JP4190003B2 - Air bleeding method - Google Patents

Description

  The present invention relates to a method for bleeding air in a brake system including an anti-lock brake system using at least hydraulic pressure as a transmission medium.

Brake fluid is injected into the brake system to enable self-running when the assembly of a vehicle equipped with at least a brake system using hydraulic pressure as a transmission medium is completed. When injecting the brake fluid, as shown in FIG. 10, while injecting the brake fluid into the brake fluid reservoir R, the brake pedal P is depressed, and the brake fluid is fed into the piping system T while turning the brake pedal P.
At that time, the breather 30 formed in the wheel cylinder Cw of the brake body B is opened. For example, a transparent resin hose H is attached to the breather 30, and the hose H is mounted on a waste oil can 40 as waste oil treatment means.
The brake fluid filled in the brake system piping T of the vehicle and surplus in the piping system T is repaired from the breather 30 to the waste oil can 40 via the hose H. The brake fluid refurbished from the hose is mixed with air supplemented by the piping system, etc., so the recovered brake fluid is cloudy.
If the brake fluid continues to be fed while the brake pedal P is further applied, the air in the piping system will eventually be mixed with the recovered brake fluid and completely removed from the piping system.

The above air bleeding is a diagram showing a method of air bleeding in a brake system not equipped with an anti-lock brake system.
On the other hand, FIG. 11 is a diagram showing a method of bleeding air in a brake system equipped with an anti-lock brake system. In other words, FIG. 11 shows an anti-lock brake system modulator 100 interposed in the area M of FIG.
When the modulator 100 is delivered to a vehicle production line, the brake fluid flow path in the modulator 100 is filled with approximately brake fluid.
However, the modulator 100 has a so-called “air pocket” in which it is difficult to remove air due to the structure described below. Therefore, according to the conventional method as shown in FIG. Had the problem of not being removed.

FIG. 12 is a simplified diagram showing the internal structure of the modulator 100.
In FIG. 12, the brake pipe on the brake valve side is connected to the brake line L1 on the modulator 100 side. The brake line L is a line for the front wheel cylinder of the vehicle (hereinafter, “for the front wheel cylinder of the vehicle” is simply referred to as “front side”) at the first branch point B1. A line Lf1 having a valve Vf1 and a line Lr1 for a rear wheel cylinder of the vehicle (hereinafter, “for the rear wheel cylinder of the vehicle” is simply referred to as “rear side”) are divided into two.

  In the front line Lf1, a front first branch point Bf1 (upstream side) and a front second branch point Bf2 (downstream side) are formed on the upstream side and the downstream side of the first on-off valve Vf1, respectively. Has been. Further, a bypass line Lfb that bypasses the first on-off valve Vf1 is formed in the front side line Lf1 with a front side first check valve 11f interposed therebetween.

A line Lf2 connected to the front reservoir 12f branches from the front first branch point Bf1.
A damping chamber 13f, a second check valve 14f, and a third check valve 15f are interposed in the line Lf2 in order of flow from the branch point Bf1, and the third check valve 15f, the front reservoir 12f, A front-side third branch point Bf3 is formed in the region between.

The second branch point Bf2 and the third branch point Bf3 communicate with each other through a line Lf3 that includes a front-side second on-off valve Vf2.
A plunger 16 is connected between the second check valve 14f and the third check valve 15f on the front side, and the plunger 16 is configured to be driven by an electric motor 17.

  By the way, the damping chamber 13f has a structure in which air is likely to accumulate, and the accumulated air is difficult to escape (easy to become an “air pocket”). Therefore, the air accumulated in the damping chamber 13f is often delivered to the vehicle production line without being completely removed.

In addition, although the technique regarding an anti-lock brake system is proposed (for example, refer patent document 1), it does not mention the problem regarding the above-mentioned air bleeding.
JP-A-6-156237

  The present invention has been proposed in view of the above-described problems of the prior art. Air that has accumulated in the modulator constituting the anti-block brake system can be easily eliminated without preparing a large-scale device. The purpose is to provide an extraction method.

