

When the brake cylinder is depressurized and the pump continues to operate even if the brake cylinder is reduced to the atmospheric pressure, the brake fluid is sucked more than necessary from the brake cylinder and the brake cylinder becomes a negative pressure. In this case, the master cylinder cut valve is in communication,
When the electromagnetic hydraulic pressure control device is restored to the increased pressure state,
Due to the negative pressure, a part of the brake fluid in the master cylinder flows into the brake cylinder, and the brake pedal is temporarily retracted accordingly.

Therefore, in order to prevent the brake cylinder from becoming negative pressure at the end of the pump operation, the applicant of the present invention has flown the brake fluid in the reservoir fluid passage from the electromagnetic fluid pressure control device toward the reservoir. Proposed that a check valve be provided that allows flow above the set valve opening pressure but blocks flow in the opposite direction.

However, in this proposal, the electromagnetic hydraulic pressure control device includes a pressure increasing valve which is a normally open electromagnetic on-off valve provided in the main fluid passage and a pressure reducing valve which is a normally closed electromagnetic on-off valve provided in the reservoir fluid passage. When implemented in a pilot type braking system that is configured as a combination and the inflow control valve is in the inflow blocking state in the normal braking state, the following problems occur. That is, in the normal braking state, a closed space partitioned by the check valve, the suction valve of the pump, and the pilot type inflow control valve is formed between the reservoir fluid passage, the pump fluid passage, the auxiliary fluid passage, and the reservoir. There is a problem that it is difficult to completely remove air from the closed space.

In view of this, the present invention has as its object to provide a brake system capable of preventing the brake cylinder from becoming negative pressure at the end of the pump operation and performing the air bleeding easily and completely. Is.

A third aspect of the present invention is intended to provide an appropriate air bleeding method for the brake system according to the second aspect of the invention.

In the brake system according to the first aspect of the present invention, when the inflow control valve cannot enter the inflow blocking state even though it is in the normal braking state due to the failure of the inflow control valve, the master cylinder causes the reservoir to operate. It becomes impossible to raise the pressure by communicating with the brake and it becomes impossible to operate the brake.

Therefore, in the invention of claim 4, by ensuring that the pilot type inflow control valve is always in the inflow blocking state in the normal braking state, the reliability of the brake system by adding the pilot type inflow control valve is improved. The problem was to prevent the decrease.

[0024]

In order to solve each of the problems, the invention of claim 1 replenishes a reservoir with brake fluid from a master cylinder when the vehicle is driven, and pumps up the brake fluid with a pump to brake the cylinder. In the main fluid passage that extends from the master cylinder to the brake cylinder of the drive wheels, a brake system that performs traction control by increasing the pressure is applied to (a) the brake fluid between the master cylinder and the brake cylinder in the normal braking state. A flow control device that permits the bidirectional flow of the brake fluid and blocks the flow of the brake fluid in at least the direction from the brake cylinder to the master cylinder in the traction control state,
(b) At least switch between a pressure increasing state in which the brake cylinder is pressurized by supplying the brake fluid in the master cylinder to the brake cylinder and a pressure reducing state in which the brake fluid in the brake cylinder is discharged to the reservoir to reduce the pressure of the brake cylinder. An electromagnetic fluid pressure control device which is replaced and which is in a pressure increasing state in a normal braking state are provided in that order, an auxiliary fluid passage extends from the master cylinder, and a flow control device and an electromagnetic fluid pressure control device in the main fluid passage are provided. The pump fluid passage extends from the portion between the auxiliary fluid passage, the electromagnetic fluid pressure control device and the reservoir fluid passage, and the auxiliary fluid passage, the pump fluid passage, and the reservoir fluid passage all reach the reservoir. In the state, the inflow blocking state that blocks the inflow of brake fluid from the master cylinder to the reservoir, traction control In this state, an inflow control valve that allows an inflow is provided, and a pump fluid passage is provided with a pump that pumps up the brake fluid in the reservoir and supplies it to the main fluid passage. A relief valve that prevents the discharge pressure of the pump from exceeding a set relief pressure is provided in the relief liquid passage that reaches a portion between the connection position of the main liquid passage and the inflow control valve in the liquid passage,
The auxiliary fluid passage is provided with a throttle between the main fluid passage connection position and the relief fluid passage connection position, and is driven when the vehicle is driven by the controller operating the pump to control the electromagnetic fluid pressure control device. It is characterized by being a brake system that performs traction control that suppresses wheel idling.

The "inflow control valve" may be of an electromagnetic type or a pilot type. When the inflow control valve is of the pilot type, the inflow blocking state may be set when the reservoir piston is in the normal position, or the inflow allowable state may be set. In the case where the inflow prevention state is adopted, in the normal braking state, the delay of the braking effect is satisfactorily avoided, and
The effect of improving the durability of the inflow control valve can be obtained by eliminating the need to repeat the opening and closing frequently.

The "throttle" can be, for example, an orifice or a choke.

The "electromagnetic hydraulic pressure control device" may be constituted by, for example, one electromagnetic directional control valve that switches between a pressure increasing position, a holding position and a pressure reducing position, or an electromagnetic switching between a pressure increasing position and a pressure reducing position. It can be configured by one direction switching valve or a combination of two or more electromagnetic switching valves.

