Hydraulic braking device

Provided is a hydraulic braking device wherein the heat of a driving coil can be absorbed by a base body, and the heat radiation performance is excellent. The hydraulic braking device having a base body that includes therein a fluid passage for brake fluid, includes: a solenoid valve disposed on one surface of the base body; and a driving coil attached around an axis of the solenoid valve, wherein the one surface of the base body is provided with a wall surface facing an outer circumferential surface of the driving coil. A lower surface of the driving coil is in contact with the one surface of the base body, and a clearance is formed between the outer circumferential surface of the driving coil and the wall surface.

TECHNICAL FIELD

The present invention relates to a hydraulic braking device including a base body that houses fluid passages of brake fluid.

BACKGROUND ART

Conventionally, as this kind of hydraulic braking device, known is a vehicle hydraulic braking device that controls hydraulic brake pressures applied to the wheel brakes of a vehicle (automobile) (for example, see Patent Literature 1).

This vehicle hydraulic braking device includes therein a base body provided with a master cylinder and fluid passages, wherein solenoid valves for opening and closing passages, a pressure sensor for detecting a hydraulic brake pressure, and other components are attached to the base body. The solenoid valves are driven by coils provided in a housing attached to the base body.

RELATED ART DOCUMENT

Patent Literature

Patent Literature 1: JP 2007-99058 A

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

When a current is applied to a driving coil for driving a solenoid valve, heat is generated by the electric resistance, and the temperature of the driving coil thus rises. If the temperature of a driving coil rises in such a manner, the temperature in a housing also rises, and there is a demand for inhibiting this situation.

The present invention has been developed in view of the above situation, and an object of the present invention is to provide a hydraulic braking device that is capable of absorbing the heat of a driving coil into a base body and is excellent in heat radiation performance.

Means for Solving the Problem

According to the present invention developed to solve such a problem, provided is a hydraulic braking device having a base body that includes therein a fluid passage for brake fluid, the hydraulic braking device including: a solenoid valve disposed on one surface of the base body; and a driving coil attached around an axis of the solenoid valve, wherein the one surface of the base body is provided with a wall surface facing an outer circumferential surface of the driving coil.

According to the hydraulic braking device of the present invention, it is possible to transfer the heat of the driving coil, whose temperature has risen to a high temperature, to the base body through the wall surface facing the outer circumferential surface. Thus, the heat of the driving coil can be absorbed by the base body, and can be radiated through the base body.

Further, according to the present invention, a lower surface of the driving coil is in contact with the one surface of the base body.

According to the hydraulic braking device of the present invention, the heat of the driving coil, whose temperature has risen to a high temperature, can be directly transferred to the base body through the lower surface of the driving coil. Thus, the heat of the driving coil can be further absorbed by the base body, and can be effectively radiated through the base body.

Still further, according to the present invention, the hydraulic braking device includes a housing for housing the driving coil, wherein an urging means for urging the driving coil toward the one surface of the base body is provided between the housing and the driving coil.

According to the hydraulic braking device of the present invention, the lower surface of the driving coil is ensured to contact with the base body by the urging means, and the heat is ensured to be transferred to the base body through the lower surface of the driving coil. Thus, heat can be effectively radiated through the base body.

Yet further, according to the present invention, a clearance is formed between the outer circumferential surface of the driving coil and the wall surface.

According to the hydraulic braking device of the present invention, even when a little deviation of the attaching position of the driving coil housed in the housing exists, it can be appropriately absorbed by clearance, and excellent assembility can be achieved.

Still further, according to the present invention, a recessed portion is provided on the one surface of the base body, the recessed portion being arranged around an attaching hole to which the solenoid valve is attached, and a circumferential wall forming the recessed portion forms the wall surface, the circumferential wall facing the outer circumferential surface of the driving coil.

According to the hydraulic braking device of the present invention, the wall surface facing the outer circumferential surface of the driving coil can be easily provided by forming a recessed portion, and the productivity is thereby excellent.

SUMMARY OF THE INVENTION

According to the present invention, a hydraulic braking device can be obtained wherein the heat of a driving coil can be absorbed by a base body, and the heat radiation performance is excellent.

EMBODIMENT FOR CARRYING OUT THE INVENTION

A vehicle braking system A provided with a master cylinder device A1(hydraulic braking device) shown inFIG. 1includes both a by-wire braking system that operates at a start of a power device (an engine, a motor, or the like) and a hydraulic braking system that operates in an emergency, at a time when the power device stops, or at other time. The vehicle braking system A includes a motor cylinder device A2that generates a hydraulic brake pressure using an electric motor (not shown) and a vehicle stability assist device A3(hereinafter, referred to as ‘a hydraulic control device A3’) for assisting the stability of vehicle behavior. The master cylinder device A1generates a hydraulic brake pressure by brake pedal effort on a brake pedal (brake operator) P. The master cylinder device A1, the motor cylinder device A2, and the hydraulic control device A3are structured as different units and communicate with each other through external pipes.

The vehicle braking system A can be mounted on a vehicle only with an engine (internal combustion engine) as a power device, and also on a hybrid vehicle also using a motor, an electric vehicle only with a motor as a power device, a fuel cell electric vehicle, or the like.

The master cylinder device A1includes a tandem master cylinder1, a stroke simulator2, a reservoir3, normally-open shutoff valves (solenoid valves)4,5, normally-closed shutoff valve (solenoid valve)6, pressure sensors7,8, main hydraulic passages (fluid passages)9a,9b, communicating hydraulic passages (fluid passages)9c,9d, and a branch hydraulic passage9e.

The master cylinder1converts a brake pedal effort on the brake pedal P into a hydraulic brake pressure, and includes a first piston1adisposed on the bottom wall side of a first cylinder hole11a, a second piston1bconnected to a push rod R, a first return spring1cdisposed between the first piston1aand the bottom wall of the first cylinder hole11a, and a second return spring1ddisposed between the pistons1a,1b. The second piston1bis connected to the brake pedal P through the push rod R. The first pistons1a,1bslide, receiving the pedal effort on the brake pedal P, and apply pressure to the brake fluid in pressure chambers1e,1f. The pressure chambers1e,1fcommunicate with the main hydraulic passages9a,9b. The brake pressures of the pressure chambers1e,1fare the same.

