JP6325944B2 - Brake system for vehicles - Google Patents

Description

  The present invention relates to a vehicle brake system.

In recent years, there are many vehicles equipped with a vehicle brake system capable of operating an ABS (Antilock Brake System) that avoids wheel lock and eliminates slip. When it is determined that slip has occurred, such a vehicle control means adjusts the braking force of the wheels to eliminate the slip.
Further, Patent Document 1 describes a braking control device (control means) for controlling mechanical braking means (friction braking force generation unit) and regenerative braking means. When the battery (power storage device) is in a fully charged state when the throttle operation is stopped, this braking control device replaces the operation of the electric braking means according to the deceleration obtained by the deceleration calculating means, By operating the mechanical braking means in accordance with the deceleration obtained by the calculation means, a necessary braking force accompanying the accelerator-off is obtained.

JP-A-10-271605

When the accelerator is turned off when the battery is in a fully charged state, the braking control device disclosed in Patent Document 1 drives the electromagnetic valve (first and second electromagnetic valves) to generate a braking force corresponding to the engine braking force. Adjust (the magnitude of the mechanical braking force).
When the ABS is operable by combining such a brake control device with the prior art, the brake control device drives the electromagnetic valve to adjust the braking force to operate the ABS.
However, when the solenoid valve is driven, an operating noise is generated. Since the solenoid valve is driven frequently during the operation of the ABS, when the solenoid valve is driven during the operation of the ABS, the operation sound becomes loud, which causes unpleasant noise for the driver of the vehicle.

  Therefore, the present invention is configured to be able to generate a regenerative braking force and a friction braking force, and when the ABS operates, the ABS operates by adjusting the friction braking force because the power storage device that stores the regenerative power is in a charge-limited state. An object is to provide a vehicle brake system in which unpleasant noise is reduced (or prevented) even in a state.

In order to solve the above-described problems, the present invention is provided in a vehicle that travels with power output from an electric motor in response to an accelerator operation, and generates a brake fluid pressure in accordance with an operation amount of a brake pedal by generating an operation of an actuator. A friction braking force generator for generating a friction braking force on the vehicle, a braking force requested by the driver as a target braking force, a control means for generating the target braking force, a solenoid valve and a pump are driven. And an ABS operation unit for avoiding wheel lock by increasing / decreasing the brake fluid pressure. Then, the control means, wherein when the power storage device for storing electric power supplied to the electric motor of the chargeable state to generate a braking force of the target regenerative braking force generated by the regenerative power generation of the motor, the accelerator operation and the brake pedal When the power storage device is in a charge limit state, the brake fluid pressure is generated by the fluid pressure generation unit of the friction braking force generation unit, so that the regeneration with respect to the target braking force is performed. When the braking force deficiency is generated by the friction braking force and it is determined that the vehicle has slipped when the power storage device is in a charge limit state, the hydraulic pressure is adjusted so that the slip ratio of the wheel becomes the target slip ratio. The brake fluid pressure generated at the generator is reduced to adjust the friction braking force to be reduced .

According to the present invention, a driving electric motor is provided, can generate a target braking force set from the braking force requested by the driver, and when the power storage device is in a charge-limited state, In a vehicle that generates a shortage of regenerative braking force with friction braking force, when the accelerator operation and the brake pedal depressing operation are released and the ABS operates when the power storage device is in a charge-restricted state, The brake fluid pressure generated at the pressure generator is adjusted to be reduced so that the friction braking force is reduced .
Therefore, when the accelerator operation and the depression operation of the brake pedal are released and the ABS is activated when the power storage device is in the charge restriction state, the ABS is activated based on the friction braking force adjusted to be reduced. Therefore, the amount of adjustment of the friction braking force by the ABS operation unit is reduced. As a result, the operating noise in the driving section of the ABS operation section is reduced, and unpleasant noise for the driver of the vehicle is reduced.