According to the present invention, there is provided a breather 3 mounted on a brake body B on the side of an automobile C , a breather opening / closing means 4 for opening / closing the breather 3, a breather opening / closing detecting means 5 for detecting opening / closing of the breather 3, and a modulator 1. The modulator 1 bypasses the first on-off valves Vf1 and Vr1 and the first on-off valves Vf1 and Vr1 on the lines Lf1 and Lr1 from the brake line L1 to which the brake pipe on the brake valve side is connected to each wheel cylinder. Bypass lines Lfb, Lrb and first check valves 11f, 11r provided in the bypass lines Lfb, Lrb are provided, and the damping chambers 13f, 13r and the second check valve are connected in series to the branch lines Lf2, Lr2. The valves 14f and 14r, the third check valves 15f and 15r, and the reservoirs 12f and 12r are connected, and the second A plunger 16 driven by an electric motor 17 is connected between the check valves 14f and 14r and the third check valves 15f and 15r, and between the third check valves 15f and 15r and the reservoirs 12f and 12r. And another line Lf3, Lr3 connecting the first on-off valve Vf1, Vr1 to the downstream side of the first on-off valve Vf1, Vr1 is an air vent method for a brake system in which the second on-off valve Vf2, Vr2 is interposed. When the first switch SW1 that closes the first on-off valve Vr1 and opens the rear-side second on-off valve Vr2 is turned on, the front-side first on-off valve Vf1 is closed and the front-side second on-off valve Vf2 is opened. When the second switch SW2 is turned on, the third switch SW3 that rotates the electric motor 17 that drives the plunger 16 and the first, second, and third switches SW1, SW2, and SW3 are controlled. The control unit 8 determines whether or not the vehicle to be bleed is equipped with a modulator when the first, second and third switches SW1, SW2 and SW3 are initially set. It is determined whether or not the breather 3 is open. If the breather 3 is closed, the breather 3 is opened. After the brake fluid is supplied from the reservoir upstream of the brake valve, the breather 3 is opened for a predetermined time. If this is done, the breather 3 is closed, the first switch SW1 is turned on, the first switch SW1 is turned off and the second switch SW2 is turned on after the lapse of a predetermined time, and the second switch SW2 is turned on after the lapse of the predetermined time. The third switch SW3 is turned off and the third switch SW3 is turned on. After a predetermined time has elapsed, the third switch SW3 is turned off.

  According to the present invention having such a configuration, a normal 24V or 12V battery can be used as the power source (2), and the breather opening / closing means (4) with a simple structure and the control means (8) with a simple configuration. It is only necessary to prepare time-eating means (timer 6) and simple one-way switches (SW1, SW2, SW3), and other devices can use existing devices.

  Applicable to any vehicle with or without anti-lock brake system.

  Since the control means (8) is provided with the power supply voltage determination means (82), the power supply (battery) voltage on the vehicle side can correspond to either 24V or 12V.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, with reference to FIG. 1, the structure of the air bleeding apparatus of this embodiment is demonstrated.

The air venting device generally indicated by the symbol A includes an anti-lock brake system modulator (hereinafter, the anti-lock brake system modulator is simply abbreviated as “modulator”) 1 and a brake fluid system for operating a brake system for an automobile C. It is comprised so that air may be removed from (pipe).
The antilock brake system modulator 1 is preferably of a type that does not assume vacuum filling. That is, in the case of a modulator that is not premised on vacuum filling, the seal portions often have a structure that cannot withstand vacuum.

  The air bleeder A has a first switch SW 1, a second switch SW 2, a third switch SW 3, which is an operation switching means for bringing the modulator 1 into an operating state, and 24 V that is an operating source of the modulator 1. (Bolt) or 12V (volt) power supply 2 (divided into 24V specification and 12V specification depending on the country of use), breather 3 installed in the brake body B on the side of the car C, and the breather Breather opening / closing means 4 for opening and closing 3, breather opening / closing detection means 5 attached to the breather 3 for detecting opening / closing of the breather 3, a timer 6 for measuring an elapsed time from a certain starting point of control, and a control as control means The unit 8 is constituted.