According to a second aspect of the present invention, in the first aspect of the invention, (1) the electromagnetic fluid pressure control device includes a pressure increasing valve which is a normally open electromagnetic on-off valve provided in the main fluid passage, and a main fluid. And a pressure reducing valve which is a normally closed electromagnetic opening / closing valve provided in the reservoir liquid passage extending from a portion of the passage between the pressure increasing valve and the brake cylinder, and (2) the reservoir is provided with a reservoir piston in the housing. Is substantially airtightly and slidably fitted to form a reservoir chamber containing the reservoir liquid in the housing, and when the volume of the reservoir chamber increases from the normal value, the reservoir piston increases in volume from the normal position. When the volume decreases from the normal value to the normal position, the volume is displaced from the normal position to the volume decreasing position. (3) The inflow control valve is operated by the reservoir piston, A pilot-type inflow control valve that is in an inflow blocking state when the over piston is in the normal position and in the volume increasing position, and is in the inflow allowing state when it is in the volume decreasing position, and that manually switches to the inflow allowing state (4) Furthermore, a check valve is provided in the reservoir fluid passage to allow a flow of brake fluid in a direction from the pressure reducing valve to the reservoir at a set valve opening pressure or more, but to prevent the flow in the opposite direction. It is characterized by that.

The "pilot type inflow control valve", for example, pays attention to the fact that it is operated by a reservoir piston, and if a rod-shaped member that is a hole that opens to the outside of the reservoir is inserted into the reservoir housing, It is possible to adopt a mode in which the tip of the piston engages with the reservoir piston. In this aspect, the operator inserts the rod-shaped member into the hole to engage the reservoir piston, and by transmitting the force to the reservoir piston via the rod-shaped member, the pilot type inflow control valve is forced to the inflow permitted state. Can be switched to.

The "check valve" is provided in a portion of the reservoir liquid passage between the pressure reducing valve and the reservoir, or in a portion of the reservoir liquid passage between the connection position of the main liquid passage and the pressure reducing valve. Can be provided.

According to a third aspect of the invention, there is provided an air bleeding method for the brake system according to the second aspect, wherein the solenoid of the pressure reducing valve is excited to open the pressure reducing valve, and the pilot type inflow control is performed. After manually setting the valve to the inflow permitted state, the air is released by removing the brake fluid from at least one port provided in at least one of the main fluid passage, the auxiliary fluid passage, the pump fluid passage, and the reservoir fluid passage. It is characterized by

The "air bleeding" is carried out, for example, by applying a negative pressure to the port to suck the brake fluid from the port and at the same time pushing the brake fluid from the master cylinder.

According to a fourth aspect of the present invention, in the first aspect of the present invention, (1) the reservoir piston is fitted in the housing in a substantially airtight and slidable manner so that the reservoir liquid is stored in the housing. A reservoir chamber to be accommodated is formed, and the reservoir piston is displaced from the normal position to the volume increasing position when the volume of the reservoir chamber increases from the normal value, and from the normal position to the volume decreasing position when the volume decreases from the normal value. (2) a pilot type inflow control valve that operates the inflow control valve by the reservoir piston and is in an inflow blocking state when the reservoir piston is in the volume increasing position and is in the inflow allowing state when the reservoir piston is in the volume reducing position. , A valve member and a valve seat that cooperate with each other to prevent the flow of brake fluid from the master cylinder to the reservoir. Two valve assemblies having the same are connected in series to each other, and two valve elements in the valve assemblies are integrally displaced by the valve piston to switch between an inflow blocking state and an inflow allowing state. It is characterized by

[0034]

In the brake system according to the first aspect of the present invention, the throttle is provided at a portion of the auxiliary liquid passage between the connection position of the main liquid passage and the connection position of the relief liquid passage. Therefore, during traction control, when excess brake fluid from the pump is circulated in the circulation circuit in which the pump, the relief valve, the inflow control valve and the reservoir are connected in series, the brake fluid from the master cylinder is circulated. There is a strong tendency that the flow path resistance when flowing into the cylinder increases and only the surplus brake fluid is supplied to the reservoir, and the brake fluid is not replenished from the master cylinder more than necessary.

Therefore, for example, when the inflow control valve is of the pilot type, when the excess brake fluid is circulated, the volume of the reservoir chamber does not increase more than necessary, and the valve piston has the pilot type inflow control valve. Is more likely to be maintained in the position where the inflow is allowed. As a result, during the traction control, the pilot type inflow control valve tends to be kept in the inflow allowable state, and if the brake operating member is operated during the traction control, the brake fluid from the master cylinder is discharged to the reservoir. This makes it possible to secure the displacement of the brake operating member. Therefore, if the brake operating member is operated during the traction control, the displacement necessary for switching the ON / OFF state of the brake switch can be easily secured, the traction control can be quickly and surely completed, and the distribution control device is normally operated. It will be quickly restored to the braking state. As a result, the flow of brake fluid in the direction from the master cylinder to the brake cylinder via the main fluid passage is immediately permitted, and the pressure in the brake cylinder can be increased quickly in response to the brake operation, and the brake operation is performed normally. Becomes

In the brake system according to a second aspect of the present invention, the electromagnetic hydraulic pressure control device according to the first aspect of the present invention is configured to include both a pressure increasing valve and a pressure reducing valve which are electromagnetic opening / closing valves, and The reservoir fluid passage in the invention of item 1 is provided with a check valve that allows the flow of the brake fluid in the direction from the pressure reducing valve toward the reservoir at a set valve opening pressure or higher. Therefore, when the pressure reducing valve is in the open state and the pressure is reduced, the brake cylinder is prevented from becoming a negative pressure unless the pressure at the suction port of the pump becomes lower than the atmospheric pressure by the set valve opening pressure or more.

Further, in this brake system,
The inflow control valve in the invention of claim 1 is of a pilot type and is manually switched to the inflow permitted state. Therefore, the operator can easily bring the pilot type inflow control valve into the inflow permitted state for air bleeding or the like.