In addition, when the control means determines that the friction coefficient of the road surface has increased after adjusting to reduce the friction braking force , the control means increases the brake hydraulic pressure generated in the hydraulic pressure generating unit to increase the friction. It adjusts so that braking force may increase .

According to the present invention, when the control means determines that the friction coefficient of the road surface has increased after adjusting to reduce the friction braking force , the control means increases the brake hydraulic pressure generated by the hydraulic pressure generating unit to increase the friction braking force. Therefore, the adjustment amount of the friction braking force by the ABS operation unit can be effectively increased according to the friction coefficient of the road surface .

  Further, the control means is configured such that when the brake fluid pressure is reduced so that the slip ratio of the wheel becomes the target slip ratio, the regeneration is performed when the power storage device changes from a charge limited state to a chargeable state. The target braking force is generated by a braking force, and the regenerative power generation amount of the electric motor is adjusted so that the slip rate of the wheel becomes the target slip rate.

  According to the present invention, when the power storage device is in a chargeable state when the ABS is operating, the target braking force is generated by the regenerative braking force. The ABS is activated by adjusting the regenerative braking force. Therefore, the driving of the ABS operation unit accompanying the operation of the ABS is stopped, and the operation sound of the ABS operation unit is greatly reduced.

  The control unit may determine that the power storage device is in a charge-limited state when the power storage device is in a fully charged state.

  According to the present invention, when the ABS operates when the power storage device is fully charged, the friction braking force is reduced, and the amount of adjustment of the friction braking force by the ABS operation unit can be effectively reduced.

  According to the present invention, the regenerative braking force and the friction braking force are configured to be generated, and when the ABS is operated, the power storage device that stores the regenerative power is in a state where the ABS is activated by adjusting the friction braking force because the charge limiting state is present. However, it is possible to provide a vehicle brake system in which unpleasant noise is reduced (or prevented).

It is a figure which shows the vehicle provided with the brake system for vehicles. 1 is a schematic configuration diagram of a vehicle brake system. It is a functional block diagram of an ABS control unit. It is a schematic diagram of the braking force generated in the vehicle, (a) is a schematic diagram showing the braking force generated when the battery is in a chargeable state, (b) is the braking force generated when the battery is in a charge limit state. It is a schematic diagram shown. It is a schematic diagram of the braking force generated when the ABS is activated, (a) is a schematic diagram showing when the battery is in a chargeable state, and (b) is a schematic diagram showing when the battery is in a charge limit state. It is a figure which shows the change of friction braking force, and the operating state of ABS. It is a figure which shows the state from which friction braking force changes into regenerative braking force during the action | operation of ABS.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
FIG. 1 shows a vehicle equipped with a vehicle brake system.
As shown in FIG. 1, the vehicle brake system 10 of the present embodiment is provided in an electric vehicle (vehicle 1) that uses an electric motor 200 as a power source. Electric power is supplied from the battery 202 to the electric motor 200. The electric motor 200 outputs power corresponding to the depression operation (accelerator operation) of the accelerator pedal 13. The battery 202 is a power storage device that stores electric power supplied to the electric motor 200.

  The vehicle 1 includes four wheels (a right front wheel WFR, a left rear wheel WRL, a right rear wheel WRR, and a left front wheel WFL). The electric motor 200 is driven by applying power to two front wheels (WFR, WFL), for example. In this case, the two front wheels are driving wheels, and the two rear wheels (WRL, WRR) are driven wheels.

  The four wheels are given a braking force generated by the vehicle brake system 10. The vehicle 1 decelerates and stops when the braking force generated by the vehicle brake system 10 is applied to the four wheels. Each wheel is provided with a wheel cylinder 32FR, 32RL, 32RR, 32FL, respectively. The vehicle brake system 10 supplies brake fluid pressure to the wheel cylinders 32FR, 32RL, 32RR, 32FL to generate a braking force (friction braking force Bfrq) on each wheel. In the present embodiment, the motor cylinder device 16 and the wheel cylinders 32FR, 32RL, 32RR, and 32FL, which will be described later, operate the actuator (electric motor 72), which will be described later, with the brake fluid pressure corresponding to the depression operation amount of the brake pedal 12. By generating it, it becomes a friction braking force generation part which generates a friction braking force to a wheel.