  The control unit 8 includes a breather open / close determining means 81 for determining whether the breather 3 is opened / closed based on a signal from the breather open / close detector 5, and a power supply voltage connected to the power supply 2 side to determine whether the power supply voltage is 24V or 12V. A determination means 82; an ABS presence / absence determination means 83 for determining whether the vehicle to be evacuated has an ABS (anti-lock brake system); and the first switch SW1 and the second switch based on the determination result. The control signal transmitting means 84 is configured to transmit a control signal to the switch SW2 and the third switch SW3.

  As shown in FIG. 2, the modulator 1 has a brake pipe (not shown) on the vehicle side connected to a brake line L1 on the modulator 1 side described in detail below. The brake line L is a line for the front wheel cylinder of the vehicle (hereinafter, “for the front wheel cylinder of the vehicle” is simply referred to as “front side”) at the first branch point B1. A line Lf1 with a valve Vf1 and a line for a rear wheel cylinder of the vehicle (hereinafter, “for the rear wheel cylinder of the vehicle” is simply referred to as “rear side”), and a rear side first on-off valve Vr1 The line is divided into two with the line Lr1 interposed.

  In the front line Lf1, a front first branch point Bf1 (upstream side) and a front second branch point Bf2 (downstream side) are formed on the upstream side and the downstream side of the first on-off valve Vf1, respectively. Has been. Further, a bypass line Lfb that bypasses the first on-off valve Vf1 is formed in the front side line Lf1 with a front side first check valve 11f interposed therebetween.

A line Lf2 connected to the front reservoir 12f branches from the front first branch point Bf1.
A damping chamber 13f, a second check valve 14f, and a third check valve 15f are interposed in the line Lf2 in order of flow from the branch point Bf1, and the third check valve 15f, the front reservoir 12f, A front-side third branch point Bf3 is formed in the region between.
The second branch point Bf2 and the third branch point Bf3 communicate with each other through a line Lf3 that includes a front-side second on-off valve Vf2.

  On the other hand, the rear side line Lr1 has a rear first branch point Br1 (upstream side) and a rear second branch point Br2 (downstream side) upstream and downstream of the first on-off valve Vr1. Each is formed. Further, a bypass line Lrb is formed in the rear side line Lr1 so as to bypass the first on-off valve Vr1 with a rear side first check valve 11r interposed therebetween.

A line Lr2 connected to the rear reservoir 12r is branched from the rear first branch point Br1.
A damping chamber 13r, a second check valve 14r, and a third check valve 15r are interposed in the line Lr2 in order of flow from the branch point Br1, and the third check valve 15r, the rear reservoir 12r, A rear-side third branch point Br3 is formed in the region between.
The second branch point Br2 and the third branch point Br3 communicate with each other through a line Lr3 that includes a rear-side second on-off valve Vr2.

  Between the front side second check valve 14f and the third check valve 15f and between the rear side third check valve 14r and the third check valve 15r are bidirectional. Plungers (which can press only one of the lines, but can be pressed simultaneously in both directions) 16 are connected together, and the bidirectional plunger 16 is driven by an electric motor 17.

  Note that FIG. 2 shows a case where normal braking is performed without operating the ABS, but in the drawing, for ease of understanding, for example, a component (open / close valve) on one side of the left and right brakes is installed. I have omitted it.

FIG. 3 shows, as a comparison, a certain moment when the ABS is operated, that is, the first and second on-off valves Vf1 and Vf2 on the front side and the first and second on-off valves Vr1 and Vr2 on the rear side. It is a state figure at the time of energizing all.
The normal lines Lf1 (front side) and Lr1 (rear side) are shut off, and instead the lines Lf3 and Lr3 communicate with each other. At this moment, a large pressure is applied in the region from the brake pipe after the modulator 1 to the damping chambers 13f and 13r. Waves may occur. In such a case, the damping chambers 13f and 13r are equipped so that the brake wave and other equipment communicating with the pipe are not destroyed by the pressure wave.