In the air bleeding method according to the third aspect of the invention, in the brake system according to the second aspect of the invention, the pressure reducing valve is excited to open the state and the pilot type inflow control valve is manually allowed to flow in. After that, air is bleeded by draining the brake fluid from at least one port provided in at least one of the main fluid passage, the auxiliary fluid passage, the pump fluid passage, and the reservoir fluid passage.

In this brake system, the pump fluid passage, the reservoir fluid passage, the
A closed space is formed between the auxiliary liquid passage and the reservoir, which is partitioned by the suction valve of the pump, the check valve, and the pilot type inflow control valve. However, if the pressure reducing valve is opened and the pilot type inflow control valve is set to the inflow permitting state, the closed space faces the direction from the pressure reducing valve to the reservoir, the direction from the suction valve of the pump to the reservoir, and The direction from the reservoir to the master cylinder is open. Therefore, if the brake fluid is drained from a specific port so that the brake fluid flows in those directions, the brake fluid in the originally closed space can flow toward the specific port. It is possible to completely and easily perform air bleeding inside.

In the brake system according to the invention of claim 4, the inflow control valve according to the invention of claim 1 is of a pilot type. Further, the inflow control valve includes two valve assemblies each having a valve element and a valve seat which cooperate with each other to prevent the flow of the brake fluid in the direction from the master cylinder toward the reservoir, and the valve assemblies are connected in series to each other. The two valve elements in the solid body are integrally displaced by the valve piston. Therefore, the pilot type inflow control valve can realize the inflow blocking state in the normal braking state unless the two valve assemblies fail at the same time and the sealing performance is not exhibited.

[0041]

As is apparent from the above description, according to the first aspect of the invention, the brake fluid is replenished by the master cylinder during the traction control by the action of the throttle, and the necessary amount of the brake fluid is replenished in the master cylinder. The effect is obtained that the brake fluid is not wasted.

The technique for increasing the flow resistance of the brake fluid in the direction from the master cylinder to the reservoir by providing the throttle is not limited to providing the throttle in the auxiliary fluid passage, but also in the main fluid passage in the master cylinder and the auxiliary fluid. It can also be implemented by providing it in a portion between the passage and the connection position. However, in the latter case, there is an inconvenience that the flow resistance of the brake fluid in the direction from the master cylinder to the brake cylinder is increased during the normal brake operation. Therefore, according to the first aspect of the present invention, it is possible to increase the flow resistance of the brake fluid in the direction from the master cylinder to the reservoir without affecting the normal brake.

In particular, when the invention of claim 1 is implemented by using the pilot type inflow control valve, the pilot type inflow control valve is maintained in the inflow allowable state as much as possible during the traction control, so that the brake operation is performed during the traction control. As a result, the effect that the traction control is immediately terminated and the brake operation is performed as usual is also obtained.

According to the second aspect of the present invention, it is further possible to prevent the brake cylinder from having a negative pressure when the pressure is reduced and to provide a brake system capable of completely and easily bleeding air.

According to the third aspect of the present invention, in the brake system according to the second aspect of the invention, the effect that the air bleeding can be completely and easily performed and the work efficiency is improved is obtained.

According to the invention of claim 4, in addition to the effect of the invention of claim 1, it is guaranteed that the pilot type inflow control valve is always in the inflow blocking state in the normal braking state, and the reliability of the brake system is improved. The effect of improvement is obtained.

[0047]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention of each claim will be specifically described below based on the illustrated embodiments. In FIG. 1, reference numeral 10 indicates a master cylinder. The master cylinder 10 is a tandem type in which two independent pressurizing chambers are arranged in series with each other. The master cylinder 10 is made to cooperate with a brake pedal 14 as a brake operating member via a booster (not shown), and the stepping force of the brake pedal 14 mechanically generates hydraulic pressures of equal height in each pressurizing chamber. Let

The brake cylinders 20 for the left and right front wheels which are non-driving wheels are connected to one pressurizing chamber of the master cylinder 10, and the brake cylinders 21 for the left and right rear wheels which are driving wheels are connected to the other pressurizing chamber. . In other words, this brake system is a front / rear two-system type. The left and right front wheels are subject to antilock control, and the left and right rear wheels are subject to both antilock control and traction control. That is, in this brake system, the brake cylinder 21 is the "brake cylinder" in the invention of each claim.
It constitutes one example.

First, the structure of the front wheel brake system will be described. In the front wheel brake system, the master cylinder 10
Is connected to the brake cylinder 20 by a main liquid passage 22 that extends from the master cylinder 10 and then branches into a bifurcated shape. A pressure increasing valve 24, which is a normally-open electromagnetic on-off valve, is provided at each branch portion of the main fluid passage 22 to open a pressure increasing state that allows a flow of the brake fluid in a direction from the master cylinder 10 to the brake cylinder 20. To be realized.
A bypass fluid passage 26 is connected to each pressure increasing valve 24, and a check valve 28 for returning the brake fluid is provided in each bypass fluid passage 26. Reservoir fluid passages 30 extend from the portions of the main fluid passages 22 between the pressure increasing valves 24 and the brake cylinders 20 to reach the reservoirs 32. Each reservoir fluid passage 30 is provided with a pressure reducing valve 34, which is a normally closed electromagnetic on-off valve, and realizes a pressure reducing state that allows the flow of brake fluid in the direction from the brake cylinder 20 to the reservoir 32 in the open state. That is, the brake cylinder pressures of the left and right front wheels can be controlled independently of each other.