The vehicle brake system 10 is controlled by the control means 150. The control means 150 controls the vehicle brake system 10 when the brake pedal 12 is depressed, and generates a braking force (BPdl braking force BP2) corresponding to the amount of depression of the brake pedal 12.
Further, when the battery 202 is in a chargeable state in which the battery 202 can be charged, the control unit 150 regenerates power by the electric motor 200 to generate the regenerative braking force Breg, and generates the BPdl braking force BP2 by the regenerative braking force Breg. For this reason, the regeneration control device 201 is connected to the electric motor 200.

In the present embodiment, it is assumed that a state where the charging rate of the battery 202 is low and further charging is possible is not a fully charged state. In addition, a state in which the charging rate of the battery 202 is high and a further charging restriction is preferable (for example, a state in which the charging rate is high such that the charging rate is 95%) is set to a fully charged state. That is, the battery 202 that is not in a fully charged state is set in a chargeable state, and the fully charged battery 202 is set in a charge limited state in which charging is preferably limited. The regenerative control device 201 inputs a signal indicating that the battery 202 is in a charge limit state to the control means 150 when the charging rate of the battery 202 is equal to or higher than a predetermined threshold (for example, 95%). The control means 150 determines whether the battery 202 is in a chargeable state or a charge limited state based on a signal input from the regeneration control device 201.
The control means 150 of this embodiment determines that the battery 202 is in the charge limit state when the battery 202 is in a fully charged state.

  The regenerative control device 201 has a function of charging the battery 202 with electric power (regenerative power) generated by the electric motor 200 with torque input from the drive wheels, and is controlled by the control means 150. For example, when a command for generating regenerative braking force Breg by generating regenerative power with the electric motor 200 is input from the control unit 150, the regenerative control device 201 switches the electric motor 200 to “generator” and regenerates electric power generated by the electric motor 200. Functions to charge the battery 202. Further, the regenerative control device 201 is configured to be able to adjust the strength of the regenerative braking force Breg by the electric motor 200, for example, by changing the field current supplied to the electric motor 200 and adjusting the amount of regenerative power generated by the electric motor 200. Is done.

Control in which the control unit 150 gives a command to the regenerative control device 201 to generate regenerative power with the electric motor 200 and generate the regenerative braking force Breg by regenerative power generation with the electric motor 200 is referred to as regenerative control.
As a technique for generating regenerative braking force Breg by regenerative power generation with the electric motor 200, a known technique can be used.

FIG. 2 is a schematic configuration diagram of the vehicle brake system.
As shown in FIG. 2, the vehicle brake system 10 according to the present embodiment provides a hydraulic pressure (brake hydraulic pressure) corresponding to an input of an operation when a brake operation unit such as a brake pedal 12 is operated by a driver. , An input device 14 for generating brake fluid as hydraulic fluid, a pedal stroke sensor St for measuring an operation amount (stroke) when the brake pedal 12 is depressed, a motor cylinder device 16, and stabilization of vehicle behavior Vehicle behavior stabilization device 18 (hereinafter referred to as VSA (vehicle stability assist) device 18, VSA; registered trademark).
The motor cylinder device 16 generates working pressure (brake fluid pressure) supplied to the wheel cylinders 32FR, 32RL, 32RR, and 32FL of each wheel (WFR, WRL, WRR, WFL) in the working fluid (brake fluid). In this embodiment, the motor cylinder device 16 serves as a hydraulic pressure generating unit that generates brake hydraulic pressure.

  These input device 14, motor cylinder device 16, and VSA device 18 are connected by, for example, a pipe line (hydraulic pressure path) formed of a pipe material such as a hose or a tube, and a by-wire type brake. As a system, the input device 14 and the motor cylinder device 16 are electrically connected by a harness (not shown).