FIG. 4 is a diagram showing an electric circuit of the air bleeding device A.
The modulator 1 is connected to the power source 2 by a wire W via connectors 91 and 92 and a flat terminal 93.
The a terminal of the connector 91 is a power supply terminal to each on-off valve (Vf1, Vf2, Vr1, Vr2; see FIG. 2), the b terminal is a power supply terminal to the motor 17, and the c terminal of the connector 92 is an on-off valve Vr2. The ground terminal, d terminal is a ground terminal of an on-off valve (not shown), e terminal is a ground terminal of the on-off valve of the on-off valve Vf2, and f terminal is a ground terminal of the on-off valve (not shown). The flat terminal 93 is a terminal for grounding the motor 17.

  The switch SW1 is interposed in a region between the power source 2 and the d (and c) terminal, the switch SW2 is interposed in a region between the power source 2 and the e (and f) terminal, and the switch SW3 is A region between the terminals 93 is interposed.

  The control unit 8 is connected to the power source 2 through the signal line S1, and can determine whether the currently connected power source is 24V or 12V and switch the connection from 24V to 12V or vice versa. Further, the control unit 8 is connected to the switch group SW (each of the switches SW1, SW2, and SW3) via the signal line S2, and controls the operation of the switches SW1, SW2, and SW3.

  FIG. 5 is a control characteristic diagram individually showing the control timing of the switches SW1 to SW3 and the time length of the switch ON. Each horizontal axis represents elapsed time, and the vertical axis represents, for example, a current value.

According to FIG. 5, the switch SW1 is connected (ON) and connected for a first predetermined time t1 (for example, 1 second).
When the switch SW1 is connected, as shown in FIG. 6, the first normally open first open / close valve Vr1 on the rear side and the second normally closed second open / close valve on the rear side are energized. Then, the first on-off valve Vr1 is closed and the second on-off valve Vr2 is opened.
At this time, the front-side normally open first on-off valve Vf1 and the front-side normally closed second on-off valve Vf2 are not energized, the on-off valve Vf1 remains open, and the on-off valve Vf2 is closed. It is in a state as it is.

  That is, although the front side circuit Lf1 is open, the rear side circuit Lr1 is blocked by the first switching valve Vr1, and the second on-off valve Vr2 side is opened. The brake fluid compressed in the cylinder-side line passes through the line Lr3 (open / close valve Vr2) and the bubbles (air) staying in the damping chamber 13r with the pressing force of the reservoir 12r applied thereto. It is discharged out of the damping chamber 13r. The bubbles discharged out of the damping chamber 13r move to the side of the line Lr1 where air is easily removed (in FIG. 6, the flow of the brake fluid is indicated by an arrow).

In FIG. 5 again, after the first predetermined time t1 has elapsed, the switch SW2 is connected (ON) simultaneously with turning off the switch SW1 (OFF) and connected for the first predetermined time t1 (for example, 1 second). Then, as shown in FIG. 7, the first on-off valve Vf1 is closed and the second on-off valve Vf2 is opened.
At this time, the first normally open first on-off valve Vr1 and the second normally closed second on-off valve Vr2 are not energized, the on-off valve Vr1 remains open, and the on-off valve Vr2 is closed. It is in a state as it is.

  That is, although the rear side circuit Lr1 is open, the front side circuit Lf1 is blocked by the first switching valve Vf1, and the second on-off valve Vf2 side is opened. The brake fluid compressed in the cylinder-side line passes through the line Lf3 (open / close valve Vr2) to remove bubbles (air) remaining in the damping chamber 13f with the pressing force of the reservoir 12f applied. It is discharged out of the damping chamber 13f. The bubbles discharged to the outside of the damping chamber 13f move to the line Lf1 side where air is easily removed (in FIG. 7, the flow of the brake fluid is indicated by an arrow).