The stroke simulator2generates a pseudo operational reaction force, and includes a piston2asliding in the second cylinder hole11b, and larger and smaller return springs2b,2curging the piston2a. The stroke simulator2communicates with the pressure chamber1ethrough the main hydraulic passage9aand the branch hydraulic passage9eto operate by a hydraulic brake pressure generated by the pressure chamber1e.

The reservoir3is a container for reserving brake fluid and includes oil supply ports3a,3bconnected to the master cylinder1, and a pipe connecting port3cto which a hose extending from a main reservoir (not shown) is connected.

The normally-open shutoff valves4,5open and close the main hydraulic passages9a,9b, and both are solenoid valves of a normal-open type. The normally-open shutoff valve4opens and closes the main hydraulic passage9ain the section from the intersection between the main hydraulic passage9aand the branch hydraulic passage9eto the intersection between the main hydraulic passage9aand the communicating hydraulic passage9c. The normally-open shutoff valve5opens and closes the main hydraulic passage9bon the upstream side of the intersection between the main hydraulic passage9band the communicating hydraulic passage9d.

The normally-closed shutoff valve6opens and closes the branch hydraulic passage9eand is a solenoid valve of a normal closed type.

As shown inFIG. 3, the normally-open shutoff valve4is configured by a solenoid valve4aand a coil26(driving coil) for driving the solenoid valve4a, and the normally-open shutoff valve5is configured by a solenoid valve5aand a coil26for driving the solenoid valve5a. The normally-closed shutoff valve6is configured by a solenoid valve6aand a coil26. In the present embodiment, coils26common to the respective valves are used.

The coils26are substantially in a cylindrical shape, and as shown inFIG. 9, have center holes260into which the solenoid valves4a,5a, and6a(only solenoid valves4aand5ashown) are inserted. The each coil26includes a bobbin261of a resin around which a coil M is wound, and a yoke262surrounding the bobbin261and forming a magnetic path.

The bobbin261includes a terminal holding portion263and a positioning protrusion264. The terminal holding portion263is provided with a connecting terminal26a. The positioning protrusion264protrudes from the bottom portion of the bobbin261toward the side (the base body10side) opposite to a housing20. The yoke262is provided with a cylindrical engaging portion266with which the positioning protrusion264engages. The lower end portion of the yoke262is provided with a skirt portion268along the solenoid valve4a,5a, or6a(only solenoid valves4aand5ashown).

The pressure sensors7,8detect the magnitudes of hydraulic brake pressure, and are as shown inFIG. 1attached to sensor openings44,45(seeFIG. 6) communicating with the main hydraulic passages9a,9b. The pressure sensor7is disposed on the downstream side of the normally-open shutoff valve4, and detects a hydraulic brake pressure generated by the motor cylinder device A2when the normally-open shutoff valve4is closed (i.e. in a state that the main hydraulic passage9ais shut off). The pressure sensor8is disposed on the upstream side of the normally-open shutoff valve5, and detects a hydraulic brake pressure generated by the master cylinder1when the normally-open shutoff valve5is closed (i.e. in a state that the main hydraulic passage9bis shut off). Information obtained by the pressure sensors7,8is output to an electric control unit (ECU) not shown.

The pressure sensors7,8are provided with terminals7a,8aas shown inFIG. 3.

As shown inFIG. 1, the main hydraulic passages9a,9bare hydraulic pressure passages originating at the master cylinder1. Output ports15a,15b, which are the end points of the main hydraulic passages9a,9bare connected with pipe members Ha, Hb reaching the hydraulic control device A3.

The communicating hydraulic passages9c,9dare hydraulic pressure passages extending from input ports15c,15dto the main hydraulic passages9a,9b. The input ports15c,15dare connected with pipe members Hc, Hd extending to the motor cylinder device A2. That is, a hydraulic brake pressure generated by the motor cylinder device A2is output to the hydraulic control device A3through the master cylinder device A1.

The branch hydraulic passage9ebranches from the main hydraulic passage9aand extends to the stroke simulator2.

The master cylinder device A1communicates with the hydraulic control device A3through the pipe members Ha, Hb. When the normally-open shutoff valves4,5are in an open state, a hydraulic brake pressure generated by the master cylinder1is input to the hydraulic control device A3through the main hydraulic passages9a,9band the pipe members Ha, Hb.

Though not shown, the motor cylinder device A2is provided with a slave piston sliding in a slave cylinder, an actuator mechanism having an electric motor and a driving force transmitting section, and a reservoir for reserving brake fluid in the slave cylinder.

The electric motor operates, based on a signal from an electric control unit not shown. The driving force transmitting section converts the rotation power of the electric motor to forward and backward motion and transmits the motion to the slave piston. The slave piston slides in the slave cylinder by the driving force of the electric motor, and applies pressure to the brake fluid in the slave cylinder.

A hydraulic brake pressure generated by the motor cylinder device A2is, as described above, input to the master cylinder device A1through the pipe members Hc, Hd, and input to the hydraulic control device A3through the communicating hydraulic passages9c,9dand the pipe members Ha, Hb. A hose extending from a main reservoir (not shown) is connected to the reservoir.

The hydraulic control device A3is configured such as to be able to execute antilock brake control (ABS control) for reducing slippage of wheels, skid control and traction control for stabilizing the behavior of the vehicle, and the like, and is connected to wheel cylinders W, W,

through pipe members. Incidentally, though not shown, the hydraulic control device A3includes a hydraulic pressure unit provided with solenoid valves, a pump, etc., a motor for driving the pump, an electronic control unit for controlling the solenoid valves, the motor, etc., and the like.

The operation of the vehicle braking system A will be briefly described below.

In a normal state in which the vehicle braking system A normally functions, the normally-open shutoff valves4,5are in a valve closed state, and the normally-closed shutoff valve6is in a valve open state. In this state, when the brake pedal P is operated, a hydraulic brake pressure generated by the master cylinder1is not transmitted to the wheel cylinders W but is transmitted to the stroke simulator2so that the piston2ais displaced, the stroke of the brake pedal P is thereby permitted, and a pseudo operational reaction force is applied to the brake pedal P.

Further, when a brake pedal effort on the brake pedal P is detected by a stroke sensor, not shown, or the like, the electric motor of the motor cylinder device A2is driven so that the slave piston is displaced and a pressure is thereby applied to the brake fluid in the cylinder.

The electronic control unit, not shown, compares the hydraulic brake pressure (hydraulic brake pressure detected by the pressure sensor7) output from the motor cylinder device A2and the hydraulic brake pressure (the hydraulic brake pressure detected by the pressure sensor8) output from the master cylinder1, and controls the number of revolutions of the electric motor and the like, based on a result of the comparison.

