Vehicle brake control unit base body and vehicle brake control unit

A base body has flow path configuring portions, has inlet and outlet ports, a central mounting hole 31, a central flow path 51 penetrating the central mounting hole 31, first inner and outer mounting holes 32, 33 disposed upstream side of the central mounting hole 31, second inner and outer mounting holes 34, 35 disposed downstream side of the central mounting hole 31, a third mounting hole 36 disposed below the second outer mounting hole 35, a wheel side sensor mounting hole 46 disposed on an extension of the outlet port 22L between the first inner mounting hole 32 and the second inner mounting hole 34, and a hydraulic pressure source side sensor mounting hole 45 disposed on a center line X of the base body so as to straddle to extend to the flow path configuring portions across the center line X.

TECHNICAL FIELD

The present invention relates to a vehicle brake control unit base body and a vehicle brake control unit.

RELATED ART

While various types of vehicle brake control units have been proposed, for example, as a hydraulic pressure circuit for a four-wheel vehicle brake control unit, there is known a hydraulic pressure circuit in which in addition to an anti-lock brake control for each wheel brake, a skid control and a traction control (hereinafter, these controls being referred collectively as a “behavior stabilizing control”) are performed in such a state that a brake actuator such as a brake pedal is not operated.

This hydraulic pressure circuit includes a brake output circuit for actuating two of four wheel brakes and another brake output circuit for actuating the remaining two wheel brakes. A control valve unit for adjusting magnitude of brake hydraulic pressure applied to the wheel brake is provided for each wheel brake. That is, two control valve units are provided for one brake output circuit. Thus, an anti-lock brake control can be performed on each wheel brake independently. Furthermore, a regulator for opening and closing a flow path between the hydraulic pressure source and the control valve units, and a pump for supplying brake fluid to a flow path between the regulator and the control valve units are provided for each brake output circuit, thereby the behavior stabilizing control is enabled.

In each brake output circuit, a set of two electromagnetic valves (an inlet valve, an outlet valve) is provided for each control valve unit, and a electromagnetic valve (a cut-off valve) which closes when performing a interlocking brake control is provided in the regulator. Furthermore, a electromagnetic valve (a suction valve) which opens when performing a behavior stabilizing control is interposed on an inlet side of the pump. In this configuration, with the two brake output circuits added together, twelve electromagnetic valves are used therein.

Furthermore, in recent years, in association with the trend that vehicle brake control units are provided with a multiplicity of functions, a hydraulic pressure sensor for measuring a brake hydraulic pressure is tend to be provided in a hydraulic pressure circuit. As a vehicle brake control unit which realizes a hydraulic pressure circuit including such a hydraulic pressure sensor, there has been such a vehicle brake control unit, for example, as is described in Japanese Patent Unexamined Publication No. JP-A-2002-347595.

In this vehicle brake control unit, on one surface of a block (base body), formed are:

four recessed portions (holes) for pressure increasing control valves;

four recessed portions (holes) for pressure reducing control valves;

four recessed portions (holes) for brake hydraulic pressure sensors;

two recessed portions for master pressure sensors;

one recessed portion for a hydraulic pressure sensor; and

a plurality of hydraulic pressure sensors. Thus, many hydraulic pressure sensors are provided within the block (base body).

In the vehicle brake control unit as is described in JP-A-2002-347595, although it becomes possible to implement various brake controls due to the large number of hydraulic pressure sensors, the enlargement of the base body is called for because a wide space is necessary to mount the hydraulic pressure sensors. Due to this, there has been caused a problem that the vehicle brake control unit itself has also to be enlarged. Then, when the vehicle brake control unit is enlarged in this way, there has also been caused a problem that the installation of such an enlarged vehicle brake control unit is limited in association with a limited space therefor in the vehicle.

SUMMARY OF THE INVENTION

From the viewpoint like this, a problem that the invention is to solve is how to provide a vehicle brake control unit base body and a vehicle brake control unit.

In order to solve this problem, according to an aspect of the invention, there is provided a vehicle brake control unit base body for a vehicle brake control unit which includes:

a first brake output circuit for actuating at least one of wheel brakes; and

a second brake output circuit for actuating the remaining wheel brakes,

the vehicle brake control unit base body including:

first and second flow path configuring portions which correspond to the respective first and second brake output circuits and are formed left and right hand parts of the base body across a center line thereof, respectively,

wherein each of the first and second flow path configuring portions includes:

an inlet port to which a piping from a hydraulic pressure source is connected;

at least one outlet port to which at least one of the wheel brakes are connected;

a central mounting hole;

a central flow path which originates from the inlet port and passes through the central mounting hole;

a first inner mounting hole and a first outer mounting hole which are provided at upstream side of the central mounting hole so as to oppose to each other via the central flow path;

a second inner mounting hole and a second outer mounting hole which are provided at downstream side of the central mounting hole so as to oppose to each other via the central flow path;

a third mounting hole which is disposed so that the first outer mounting hole, the second outer mounting hole and the third mounting hole are arranged in this order in a vertical direction;

a wheel side sensor mounting hole which is disposed on an extension of the outlet ports and also between the first inner mounting hole and the second inner mounting hole, and mounts a wheel side brake hydraulic pressure sensor measuring brake hydraulic pressure outputted to one of the wheel brakes; and

a hydraulic pressure source side sensor mounting hole which is disposed on the center line of the base body so as to straddle the center line to extend to the respective flow path configuring portions and mounts a hydraulic pressure source side brake hydraulic pressure sensor for measuring brake hydraulic pressure outputted from the hydraulic pressure source,

wherein the respective central mounting hole, the first inner and outer mounting holes, the second inner and outer mounting holes and the third mounting hole mounts an electromagnetic valve.

According to the vehicle brake control unit base body which has the positional relationship described above, when the base body is applied to a brake control unit, the brake control unit can be made small in size while the twelve electromagnetic valves and the plurality of (three) hydraulic pressure sensors are provided in one surface of the base body. Furthermore, with the vehicle brake control unit to which the base body is applied, it becomes possible to implement multiple complex and highly accurate safety functions which involve the control of vehicle brakes.

In addition, according to another aspect of the invention, there is provided a vehicle brake control unit including:

a brake output circuit for actuating at least one of wheel brakes;

a brake output circuit for actuating the remaining wheel brakes;

the base body as set forth in Claim1;

normally open type electromagnetic valves which constitute inlet valves mounted in the first inner mounting holes and the first outer mounting holes, respectively;

normally closed type electromagnetic valves which constitute suction valves mounted in the central mounting holes;

normally closed type electromagnetic valves which constitute outlet valves mounted in the second inner mounting holes and the second outer mounting holes, respectively;

normally open type electromagnetic valves which constitute cut-off valves mounted in the third mounding holes;

a hydraulic pressure source side brake hydraulic pressure sensor mounted in the hydraulic pressure source side sensor mounting hole and measuring magnitude of brake hydraulic pressure in the hydraulic pressure source;

wheel side brake hydraulic pressure sensors mounted in the wheel side sensor mounting holes and measuring magnitude of brake hydraulic pressure applied to the wheel brake;

a motor which is assembled on a rear side of the base body and drives a pump;

a control housing assembled on a front side of the base body so as to cover the respective electromagnetic valves; and

a control unit which is accommodated in the control housing and controls operations of the motor and the respective electromagnetic valves.

According to the vehicle brake control unit having the positional relationship described above, the brake control unit can be made small in size while the twelve electromagnetic valves and the plurality of (three) hydraulic pressure sensors are provided in one surface of the base body. Furthermore, it becomes possible to implement multiple complex and highly accurate safety functions which involve the control of vehicle brakes.

In addition, in the vehicle brake control unit, it is preferable that

the first brake output circuit is connected to the wheel brakes of a front wheel and a rear wheel,

the second brake output circuit is connected to the wheel brakes of the other front wheel and the other rear wheel and

each of the wheel side brake hydraulic pressure sensors measures magnitude of the brake hydraulic pressure applied to the front wheel.

According to the configuration described above, since the brake hydraulic pressures on the wheel brakes of the front wheels to which more brake load is applied can be detected by the wheel side brake hydraulic pressure sensors while realizing the miniaturization of the unit. Thus, a brake hydraulic pressure control can be implemented in which emphasis is placed on braking force control, thereby making it possible to enhance further the accuracy of the brake hydraulic pressure control.