  After the elapse of the first predetermined time t1, the switch SW3 is connected simultaneously with turning off the switch SW2, and connected for the second predetermined time (for example, 2 seconds). Then, as shown in FIG. 8, the first on-off valve Vf1 is opened and the second on-off valve Vf2 is closed. The electric motor 17 is rotated by the connection of the switch SW3, and the bidirectional plunger 16 is driven by the rotational force for a third predetermined time (2 seconds).

That is, the plunger 16 is driven by the rotation of the electric motor 17, the brake fluid in the region below the plunger 16 in FIG. 8 of the lines Lf2 and Lr2 is sucked, and the brake fluid in the region above the plunger 16 in the same line. Is pressed.
As a result, bubbles remaining in the brake fluid in the region above the plunger 16 on the same line are completely discharged from the lines Lf2 and Lr2. In addition, the bubbles moved to the line Lf1 and the line Lr1 are further sent out to the front and rear wheel cylinders.

  As described above, if the process shown in FIGS. 6 to 8 is one cycle, the bubbles in the brake pipe are completely discharged out of the brake pipe by repeating the cycle a predetermined number of times.

  Next, with reference to FIG. 9, the air bleeding method (air bleeding control method) in the present embodiment will be described.

  First, the switches SW1 to SW3 are initially set (all OFF) (step S1), and the control unit 8 determines whether or not the vehicle to be vented is equipped with an ABS (step S2). If there is an ABS (YES in step S2), the process proceeds to the next step S3. If there is no ABS (NO in step S2), the control is terminated.

  In step S3, it is determined whether the vehicle is 24V specification or 12V specification. If it is 24V specification, it is set to 24V power supply in step S4, and if it is 12V specification, it is set to 12V power supply in step S5.

  In the next step S6, the control unit 8 determines whether or not the breather (reference numeral 3 in FIG. 1) of the brake body of the vehicle is open. If not (NO in step S6), the breather 3 is determined in step S7. If the breather 3 is open (YES in step S6), brake fluid is introduced from the reservoir upstream of the brake valve into the brake system in step S8 (see FIG. 11).

In the next step S9, the control unit 8 keeps monitoring until a predetermined time, for example, 1 second elapses with the breather 3 opened (loop in step S9).
Here, the predetermined time is determined in advance for how many minutes, for example, each vehicle has passed before the brake fluid reaches the brake system, and the required time is set to the predetermined time.

  After a predetermined time has elapsed, the breather 3 is closed (step S10), and the switch SW1 is connected (step S11). In step S12, the control unit 8 checks whether or not a first set time (first predetermined time) t1 (for example, 1 second) has elapsed while the switch SW1 is ON (loop in step S12). If 1 second has elapsed (YES in step S12), the process proceeds to step S13. In step S13, the switch SW1 is turned off and the switch SW2 is turned on at the same time.

When the switch SW1 is connected, as shown in FIG. 6, the first normally open first open / close valve Vr1 on the rear side and the second normally closed second open / close valve on the rear side are energized. Then, the first on-off valve Vr1 is closed and the second on-off valve Vr2 is opened.
At this time, the front-side normally open first on-off valve Vf1 and the front-side normally closed second on-off valve Vf2 are not energized, the on-off valve Vf1 remains open, and the on-off valve Vf2 is closed. It is in a state as it is.

  That is, although the front side circuit Lf1 is open, the rear side circuit Lr1 is blocked by the first switching valve Vr1, and the second on-off valve Vr2 side is opened. The brake fluid compressed in the cylinder side line passes through the line Lr3 (open / close valve Vr2), and the bubbles (air) retained in the damping chamber 13r in a state where the concave pressure of the reservoir 12r is also applied. It is discharged out of the damping chamber 13r. The bubbles discharged out of the damping chamber 13r move to the line Lr1 side where air can be easily released.