The hydraulic brake pressure generated by the motor cylinder device A2is transmitted through the hydraulic control device A3to the wheel cylinders W, W, and the respective wheel cylinders W operate, thereby applying a braking force to the respective wheels.

Incidentally, in a state that the motor cylinder device A2does not operate (for example, in a case of unavailability of electric power, emergency, or the like), both the normally-open shutoff valves4and5become into a valve open state and the normally-closed shutoff valve6becomes into a valve closed state, and accordingly, a hydraulic brake pressure generated by the master cylinder1is transmitted to the wheel cylinders W, W.

A concrete structure of the master cylinder device A1will be described below.

The master cylinder device A1in the present embodiment is structured by attaching the above-described various components to the inside or outside of the base body10inFIGS. 2A and 2B, and covering by the housing20electric components (the normally-open shutoff valves4,5, the normally-closed shutoff valve6, and the pressure sensors7,8(seeFIG. 1)), which are electrically operated. Incidentally, mechanical components and the like may be housed in the housing20.

The base body10is a cast product of an aluminum alloy, and is provided with a cylinder section11(seeFIG. 2B, the same hereinafter), a vehicle body fixing section12, a reservoir fitting section13(seeFIG. 2B, the same hereinafter), a housing fitting section14, and a pipe connecting section15. Further, holes to be the main hydraulic passages9a.9band the branch hydraulic passage9e, and the like are formed inside the base body10. The hydraulic passaged (fluid passages) will be described later in detail.

The cylinder section11is provided with the first cylinder hole11afor the master cylinder and the second cylinder hole11bfor the stroke simulator (both shown by dashed lines inFIG. 2B). The cylinder holes11a,11bare both in a bottomed cylindrical shape, open at the vehicle body fixing section12, and extending toward the pipe connecting section15. In the first cylinder hole11a, inserted are the components (the first piston1a, the second piston1b, the first return spring1c, and the second return spring1d) constructing the master cylinder1(seeFIG. 1), and in the second cylinder hole11b, inserted are the components (the piston2a, and the return springs2b,2c) constructing the stroke simulator2.

The vehicle body fixing section12is fixed to a fixing part on the vehicle side, such as a toe board, not shown. The vehicle body fixing section12is formed in a flange shape at the posterior face portion of the base body10. The marginal portion (the portion expanding from the cylinder section11) of the vehicle body fixing section12is provided with a bolt insertion hole12a(seeFIG. 3). A fixing bolt12b(seeFIG. 2A) is fixed to the bolt insertion hole12a.

As shown inFIG. 2BandFIG. 5A, the reservoir fitting section13is a part serving as the fitting seat of the reservoir3. The reservoir fitting section13is formed in two pieces (only one piece is shown inFIG. 2B) at the upper face portion of the base body10. The reservoir fitting section13is provided with a reservoir union port. Incidentally, the reservoir3is fixed to the base body10through a connecting portion13a(seeFIG. 5A) protruding on the upper face of the base body10.

The reservoir union port is in a cylindrical shape and communicates with the first cylinder hole11athrough a hole extending from the bottom surface thereof toward the first cylinder hole11a. The reservoir union port is connected with a fluid supply port, not shown, protruding from the lower portion of the reservoir3. The main body of the container of the reservoir3is mounted on the upper end of the reservoir union port.

The pipe connecting section15is a part serving as a pipe fitting seat, and as shown inFIG. 2A, formed at the anterior face portion of the base body10. As shown inFIG. 2B, the pipe connecting section15is provided with the two output ports15a,15b, and the two input ports15c,15d. The pipe members Ha, Hb (seeFIG. 1) reaching the hydraulic control device A3are connected to the output ports15a,15b, and the pipe members Hc, Hd (seeFIG. 1) reaching the motor cylinder device A2are connected to the input ports15c,15d.

The housing fitting section14is a part serving as a fitting seat of the housing20, and as shown inFIG. 3, in a flange shape. The housing fitting section14has an attaching surface14a(a surface substantially perpendicular to the axial line (the central axis O of the master cylinder1) of the base body10) to which the housing20is attached.

As shown inFIG. 4A, the attaching surface14ais a flat surface formed substantially in a rectangular shape in a side view (seeFIGS. 5A and 5B), wherein the four corner edge portions thereof are provided with four fitting hole portions16for fitting the housing20.

Further, the attaching surface14ais provided with three valve attaching holes141,142,143, two sensor attaching holes145,146, two fluid passage holes (horizontal holes)147,148, and three rotation preventing recessed portions151,152,153.

The normally-open shutoff valve4for the master cylinder1is attached to the first valve attaching hole141, and the second normally-open shutoff valve5for the master cylinder1is attached to the second valve attaching hole142. Further, the normally-closed shutoff valve6for the stroke simulator2is attached to the third valve attaching hole143.

Recessed portions30,30in a counterbore shape recessed from the attaching surface14atoward the inner portion side of the base body10are provided around the valve attaching holes141,143out of the three valve attaching holes141-143, wherein the valve attaching holes141,143are formed being recessed by a step compared with the valve attaching hole142toward the inner side of the base body10. That is, the valve attaching hole142is open at the flat surface, which is the most part of the attaching surface14a, while the valve attaching holes141,143are open at respective bottom surfaces31of the recessed portions30, the bottom surfaces31being lower by one step than the flat surface.

The each recessed portion30has the bottom surface31and an inner circumferential surface (a circumferential wall or a wall surface)32(seeFIG. 10A). As shown inFIG. 9, the lower surface269of the yoke262of the coil26is in contact with the bottom surface31, and the lower outer circumferential surface267(seeFIG. 10B) of the yoke262is disposed facing the inner circumferential surface32. That is, the coil26is in contact with one surface (attaching surface14a) of the base body10inside the recessed portion30.

The relationship between a recessed portion30and a coil26will be described later in detail.

The pressure sensors7,8are fitted to the two sensor attaching holes145,146. Two fluid passage holes147,148are open at the bottom surfaces31of the respective recessed portions30, wherein a spherical body for closing the opening is pressure fitted to the fluid passage holes147,148.

The three rotation preventing recessed portions151-153are arranged adjacent to the circumferences of the three valve attaching holes141-143. The three rotation preventing recessed portions151-153are arranged corresponding to the positioning protrusions264(seeFIG. 9) of the coils26, wherein the positioning protrusions264are engaged with these to function as rotation preventing recessed portions for the coils26.