  Among these, the hydraulic path will be described. The connection port 20a of the input device 14 and the connection point A1 are connected by the first piping tube 22a with reference to the connection point A1 in FIG. 2 (slightly below the center). The output port 24a of the motor cylinder device 16 and the connection point A1 are connected by the second piping tube 22b, and the introduction port 26a of the VSA device 18 and the connection point A1 are connected by the third piping tube 22c.

  With reference to another connection point A2 in FIG. 2, the other connection port 20b of the input device 14 and the connection point A2 are connected by the fourth piping tube 22d, and the other output port 24b of the motor cylinder device 16 is connected. The connection point A2 is connected by the fifth piping tube 22e, and the other introduction port 26b of the VSA device 18 and the connection point A2 are connected by the sixth piping tube 22f.

  The VSA device 18 is provided with a plurality of outlet ports 28a to 28d. The first outlet port 28a is connected to the wheel cylinder 32FR of the disc brake mechanism 30a provided on the right front wheel WFR by the seventh piping tube 22g. The second outlet port 28b is connected to a wheel cylinder 32RL of the disc brake mechanism 30b provided on the left rear wheel WRL by an eighth piping tube 22h. The third outlet port 28c is connected to the wheel cylinder 32RR of the disc brake mechanism 30c provided on the right rear wheel WRR by the ninth piping tube 22i. The fourth outlet port 28d is connected to a wheel cylinder 32FL of the disc brake mechanism 30d provided on the left front wheel WFL by a tenth piping tube 22j.

  In this case, the brake fluid is supplied to the wheel cylinders 32FR, 32RL, 32RR, 32FL of the disc brake mechanisms 30a-30d by the piping tubes 22g-22j connected to the outlet ports 28a-28d, and the wheel cylinders 32FR, 32FR, As the brake fluid pressure in 32RL, 32RR, and 32FL increases, each wheel cylinder 32FR, 32RL, 32RR, and 32FL is operated, and the frictional force with the corresponding wheel (WFR, WRL, WRR, WFL) is increased. A braking force is applied.

  The right front wheel WFR, the left rear wheel WRL, the right rear wheel WRR, and the left front wheel WFL are provided with wheel speed sensors 35a, 35b, 35c, and 35d, respectively, for detecting the wheel speed, and the wheel speed sensors 35a and 35b are provided. , 35c, and 35d measure the wheel speed of each wheel and are input to the control means 150.

  The input device 14 includes a tandem master cylinder 34 that can generate hydraulic pressure in the brake fluid by the driver operating the brake pedal 12, and a reservoir (first reservoir 36) attached to the master cylinder 34. In the cylinder tube 38 of the master cylinder 34, two pistons (secondary piston 40a and primary piston 40b) spaced apart by a predetermined distance along the axial direction of the cylinder tube 38 are slidably disposed. The secondary piston 40 a is disposed close to the brake pedal 12 and is connected to the brake pedal 12 via the push rod 42. Further, the primary piston 40b is arranged farther from the brake pedal 12 than the secondary piston 40a.

  Further, on the inner wall of the cylinder tube 38, a pair of ring-shaped cup seals 44Pa and 44Pb slidably contacting the outer periphery of the primary piston 40b, and a pair of ring-shaped cup seals 44Sa and 44Sb slidably contacting the outer periphery of the secondary piston 40a. Is installed. Further, a spring member 50a is disposed between the secondary piston 40a and the primary piston 40b, and another spring member 50b is disposed between the primary piston 40b and the side end portion 38a on the closed end side of the cylinder tube 38. Established.

A guide rod 48b extends from the side end 38a of the cylinder tube 38 along the sliding direction of the primary piston 40b, and the primary piston 40b slides while being guided by the guide rod 48b.
A guide rod 48a extends from the end of the primary piston 40b on the secondary piston 40a side along the sliding direction of the secondary piston 40a, and the secondary piston 40a slides while being guided by the guide rod 48a.
The secondary piston 40a and the primary piston 40b are connected by a guide rod 48a and arranged in series.