Furthermore, in the vehicle brake control unit, it is preferable that

the first brake output circuit is connected to the wheel brakes of a front wheel and a rear wheel,

the second brake output circuit is connected to the wheel brakes of the other front wheel and the other rear wheel and

each of the wheel side brake hydraulic pressure sensors measures magnitude of brake hydraulic pressure applied to the wheel brake of the front wheel or the rear wheel which constitutes a drive wheel.

According to the configuration described above, since the brake hydraulic pressures on the wheel brakes of the drive wheels can be detected by the wheel side brake hydraulic pressure sensors while realizing the miniaturization of the unit, a brake hydraulic pressure control can be implemented in which emphasis is placed on traction control, thereby making it possible to enhance further the accuracy of the brake hydraulic pressure control.

According to the vehicle brake control unit base body and the vehicle brake control unit according to the invention, the vehicle brake control unit can be made small in size while having the plurality of (three) hydraulic pressure sensors. Furthermore, it becomes possible to implement multiple complex and highly accurate safety functions which involve the control of vehicle brakes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a best mode for carrying out the invention will be described in detail by reference to the accompanying drawings.

As shown inFIG. 1, a vehicle brake control unit U (hereinafter, referred to as a “brake control unit U”) is configured to include a base body (a pump body)100, a motor200which is assembled on a rear side of the base body100, a control housing300which is assembled on a front side of the base body100and a control unit400which is accommodated in the control housing300.

The brake control unit U embodies a hydraulic pressure circuit shown inFIG. 10. The brake control unit U includes a brake output circuit K1for controlling two wheel brakes RL, FR among four wheel brakes RL, FR, FL, RR; and a brake output circuit K2for controlling the remaining two wheel brakes FL, RR. Accordingly, independent anti-lock brake controls can be performed on four wheels by control valve units V which are provided individually for the wheel brakes RL, FR, FL, RR (that is, two control valve units per brake output circuit). Furthermore, a behavior stabilizing control is enabled by regulators R, suction valves4and pumps6which are provided for the brake output circuits k1, K2, respectively, working in cooperation with one another.

The brake output circuit K1applies brakes on left rear and right front wheels. The brake output circuit K1constitutes a system running from an inlet port21to outlet ports22L,22R. A piping H11, which reaches an output port M11of a master cylinder M constituting a hydraulic pressure source, is connected to the inlet port21, and pipings H12, H12, which reach the wheel brakes RL, FR, respectively, are connected to the outlet ports22L,22R, respectively.

The brake output circuit K2applies brakes on right rear and left front wheels and constitutes a system running from an inlet port23to outlet ports24L,24R. A piping H21, which reaches an output port M12of the master cylinder M constituting the same hydraulic pressure source as that for the brake output circuit K1, is connected to the inlet port23. Further, pipings H22, H22, which reach the wheel brakes RR, FL, respectively, are connected to the outlet ports24L,24R, respectively.

Note that there is provided only one master cylinder M. To this master cylinder M, a brake pedal L which constitutes a brake operation element is connected. Namely, the four wheel brakes RL, FR, FL, RR can be applied only by exerting pedal effort on to the single brake pedal L.

Note that since the brake output circuits K1, K2have substantially the same configuration, in the following description, the brake output circuit K1will mainly be described, and the brake output circuit K2will only be described as required.

Provided on the brake output circuit K1for the front wheel are a regulator R, control valve units V, a suction valve4, a reservoir5, a pump6, a damper7, an orifice7a, a hydraulic pressure source side brake hydraulic pressure sensor8and a wheel side brake hydraulic pressure sensor9.

Note that in the following description,

“output hydraulic pressure line A” means a flow path (a fluid line) running from the inlet port21to the regulator R;

“wheel hydraulic pressure line B” means a flow path running from the regulator R to the outlet ports22L,22R;

“suction hydraulic pressure line C” means a flow path running from the output hydraulic pressure line A to the pump6;

“discharge hydraulic pressure line D” means a flow path running from the pump6to the wheel hydraulic pressure line B; and

“release line E” means a flow path running from the wheel hydraulic pressure line B to the suction hydraulic pressure line C.

In addition, an “upstream side” indicates a side which connects to the master cylinder M or a master cylinder M side, and a “downstream side” indicates a side which connects to wheel brake RL/FR (FL/RR) or a wheel brake1L/FR (FL/RR) side.

The regulator R has:

a function to switch between a state in which a flow of brake fluid from the output hydraulic pressure line A to the wheel hydraulic pressure line B is permitted and a state in which the flow concerned is interrupted; and

a function to adjust brake hydraulic pressures in the wheel hydraulic pressure line B and the discharge hydraulic pressure line D to be a predetermined value or less, when the flow of brake fluid from the output hydraulic pressure line A to the wheel hydraulic pressure line B is interrupted.

The regulator R includes a cut-off valve1, a check valve1aand a relief valve1b.

The cut-off valve1is made up of a normally open type electromagnetic valve which is interposed between the output hydraulic pressure line A and the wheel hydraulic pressure line B. The cut-off valve1permits the brake fluid to flow from an upstream side to a downstream side thereof when in an open state and also the cut-off valve1interrupts the flow concerned when in a closed state. The normally open type electromagnetic valve, which makes up the cut-off valve1, is electrically connected to a control unit400via a solenoid coil which drives a valve body thereof. When the solenoid coil is energized depending on a command from the control unit400, the electromagnetic valve closes to interrupt the flow of brake fluid from the upstream side to the downstream side thereof. On the other hand, when the solenoid coil is deenergized, the electromagnetic valve opens to permit the flow of brake fluid from the upstream side to the downstream side thereof.

The check valve1ais a valve which permits only a flow of brake fluid from an upstream side to a downstream side thereof and is connected parallel to the cut-off valve1.

The relief valve1bis connected parallel to the cut-off valve1and opens when a difference between the brake hydraulic pressure in the output hydraulic pressure line A and the brake hydraulic pressure in the wheel hydraulic pressure line B reaches or exceeds a predetermined value.

The control valve units V are provided for the wheel brakes RL, FR, one for each wheel brake. The control valve unit V has a function to switch over among:

a state in which the release line E is interrupted while the wheel hydraulic pressure line B is opened;

a state in which the release line E is opened while the wheel hydraulic pressure line B is interrupted; and

a state in which the wheel hydraulic pressure line B and the release line E are interrupted.

The control valve unit V includes an inlet valve2, a check valve2aand an outlet valve3.

The inlet valve2is made up of a normally open type electromagnetic valve provided on the wheel hydraulic pressure line B. The inlet valve2permits the brake fluid to flow from an upstream side to a downstream side thereof when in an open state and also the inlet valve2interrupts the flow concerned when in a closed state. The normally open type electromagnetic valve, which makes up the inlet valve2, is electrically connected to the control unit400via a solenoid coil which drives a valve body thereof, so that the inlet valve2closes when the solenoid coil is energized based on a command from the control unit400and opens when the solenoid coil is deenergized.

The check valve2ais a valve which permits only a flow of brake fluid from a downstream side to an upstream side thereof and is connected parallel to the inlet valve2.

The outlet valve3is made up of a normally closed type electromagnetic valve interposed between the wheel hydraulic pressure line B and the release line E. The outlet valve3interrupts a flow of brake fluid from a wheel brake RL/FR (FL/RR) side to a reservoir5side thereof when in a closed state and the outlet valve3permits the flow when in an open state. The normally closed type electromagnetic valve, which makes up the outlet valve3, is electrically connected to the control unit400via a solenoid coil which drives a valve body thereof, so that the electromagnetic valve concerned opens when the solenoid coil is energized based on a command from the control unit400and closes when the solenoid coil is deenergized.

The inlet valve4switches between a state in which the suction hydraulic pressure line C is opened and a state in which the suction hydraulic pressure line C is interrupted. The inlet valve4is made up of a normally closed type electromagnetic valve provided on the suction hydraulic pressure line C. The normally closed type electromagnetic valve, which makes up the suction valve4, is electrically connected to the control unit400via a solenoid coil which drives a valve body thereof, so that the electromagnetic valve concerned opens when the solenoid coil is energized based on a command from the control unit400and closes when the solenoid coil is deenergized.