In the next step S14, the control unit 8 checks whether the same first set time (first predetermined time) t1, for example, 1 second has elapsed with the switch SW1 being OFF and the switch SW2 being ON. If one second has elapsed (YES in step S14), the process proceeds to step S15.
Since SW1 is OFF and SW2 is ON, as shown in FIG. 7, the first on-off valve Vf1 on the front side is closed and the second on-off valve Vf2 is opened.
At this time, the first normally open first on-off valve Vr1 and the second normally closed second on-off valve Vr2 are not energized, the on-off valve Vr1 remains open, and the on-off valve Vr2 is closed. It is in a state as it is.

  That is, although the rear side circuit Lr1 is open, the front side circuit Lf1 is blocked by the first switching valve Vf1, and the second on-off valve Vf2 side is opened. The brake fluid compressed in the cylinder-side line passes through the line Lf3 (open / close valve Vr2) to remove bubbles (air) remaining in the damping chamber 13f with the concave pressure of the reservoir 12f applied. It is discharged out of the damping chamber 13f. The bubbles discharged out of the damping chamber 13f move to the line Lf1 side where air can be easily released.

In step S15, after the first predetermined time t1 (1 second) has elapsed, the switch SW2 is turned on simultaneously with the switch SW3 being connected, and the second predetermined time t3 (for example, 2 seconds) is connected.
Then, as shown in FIG. 8, the first on-off valve Vf1 is opened and the second on-off valve Vf2 is closed. The electric motor 17 is rotated by the connection of the switch SW3, and the bidirectional plunger 18 is driven only for the third predetermined time by the rotational force.

That is, the plunger 16 is driven by the rotation of the electric motor 17, the brake stations in the area below the plunger in the illustration of the lines Lf2 and Lr2 are sucked, and the brake fluid in the area above the plunger 16 in the same line is pressed. Is done.
As a result, bubbles remaining in the brake fluid in the region above the plunger 16 in the same line are completely discharged from the moving line. In addition, the bubbles moved to the line Lf1 and the line Lr1 are further sent out to the front and rear wheel cylinders.

  In step S16, the control unit 8 checks whether a predetermined time t2 (for example, 2 seconds) has elapsed with the switch SW3 being ON. If the predetermined 2 seconds have elapsed (YES in step S16), the process proceeds to step S17, the switch SW3 is turned off, and the process proceeds to step S18.

In step S18, it is determined whether to repeat step S11 and subsequent steps. When determining whether to repeat step S11 or more, the steps from step S11 to step S17 are defined as one cycle by the same vehicle and vehicles similar to the vehicle, and how many cycles the vehicle performs the cycle. It is preferable to calculate in advance.

If step S11 and subsequent steps are repeated (YES in step S18), the process returns to step S11, and step S11 and subsequent steps are repeated again.
On the other hand, if air bleeding is completely completed and there is no need to repeat (NO in step S18), the breather 3 is closed (step S19), and the control is terminated.

    According to the air venting apparatus and the air venting method as described above, a normal 24V or 12V battery can be used as the power source 2, and the breather opening / closing means 4 having a simple structure and the control unit 8 having a simple structure can be used. A timer 6 and simple one-way switches (SW1, SW2, SW3) may be prepared, and existing devices can be used as other devices.

  Since the control unit 8 can automatically determine the presence / absence of ABS by the ABS presence / absence determination means 83, the control unit 8 can be applied to a vehicle of any specification regardless of the presence / absence of an antilock brake system.

  By providing the power supply voltage determination means 82, the power supply (battery) voltage on the vehicle side can correspond to both 24V and 12V.

The illustrated embodiment is merely an example, and is not intended to limit the technical scope of the present invention.
For example, the breather opening / closing means 4 and the breather opening / closing detection means 5 may be omitted, and both the opening and closing of the breather 3 and the detection of whether or not the breather is open may be manual.