The rotation preventing recessed portions151,153are formed such as to be open at the bottom surfaces31,31of the recessed portions30,30. At the bottom surfaces31,31, the rotation preventing recessed portions151,153are disposed with a space along the circumferential direction from the above-described fluid passage holes147,148. In the present embodiment, the rotation preventing recessed portions151,153are disposed with a space by 90 degrees along the circumferential direction at the bottom surfaces31,31.

The valve attaching holes141-143and the sensor attaching holes145,146communicate with the main hydraulic passages9a,9b(seeFIG. 1, the same hereinafter) in which brake fluid flows. Incidentally, inFIG. 3, the spherical bodies pressure fitted to the fluid passage holes147,148are not shown.

Herein, the valve attaching holes141,142are formed one above the other, with the central axis O of the master cylinder1therebetween, in a view from the right side in the direction perpendicular to the attaching surface14a(seeFIG. 4A). That is, as shown inFIG. 4B, the valve attaching holes141,142are disposed one above the other, with the reference surface S including the central axis O and being perpendicular to the attaching surface14aas the boundary. Thus, the normally-open shutoff valves4,5for the master cylinder1for opening and closing the main hydraulic passages9a,9bare disposed one above the other, with the central axis O of the master cylinder1therebetween.

Further, the two attaching holes, namely, the sensor attaching hole145and the valve attaching hole143are formed one above the other likewise, with the central axis O (reference surface S) of the master cylinder1therebetween. That is, the pressure sensor7for detecting the pressure of the main hydraulic passage9aand the normally-closed shutoff valve6for opening and closing the branch hydraulic passage9e(seeFIG. 1) are disposed one above the other, with the central axis O of the master cylinder1therebetween.

Further, the three valve attaching holes141-143and the sensor attaching hole145are disposed such as to form the corners of a quadrilateral. That is, as shown inFIG. 4A, disposition is arranged on the attaching surface14asuch that a quadrilateral (trapezoid) is formed by lines L1, L2, L3, and L4connecting the central positions of the three valve attaching holes141-143and the central position of the sensor attaching hole145, and a quadrilateral (trapezoid) is formed by the three solenoid valves4a-6aand the pressure sensor7.

Further, Lines L1, L2, L5connecting the central positions of the three valve attaching holes141-143are disposed such as to form an isosceles triangle. Further, the one sensor attaching hole146out of the two sensor attaching holes145,146is disposed on a isosceles line L6extending from an apex P1 of this isosceles triangle.

The one sensor attaching hole146is disposed in a region on the outer side of the above-described isosceles triangle. The one sensor attaching hole146is disposed in a region on the outer side of the above-described isosceles triangle and on the inner side of the above-described quadrilateral. Further, the one sensor attaching hole146is disposed between the recessed portions30,30.

The one sensor attaching hole146is disposed on a line, not shown, connecting the central positions of the fluid passage holes147,148of the recessed portions30,30.

The housing20is in a box shape of a synthetic resin and includes, as shown inFIG. 9, a circumferential wall portion21open on the front side and rear side, a cover22closing the opening21aon the front side of the circumferential wall portion21, a flange portion23protruding from the outer circumferential marginal portion of the opening21bon the rear side of the circumferential wall portion21, two connectors24,25(seeFIG. 6) protruding from the circumferential wall portion21, an in-between wall portion40arranged inside the circumferential wall portion21, and a coil busbar51and a sensor busbar52(seeFIG. 3, hereinafter referred to as busbars51,52) buried in the in-between wall portion40.

The circumferential wall portion21is a part that liquid-tightly covers components (the normally-open shutoff valves4,5, the normally-closed shutoff valve6, and the pressure sensors7,8, seeFIG. 1, the same hereinafter) fitted to the housing20, and the outer circumference thereof is formed substantially in a quadrilateral shape (seeFIG. 8A).

The cover22is, as shown inFIGS. 2A and 2B, a lid body for tightly closing the opening21aon the front side of the circumferential wall portion21, and is fixed to the end surface on the front side of the circumferential wall portion21by means of welding, adhering, or the like.

The flange portion23is a part press-attached to the housing fitting section14. At the four corners of the flange portion23, formed are screw holes23a, meeting with the fitting hole portions16(seeFIG. 3) of the housing fitting section14. Screws17(seeFIG. 2A) inserted through these screw holes23aare screw-engaged with the fitting hole portions16of the housing fitting section14, and the housing20is thereby fixed to the housing fitting section14.

Further, as shown inFIG. 9, an endlessly shaped seal member23btightly attaching to the housing fitting section14(the attaching surface14a) is attached to the end surface on the rear side of the flange portion23.

As shown inFIG. 7, the connectors24,25are in an edged hollow tube shape and are protruding from the anterior surface of the circumferential wall portion21, with a gap along the vertical direct ion. The upper connector24is connected with a cable, not shown, for supplying power to the respective coils26. The lower connector25is connected with a cable for transmitting detection signals outputted from the pressure sensors7,8to an electronic control unit not shown.

The in-between wall portion40is, as shown inFIG. 9, a partitioning wall for partitioning the space inside the circumferential wall portion21into a front side and a rear side. The in-between wall portion40is, as shown inFIG. 6, formed substantially in a quadrilateral shape, wherein the corner portion42bon the posterior lower side of the in-between wall portion40is offset (protruding) to the front side compared with other parts. Thus, a recessed portion49(seeFIG. 7) is formed on the rear face side of the in-between wall portion40by the offset, as shown inFIG. 8B. The recessed portion49has a size large enough to house a coil26. Thus, as describe later, it is possible to offset the attachment position of the solenoid valve5aof the normally-open shutoff valve5at the corner portion42bto the front side of the in-between wall portion40.

On the rear side of the in-between wall portion40, as shown inFIG. 7, a housing room27is provided to house the normally-open shutoff valves4,5, the normally-closed shutoff valve6, and the pressure sensors7,8.

As shown inFIG. 8A, three valve inserting holes41,42,43, three coil openings41a,42a,43a, and two sensor openings44,45penetrate through the in-between wall portion40along the front/rear direction.

The first valve inserting hole41is a cylindrical hole where the upper end portion of the solenoid valve4aof the normally-open shutoff valve4for the master cylinder1is inserted, and the valve inserting hole41is formed at the corner portion41bon the posterior upper side of the in-between wall portion40.