The cylinder tube 38 of the master cylinder 34 has two supply ports (second supply port 46a and first supply port 46b), two relief ports (second relief port 52a and first relief port 52b), Two output ports 54a and 54b are provided. In this case, the second supply port 46a, the first supply port 46b, the second relief port 52a, and the first relief port 52b are provided so as to join and communicate with a reservoir chamber (not shown) in the first reservoir 36, respectively.
Further, the pair of cup seals 44Sa and 44Sb that are in sliding contact with the outer periphery of the secondary piston 40a are disposed with the second relief port 52a interposed in the sliding direction of the secondary piston 40a. Further, the pair of cup seals 44Pa and 44Pb slidably in contact with the outer periphery of the primary piston 40b is disposed with the first relief port 52b interposed in the sliding direction of the primary piston 40b.

Further, in the cylinder tube 38 of the master cylinder 34, a second pressure chamber 56a and a first pressure chamber 56b that generate a hydraulic pressure corresponding to the depression force that the driver steps on the brake pedal 12 are provided. The second pressure chamber 56a is provided so as to communicate with the connection port 20a via the second hydraulic pressure path 58a, and the first pressure chamber 56b communicates with the other connection port 20b via the first hydraulic pressure path 58b. To be provided.
A space between the first pressure chamber 56b and the second pressure chamber 56a is liquid-tightly sealed by a pair of cup seals 44Pa and 44Pb. Further, the brake pedal 12 side of the second pressure chamber 56a is liquid-tightly sealed by a pair of cup seals 44Sa and 44Sb.

The first pressure chamber 56b is configured to generate a hydraulic pressure corresponding to the displacement of the primary piston 40b, and the second pressure chamber 56a is configured to generate a hydraulic pressure corresponding to the displacement of the secondary piston 40a. .
The secondary piston 40 a is connected to the brake pedal 12 via the push rod 42 and is displaced in the cylinder tube 38 with the operation of the brake pedal 12. Further, the primary piston 40b is displaced by the hydraulic pressure generated in the second pressure chamber 56a by the displacement of the secondary piston 40a. That is, the primary piston 40b is displaced in response to the secondary piston 40a.

  Between the master cylinder 34 and the connection port 20a, a pressure sensor Pm is disposed on the upstream side of the second hydraulic pressure path 58a, and a normally open type is provided on the downstream side of the second hydraulic pressure path 58a. A second shut-off valve 60a composed of a (normally open) solenoid valve is provided. The pressure sensor Pm measures the hydraulic pressure upstream of the second shutoff valve 60a on the master cylinder 34 side on the second hydraulic pressure path 58a.

  Between the master cylinder 34 and the other connection port 20b, on the upstream side of the first hydraulic pressure path 58b, a first shutoff valve 60b composed of a normally open type (normally open type) solenoid valve is provided. A pressure sensor Pp is provided on the downstream side of the first hydraulic pressure path 58b. This pressure sensor Pp measures the hydraulic pressure downstream of the wheel cylinders 32FR, 32RL, 32RR, 32FL from the first shutoff valve 60b on the first hydraulic pressure path 58b.

  The normal open in the second shut-off valve 60a and the first shut-off valve 60b is a valve configured such that the normal position (the position of the valve body when not energized) is in the open position (normally open). Say. In FIG. 2, the second shut-off valve 60a and the first shut-off valve 60b respectively show a closed state in which a solenoid (not shown) is actuated by energizing the solenoid.

  The first hydraulic pressure path 58b between the master cylinder 34 and the first shut-off valve 60b is provided with a branch hydraulic pressure path 58c branched from the first hydraulic pressure path 58b, and the branch hydraulic pressure path 58c is normally closed. A third shut-off valve 62 composed of a type (normally closed) solenoid valve and a stroke simulator 64 are connected in series. The normal close in the third shut-off valve 62 refers to a valve configured such that the normal position (the position of the valve body when not energized) is in the closed position (normally closed). In FIG. 2, the third shut-off valve 62 shows a valve open state in which a solenoid (not shown) is actuated by energizing a solenoid.