The reservoir 32 has a housing in which a reservoir piston 36 is fitted in a substantially airtight and slidable manner, and the brake fluid in the reservoir chamber formed by the fitting is pressed by a spring 38 as an urging means. To be housed in. The reservoir 32 is provided in the master cylinder 1 of the main liquid passage 22 by the pump liquid passage 40.
It is connected to a portion between 0 and each pressure increasing valve 24. A pump 44 driven by a motor 42 is provided in the pump liquid passage 40. The pump 44 pumps up the brake fluid discharged from the brake cylinder 20 to the reservoir 32 and returns it to the main fluid passage 22. A suction valve 46, which is a check valve, is provided on the suction side of the pump 44, and a discharge valve 48, which is a check valve, is provided on the discharge side.

Next, the structure of the rear wheel brake system will be described.
However, a part common to the front wheel brake system will be briefly described.

In the rear wheel braking system, the master cylinder 10 is connected to the brake cylinder 21 by a bifurcated main fluid passage 54 as in the case of the front wheel braking system. A pressure increasing valve 56 and a reservoir liquid passage 58 are provided at respective branched portions of the main liquid passage 54, a bypass liquid passage 62 having a check valve 60 is provided at each pressure increasing valve 56, and each reservoir liquid passage 58 is respectively provided. Pressure reducing valve 6
4 are provided. That is, the brake cylinder pressures of the left and right rear wheels can be controlled independently of each other. A reservoir 70 is provided at the tip of each reservoir liquid passage 58. The reservoir 70 is an example of the "reservoir" in the invention of each claim, and the details of the reservoir 70 will be described later. A pump liquid passage 72 extends from the reservoir 70 to allow the master cylinder 1 of the main liquid passage 54.
It reaches a portion between 0 and each pressure increasing valve 56. A pump 76 driven by a motor 74 is installed in the pump liquid passage 72.
Is provided. The suction side of the pump 76 is a suction valve 77a which is a check valve, and the discharge side is a discharge valve 77b which is a check valve.
Are provided respectively. An orifice 78 is provided in a portion of the pump liquid passage 72 on the discharge side of the pump 76 to reduce pulsation of the pump 76.

Each pressure reducing valve 64 in each reservoir liquid passage 58
Check valves 79 are respectively provided in a portion between the reservoir 70 and the reservoir 70. The reason for providing the check valve 79 is as follows. That is, during depressurization, the pump 76 is usually operated even after the hydraulic pressure of the brake cylinder 21 becomes atmospheric pressure, and therefore the brake cylinder 21 may become negative pressure. On the other hand, to prevent negative pressure, the pump 76
It may be considered that the valve opening pressure of the suction valve 77a of the pump 70 is slightly increased.
Since the brake fluid stored at approximately atmospheric pressure is pumped up, the pump 76 cannot smoothly pump up the brake fluid if the opening pressure of the suction valve 77a is high. Therefore,
In this embodiment, the pump 7 is provided separately from the suction valve 77a.
The check valve 79 is provided in the passage that does not affect the operation responsiveness of No. 6, so that the brake cylinder 21 is prevented from becoming negative pressure when the pressure is reduced. Therefore, when decompressing,
As long as the pressure at the suction port of the pump 76 does not decrease from atmospheric pressure by the set valve opening pressure or more, the brake cylinder 21 is prevented from becoming negative pressure.

The check valve 79 is provided only in the rear wheel brake system, not in the front wheel brake system.
This is because in the front wheel braking system, the reservoir 32 is of a pressurizing type, and the flow of the brake fluid in the direction from the reservoir 32 toward the pump 44 is caused by the reservoir 32 itself, so that the valve opening pressure of the intake valve 46 is increased. This is because it can be set and the purpose of the check valve 79 can be achieved by the suction valve 46 itself.

In the rear wheel brake system, unlike the case of the front wheel brake system, a master cylinder which is an electromagnetic on-off valve is provided in a portion of the main fluid passage 54 between the master cylinder 10 and the connection position of the pump fluid passage 72. A cut valve 80 is provided. The master cylinder cut valve 80 is in an open state (communication state) in the normal braking state and the antilock control state, and makes the brake cylinder 21 communicate with the master cylinder 10 to allow the master cylinder 10 to increase the pressure of the brake cylinder 21. On the other hand, in the traction control state, the brake cylinder 21 and the pump 76 are closed (shut-off state), and the master cylinder 1
Shut off from 0, pump 76 brake cylinder 2
It is possible to increase the pressure of 1.

A bypass liquid passage 82 is provided in the master cylinder cut valve 80, and the bypass liquid passage 82 is provided.
Is provided with a check valve 84. The check valve 84 allows the flow of the brake fluid in the direction from the master cylinder 10 to the brake cylinder 21, but blocks the flow in the opposite direction. This check valve 84 is used for the pump 7 during traction control.
6 to increase the pressure of the brake cylinder 21, and when the brake pedal 14 is depressed during traction control to generate hydraulic pressure in the master cylinder 10, the hydraulic pressure is higher than the hydraulic pressure of the brake cylinder 21. Master cylinder 10 to brake cylinder 2 when
By allowing the flow of the brake fluid in the direction toward 1, the brake operation by the driver is realized.
That is, in the present embodiment, the master cylinder cut valve 80, the bypass liquid passage 82, and the check valve 84 cooperate with each other to form an example of the "flow control device" in the invention of each claim.

Also in the rear wheel brake system, unlike the front wheel brake system, the auxiliary liquid passage 90 extends from the portion of the main liquid passage 54 between the master cylinder 10 and the master cylinder cut valve 80, and the pilot type It is connected to the reservoir 70 via an inflow control valve 92. The details of the pilot type inflow control valve 92 will be described later.