The second valve inserting hole42is a cylindrical hole where the upper end portion of the solenoid valve5aof the normally-open shutoff valve5for the master cylinder1is inserted, and the second valve inserting hole42is formed at the corner portion42bon the posterior lower side of the in-between wall portion40.

The third valve inserting hole43is a cylindrical hole where the upper end portion of the solenoid valve6aof the normally-closed shutoff valve6for the stroke simulator2is inserted, and the third valve inserting hole43is formed at the corner portion43bon the anterior lower side of the in-between wall portion40.

The first coil opening41ais an opening which the connecting terminal26a(seeFIG. 3, the same in the following) of the coil26of the normally-open shutoff valve4is inserted through, and is disposed on the lower side of the valve inserting hole41.

The second coil opening42ais an opening which the connecting terminal26aof the coil26of the normally-open shutoff valve5is inserted through, and is disposed on the upper side of the valve inserting hole42.

The third coil opening43ais an opening which the connecting terminal26aof the coil26of the normally-closed shutoff valve6is inserted through, and is disposed on the upper side of the valve inserting hole43.

The connecting terminals26aof the coils26are electrically connected to the busbars51through the respective coil openings41a,42a,43a.

The sensor opening44is open at the corner portion44bon the upper anterior side of the in-between wall portion40. The terminal7a(seeFIG. 3) of the pressure sensor7is inserted in the sensor opening44. The terminal7aof the pressure sensor7is electrically connected with the busbar52through the sensor opening44.

The sensor opening45is open at the central portion of the in-between wall portion40. The connecting terminal8a(seeFIG. 3) of the pressure sensor8is inserted in the sensor opening45. The connecting terminal8ais electrically connected with the busbar52through the sensor opening45.

In the present embodiment, as shown inFIG. 7, elastic members46are arranged as urging means between the rear surface40bof the in-between wall portion40and the respective coils26. The elastic members46are, as shown inFIG. 9, blade springs formed substantially in a V-shape in a side view, absorb the vibration of the respective coils26, and restrict the rotation of the respective coils26. Incidentally, elastic members in a coil shape may be used as the urging means.

Further, the elastic members46urge the respective coils26toward the base body10. Thus, as shown inFIG. 9, the lower surface269of the yoke262of a coil26enters a recessed portion30provided on the attaching surface14ato contact with the bottom surface31of the recessed portion30.

Further, the lower surface269of the yoke262of the coil26of the normally-open shutoff valve5contacts with the attaching surface14a. Still further, though not shown, the lower surface269of the yoke262of the coil26of the normally-closed shutoff valve6enters a recessed portion30to contact with the bottom surface31of the recessed portion30.

By making a coil26contact with the base body10, a heat generated by the coil26can be transferred to the base body10through the lower surface269of the yoke262.

As shown inFIG. 10B, in a state that the lower surface269of a yoke262is in contact with the bottom surface31of a recessed portion30, a clearance C is formed between the lower outer circumferential surface267of the yoke262and the inner circumferential surface32of the recessed portion30, the inner circumferential surface32acting as a wall surface. That is, the lower outer circumferential surface267of the yoke262is not in contact with the inner circumferential surface32of the recessed portion30, and faces the inner circumferential surface32with the clearance C therebetween.

Fluid passages provided in the master cylinder device A1will be described blow in detail. Incidentally, it is assumed in the following description that the side where the pipe connecting section15is arranged along the anterior/posterior direction of the master cylinder device A1(base body10) is referred to as the anterior face, the side where the vehicle body fixing section12is arranged is referred to as the posterior face, the wide where the reservoir3is attached is the upper face, the side opposite to the upper face is the lower face, the side where the stroke simulator2is disposed is the left side face, and the side where the attaching surface14ais formed is the right side face.

As shown inFIG. 16, the reservoir fitting sections13,13are bottomed cylindrical holes. As shown inFIG. 12, the reservoir fitting sections13,13are disposed with a distance therebetween along the anterior/posterior direction (the axial direction of the master cylinder1). As shown inFIG. 15A, the reservoir fitting section13on the side close to the front face communicates with the first cylinder hole11a(the first piston1aside, hereinafter referred to as the primary side) of the master cylinder1through a first fluid passage61. Further, as shown inFIG. 15B, the reservoir fitting section13on the side close to the posterior face communicates with the first cylinder hole11a(the second piston1bside, hereinafter referred to as the secondary side) of the master cylinder1through a second fluid passage62. The first fluid passage61and the second fluid passage62are vertical holes protruding from the bottom surfaces of the reservoir fitting sections13,13toward the first cylinder hole11aof the master cylinder1.

As shown inFIG. 18, a horizontal hole61acommunicates with the first fluid passage61, and a horizontal hole61bcommunicates with a portion of the horizontal hole61asuch as to be perpendicular to the horizontal hole61a. The horizontal hole61ais disposed above the anterior part (face) of the second cylinder hole11b. The horizontal hole61ais protruding from the left side face of the base body10toward the right side face such as to be over the anterior part of the second cylinder hole11b, and the right end thereof communicates with the first fluid passage61. The horizontal hole61bprotrudes from the inner surface of the stepped portion11b1of the second cylinder hole11btoward the anterior face, and the front end thereof communicates with the horizontal hole61a.

The primary side of the first cylinder hole11acommunicates with the valve attaching hole143through a third fluid passage63, as shown inFIG. 17. The third fluid passage63is structured by a cylinder side horizontal hole63a, a vertical hole63b, and a valve side horizontal hole63c. The cylinder side horizontal hole63aprotrudes in the direction from the right side face of the base body10toward the left side face, and the left end thereof communicates with the primary side of the first cylinder hole11a. The vertical hole63bprotrudes in the direction from the lower face of the base body10toward the upper face, and the upper end thereof communicates with the cylinder side horizontal hole63a. The valve side horizontal hole63cprotrudes in the direction from the anterior face toward the posterior side of the base body10, interests with the vertical hole63b, and penetrates through the circumferential wall of the valve attaching hole143so that the posterior end thereof reaches the vicinity of the valve attaching hole142, as shown inFIG. 11.