  The stroke simulator 64 is a device that gives a stroke and reaction force to the depression operation of the brake pedal 12 during the by-wire control, and makes the driver feel as if braking force is generated by the depression force. The first hydraulic pressure path 58b is disposed closer to the master cylinder 34 than the first shutoff valve 60b. The stroke simulator 64 is provided with a hydraulic pressure chamber 65 communicating with the branch hydraulic pressure path 58c, and brake fluid (brake fluid) led out from the first pressure chamber 56b of the master cylinder 34 via the hydraulic pressure chamber 65 is provided. Absorbable.

The stroke simulator 64 is a simulator piston that is urged by a first return spring 66a having a high spring constant, a second return spring 66b having a low spring constant, and first and second return springs 66a and 66b arranged in series with each other. 68, the pedal reaction force of the brake pedal 12 depresses the existing master cylinder 34 by setting the pedal reaction force increasing gradient low during the first half of the depression of the brake pedal 12 and setting the pedal reaction force high during the second half of the depression. It is provided to be equivalent to the pedal feeling when operated.
That is, the stroke simulator 64 is configured to generate a reaction force corresponding to the hydraulic pressure of the brake fluid derived from the first pressure chamber 56 b and to apply the reaction force to the brake pedal 12 via the master cylinder 34. .

  The hydraulic pressure path is roughly divided into a second hydraulic pressure system 70a that connects the second pressure chamber 56a of the master cylinder 34 and the plurality of wheel cylinders 32FR, 32RL, a first pressure chamber 56b of the master cylinder 34, and a plurality of pressure paths. The first hydraulic system 70b is connected to the wheel cylinders 32RR and 32FL.

  The second hydraulic system 70a includes a second hydraulic path 58a that connects the output port 54a of the master cylinder 34 (cylinder tube 38) and the connection port 20a in the input device 14, and the connection port 20a of the input device 14 and the motor cylinder. Piping tubes 22a and 22b connecting the output port 24a of the device 16, piping tubes 22b and 22c connecting the output port 24a of the motor cylinder device 16 and the introduction port 26a of the VSA device 18, and a lead-out port of the VSA device 18 28a, 28b and pipe tubes 22g, 22h connecting the wheel cylinders 32FR, 32RL, respectively.

  The first hydraulic system 70b includes a first hydraulic path 58b that connects the output port 54b of the master cylinder 34 (cylinder tube 38) in the input device 14 and the other connection port 20b, and another connection port of the input device 14. Piping tubes 22d and 22e for connecting 20b and the output port 24b of the motor cylinder device 16, piping tubes 22e and 22f for connecting the output port 24b of the motor cylinder device 16 and the introduction port 26b of the VSA device 18, and a VSA device 18 lead-out ports 28c, 28d and pipe tubes 22i, 22j connecting the wheel cylinders 32RR, 32FL, respectively.

  The motor cylinder device 16 includes an electric motor 72 (actuator), an actuator mechanism 74, and a cylinder mechanism 76 biased by the actuator mechanism 74, and functions as a hydraulic pressure generating unit in the present embodiment.

The actuator mechanism 74 is provided on the output shaft 72 b side of the electric motor 72, and rotates through the gear mechanism 78 and a gear mechanism (deceleration mechanism) 78 that meshes a plurality of gears to transmit the rotational driving force of the electric motor 72. The ball screw structure 80 includes a ball screw shaft 80a and a ball 80b that move forward and backward along the axial direction by transmitting a driving force.
In the present embodiment, the ball screw structure 80 is housed in the mechanism housing portion 173 a of the actuator housing 172 together with the gear mechanism 78.