In the rear wheel brake system, unlike the front wheel brake system, the relief liquid passage 94 extends from the portion of the pump liquid passage 72 on the discharge side of the pump 76, and the main liquid passage 54 of the auxiliary liquid passage 90 is extended. Of the pilot type inflow control valve 92.
A relief valve 96 is provided in the relief liquid passage 94. A relief pressure of the relief valve 96 is set by a spring so that the discharge pressure of the pump 76 does not exceed the relief pressure.

An orifice 98 is provided in a portion of the auxiliary liquid passage 90 between the connecting position of the main liquid passage 54 and the connecting position of the relief liquid passage 94, and the brake liquid from the master cylinder 10 flows into the reservoir 70. The flow path resistance at the time of performing is increased. That is, the orifice 98 is an example of the "throttle" in the invention of each claim.

The pressure increasing valves 24 and 56 and the pressure reducing valve 3 described above
4, 64, the master cylinder cut valve 80, the motors 42 and 74 are connected to the controller 100. The controller 100 is mainly composed of a computer. Various programs for executing antilock control and traction control are stored in the ROM thereof, and the CPU executes the various programs while utilizing the RAM to execute antilock control and traction control.

In the anti-lock control, the pressure increasing valves 24 and 56 are open and the pressure reducing valves 34 and 64 are open while monitoring the rotation speed of each wheel and the traveling speed of the vehicle body through a speed sensor (not shown).
Is a closed pressure increasing state, and pressure increasing valves 24 and 56 are also pressure reducing valves 3.
Holding state and pressure increasing valves 24, 5 in which 4, 64 are also closed
6 is a control for preventing each wheel from locking when the vehicle is braked by selectively realizing the pressure reduction state in which the pressure reduction valve 6 is closed and the pressure reduction valves 34 and 64 are opened. During the antilock control, the pumps 44 and 76 are operated, and the reservoirs 32 and 7 are
The brake fluid in 0 is pumped up and the main fluid passages 22, 54
Is returned to.

On the other hand, the traction control causes the pump 76 to function as a pressure source by operating the pump 76, and monitors the rotational speeds of the left and right rear wheels, which are the driving wheels, and the traveling speed of the vehicle body through the speed sensor, Booster valve 56
By selectively realizing the pressure increasing state, the holding state and the pressure reducing state by the pressure reducing valve 64, the left and right rear wheels are prevented from idling when the vehicle is driven.

As is clear from the above description, in the present embodiment, the combination of the pressure increasing valve 56 and the pressure reducing valve 64 constitutes an example of the "electromagnetic pressure control device" in the invention of claim 1, and The pump 76 constitutes an example of a “pump”, and the part of the controller 100 that executes traction control constitutes an example of a “controller”.

Here, the structures of the reservoir 70 and the pilot type inflow control valve 92 will be described in detail. As shown enlarged in FIG. 2, the reservoir 70 and the pilot type inflow control valve 92 are configured in the same housing 200.
The housing 200 has a large-diameter hole 202 which has a bottom.
And the small diameter hole 204 are formed coaxially. Small hole 20
4 is opened on the bottom surface of the large diameter hole 202. The large diameter hole 202 and the small diameter hole 204 are separated from each other by a partition member 206. The partition member 206 is airtightly fixed to the small diameter hole 204 by caulking.

A reservoir chamber 212 is formed in a portion between the reservoir piston 210 and the partition member 206 by fitting the reservoir piston 210 into the large diameter hole 202 in a substantially airtight and slidable manner. The pump liquid passage 72 is connected to the liquid passage 213 communicating with the reservoir chamber 212.
And the reservoir liquid passage 58 are connected to each other. In the figure, reference numeral 214 indicates an O-ring as a bidirectional seal member. The open end of the large diameter hole 202 is a plug 215.
Is closed by the spring 2 as a biasing means between the plug 215 and the reservoir piston 210.
16 are provided.

The spring 216 is provided with a reservoir piston 210 via a flanged cylindrical bottomed retainer 218.
Is engaged with. Retainer 218 has a large diameter hole 202
Is fitted to the flange of the housing 200.
The limit of access to the reservoir chamber 212 is defined by the contact with the stepped portion of. Therefore, the original position of the retainer 218 defines the normal position of the reservoir piston 210, and when the volume of the reservoir chamber 212 increases, the reservoir piston 210 together with the retainer 218 causes the spring 2 to move.
While compressing 16, 16 is moved from the normal position to the retracted position (volume increasing position). However, since the reservoir piston 210 is loosely fitted to the retainer 218, the reservoir piston 210 can be independently advanced with the retainer 218 left in the original position (see FIG. 3), and the volume of the reservoir chamber 212 is small. When decreasing, only the reservoir piston 210 moves from the normal position to the forward position (volume reduction position).

A through hole 220 is formed at the center of the partition member 206 so that the reservoir chamber 212 and the space inside the small diameter hole 204 communicate with each other. A tapered and annular valve seat 222 is formed on the end surface of the partition member 206 on the side of the small-diameter hole 204 among the end surfaces of the partition member 206. The through hole 220 is opened in the center of the valve seat 222. Valve seat 222
A spherical valve 224 is seated on the seat.