The valve attaching hole143is a bottomed and stepped cylindrical hole, and as shown inFIG. 13,FIG. 15A, andFIG. 19, communicates with the second cylinder hole11bof the stroke simulator2through a fourth fluid passage64. The fourth fluid passage64includes a valve side horizontal hole64a, a vertical hole64b, a cylinder side first horizontal hole64c, and a cylinder side second horizontal hole64d. The valve side horizontal hole64aprotrudes from the bottom surface of the valve attaching hole143toward the left side face of the base body10. The valve side horizontal hole64aextends below the anterior portion of the first cylinder hole11ato reach a region between the first cylinder hole11aand the second cylinder hole11b. The vertical hole64bprotrudes from the lower face toward the upper face of the base body10and interests with the left end of the valve side horizontal hole64a.

As shown inFIG. 12, the cylinder side first horizontal hole64cprotrudes from the anterior face toward the posterior face of the base body10, and the posterior end thereof communicates with the upper end of the vertical hole64b. The cylinder side second horizontal hole64dprotrudes from the left side face toward the right side face of the base body10, penetrates through the circumferential wall at the upper portion on the anterior side of the second cylinder hole11b, and the right end thereof communicates with a portion of the cylinder side first horizontal hole64c. Incidentally, the cylinder side second horizontal hole64dis provided with a fluid introduction port64e.

The above-described valve side horizontal hole63cof the third fluid passage63communicates, as shown inFIG. 11andFIG. 17, with the valve attaching hole141through a fifth fluid passage65. The fifth fluid passage65includes a vertical hole65a, a first horizontal hole65b(seeFIG. 17), and a second horizontal hole65c(seeFIG. 17). The vertical hole65aprotrudes from the lower face toward the upper face of the base body10in a region between the valve attaching hole141and the valve attaching hole143, and a portion thereof interests with the posterior end of the valve side horizontal hole63cof the third fluid passage63. The first horizontal hole65bis disposed anterior to the valve attaching hole141, protrudes from the bottom surface31(seeFIG. 3, the same in the following) of the recessed portion30toward the left side face of the base body10, and a portion thereof intersects with the upper end of the vertical hole65a, as shown inFIG. 17. The second horizontal hole65cis disposed above the first cylinder hole11a(seeFIG. 15B), protrudes from the posterior face toward the anterior face of the base body10, penetrates along the anterior/posterior direction through the side wall of the bottom portion of the valve attaching hole141formed in a bottomed and stepped cylindrical shape, and reaches the posterior end of the first horizontal hole65b.

As shown inFIG. 12andFIG. 17, the valve attaching hole141communicates with the sensor attaching hole145, the output port15a, and the input port15cthrough a sixth fluid passage66. The sixth fluid passage66includes a first horizontal hole66a, a vertical hole66b, a second horizontal hole66c, a third horizontal hole66d, and a fourth horizontal hole66e. The first horizontal hole66aprotrudes from the anterior face toward the posterior face of the base body10, penetrates through the upper circumferential wall of the sensor attaching hole145, and reaches the upper circumferential wall of the valve attaching hole141. The intersection position between the first horizontal hole66aand the valve attaching hole141is on the attaching surface14aside of the intersection position between the second horizontal hole65cof the fifth fluid passage65and the valve attaching hole141. The vertical hole66bprotrudes from the upper face toward the lower face of the base body10, and the lower end thereof communicates with the first horizontal hole66a. As shown inFIG. 11, the second horizontal hole66cprotrudes from the bottom surface of the input port15cin a bottomed cylindrical shape toward the posterior face of the base body10, and the posterior end thereof communicates with the vertical hole66b.

As shown inFIG. 12, the third horizontal hole66dprotrudes from the bottom surface of the sensor attaching hole145toward the left side face of the base body10. The fourth horizontal hole66eprotrudes from the bottom surface of the output port15ain a bottomed cylindrical shape toward the posterior face of the base body10, and communicates with the left end of the third horizontal hole66d.

That is, the output port15aand the input port15ccommunicate with each other through the sixth fluid passage66. Incidentally, the input port15cis located obliquely right above the output port15a.

As shown inFIG. 15B, the secondary side of the first cylinder hole11acommunicates with the sensor attaching hole146and the valve attaching hole142through a seventh fluid passage67. The seventh fluid passage67includes a sensor horizontal hole67a, a vertical hole67b, and a horizontal hole67c. The sensor horizontal hole67aprotrudes from the bottom surface of the sensor attaching hole146toward the left side face of the base body10, and the posterior end thereof communicates with the secondary side of the first cylinder hole11a. On the right side (the attaching surface14aside) of the first cylinder hole11a, the vertical hole67bprotrudes from the lower face toward the upper face of the base body10, and the upper end thereof communicates with the bottom surface of the sensor attaching hole146. As shown inFIG. 16, the horizontal hole67cprotrudes from the posterior face toward the anterior face of the base body10, penetrates along the anterior/posterior direction through the side wall of the bottom portion of the sensor attaching hole146, and the anterior end thereof intersects with the vertical hole67b.

The valve attaching hole142is a bottomed and stepped cylindrical hole, and as shown inFIG. 17, communicates with the output port15band the input port15dthrough an eighth fluid passage68. The eighth fluid passage68includes a valve side vertical hole68a, a lower horizontal hole68b, a port side vertical hole68c, a first upper horizontal hole68d, and a second upper horizontal hole68e. As also shown inFIG. 14andFIG. 20, the valve side vertical hole68aprotrudes from the lower face toward the upper face of the base body10, and communicates with the lower portion of the circumferential wall of the valve attaching hole142. The lower horizontal hole68bprotrudes from the bottom face toward the posterior face of the input port15din a bottomed cylindrical shape, and the posterior end thereof communicates below the valve attaching hole143with the valve side vertical hole68a. The port side vertical hole68cprotrudes from the lower face toward the upper face of the base body10, anteriorly to the valve attaching hole143, and a portion thereof intersects with the lower horizontal hole68b. The first upper horizontal hole68dprotrudes from the bottom surface31of the recessed portion30toward the left side face of the base body10, anteriorly to the valve attaching hole143. The second upper horizontal hole68eprotrudes from the bottom surface of the output port15bin a bottomed cylindrical shape toward the posterior face of the base body10, and the posterior end thereof communicates with the left end of the first upper horizontal hole68d.

That is, the output port15band the input port15dcommunicate with each other through the eighth fluid passage68. Incidentally, the input port15dis located obliquely right below the output port15b.