The reservoir5is provided on the release line E and has a function to temporarily store brake fluid which is relieved by each outlet valve3being opened. In addition, a check valve5ais interposed between the reservoir5and the pump6for permitting only a flow of brake fluid from a reservoir5side to a pump6side thereof.

The pump6is interposed between the suction hydraulic pressure line C which communicates with the output hydraulic pressure line A and the discharge hydraulic pressure line D which communicates with the wheel hydraulic pressure line B. The pump6is driven by the rotational force of the motor200and sucks the brake fluid stored temporarily in the reservoir5to discharge it to the discharge hydraulic pressure line D. In addition, when the cut-off valve1is in a closed state and the suction valve4is in an open state, the pump6sucks brake fluid stored in the master cylinder M, the output hydraulic pressure line A, the suction hydraulic pressure line C and the reservoir5to discharge it to the discharge hydraulic pressure line D, whereby a brake hydraulic pressure produced by operating the brake pedal L can be increased. Furthermore, the pump6can allow brake hydraulic pressure to be applied to the wheel brakes RL, FR (FL, RR) even in a state that the brake pedal L is not operated.

In addition, the damper7and the orifice7acooperate with each other to attenuate the pulsation of brake fluid discharged from the pump6.

The hydraulic pressure source side brake hydraulic pressure sensor8measures a brake hydraulic pressure in the output hydraulic pressure line A, that is, magnitude of brake hydraulic pressure in the master cylinder M. Only one hydraulic pressure source side brake hydraulic pressure sensor8is disposed for one of the brake output circuits (in the case of this embodiment, the brake output circuit K1), and no such sensor is provided on the other brake output circuit (in the case of this embodiment, the brake output circuit K2). The value of the brake hydraulic pressure measured by the hydraulic pressure source side brake hydraulic pressure sensor8is successively captured into the control unit400, and whether or not a brake hydraulic pressure is outputted from the master cylinder M, that is, whether or not the brake pedal L is depressed is determined by the control unit400. Furthermore, the behavior stabilizing control is implemented based on the magnitude of the brake hydraulic pressure measured by the hydraulic pressure source side brake hydraulic pressure sensor8.

The wheel side brake hydraulic pressure sensor9measures magnitude of brake hydraulic pressure applied to the wheel brake FR (FL) of the front wheel. The value of the brake hydraulic pressure measured by the wheel side brake hydraulic pressure sensor9is successively captured into the control unit400, so that the anti-lock brake control and the behavior stabilizing control are implemented based on the magnitude of the brake hydraulic pressure measured by the wheel side brake hydraulic pressure sensor9.

The motor200is a common power supply for the pump6provided on the brake output circuit K1on the front wheel side and the pump6provided on the brake output circuit K2on the rear wheel side and operates based on a command from the control unit400.

The control unit400controls the opening and closing of the cut-off valves1of the regulators R, the inlet valves2and the outlet valves3of the control valve units V and the suction valves4and the operation of the motor200based on outputs from the hydraulic pressure source side brake hydraulic pressure sensor8, the wheel side brake hydraulic pressure sensors9, a wheel speed sensor401for the right front wheel, a wheel speed sensor402for the left front wheel, a wheel speed sensor403for the right rear wheel and a wheel speed sensor404for the left rear wheel.

Next, referring to the hydraulic pressure circuit inFIG. 10, a normal brake control, an anti-lock brake control and a behavior stabilizing control which are realized by the control unit400will be described. Note that in the embodiment, which will be described below, a description will be made by taking a front-wheel-drive vehicle as an example.

In a normal brake control that is carried out when the wheels are unlikely to lock up, the plurality of solenoid coils which drives the plurality of electromagnetic valves are all deenergized by the control unit400. Namely, in the normal brake control, the cut-off valves1and the inlet valves2are in the open state, while the outlet valves3and the suction valves4are in the closed state.

When the driver pushes on the brake pedal L in the situation like this, a brake hydraulic pressure produced by brake effort produced by the brake pedal L so pushed is transmitted to the wheel brakes FL, RR, RL, FR as it is to thereby slow the wheels.

When the normal brake control that has been described above is performed, since the brake hydraulic pressures in the wheel hydraulic pressure lines B which connect to the right front and left front wheel brakes FR, FL are actually measured by the wheel side brake hydraulic pressure sensors9,9, respectively, the fact can be verified that a preferred brake hydraulic pressure is being applied to the wheel brakes FR, FL.

An anti-lock brake control is executed when the wheels are likely to lockup and is realized by controlling the control valve units V which are associated, respectively, with the wheel brakes FL, RR, RL, FR of the wheels which are likely to lock up so as to selectively reduce, increase or hold constant the brake hydraulic pressures applied to the wheel brakes FL, RR, RL, FR. Whether the brake hydraulic pressures are selectively reduced, increased or held constant is determined by the control unit400based on wheel speeds obtained by the wheel speed sensor401for the right front wheel, the wheel speed sensor402for the left front wheel, the wheel speed sensor403for the right rear wheel and the wheel speed sensor404for the left rear wheel.

When the wheels are about to lock up while the brake pedal L is being depressed, an anti-lock brake control is started by the control unit400.

Followings, the operation of the anti-lock brake control will be described assuming that the right front wheel (the wheel which is caused to slow by the wheel brake FR) is about to lock up.

When it is determined by the control unit400that the brake hydraulic pressure applied to the wheel brake FR is to be reduced, the wheel hydraulic pressure line B is interrupted and the release line E is opened by the control valve unit V associated with the wheel brake FR. Specifically, the inlet valve2is energized to be put in the closed state by the control unit400, while the outlet valve3is energized to be put in the open state by the control unit400. When the valves are controlled in this way, the brake fluid in the wheel hydraulic pressure line B which communicates with the wheel brake FR flows into the reservoir5by way of the release line E, and as a result, the brake hydraulic pressure applied to the wheel brake FR is reduced. As this occurs, the brake hydraulic pressure in the wheel hydraulic pressure line B is measured by the wheel side brake hydraulic pressure sensor9, and the measured value is then captured into the control unit400.

In addition, when the anti-lock brake control is executed, the motor200is driven by the control unit400so as to actuate the pump6, so that brake fluid stored in the reservoir5is caused to flow back to the wheel hydraulic pressure line B via the discharge hydraulic pressure line D.

In addition, when it is determined by the control unit400that the brake hydraulic pressure applied to the wheel brake FR is to be held constant, both the wheel hydraulic pressure line B and the release line E are interrupted by the control valve unit V associated with the wheel brake FR. Specifically, the inlet valve2is energized to be put in the closed state by the control unit400, while the outlet valve3is deenergized to be put in the closed state by the control unit400. When the valves are controlled in this way, a situation occurs in which the brake fluid is confined within a flow path which is closed by the wheel brake FR, the inlet valve2and the outlet valve3, and as a result, the brake hydraulic pressure applied to the wheel brake FR is held constant.

Furthermore, when it is determined by the control unit400that the brake hydraulic pressure applied to the wheel brake FR is to be increased, the wheel hydraulic pressure line B is opened and the release line E is interrupted by the control valve unit V associated with the wheel brake FR. Specifically, the inlet valve2is deenergized to be put in the open state by the control unit400, while the outlet valve3is deenergized to be put in the closed state by the control unit400. When the valves are controlled in this way, the brake hydraulic pressure produced by brake effort produced by the brake pedal L is applied directly to the wheel brake FR, and as a result, the brake hydraulic pressure applied to the wheel brake FR is increased.

When the anti-lock brake control that has been described above is executed, since the brake hydraulic pressure in the wheel hydraulic pressure line B which connects to the right front wheel brake FR is actually measured by the wheel side brake hydraulic pressure sensor9, a detailed hydraulic pressure control can be performed based on the brake hydraulic pressure so measured in the control unit400. Specifically, while sensing the brake hydraulic pressure within the wheel hydraulic pressure line B, the outlet valve3is controlled to be opened or closed so that the hydraulic pressure concerned is not reduced excessively. In addition, the opening and the opening time of the outlet valve3may be set such that the brake hydraulic pressure is not reduced excessively. When the valve is controlled in this way, it becomes possible to perform a highly accurate brake control based on the magnitude of the brake hydraulic pressure which has been measured by the wheel side brake hydraulic pressure sensor9, and when it is determined that the situation is over in which the wheel concerned is about to lock up and the brake hydraulic pressure which is being applied to the wheel brake FR be increased, the brake hydraulic pressure can be returned to a desired pressure on the spot. In addition, also when it is determined that the brake hydraulic pressure which is being applied to the wheel brake FR is to be held constant, by controlling the inlet valve2and the outlet valve3to be opened or closed while actually measuring the brake hydraulic pressure which is being applied to the wheel brake, a most suitable brake hydraulic pressure to the wheel brake FR can be held in an ensured fashion and with ease.