A cylindrical holding member 230 is coaxially fixed to the end surface on the same side of the partition member 206 at an annular portion located outside the valve seat 222. This holding member 23
0 is a cylindrical valve seat member 2 on the outer peripheral surface thereof.
32 is held airtight and non-separable. Valve seat member 23
2 is also in close contact with the partition member 206. Of the both end surfaces of the valve seat member 232, the end surface opposite to the partition member 206 side is a valve seat 234. Plunger 236
Is closer to the valve seat 222 side than the plunger 236.
Is regulated by abutting of the holding member 230. A cylindrical plunger 236 having a bottom is loosely fitted in the small-diameter hole 204, and the bottom of the plunger 236 is made to function as a valve element 238, which is a valve seat 234.
Is supposed to sit down. Of the space inside the small diameter hole 204, the space partitioned by the bottom of the small diameter hole 204 and the bottom of the plunger 236 serves as a valve chamber 239, and passes through the liquid passage 240 formed in the housing 200 and the auxiliary liquid passage 90, and the master cylinder 10 It is connected to the.

A spring 242 as a biasing means is provided between the bottom of the plunger 236 and the valve element 224 to prevent the valve element 224 from moving unintentionally. Further, a spring 244 as an urging means is disposed between the bottom of the plunger 236 and the bottom of the small diameter hole 204, and presses the plunger 236 against the valve seat member 232. An engaging portion 246 is formed at the bottom of the plunger 236 so as to project toward the valve element 224 and engage with the valve element 224. However, the engagement portion 246 is not included in the plunger 23.
In the state in which 6 contacts the holding member 230, the plunger 2
36 does not press the valve element 224 against the valve seat 222, and the valve element 224 and the valve seat 222 are opposed to each other with a gap therebetween by engagement with a pin 250 described later.

That is, the valve element 224, the valve seat 222 and the spring 242 constitute the first valve assembly 248, and the plunger 236, the valve seat member 232 and the spring 244 constitute the second valve assembly 249. Moreover, the first valve assembly 248 and the second valve assembly 249 are connected to each other in series along the flow of the brake fluid in the direction from the master cylinder 10 to the reservoir 70. Therefore, the first valve assembly 248 and the second valve assembly 249 form an example of the "first valve assembly and the second valve assembly" in the invention of claim 4. A holder 251 having a bottomed cylindrical shape is fitted inside the small-diameter hole 204.
The holding member 232 is held at 1. Holder 25
1 allows the first valve assembly 248 to be fitted into the small-diameter hole 204 in a sub-assembled state (a state where the first valve assembly 248 is assembled prior to the main assembly for assembling the pilot type inflow control valve 92). The assembly of the second valve assembly 249 is facilitated. Holder 2
A through hole is provided at the bottom of the liquid passage 240.
The communication between the valve chamber 239 and the valve chamber 239 is secured.

The valve element 224 and the reservoir piston 210 are engaged with each other via a pin 250 as a linking member. The pin 250 engages the valve element 224 with the reservoir piston 210 in the normal position shown,
0, the valve element 224 and the plunger 236 are engaged with each other. Then, when the reservoir piston 210 moves from the normal position to the forward position, the pin 250 moves the plunger 236 against the spring 242 in the direction away from the valve seat member 232.

The operation of the reservoir 70 and the pilot type inflow control valve 92 configured as described above is as follows.

In the normal braking state, the elastic force of the spring 244 causes the plunger 236 to move to the valve seat member 2.
It is in close contact with 32 and blocks the flow of brake fluid from the master cylinder 10 into the reservoir 70. Therefore, the master cylinder 10 is in a state in which the pressure can be increased, and when the driver depresses the brake pedal 14, hydraulic pressure is generated in the master cylinder 10, which is the driving wheel via the master cylinder cut valve 80 and the pressure increasing valve 56. It is transmitted to the brake cylinders 21 of the left and right rear wheels, and the brake is operated.

When the seal between the plunger 236 and the valve seat member 232 is no longer achieved for some reason, the brake fluid from the master cylinder 10 first flows into the reservoir chamber 212 through the following route. That is, the liquid passage 240, the valve chamber 239, the holder 251, and the plunger 2
36, a cylindrical clearance between the valve housing 236 and the valve seat 232, a clearance between the plunger 236 and the valve seat member 232, a space between the plunger 236 and the valve seat 222, a valve chamber 252, a valve 224 and a valve seat 222.
It flows into the reservoir chamber 212 through the gap between the and and the through hole 220 in order. Due to this inflow, the reservoir piston 210 is retracted against the spring 216, and the pin 250 is also retracted accordingly, so that the valve element 224 is seated on the valve seat 222, whereby the master cylinder 10 moves to the reservoir chamber. Inflow of brake fluid to 212 is blocked, and pressurization of master cylinder 10 is ensured.

That is, as long as the first valve assembly 248 and the second valve assembly 249 are arranged in series with each other and the first valve assembly 248 fails, the second valve assembly 249 does not fail. Master cylinder 10 in normal braking state
Therefore, the reliability of the brake system is improved even though the pilot type inflow control valve 92 is used.

On the other hand, when the traction control is started and the pump 76 is operated, the brake fluid in the reservoir chamber 212 is pumped up by the pump 76, so that the reservoir chamber 212 becomes negative pressure and the reservoir piston 210. Moves from the normal position to the volume reduction position.
Accordingly, the pin 250 moves the valve element 224 and the plunger 236 in a direction in which the spring 242 is compressed, and as a result, the brake fluid can flow from the master cylinder 10 into the reservoir 70. Therefore, the pump 76 operates by replenishing the reservoir chamber 212 with the brake fluid from the master cylinder 10, thereby increasing the pressure in the brake cylinder 21 and activating the brake to reduce an excessive drive torque.