The block diagram which shows the whole structure of embodiment of this invention. The block diagram which abbreviate | omitted and showed the internal structure of the anti-skid brake system modulator in 1st Embodiment of this invention, and the figure which showed the normal brake state (state where an anti-skid brake system does not operate | move). The figure which showed the state when an anti-skid brake system act | operates with the block diagram which abbreviate | omitted and showed the internal structure of the anti-skid brake system modulator in 1st Embodiment of this invention. The electric circuit diagram in the embodiment of the present invention. The control characteristic figure of the switch action used for control in the embodiment of the present invention. The figure which showed the state when switch SW1 was turned on by the block diagram which abbreviate | omitted and showed the internal structure of the anti-skid brake system modulator in embodiment of this invention. The figure which showed the state when switch SW2 was turned on by the block diagram which abbreviate | omitted and showed the internal structure of the anti-skid brake system modulator in embodiment of this invention. The figure which showed the state at the time of turning on switch SW3 with the block diagram which abbreviate | omitted and showed the internal structure of the anti-skid brake system modulator in embodiment of this invention. The flowchart which showed the procedure of the air bleeding method in embodiment of this invention. Explanatory drawing which showed the air bleeding method of the vehicle which is not equipped with the anti skid brake system in a prior art. Explanatory drawing which showed the air bleeding method of the vehicle equipped with the anti skid brake system in the prior art. An explanatory view showing a mechanism in which air accumulates at a specific location in the anti-skid brake system modulator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Anti-lock brake system modulator / modulator 2 ... Power supply 3 ... Breather 4 ... Breather opening / closing switching means 5 ... Breather opening / closing detection means 6 ... Timing means / timer 8 ... Control Unit 12f: Front side reservoir 13f ... Front side damping chamber 14f ... Front side second check valve 16 ... Plunger 17 ... Electric motor 81 ... Breather opening / closing judgment means 82 ..Power supply voltage judgment means

Claims (1)

Breather (3) mounted on the brake body (B) on the automobile (C) side, breather opening / closing means (4) for opening / closing the breather (3), and breather opening / closing detection means (5) for detecting opening / closing of the breather (3) ) And a modulator (1). The modulator (1) has a first opening and closing on the lines (Lf1, Lr1) from the brake line (L1) connected to the brake piping on the brake valve side to each wheel cylinder. Bypass lines (Lfb, Lrb) bypassing the valves (Vf1, Vr1) and the first on-off valves (Vf1, Vr1) and first check valves (11f, 11r) provided in the bypass lines (Lfb, Lrb) ) And a branch line (Lf2, Lr2) in series with a damping chamber (13f, 13r), a second check valve (14f, 14r), and a third check valve (15f, 15r) A reservoir (12f, 12r) is connected, and a plunger (17) driven by an electric motor (17) is provided between the second check valve (14f, 14r) and the third check valve (15f, 15r). 16) is connected and another line (Lf3) connecting the third check valve (15f, 15r) and the reservoir (12f, 12r) and the downstream side of the first on-off valve (Vf1, Vr1). , Lr3) is a brake system air venting method in which the second on-off valves (Vf2, Vr2) are interposed. When turned on, the rear-side first on-off valve (Vr1) is closed and the rear-side second on-off valve is opened. When the first switch (SW1) for opening the valve (Vr2) is turned on, the first switch (SW2) for opening the front-side second on-off valve (Vf2) is closed by closing the first on-off valve (Vf1) on the front side When turned on, the power to drive the plunger (16) A third switch (SW3) for rotating the motor (17) and a control unit (8) for controlling the first, second and third switches (SW1, SW2, SW3). 8) If the first, second and third switches (SW1, SW2, SW3) are initially set, it is determined whether or not the vehicle to be vented is equipped with a modulator. If the modulator is equipped, the breather (3) is opened. If the breather (3) is closed, the breather (3) is opened. After the brake fluid is introduced from the reservoir upstream of the brake valve, the breather (3) is opened for a predetermined time. If this happens, the breather (3) is closed and the first switch (SW1) is turned on. After a predetermined time has elapsed, the first switch (SW1) is turned off and the second switch (SW2) is turned on. The air release of the brake system is characterized in that the second switch (SW2) is turned off and the third switch (SW3) is turned on after the lapse of a predetermined time, and the third switch (SW3) is turned off after the lapse of the predetermined time. Method.

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