A behavior stabilizing control is such as to prevent disturbance to the behavior of the vehicle which occurs due to a change in driving conditions which occurs when running in rain or cornering on a snow-covered road.

Depending upon the conditions of the vehicle, a behavior stabilizing control such as a skid control or traction control is started by the control unit400. Note that in the following description, a situation is assumed in which the behavior of the vehicle is stabilized by causing the right front wheel (the wheel which is caused to slow by the wheel brake FR) to slow when the brake pedal L (refer toFIG. 10) is not operated.

When it is determined by the control unit400that the right front wheel is to be caused to slow with the brake pedal L not operated, the cut-off valve1is energized to be put in the closed state by the control unit400, while the suction valve4is energized to be put in the open state by the control unit400. Furthermore, the inlet valves2which are not associated with the right front wheel are energized to be put in the closed state by the control unit400, and in this state, the motor200is actuated to drive the pump6. By this control, brake fluid stored in the master cylinder M, the output hydraulic pressure line A and the suction hydraulic pressure line C is caused to flow only into the wheel hydraulic pressure line B which communicates with the wheel brake FR by way of the pump6and the discharge hydraulic pressure line D. As a result, the brake hydraulic pressure is applied to the wheel brake FR, whereby the right front wheel is caused to slow.

Note that when a difference between the brake hydraulic pressure in the output hydraulic pressure line A and the brake hydraulic pressure in the wheel hydraulic pressure line B becomes equal to or more than a predetermined value, brake fluid within the wheel hydraulic pressure line B is relieved to the output hydraulic pressure line A by the action of a relief valve1b.

In addition, since pulsation produced in the discharge hydraulic pressure line D or the like due to the operation of the regulator R is absorbed to be suppressed by the cooperation of the damper7and the orifice7a, the operation noise attributed to the pulsation is reduced.

When executing the behavior stabilizing control that has been described above, since the brake hydraulic pressure in the wheel hydraulic pressure line B which connects to the right front wheel brake FR is actually measured by the wheel side brake hydraulic pressure sensor9, a delicate hydraulic pressure control can be performed by the control unit400so that the brake hydraulic pressure within the wheel hydraulic pressure line B becomes a desired value, thereby making it possible to implement a highly accurate brake control.

Next, a specific construction of the brake control unit U will be described in detail by reference toFIGS. 1 to 3.

As has been described above, the brake control unit U is configured to include the base body (the pump body)100, the motor200, the control housing300and the control unit400.

The base body100is made up of an extruded material or a cast product which is formed substantially into a rectangular parallelepiped body and is made of aluminum alloy. A front side11of the obtained one is extruded or cast into a flat plane substantially free from irregularities. Two flow path configuring portions100A,100B are formed in the base body100so as to correspond to the two brake output circuits K1, K2(refer toFIG. 10), respectively. Specifically, the flow path configuring portion100A associated with the brake output circuit K1is formed in a right-hand half portion (a region which lies further rightwards than a center line X shown in the figures concerned) of the base body100as viewed from the side of the front side11, while the flow path configuring portion100B associated with the brake output circuit K2is formed in a left-hand half portion (a region which lies further leftwards than the center line X shown in the figures concerned) of the base body100. In this embodiment, the flow path configuring portions100A,100B are formed substantially laterally symmetrical, and their interior configurations are the same.

In addition to the inlet port21which opens in a rear side12(refer toFIG. 3) and the two outlet ports22L,22R which open in an upper side15, the flow path configuring portion100A includes:

a central mounting hole31which lies at almost the same height as a bearing hole43into which an output shaft210(refer toFIG. 1) of the motor200is inserted, as shown inFIG. 5A;

a central flow path51(refer toFIG. 5A) which originates from the inlet port21and passes through the central mounting hole31vertically;

a first inner mounting hole32and a first outer mounting hole33which lie upstream side of the central mounting hole31and opposes each other via the central flow path51;

a second inner mounting hole34and a second outer mounting hole35which lie downstream side of the central mounting hole31and opposes each other via the central flow path51; and

a third mounting hole36which is disposed below the second outer mounting hole35;

a reservoir hole37which opens in a lower side16;

a pump hole38which opens in a lateral side14;

a damper hole39(refer toFIG. 5B) which opens the upper side15; and

a wheel side sensor mounting hole46which is disposed on an extension of the outlet port22L of the outlet ports between the first inner mounting hole32and the second inner mounting hole34.

To the wheel side sensor mounting hole46, the wheel side brake hydraulic pressure sensor9(refer toFIGS. 1 and 10) is mounted for measuring a brake hydraulic pressure outputted to the wheel brake FR (in this embodiment, the right front wheel brake) of the wheel brakes.

Note that as shown inFIGS. 1 and 2, the central mounting hole31, the first inner mounting hole32, the first outer mounting hole33, the second inner mounting hole34, the second outer mounting hole35and the third mounting hole36open in the same plane of the front side11of the flow path configuring portion100A. In addition, in this embodiment, hole diameters of the central mounting hole31, the first inner mounting hole32, the first outer mounting hole33, the second inner mounting hole34, the second outer mounting hole35and the third mounting hole36are all made the same in size.

In addition, in this embodiment, it is understood that a piping H12(refer toFIG. 10) which reaches the wheel brake FR is connected to the outlet port22L which lies inboards (leftwards inFIG. 5A), while a piping H12(refer toFIG. 10) which reaches the wheel brake RL is connected to the outlet port22R which lies outboards (rightwards inFIG. 5A).

As shown inFIGS. 6A,6B and7, the inlet port21is a bottomed cylindrical hole and communicates with the central mounting hole31via the central flow path51(hereinafter, referred to as a “first flow path”). The first flow path51is made up of a horizontal hole51abored from a bottom side of the inlet port21towards the front side of the flow path configuring portion100A and a vertical hole51bbored downwards from the upper side15of the flow path configuring portion100A. The vertical hole51bintersects with the horizontal hole51aand passes through a side wall of the central mounting hole31vertically (refer toFIG. 5A).

As shown inFIGS. 6A,6B and7, the outlet port22L, which lies inboards, is a bottomed cylindrical hole and communicates with the first inner mounting hole32via a second flow path52. As shown inFIGS. 5A and 5B, the second flow path52is made up of a vertical hole bored from a bottom side of the outlet port22L, which lies inboards, towards the lower side16of the flow path configuring portion100A and passes through a side wall of the first inner mounting hole32and a side wall of the wheel side sensor mounting hole46vertically to reach the second inner mounting hole34.

As shown inFIGS. 6A,6B and7, the outlet port22R, which lies outboards, is a bottomed cylindrical hole and communicates with the first outer mounting hole33via a fourth flow path54. As shown inFIGS. 5A and 5B, the fourth flow path54is made up of a vertical hole bored from a bottom side of the outlet port22R, which lies outboards, towards the lower side16of the flow path configuring portion100A and passes through a side wall of the first outer mounting hole33vertically to reach the second outer mounting hole35.

The central mounting hole31is a bottomed, stepped cylindrical hole into which a normally closed type electromagnetic valve4s(refer toFIG. 1) is mounted which constitutes the suction valve4(refer toFIG. 10) and directly communicates with a side portion of the pump hole38at a bottom portion thereof. In addition, a connecting portion between the bottom portion of the central mounting hole31and the side portion of the pump hole38corresponds to the suction hydraulic pressure line C shown inFIG. 10.