When the discharge pressure of the pump 76 is about to exceed the set relief pressure of the relief valve 96 during traction control, the relief valve 96 is opened and excess brake fluid is discharged from the pump 76 to the relief fluid passage 94. To be done. Since the pressure in the reservoir chamber 212 tends to be a negative pressure by the pump 76, the surplus brake fluid discharged to the relief fluid passage 94 is included in the relief fluid passage 9 of the auxiliary fluid passage 90.
It is returned to the reservoir 70 via a portion between the connection position 4 and the reservoir 70. That is, the surplus brake fluid is circulated in the circulation circuit in which the pump 76, the relief valve 96, the pilot type inflow control valve 92 and the reservoir 70 are connected in series.

When the excess brake fluid is circulated in the circulation circuit, the flow passage resistance when the brake fluid from the master cylinder 10 flows into the circulation circuit increases due to the action of the orifice 98, and only the excess brake fluid is discharged. Is the reservoir 70
The brake fluid supplied from the master cylinder is not likely to be replenished more than necessary. Therefore, during the traction control, when the surplus brake fluid is circulated, the volume of the reservoir chamber 212 does not increase more than necessary, and the reservoir piston 210 keeps the pilot type inflow control valve 92 in the inflow permitted state. The tendency to become stronger. Therefore, during the traction control, the pilot type inflow control valve 92 is more likely to be kept in the inflow permitted state, the inflow of the brake fluid from the master cylinder 20 to the reservoir 70 is permitted, and the brake pedal 14 is depressed during the traction control. If so, the master cylinder 10
The brake fluid can be discharged from the brake pedal, and the depression of the brake pedal 14 is ensured.

Therefore, if the brake pedal 14 is depressed during the traction control, the brake switch 260 is in the OFF state when the brake pedal 14 is in the non-acting position and is in the ON state when the brake pedal 14 is in the actuating position (stepping position) (see FIG. 1). ) Output signal from OFF state to ON
The displacement required for switching to the state is easily secured, the traction control is quickly and surely completed, and the master cylinder cut valve 80 is quickly restored to the communicating state. As a result, the flow of the brake fluid in the direction from the master cylinder 10 to the brake cylinder 21 is quickly allowed, and the brake cylinder 21 is quickly supplied in response to the brake operation.
The pressure can be increased, and the brake operation will be performed normally.

The pilot type inflow control valve 92 described above
Is always in the inflow blocking state, but is supposed to be manually switched to the inflow allowing state. Specifically, as shown in FIG. 2, holes 270 and 272 that coaxially penetrate through the plug 215 and the retainer 218 are provided, and as shown in FIG. 3, the operator inserts the rod-shaped member 280 into the holes 270 and 270. Two
Once through 72 to engage the bottom of reservoir piston 210, the force of the operator causes reservoir piston 210 to move from its normal position to its reduced volume position, which causes valve element 224 and plunger 236 to move to their respective valve seats. 22
The inflow permitted state is realized by being separated from 2, 234.

It is necessary to manually switch the pilot type inflow control valve 92 to the inflow permitted state, for example, when bleeding air from the rear wheel brake system. In this brake system, the pump liquid passage 72, the reservoir liquid passage 58, and the auxiliary liquid passage 90 are originally in the normal braking state.
And the reservoir chamber 212 between the suction valve 7 of the pump 76.
7a, the check valve 79, and the pilot type inflow control valve 92 form a closed space. And
Since the opening pressure of the check valve 79 is 1 atm or more, the pressure reducing valve 6
It is difficult to completely bleed the air in the closed space only by making the open state. Therefore, in this brake system, it is necessary to manually switch the pilot type inflow control valve 92 to the inflow permitted state to perform air bleeding.

Air bleeding for the rear wheel brake system is specifically performed as follows. As shown in FIG. 4, the operator first energizes the solenoid of the pressure reducing valve 64 to open the pressure reducing valve 64, and manually sets the pilot type inflow control valve 92 to the inflow allowable state. The operator then uses the master cylinder 10 and the auxiliary liquid passage 90 in the main liquid passage 54.
By applying a negative pressure to the port a provided in the portion between the connection position of the main fluid passage 54 and the port b and the port c provided in the vicinity of each brake cylinder 21 in each branch portion of the main fluid passage 54. At the same time as sucking the brake fluid from the ports a, b and c, the brake fluid is pushed out from the master cylinder 10 into the rear wheel brake system.
As a result, the rear wheel brake system is filled with the brake fluid while expelling the bubbles in the brake fluid.

At this time, the closed space is closed by the pressure reducing valve 64.
From the direction toward the reservoir 70, the direction from the intake valve 77a to the reservoir 70, and the direction from the reservoir 70 to the master cylinder 10 are opened. Therefore, the brake fluid is evacuated to generate a flow of the brake fluid in those directions, and the brake fluid in the originally closed space can flow toward the ports a, b, and c, and the air in the space is closed. It becomes possible to perform the removal completely and easily.

In addition, in addition, the technical concept of manually switching the pilot type inflow control valve to the inflow permitted state and the flow of the brake fluid in the direction from the pressure reducing valve to the reservoir at the set valve opening pressure or more are allowed. In a brake system that simultaneously adopts the check valve and the brake valve that adopts the check valve, the pilot type inflow control valve is manually allowed to flow and the pressure reducing valve is opened to release the brake fluid from a specific port when bleeding air. The technical idea of pulling out and the technical idea of arranging two valve assemblies in series with each other in the pilot type inflow control valve are not essential to be implemented simultaneously with the invention of claim 1,
The invention can be carried out independently from the invention of claim 1, and even if it is carried out alone, the effect peculiar to each technical idea is exhibited.

Although the invention of each claim has been specifically described based on the illustrated embodiments, various modifications and changes can be made based on the knowledge of those skilled in the art without departing from the scope of the claims. It goes without saying that the inventions of the respective claims can be carried out in an improved mode.