Incidentally, as shown inFIG. 16, the vehicle body fixing section12of the base body10is provided with a vent70. This vent70is in a bottomed cylindrical shape and has a communication hole70aprotruding from the bottom face thereof toward the anterior face of the base body10. A hole portion71protruding from the right side face (attaching surface14a) toward the left side face of the base body10communicates with the anterior end of the communication hole70a. The vent70is closed by a breathable water-resistant member, not shown, that prevents water immersion and only permits air to pass through. The breathable water-resistant member can be formed, for example, of Gore-Tex (registered trademark). Thus, the outer portion of the base body10and the inner portion of the housing20tightly fixed to the attaching surface14acommunicate with each other through the vent70.

Herein, the main hydraulic passage9ais structured by a fluid passage that extends from the third fluid passage63to the fifth fluid passage65, extends from the first horizontal hole66aof the sixth fluid passage66through the valve attaching hole141to the sensor attaching hole145, and further extends through the third horizontal hole66dand the fourth horizontal hole66eto the output port15a.

The main hydraulic passage9bis structured by a fluid passage that extends from the seventh fluid passage67(sensor attaching hole146) through the valve attaching hole142and the eighth fluid passage68to the output port15b.

The communicating hydraulic passage9cis structured by the sixth fluid passage66(the second horizontal hole66c, the vertical hole66b, and the first horizontal hole66a) connected by the input port15c.

The communicating hydraulic passage9dis structured by the eighth fluid passage68(the lower horizontal hole68b) connected to the input port15d.

The branch hydraulic passage9eis structured by a fluid passage that extends from the valve attaching hole143through the fourth fluid passage64to the second cylinder hole11bof the stroke simulator2.

The flow of brake fluid in the master cylinder device A1(base body10) will be described below.

During when the vehicle braking system A (seeFIG. 1) is normally functioning, in other words, in a state that the normally-open shutoff valves4,5are closed and the normally-closed shutoff valve6is open, when the brake pedal P (seeFIG. 1) is operated, a hydraulic brake pressure generated by the master cylinder1flows, as shown by arrow inFIG. 17, from the third fluid passage63through the valve attaching hole143to the fourth fluid passage64, and thereafter, as shown by arrow inFIG. 15A, flows through the fourth fluid passage64into the second cylinder hole11bof the stroke simulator2.

Incidentally, a change in the inner volume due to operation of the stroke simulator2pushes out brake fluid from the second cylinder hole11b, and this pushed out brake fluid flows through the horizontal hole61band the horizontal hole61ainto the first fluid passage61to be returned to the master cylinder1(reservoir3) (seeFIG. 18).

Thus, the hydraulic brake pressure generated by the master cylinder1is transmitted not to the wheel cylinders W but to the stroke simulator2so that the piston2ais displaced, ant a stroke of the brake pedal P is thereby permitted and a pseudo operation reaction force is applied to the brake pedal P.

Further. when brake a pedal effort on the brake pedal P is detected by a stroke sensor or the like, not shown, the electric motor of the motor cylinder device A2is driven so that the slave piston is displaced, thereby a pressure being applied to the brake fluid in the cylinder.

The pressurized brake fluid is input through the pipe member Hc (seeFIG. 1) to the input port15c, and, as shown by arrow inFIG. 18, flows from the input port15cthrough the sixth fluid passage66(sensor attaching hole145) to the output port15a.

Then, the pressurized brake fluid flows from the output port15athrough the hydraulic control device A3to the wheel cylinders W, W. Thus, the respective wheel cylinders W operate, and thereby a braking force is applied to the respective wheels.

Further, the brake fluid pressurized by the motor cylinder device A2is input through the pipe member Hd (seeFIG. 1) to the input port15d, and as shown by arrow inFIG. 19, flows from the input port15dthrough the eighth fluid passage68to the output port15b.

On the other hand, in a state that the motor cylinder device A2does not operate (for example, in a case of unavailability of electric power, emergency, or the like), both the normally-open shutoff valves4,5become into a valve open state and the normally-closed shutoff valve6becomes into a valve closed state. Consequently, a hydraulic brake pressure generated by the master cylinder1is directly transmitted to the wheel cylinders W, W, through the main hydraulic passages9a,9b.

That is, on the primary side of the master cylinder1, a hydraulic brake pressure generated by the master cylinder1flows to the third fluid passage63, the fifth fluid passage65, the valve attaching hole141, and the sixth fluid passage66(sensor attaching hole145), which form the main hydraulic passage9a, and is output through the output port15a.

Further, on the secondary side of the master cylinder1, the hydraulic brake pressure generated by the master cylinder1flows, as shown by arrow inFIG. 15B, from the seventh fluid passage67(sensor attaching hole146) forming the main hydraulic passage9bto the valve attaching hole142, and is output thereafter through the eighth fluid passage68and the output port15b, as shown by arrow inFIG. 14.

According to the above-described present embodiment, the two normally-open shutoff valves4,5opening and closing flow passages are disposed, sandwiching the central axis O of the master cylinder1therebetween in a view from the direction perpendicular to the one surface of the base body10. Accordingly, it is possible to form fluid passages with a short length, the fluid passages connecting the master cylinder1and the two normally-open shutoff valves4,5. Thus, the structure of the fluid passages can be made simple, and downsizing of the base body10(master cylinder device A1) can be achieved.

As the normally-open shutoff valves5,6for opening and closing the two main hydraulic passages9a,9bconnected to the master cylinder1are disposed, sandwiching the central axis O of the master cylinder1therebetween, it is possible to form the two main hydraulic passages9a,9bconnects to the master cylinder1with a short length even if the master cylinder1is a tandem type. Thus, the structure of the fluid passages can be made simple, and downsizing of the base body10(master cylinder device A1) can be achieved.

Further, as recessed portions30,30are provided on the valve attaching holes141,143, the attaching positions of the normally-open shutoff valve4and the normally-closed shutoff valve6can be changed by the depth of the recessed portions30,30. Thus, the positions of forming the fluid passages connected to the normally-open shutoff valve4and the normally-closed shutoff valve6can be changed, and the degree of freedom of forming the fluid passages is thereby increased. In such a manner, the structure of a fluid passage can also be simplified, enabling downsizing of the base body10(master cylinder device A1).

Recessed portions30,30are arranged for the normally-open shutoff valve4and the normally-closed shutoff valve6provided on the fluid passage (the main fluid passage9a) of the same system, and are not arranged for the fluid passage (the main hydraulic passage9b) of the other system. Thus, the position of forming a fluid passage can be made different, depending on the system so that the degree of freedom of forming a fluid passage is increased. In such a manner, the stricture of a fluid passage can be simplified, and downsizing of the base body10(master cylinder device A1) can be achieved.