The first inner mounting hole32is a bottomed, stepped cylindrical hole into which a normally open type electromagnetic valve2s(refer toFIG. 1) is mounted, which constitutes the inlet valve2(refer toFIG. 10) of the control valve unit V associated with the wheel brake FR. The first inner mounting hole32communicates with the second inner mounting hole34via the second flow path52as shown inFIG. 5Aand communicates with the first outer mounting hole33via a third flow path53as shown inFIG. 5B. The third flow path53is, as shown inFIG. 6B, made up of:

a horizontal hole53abored from a bottom side of the first inner mounting hole32towards the rear side of the flow path configuring portion100A;

a horizontal hole53bbored from the lateral side14(refer toFIG. 5B) of the flow path configuring portion100A so as to reach the horizontal hole53a; and

a horizontal hole53c(refer toFIG. 5B) bored from a bottom side of the first outer mounting hole33towards the rear side12of the flow path configuring portion100A so as to reach the horizontal hole53b.

An opening in the horizontal hole53bis closed tightly by a plug member, not shown. Note that, the second flow path52and the third flow path53correspond to the wheel hydraulic pressure line B shown inFIG. 10.

The first outer mounting hole33is a bottomed, stepped cylindrical hole into which a normally open type electromagnetic valve2s(refer toFIG. 1) is mounted, which constitutes the inlet valve2(refer toFIG. 10) of the control valve unit V associated with the wheel brake RL. Further, the first outer mounting hole33communicates with the second outer mounting hole35via the fourth flow path54as shown inFIG. 5A. Note that the fourth flow path54corresponds to the wheel hydraulic pressure line B shown inFIG. 10.

The second inner mounting hole34is a bottomed, stepped cylindrical hole into which a normally closed type electromagnetic valve3sis mounted, which constitutes the outlet valve3(refer toFIG. 10) of the control valve unit V associated with the wheel brake FR. The second inner mounting hole34communicates with the reservoir hole37via a fifth flow path55which originates from a bottom portion thereof as shown inFIG. 5B. The fifth flow path55is made up of a vertical hole bored from a bottom side of the reservoir hole37so as to reach the bottom portion of the second inner mounting hole34.

The second outer mounting hole35is a bottomed, stepped cylindrical hole into which a normally closed type electromagnetic valve3sis mounted, which constitutes the outlet valve3(refer toFIG. 10) of the control valve unit V associated with the wheel brake RL. Further, the second outer mounting hole35communicates with a bottom portion of the second inner mounting hole34via a sixth flow path56and also communicates with the reservoir hole37via the fifth flow path55, as shown inFIG. 5B. The sixth flow path56passes through a bottom portion of the second outer mounting hole35horizontally and is made up of a horizontal hole56abored from the lateral side14of the flow path configuring portion100A so as to reach the bottom portion of the second inner mounting hole34. Note that an opening of this horizontal hole56ais closed tightly by a plug member, not shown.

The third mounting hole36is a bottomed, stepped cylindrical hole into which a normally open type electromagnetic valve is (refer toFIG. 1) is mounted, which constitutes the cut-off valve1(refer toFIG. 10). The third mounting hole36communicates with the inlet portion21via the first flow path51and a seventh flow path57at a side wall thereof as shown inFIG. 5Aand, also communicates with the first inner mounting hole32and the first outer mounting hole33via an eighth flow path58and the third flow path53, respectively, at a bottom portion thereof as shown inFIG. 5B. The seventh flow path57passes through the side wall of the third mounting hole36horizontally and is made up of a horizontal hole57abored from the lateral side14of the flow path configuring portion100A so as to intersect the first flow path51. Note that the horizontal hole57areaches a hydraulic pressure source side sensor mounting hole45, which will be described later.

The eighth flow path58is made up of:

a vertical hole58abored from a bottom side of the damper hole39so as to intersect the horizontal hole53bof the third flow path53and to pass through a discharge side of the pump hole38vertically so as to reach the vicinity of the third mounting hole36;

a horizontal hole58bbored from the lateral side14of the flow path configuring portion100A so as to intersect the vertical hole58aand to reach a bottom portion of the third mounting hole36; and

a horizontal hole58c(refer toFIG. 6B) bored from a bottom side of the third mounting hole36so as to reach the horizontal hole58b.

Note that openings of the vertical hole58aand the horizontal hole58bare closed tightly by plug members, not shown, respectively. Here, the first flow path51and the seventh flow path57correspond to the output hydraulic pressure line A shown inFIG. 10, and the eighth flow path58, the third flow path53and the second flow path52correspond to the wheel hydraulic pressure line B shown inFIG. 10.

The reservoir hole37is a bottomed cylindrical hole into which the reservoir5(refer toFIGS. 1,10) is mounted and communicates with the pump hole38via a ninth flow path59as shown inFIG. 5B. The ninth flow path59is made up of a vertical hole bored from a bottom side of the reservoir hole37so as to reach a suction side of the pump hole38. Note that a one-way valve which constitutes the check valve5awhich is shown inFIGS. 9 and 10is mounted on the ninth flow path59. In addition, the fifth flow path55, the sixth flow path56and the ninth flow path59correspond to the release line E shown inFIG. 10.

The pump hole38is a stepped cylindrical hole into which the pump6(refer toFIGS. 1,10) is mounted, is formed so that a center line thereof passes through the center of the bearing hole43and communicates with the damper hole39via the eighth flow path58. The vertical hole58aof the eighth flow path58passes through a discharge side of the pump hole38vertically. Note that the eighth flow path58corresponds to the discharge hydraulic pressure line D shown inFIG. 10.

The damper hole39is a cylindrical hole which constitutes the damper7(refer toFIG. 10), and an opening thereof is closed tightly by a lid member, not shown.

The wheel side sensor mounting hole46is a hole into which the wheel side brake hydraulic pressure sensor9(refer toFIGS. 1,10) is mounted, exhibits a bottomed cylindrical shape and is disposed on a downward extension of the outlet port22L (in this embodiment, provided on the side lying inboards) of the outlet ports between the first inner mounting hole32and the second inner mounting hole34. Specifically, the wheel side sensor mounting hole46is connected to the second flow path52with which a bottom portion thereof communicates below the outlet portion22L and communicates with the outlet port22L.

As shown inFIG. 1, the hydraulic pressure source side sensor mounting hole45, into which the hydraulic pressure source side brake hydraulic pressure sensor8is mounted, is formed so as to straddle the center line X (refer toFIG. 1) of the base body100to extend to the flow path configuring portions100A,100B in a central portion (a boundary portion between the flow path configuring portions100A,100b) of the front side of the base body100which lies below the bearing hole43(refer toFIG. 5A). The hydraulic pressure source side sensor mounting hole45is formed into a bottomed cylindrical shape, is disposed in such a manner that a central portion thereof is positioned on the center line X (refer toFIG. 1) and is made to open to the front side of the base body100. In addition, as shown inFIG. 5A, the seventh flow path57is made to open to a side wall of the hydraulic pressure source side sensor mounting hole45, whereby the hydraulic pressure source side sensor mounting hole45communicates with the inlet port21via the seventh flow path57and the first flow path51.

In addition, as shown inFIG. 4, the bearing hole43into which the output shaft210of the motor200is inserted and a terminal hole44into which a terminal rod220of the motor200is inserted are formed in the central portion (that is, the boundary portion between the flow path configuring portions100A,100B) of the base body100. The bearing hole43is formed into a bottomed, stepped cylindrical shape and is made to open to the rear side12of the base body100. In addition, the pump hole38(refer toFIGS. 5A,5B) is made to open to a side wall of the bearing hole43, and a ball bearing212, which is fitted on an eccentric shaft portion211of the output shaft210so as to push on a plunger162of the pump6, is accommodated in the vicinity of the opening in the pump hole38. The terminal hole44is formed above the bearing hole43and passes through the base body100from the front to the rear thereof.

Next, configurations of the various valve components which are mounted in the respective holes will be described by reference toFIG. 8. Here,FIG. 8Ais a perspective view showing the normally open type electromagnetic valve is,2s,FIG. 8Bis a sectional view showing a section of the normally open type electromagnetic valve2s,FIG. 8Cis a perspective view showing the normally closed type electromagnetic valve3s,4sandFIG. 4Dis a sectional view showing a section of the normally closed type electromagnetic valve3s.

As shown inFIG. 8A, the normally open type electromagnetic valve is which constitutes the cut-off valve1and the normally open type electromagnetic valve2swhich constitutes the inlet valve2are put in such a state (an open state) that an opening111awhich is provided in a lateral side and an opening11bwhich is provided in a bottom side thereof are made to communicate with each other when a magnet coil340(refer toFIG. 4) is deenergized by the control unit400(refer toFIG. 1), whereby a state results in which brake fluid can flow to pass through an interior of the electromagnetic valve concerned. When the solenoid coil340is energized by the control unit400, a state results in which the communication between the opening111alying in the lateral side and the opening111blying in the bottom side thereof is interrupted (a closed state).