[Brief description of drawings]

FIG. 1 is a system diagram showing a brake system that is an embodiment common to the inventions of claims 1 to 4.

2 is an enlarged sectional view showing a reservoir 70 and a pilot type inflow control valve 92 in FIG.

FIG. 3 is a cross-sectional view for explaining how the pilot type inflow control valve 92 in FIG. 2 is manually brought into an inflow permitted state.

FIG. 4 is a system diagram for explaining how air is bleeding in the brake system shown in FIG.

[Explanation of symbols]

 10 master cylinder 21 brake cylinder 54 main liquid passage 56 pressure increasing valve 58 reservoir liquid passage 64 pressure reducing valve 70 reservoir 72 pump liquid passage 76 pump 80 master cylinder cut valve 90 auxiliary liquid passage 92 pilot type inflow control valve 94 relief liquid passage 96 relief valve 98 Orifice 200 Housing 210 Reservoir piston 212 Reservoir chamber 222 Valve seat 232 Valve seat member 234 Valve seat 224, 238 Valve 248 First valve assembly 249 Second valve assembly

Claims (4)

[Claims] 1. A main fluid passage extending from a master cylinder to a brake cylinder of a drive wheel, wherein (a) in a normal braking state, a bidirectional flow of brake fluid between the master cylinder and the brake cylinder is allowed to allow traction. In the controlled state, at least a flow control device that blocks the flow of brake fluid in the direction from the brake cylinder to the master cylinder, and (b) an increase pressure that increases the brake cylinder pressure by supplying the brake fluid in at least the master cylinder to the brake cylinder. The electromagnetic hydraulic pressure control device that switches between the state and the depressurized state in which the brake cylinder is depressurized by discharging the brake fluid in the brake cylinder to the depressurized state, and in the normal braking state, the pressure-increased state is provided in that order. The auxiliary fluid passage extends from the master cylinder, A pump liquid passage extends from a portion between the communication control device and the electromagnetic hydraulic pressure control device, and a reservoir liquid passage extends from the electromagnetic hydraulic pressure control device. The auxiliary liquid passage, the pump liquid passage, and the reservoir liquid passage are all connected to the reservoir. The auxiliary fluid passage is equipped with an inflow control valve that prevents the inflow of brake fluid from the master cylinder to the reservoir in the normal braking state, and an inflow permission state that allows it in the traction control state. , A pump for pumping the brake fluid in the reservoir and supplying it to the main fluid passage is provided, and extends from the discharge port of the pump to reach a portion of the auxiliary fluid passage between the connection position of the main fluid passage and the inflow control valve. The relief liquid passage is provided with a relief valve for preventing the discharge pressure of the pump from exceeding the set relief pressure,
The auxiliary fluid passage is provided with a throttle between the main fluid passage connection position and the relief fluid passage connection position, and is driven when the vehicle is driven by the controller operating the pump to control the electromagnetic fluid pressure control device. A braking system characterized by performing traction control for suppressing idling of wheels. 2. The brake system according to claim 1, wherein the electromagnetic hydraulic pressure control device includes a pressure increasing valve which is a normally open electromagnetic on-off valve provided in the main liquid passage, and a main liquid passage. A pressure reducing valve which is a normally closed electromagnetic on-off valve provided in the reservoir liquid passage extending from a portion between the pressure increasing valve and the brake cylinder, wherein the reservoir substantially includes a reservoir piston in the housing. By being fitted in an airtight and slidable manner, a reservoir chamber for containing a reservoir liquid is formed in the housing,
The reservoir piston is displaced from the normal position to the volume increasing position when the volume of the reservoir chamber is increased from the normal value, and is displaced from the normal position to the volume decreasing position when the volume is decreased from the normal value. A pilot type inflow control valve which is operated by the reservoir piston and is in an inflow blocking state when the reservoir piston is in a normal position and a volume increasing position and is in an inflow allowing state when the reservoir piston is in a volume decreasing position, The flow is manually switched to the inflow permitted state, and the flow of the brake fluid in the direction from the pressure reducing valve to the reservoir is allowed in the reservoir fluid passage at a set valve opening pressure or more, but the flow in the opposite direction is not allowed. Brake system with check valve to prevent. 3. An air bleeding method for a brake system according to claim 2, wherein the solenoid of the pressure reducing valve is excited to open the pressure reducing valve, and the pilot type inflow control valve is manually allowed to inflow. After the state, air is vented by draining brake fluid from at least one port provided in at least one of the main fluid passage, the auxiliary fluid passage, the pump fluid passage, and the reservoir fluid passage. How to pull out. 4. The brake system according to claim 1, wherein the reservoir contains a reservoir fluid in the housing such that a reservoir piston is fitted in the housing in a substantially airtight and slidable manner. The chamber is formed,
The reservoir piston is displaced from the normal position to the volume increasing position when the volume of the reservoir chamber is increased from the normal value, and is displaced from the normal position to the volume decreasing position when the volume is decreased from the normal value. A pilot type inflow control valve, wherein the control valve is actuated by the reservoir piston and is in an inflow blocking state when the reservoir piston is in a normal position and a volume increasing position and is in an inflow allowing state when the reservoir piston is in a volume decreasing position, Two valve assemblies each having a valve seat and a valve seat that cooperate with each other to prevent the flow of brake fluid from the master cylinder into the reservoir are connected in series, and the two valve assemblies in the valve assembly are connected to each other. A switch between an inflow blocking state and an inflow allowing state by being integrally displaced by the valve piston The braking system that is.