Incidentally, arrangement may be made such that a recessed portion30is arranged only for the normally-open shutoff valve5on the fluid passage (the main fluid passage9b) of the other system, and a position of forming the fluid passage may be arranged differently from the position of the main hydraulic passage9a.

For example, in the present embodiment, as shown inFIG. 21A, as the valve attaching hole141is offset to the inner side of the base body10by the recessed portion30, the positions of forming the fluid passages for the valve attaching hole141and the sensor attaching hole145agree with each other with respect to the anterior/posterior direction of the base body10, and these can be connected by a single first horizontal hole66a. Incidentally, the positions of forming the fluid passages for the valve attaching hole141and the sensor attaching hole145are naturally limited by the structures of the pressure sensor7and the normally-open shutoff valve4.

Herein, as shown inFIG. 21B, if the valve attaching hole141were not provided with the recessed portion30, when a valve and a sensor with different sizes with respect to the left/right direction of the base body10are disposed at the valve attaching hole141and the sensor attaching hole145, a gap would occur between the positions of forming the fluid passages, and it would be necessary to additionally form two horizontal holes81,82on the base body10to make these communicate with each other. Thus, work for processing the horizontal holes81,82is necessary and the number of fluid passages increases, resulting in a decrease in the degree of freedom of the layout of fluid passages.

In contrast, in the present embodiment, as it is possible to connect the valve attaching hole141and the sensor attaching hole145by the single first horizontal hole66a, it is only necessary to process minimum necessary fluid passages, and it is thus possible to obtain an advantage of improving the degree of freedom of the layout of fluid passages.

Further, according to the present embodiment, as it is possible to easily provide the inner circumferential surfaces32(wall surfaces) facing the lower outer circumferential surfaces267of coils26by forming recessed portions30,30, an excellent productivity is attained.

Further, in a view from a direction perpendicular to the one surface of the base body10, the normally-open shutoff valve5and the normally-closed shutoff valve6are disposed on one side (lower side), and the normally-open shutoff valve4and the pressure sensor7are disposed on the other side (upper side), with the central axis O of the master cylinder1therebetween, and these are disposed such as to form the corners of a quadrilateral. Accordingly, compared with a case, for example, that these are arrayed for example on a line, the fluid passages can be made short and disposed closely, and as a result, it is possible to realize downsizing of the base body10(master cylinder device A1).

Further, in a structure including the stroke simulator2and the normally-closed shutoff valve6for opening and closing the fluid passage to the stroke simulator2, the structure of the fluid passage can be simplified to enable downsizing of the base body10(master cylinder device A1).

Still further, as the inner circumferential surfaces32of recessed portions30face the lower outer circumferential surfaces267of the respective coils26, it is possible to transfer the heat of the coils26, whose temperature has become a high temperature, to the base body10from the respective lower outer circumferential surfaces267through the inner circumferential surfaces32. Thus, the heat of the coils26can be absorbed by the base body10and radiated through the base body10.

Yet further, as the lower surfaces269of coils26are in contact with the bottom surfaces31of respective recessed portions30, the heat of the coils26, whose temperature has become a high temperature, can be directly transferred to the base body10through the lower surfaces269of the respective coils26. Thus, the heat of the coils26can be further absorbed by the base body10, and heat radiation can be effectively carried out through the base body10.

Further, the elastic members46for urging coils26toward the attaching surface14aof the base body10are arranged between the in-between wall portion40of the housing20and the coils26. Accordingly, the lower surfaces269of the coils26are ensured to contact with the attaching surface14a, and heat can be surely transferred through the lower surfaces269to the base body10. Thus, heat radiation can be effectively carried out through the base body10.

Still further, clearances C are formed between the lower outer circumferential surfaces267of coils26and the inner circumferential surfaces32of recessed portions30, even when a little deviation of the attaching position of the coils26housed in the housing20exists in attaching the housing20to the attaching surface14a, it can be appropriately absorbed by the clearances C, and excellent assembility can be achieved.

Heat radiation gel having a heat radiation effect may be disposed to bury the clearances C. Further, also by arranging recessed portions30,30such as to eliminate the clearances C, heat radiation effect can be obtained, and positioning is possible in holding or attaching coils26.

In the foregoing embodiment, although recessed portions30,30are provided at the valve attaching holes141,143, arrangement may be made such as to provide a recessed portion30at at least one of the valve attaching holes141-143.

Further, as the communicating hydraulic passages (fluid passages)9c,9dare disposed anterior to the normally-open shutoff valves4,5, the normally-closed shutoff valve6, and the pressure sensors7,8, the communicating hydraulic passages9c,9ddo not interfere with the normally-open shutoff valves4,5, the normally-closed shutoff valve6, or the pressure sensors7,8, and optimization of fluid passages and downsizing of the device can be achieved.

Still further, the fluid passage to the stroke simulator2is disposed with a shift to the left side from the central portion with respect to the width direction of the master cylinder1in a view form the anterior of the base body10, and the other fluid passage is disposed with a shift to the right side in a view from the anterior. Thus, optimization of fluid passages and downsizing of the device can be achieved.

Yet further, as shown inFIG. 22, recessed portions30A,30A may be provided around the valve attaching holes141,143such as to be continuous from the upper end or the lower end of the attaching surface14a. By arranging such recessed portions30A,30A, thinning of the attaching surface14acan be achieved, and the cost can be thereby reduced.

Further, in the foregoing embodiment, by providing recessed portions30,30A, the inner circumferential surfaces32(wall surfaces) facing the lower outer circumferential surfaces267of coils26are formed, however, without being limited thereto, wall surfaces in a limb shape protruding from the attaching surface14amay be provided such as to face the lower outer circumferential surfaces267of the coils26. Also by such arrangement, the heat of coils26can be appropriately transferred through the wall surfaces in a limb shape to the base body10.

In the forgoing embodiment, a structure of the master cylinder device A1provided with the inner circumferential surfaces32facing the lower outer circumferential surfaces267of coils26has been described, however, without being limited thereto, the structure can also be appropriately applied to the hydraulic control device A3as a hydraulic brake pressure device.

Still further, the positions of disposing the normally-open shutoff valves4,5, the normally-closed shutoff valve6, the pressure sensors7,8, the master cylinder1, and the stroke simulator2can be changed, as appropriate, depending on the relationship with the main fluid passages9a,9b, the position of arranging the stroke simulator2, or the like.

DESCRIPTION OF REFERENCE SYMBOLS