Note that since the normally open type electromagnetic valves1s,2shave the same configuration, hereinafter, a detailed description of the electromagnetic valve2swill made.

As shown inFIG. 8B, the normally open type electromagnetic valve2sincludes mainly:

a cylindrical stationary core111;

a valve seat112which is mounted on a distal end side of the stationary core111in an interior thereof;

a valve body113which is similarly mounted in the interior of the stationary core111on a proximal end side thereof so as to slide therein; and

a movable core114which pushes on the valve body113.

In addition, a through hole111cis formed in a lateral side of the stationary core111, which constitutes an opening111athrough which brake fluid which flows into an interior of the electromagnetic valve2sis made to flow out into the second flow path52or the fourth flow path54. Then, when the solenoid coil340shown inFIG. 4is energized, the valve body113moves towards the valve seat112so as to close an opening in the valve seat112in association with the movement of the movable core114which is attracted by the stationary core111. As a result, a state results in which the opening111aprovided in the lateral side and the opening111bprovided in the bottom side of the stationary core111are cut off from each other. In addition, when the solenoid coil340is deenergized, in association with the separation of the movable core114from the stationary core111, the valve body113moves towards the movable core114so as to open the opening in the valve seat112. As a result, the opening111aprovided in the lateral side and the opening111bprovided in the bottom side of the stationary core111are made to communicate with each other.

As shown inFIG. 8C, when the solenoid coil340(refer toFIG. 4) is energized by the control unit400, the normally closed type electromagnetic valve3swhich constitutes the outlet valve3and the normally closed type electromagnetic valve4swhich constitutes the suction valve4are put in a state (an open state) in which an opening132aprovided in a lateral side and an opening132bprovided in a bottom side thereof are made to communicate with each other, whereby brake fluid can flow through an interior of the electromagnetic valve concerned. Whereas when the solenoid coil is deenergized by the control unit400, a state (a closed state) results in which the opening132aprovided in the lateral side and the opening132bprovided in the bottom side are cut off from each other.

Note that since the normally closed type electromagnetic valves3s,4shave the same configuration, the electromagnetic valve3swill be described in detail Herebelow.

The normally closed type electromagnetic valve3sincludes mainly:

a cylindrical valve housing131;

a cylindrical stationary member132which is mounted on a proximal end side in an interior of the valve housing131;

a stationary core133which is secured to a distal end side of the valve housing131in the interior thereof;

a movable core134which is mounted slidably between the stationary member132and the stationary core133in the interior of the valve housing131; and

a bottomed cylindrical valve seat135which is secured in an interior of the stationary member132.

An opening132ais formed in a lateral side of the stationary member132, through which braked fluid which is supplied thereto via the second flow path52or the fourth flow path54(refer toFIG. 5A) is allowed to flow thereinto. Furthermore, a biasing member136is provided between the stationary core133and the movable core134for biasing the movable core134towards the valve seat135. Consequently, in such a state that the solenoid coil340(refer toFIG. 4) which is mounted in the control housing300is deenergized, a valve body137provided at a distal end of the movable core134is closely secured to the valve seat135. As a result, the state results in which the opening132aprovided in the lateral side of the stationary member132and the opening132bprovided in the bottom side thereof are cut off from each other. Then, when the solenoid coil340(refer toFIG. 4) is energized, the movable core134is attracted by the stationary core133to move, and the movable core134moves towards the stationary core133, whereby the valve seat135moves apart from the valve body137. As a result, the state results in which the opening132aprovided in the lateral side and the opening132bprovided in the bottom side of the stationary member132are allowed to communicate with each other.

As shown inFIG. 1, the reservoir5includes:

a substantially bottomed cylindrical reservoir piston151which is mounted in the reservoir hole37;

a reservoir spring152for biasing the reservoir piston151towards the bottom side (the upper side) of the reservoir hole37;

a substantially bottomed cylindrical spring receiving member153which closes an opening in the reservoir37; and

a lid member154.

The reservoir piston151is made to freely slide along an inner circumferential surface of the reservoir hole37on an outer circumferential surface thereof, and when brake fluid flows thereinto via the fifth flow path55(refer toFIG. 5B), the reservoir piston151moves towards the spring receiving member153, so as to store the brake fluid. In addition, the check valve5a(refer toFIG. 10) is mounted on the ninth flow path59shown inFIG. 5B, which permits only a flow of brake fluid from the reservoir hole37side to the eight flow path58side thereof.

As shown inFIG. 9, the pump6includes a cylinder161, a plunger162, a return spring163, a seal stopper164, a suction valve unit165, a cap166, a discharge valve unit167and a discharge side filter168.

The cylinder161is made up of a bottomed cylindrical metal member whose inner circumferential surface is formed into a cylindrical surface, so as to form a suction valve chamber S1which accommodates the suction valve unit165.

The cylinder161includes:

a small diameter portion161awhich faces the pump hole38with a gap provided therebetween;

a press-fit portion161bwhich is press fitted (fitted) into the pump hole38;

a locking portion161cwhich is made larger in diameter than the press fit portion161band is adapted to be locked in a stepped portion of the pump hole38; and

a bottom portion161d(hereinafter, referred to as a “cylinder bottom portion161d”) which is made smaller in diameter than the locking portion161cand is adapted to be fitted in a large diameter recessed portion166ain the cap166.

In addition, a through hole is formed in a central portion of the cylinder bottom portion161d, which constitutes a discharge path161ethrough which brake fluid sucked into the suction valve chamber S1is discharged towards the cap166.

Furthermore, a locking recessed portion161fis formed on an outer circumferential surface of a lower end portion (a distal end portion of the small diameter portion161a) of the cylinder161for holding the seal stopper164, which will be described later.

The plunger162makes a reciprocating motion in an interior hollow space of the cylinder161in association with a rotary motion of the eccentric shaft portion211(refer toFIG. 1) of the motor200. The plunger162includes:

a contact portion162awhich is brought into abutment with the ball bearing212which is mounted on the eccentric shaft portion211(refer toFIG. 1);

a suction portion162bwhich constitutes a suction port for brake fluid;

a sliding portion162cwhich reciprocates in the interior hollow space in the cylinder161while sliding;

a valve seat portion162dwhich constitutes a valve seat of the suction valve unit165, which will be described later; and

a suction path162hformed in an interior of the plunger162.

The suction path162hestablishes a communication between an annular space S2which is formed on the periphery of the suction portion162band the suction valve chamber S1and is made to open to an outer circumferential surface of the suction portion162b(an outer circumferential surface of the plunger162) and an end face of the valve seat portion162d(an upper end face of the plunger162).

The contact portion162ais loosely inserted in the pump hole38and protrudes into the bearing hole43for the motor200at a distal end portion thereof. In addition, an annular seal member162eand a bush162f, which are brought into abutment with the pump hole38, are mounted slidably on the contact portion162a. The suction portion162bis formed between the contact portion162aand the sliding portion162cand at least part thereof project from an opening in the cylinder161. The sliding portion162cis a portion which slides in the inner hollow portion of the small diameter portion161aof the cylinder161, and an outside diameter of the sliding portion162cis made larger than outside diameters of the suction portion162band the valve seat portion162dwhich lie adjacent thereto and is made slightly smaller than an inside diameter of the small diameter portion161aof the cylinder161. The valve seat portion162dis formed closer to the suction valve chamber S1than the sliding portion162c, and an annular seal ring162gis annularly placed on the circumference of the valve seat portion162d. The seal ring162gseals the interior of the suction valve chamber S1fluid tightly while sliding along an inner circumferential portion of the cylinder161.

The return spring163is disposed in the suction valve chamber S1in a compressed state and pushes the plunger162towards the bearing hole43by virtue of the restoring force thereof. The return spring163according to the embodiment is disposed between the cylinder bottom portion161dof the cylinder161and the seal ring162gannularly placed on the plunger162, to thereby push on the plunger162via the seal ring162g.

The seal stopper164is a frame-shaped member for preventing the dislocation of the seal member162eand includes a frame body164awhich is disposed so as to surround the suction portion162bof the plunger162and a locking piece164bwhich extends outwards from the frame body164atowards the cylinder161, whereby the seal stopper164is held in the cylinder161by the locking piece164bbeing locked in the locking recessed portion161fof the cylinder161.

The suction valve unit165opens and closes the suction path162hand is accommodated in the suction valve chamber S1. More specifically, the suction valve unit165includes:

a spherical suction valve body165awhich is disposed so as to close an opening in the suction path162h;

a retainer165bwhich is disposed so as to cover the suction valve body165a; and

a suction valve spring165cwhich is disposed in a compressed state between the suction valve body165aand the retainer165b. The suction valve body165ais biased against the plunger162by virtue of the restoring force of the suction valve spring165c. Note that the retainer165bis fitted on the valve seat portion162dof the plunger162at a lower end portion thereof and is held against the seal ring162gby virtue of the restoring force of the return spring163.

The cap166is provided to be placed on the cylinder bottom portion161dof the cylinder161from the outside so as to cover it and is made up of a bottomed cylindrical metal member which is separate from the cylinder161. Formed on an inside of the cap166are a lager diameter recessed portion into which the cylinder bottom portion161dis press fitted and a small diameter recessed portion166bwhich is made smaller in diameter than the Large diameter recessed portion166a. The small diameter recessed portion166bdefines a discharge valve chamber S3which accommodates therein the discharge valve unit167and the discharge side filter168together with the cylinder bottom portion161d.

An outer circumferential surface of the cap166is recessed in a circumferential direction thereof so as to provide an annular locking groove166c. A plastically deformed portion which is formed on a hole wall of the pump hole38fits in the locking groove166c. In this embodiment, an outside diameter of an upper lid portion166ewhich lies adjacent to the locking groove166cin an upward direction is made smaller than an outside diameter of a lower lid portion166dwhich lies adjacent to the locking groove166cin a downward direction. The lower lid portion166dis substantially the same as an inside diameter at portion lying further inwards than a stepped portion in an inlet portion of the pump hole38and is inserted in the portion concerned. The upper lid portion166eprojects from a bottom side of the stepped portion in the inlet portion of the pump hole38and a circumferential edge portion166fof the projecting portion is chamfered.

An outside diameter of a flow path configuring portion166gof the cap166which lies below the lower lid portion166dis made smaller than the outside diameter of the lower lid portion166d. An annular space S4which communicates with the eighth flow path58is defined by an outer circumferential surface of the flow path configuring portion166gand the pump hole38. In addition, an outlet hole166his formed in the flow path configuring portion166g, which establish a communication between the discharge valve chamber S3and the annular space S4. The outlet hole166hfunctions as an orifice which mitigates pulsation occurring in association with the reciprocation of the plunger162.

The discharge valve unit167opens and closes the discharge path161eformed in the cylinder bottom portion161dof the cylinder161and is accommodated in the discharge valve chamber S3. More specifically, the discharge valve unit167is configured to include a spherical discharge valve body167awhich is disposed so as to close the discharge path161eof the cylinder161, and a discharge valve spring167bwhich is disposed in a compressed state in the discharge valve chamber S3. The discharge valve body167ais biased towards the discharge path161eby virtue of the restoring force of the discharge valve spring167b.

The discharge side filter168filtrating the brake fluid discharged from the discharge path161e, is disposed so as to surround the discharge valve unit167within the discharge valve chamber S3, and is held by the cylinder161and the cap166therebetween so that at least portion thereof is compressed in an axial direction. More specifically, the discharge side filter168includes a filter main body168B which allows brake fluid discharged from the discharge path161eto pass therethrough to filtrate the brake fluid and a holding member168A which holds the filter main body168B.

Following this, the motor200and the control housing300which are assembled to the base body100will be described in detail.

The motor200shown inFIG. 1constitutes a power supply for the pump6and is integrally secured to the rear side12(refer toFIG. 4) of the base body100. As shown inFIG. 4, the eccentric shaft portion211is provided on the output shaft210of the motor200. Further, as has been described above, the ball bearing212is fitted on the eccentric shaft portion211. In addition, the terminal rod220for supplying current to a rotor is provided above the output shaft210so as to project. The terminal rod220is inserted into the terminal hole44formed in a central upper portion of the base body100, and a distal end portion thereof is connected to a connecting terminal331of the control housing300.

As shown inFIG. 1, the control housing300includes a control case310which is integrally secured to the front side11of the base body100so as to cover the electromagnetic valves1sto4s, the hydraulic pressure source side brake hydraulic pressure sensor8and the wheel side brake hydraulic pressure sensor9and a control cover320which closes tightly an opening in the control cover310. In addition, the control case310includes a mounting portion311which covers the front side11of the base body100and a connector portion312in which connecting terminals to a battery and wheel speed sensors (not shown) are formed, and an endless seal member313(refer toFIG. 4) is mounted on the mounting portion311. In addition, as shown inFIG. 4, a support plate portion314in which a bus bar330is embedded is formed integrally in an interior of the control case310. In addition, the solenoid coils340for driving the electromagnetic valves1sto4sinstalled in the base body1400are mounted on the support plate314. In addition to the connecting terminal331to the terminal rod220of the motor200, a connecting terminal (not shown) to the control unit400and connecting terminals333to the solenoid coils are provided on the bus bar330so as to project therefrom.

In addition, since the interior of the control housing is made to communicate with the outside via a recessed portion41and a vent hole42shown inFIGS. 6A,6B, an interior pressure of the control housing300is held at a similar level to the atmospheric pressure. Namely, the occurrence of intrusion of water and the like from the outside can be prevented by changing interior pressure of the control housing300. Here, as shown inFIG. 6, since a water vapor permeation preventive material, not shown, is applied to the recessed portion41of the base body100, there emerges no situation in which water or the like intrudes into the control housing300.

The control unit400shown inFIG. 1is such that a semiconductor chip is installed on a substrate on which an electronic circuit is printed. Also, the control unit400controls the opening and closing of the electromagnetic valves1sto4sand the operation of the motor200based on information obtained from the various sensors such as the hydraulic pressure source side brake fluid sensor8, the wheel side brake hydraulic pressure sensor9, the wheel speed sensors401,402,403,404(refer toFIG. 10) and programs which are stored therein in advance.

Following this, actual flows of brake fluid will be described in detail which result when performing the normal brake control, the anti-lock brake control and the behavior stabilizing control.

In the normal brake control, as has been described above, the normally closed type electromagnetic valve4s(refer toFIG. 1) which constitutes the suction valve4is in the closed state and the normally open type electromagnetic valve is (refer toFIG. 1) which constitutes the cut-off valve1is in the open state. Thus, brake fluid which has flowed in from the inlet port21flows, as shown inFIG. 5A, into the third mounting hole36via the first flow path51and the seventh flow path57and the flows into the eighth flow path58(refer toFIG. 5B) through the interior of the electromagnetic valve1s(refer toFIG. 1) which is being in the open state. As shown inFIG. 5B, the brake fluid that has flowed into the eighth flow path58flows upwards through the annular space S4and thereafter flows into the bottom portion of the first inner mounting hole32and the bottom portion of the first outer mounting hole33through the third flow path53. Then, as shown inFIG. 6A, the brake fluid that has flowed into the bottom portion of the first inner mounting hole32flows into the second flow path52through the interior of the electromagnetic valve2s(refer toFIG. 1) which is being in the open state to thereby reach the wheel brake FR through the outlet port22L. Similarly, the brake fluid that has flowed into the bottom portion of the first outer mounting hole33flows into the fourth flow path54through the interior of the electromagnetic valve2s(refer toFIG. 1) which is being in the open state to thereby reach the wheel brake RL through the outlet port22R.

Here, the brake fluid which has flowed into the second flow path52which reaches the right front wheel brake FR flows into the wheel side sensor mounting hole46. Then, the brake hydraulic pressure within the wheel hydraulic pressure line. B is measured by the wheel side brake hydraulic pressure sensor9, and the measured value is then captured into the control unit400.

In the anti-lock brake control, for example, when the brake hydraulic pressure which is applied to the wheel brake FR is reduced, as has been described above, the control unit400(refer toFIG. 10) puts the inlet valve2associated with the wheel brake FR in the closed state and the outlet valve3in the open state. Then, the brake fluid which is applied to the wheel brake FR flows, as shown inFIG. 5A, into the side portion of the second inner mounting hole34through the outlet port22L and the second flow path52and furthermore flows, as shown inFIG. 5B, into the fifth flow path55through the interior of the electromagnetic valve3s(refer toFIG. 1) which is being in the open state to thereby flow into the reservoir hole37. In addition, since the electromagnetic valve2sis being in the closed state, the brake fluid that has flowed into the first inner mounting hole32does not flow into the third flow path53but passes through a space between the side wall of the first inner mounting hole32and the outer circumferential surface of the electromagnetic valve2s(refer toFIG. 1) to flow out towards the second inner mounting hole34. In addition, when executing an anti-lock brake control, the motor200is driven by the control unit400so as to actuate the pump6. As a result, brake fluid stored in the reservoir hole37is sucked into the pump hole38by way of the ninth flow path59and is then discharged to the eighth flow path58. When reducing the brake hydraulic pressure applied to the wheel brake RL (refer toFIG. 10), as shown inFIG. 5A, the brake fluid passes through the outlet port22R and the fourth flow path54to flow into the side portion of the second outer mounting hole35. Furthermore, as shown inFIG. 5B, the brake fluid passes through the interior of the electromagnetic valve (refer toFIG. 1) which is being in the open state and flows into the sixth flow path56, then, passing through the fifth flow path55to flow into the reservoir hole37.

When holding constant the brake hydraulic pressure applied to the wheel brake FR in the anti-lock brake control, as has been described above, since the inlet port2and the outlet port3are put in the closed state by the control unit400(refer toFIG. 10), there occurs neither the flow of brake fluid into the second flow path52nor the flow of brake fluid out of the second flow path52.

In addition, when increasing the brake hydraulic pressure applied to the wheel brake FR in the anti-lock brake control, as has been described above, since the inlet valve2is put in the open state and the outlet port3is put in the closed state by the control unit400, the flow of brake fluid becomes identical to that occurring in the normal brake control.

In this embodiment, the wheel side brake hydraulic pressure sensor9is mounted in the wheel side sensor mounting hole46which communicates with the right front wheel brake FR via the outlet port22L and the second flow path52. Thus, when executing the anti-lock brake control that has been described above, the brake hydraulic pressure within the wheel hydraulic pressure line B which links to the wheel brake FR can be actually measured. Therefore, in the control unit400, a delicate hydraulic pressure control can be implemented according to the brake hydraulic pressure so measured, and a brake hydraulic pressure which is best suitable for the wheel brake FR can be held in an ensured manner and with ease.

In particular, in this embodiment, by measuring the brake hydraulic pressures applied to the wheel brakes FR, FL of the front wheels to which more brake load is applied, a brake hydraulic pressure control is implemented in which emphasis is placed on braking force control. Furthermore, since the front wheels constitute the drive wheels, a brake hydraulic pressure control is also implemented in which emphasis is placed on traction control.

In the behavior stabilizing control, for example, when actuating the wheel brake FR, as has been described above, after the control unit400puts the cut-off valve1in the closed state and the suction valve4in the open state, the motor200is actuated to drive the pump6(refer toFIG. 9). When the pump6is driven, brake fluid remaining in the inside of the pump hole38is discharged to the eighth flow path58, as shown inFIG. 7. The brake fluid discharged into the eighth flow path58flows into the first inner mounting hole32through the third flow path53and flows further to the second flow path52through the interior of the electromagnetic valve2s(refer toFIG. 1) which is being in the open state, then reaching the wheel brake FR through the outlet port22L. In addition, when the pump6is actuated, since the electromagnetic valve4s(refer toFIG. 1) is in the open state, brake fluid remaining on the first flow path51side (including the brake fluid remaining in the master cylinder M) flows into the pump hole38through the interior of the electromagnetic valve4s.

Also when executing the behavior stabilizing control that has been described above, the brake hydraulic pressure within the wheel hydraulic pressure line B which links with the right front wheel brake FR can actually be measured by the wheel side brake hydraulic pressure sensor9. Thus, in the control unit400, a delicate hydraulic pressure control can be implemented so that the brake hydraulic pressure in the wheel hydraulic pressure line B becomes a desired value, thereby making it possible to implement a highly accurate brake control.

According to the base body100of the brake control unit U which has the specific positional relationship that has been described heretofore, the miniaturization of the unit can be realized while keeping the twelve electromagnetic valves is,2s,3s,4sand the plurality of (three) hydraulic pressure sensors8,9,9on the one side (the front side11) of the base body100. Furthermore, in the brake control unit U to which the base body100so configured is applied, it becomes possible to implement the multiple complex and highly accurate safety functions which involve the control of the vehicle brakes.

In addition, the wheel side brake hydraulic pressure sensors9,9are mounted in the wheel side sensor mounting holes46which communicate, respectively, with the outlet ports22L,22R which link, respectively, with the wheel brakes FR, FL of the front wheels, so that magnitudes of brake hydraulic pressures which are applied to the wheel brakes FR, FL of the front wheels can be measured. Consequently, since the wheel side brake hydraulic pressure sensor9can be used to detect the brake hydraulic pressure of the front wheel to which more brake load is applied, the accuracy of the brake hydraulic pressure control can be enhanced further. In addition, since a brake hydraulic pressure sensor for detecting the brake hydraulic pressure of the rear wheel does not have to be provided, the miniaturization of the brake control unit U is attained, and the reduction in weight of the brake control unit u can also be attained.

Note that while in the embodiment, the first inner mounting hole32and the second inner mounting hole33are disposed in the same height positions, the mounting holes may be disposed offset vertically. Similarly, the second inner mounting hole34and the second outer mounting hole35may also be disposed offset vertically.

In addition, while in the embodiment, the first inner mounting hole32and the second inner mounting hole34are disposed in such a manner that a line which connects centers of the respective mounting holes becomes parallel to the first flow path51, the invention is not limited thereto and hence, they may be disposed offset horizontally.

Additionally, while in the embodiment, the first outer mounting hole33, the second outer mounting hole35and the third mounting hole36are disposed on the straight line so as to be aligned with one another, the invention is not limited thereto, and hence, they may be disposed offset horizontally.

Note that the arrangement of the electromagnetic valves and the hydraulic pressure sensors which are mounted in the mounting holes31to36may be changed. For example, in the brake control unit, after the configurations of the flow paths residing in the interiors of the flow path configuring portions100A,100B, the normally closed type electromagnetic valves which constitute the output valves3may be mounted in the first inner mounting hole32and the first outer mounting hole33, and the normally open type electromagnetic valves which constitute the inlet valves2may be mounted in the second inner mounting hole34and the second outer mounting hole35.

Furthermore, while in the embodiment, the brake hydraulic pressures applied to the wheel brakes FR, FL of the front wheels are made to be measured by the wheel side brake hydraulic pressure sensors9,9, it is possible to increase the accuracy of brake hydraulic pressure control even though a configuration may be adopted, in which the brake hydraulic pressures applied to the wheel brakes RR, RL of the rear wheels are measured irrespective of whether the drive wheels are constituted by the front wheels or the rear wheels.

In addition, while in the embodiment, the description has been made as the invention being applied to the front-wheel-drive vehicle, needless to say, the invention can, of course, be applied to a rear-wheel-drive vehicle and a four-wheel-drive vehicle. In the case of the rear-wheel-drive vehicle, in the event that the brake hydraulic pressures applied to the wheel brakes RR, RL of the rear wheels which are drive wheels by the wheel side brake hydraulic pressure sensors9,9, a brake hydraulic pressure control can be implemented in which emphasis is placed on traction control, while the brake hydraulic pressures applied to the wheel brakes FR, FL of the front wheels are measured by the wheel side brake hydraulic pressure sensors9,9, a brake hydraulic pressure control can be implemented in which emphasis is placed on braking force control. In addition, in the case of the four-wheel-drive vehicle, in the event that the brake hydraulic pressures applied to the wheel brakes FR, FL of the front wheels, a brake hydraulic pressure control can be implemented in which emphasis is placed on both traction control and braking force control.

While the invention has been described in connection with the exemplary embodiments, it will be obvious to those skilled in the art that various changes and modification may be made therein without departing from the present invention, and it is aimed, therefore, to cover in the appended claim all such changes and modifications as fall within the true spirit and scope of the present invention.