The cylinder mechanism 76 includes a substantially cylindrical cylinder body 82 and a second reservoir 84 attached to the cylinder body 82. The second reservoir 84 is connected to the first reservoir 36 attached to the master cylinder 34 of the input device 14 by a piping tube 86, and the brake fluid stored in the first reservoir 36 is passed through the piping tube 86 to the second reservoir 84. 84 is provided so as to be supplied in the inside. Note that the piping tube 86 may be provided with a tank for storing brake fluid.
An open end (open end) of the cylinder body 82 having a substantially cylindrical shape is fitted into an actuator housing 172 including a housing body 172F and a housing cover 172R, and the cylinder body 82 and the actuator housing 172 are coupled to each other. A cylinder device 16 is configured.

  In the cylinder body 82, a second slave piston 88a and a first slave piston 88b that are spaced apart from each other by a predetermined distance along the axial direction of the cylinder body 82 are slidably disposed. The second slave piston 88a is disposed in the vicinity of the ball screw structure 80, contacts the one end of the ball screw shaft 80a, and is displaced integrally with the ball screw shaft 80a in the direction of the arrow X1 or X2. The first slave piston 88b is arranged farther from the ball screw structure 80 side than the second slave piston 88a.

Further, the electric motor 72 in the present embodiment is configured to be covered with a motor casing 72a formed separately from the cylinder body 82, and the output shaft 72b slides between the second slave piston 88a and the first slave piston 88b. It arrange | positions so that it may become substantially parallel to (axial direction).
The rotational drive of the output shaft 72b is transmitted to the ball screw structure 80 via the gear mechanism 78.

  The gear mechanism 78 is, for example, a third gear 78a that is attached to the output shaft 72b of the electric motor 72 and a ball 80b that moves the ball screw shaft 80a back and forth in the axial direction about the axis of the ball screw shaft 80a. The gear 78c is composed of three gears, a second gear 78b that transmits the rotation of the first gear 78a to the third gear 78c, and the third gear 78c rotates around the axis of the ball screw shaft 80a.

  The actuator mechanism 74 in the present embodiment converts the rotational driving force of the output shaft 72b of the electric motor 72 into the advancing / retreating driving force (linear driving force) of the ball screw shaft 80a by the structure described above.

A pair of slave cup seals 90a and 90b are mounted on the outer peripheral surface of the first slave piston 88b via an annular stepped portion. A first back chamber 94b communicating with a reservoir port 92b described later is formed between the pair of slave cup seals 90a and 90b.
A second return spring 96a is disposed between the second and first slave pistons 88a and 88b, and a first return spring 96b is provided between the first slave piston 88b and the side end of the cylinder body 82. Is disposed.

An annular guide piston 90c that seals between the outer peripheral surface of the second slave piston 88a and the mechanism housing portion 173a in a fluid-tight manner and guides the second slave piston 88a so as to be movable in the axial direction. The cylinder body 82 is provided as a seal member behind the second slave piston 88a. It is preferable that a slave cup seal (not shown) is attached to the inner peripheral surface of the guide piston 90c through which the second slave piston 88a penetrates, and the second slave piston 88a and the guide piston 90c are liquid-tightly configured. Further, a slave cup seal 90b is attached to the front outer peripheral surface of the second slave piston 88a via an annular step portion.
With this configuration, the brake fluid filled in the cylinder body 82 is sealed in the cylinder body 82 by the guide piston 90c and does not flow into the actuator housing 172 side.
A second back chamber 94a communicating with a reservoir port 92a described later is formed between the guide piston 90c and the slave cup seal 90b.

  The cylinder body 82 of the cylinder mechanism 76 is provided with two reservoir ports 92a and 92b and two output ports 24a and 24b. In this case, the reservoir port 92a (92b) is provided so as to communicate with a reservoir chamber (not shown) in the second reservoir 84.

  Further, in the cylinder body 82, a second hydraulic pressure chamber 98a for controlling the brake hydraulic pressure output from the output port 24a to the wheel cylinders 32FR, 32RL side, and the other output port 24b to the wheel cylinders 32RR, 32FL side. A first hydraulic pressure chamber 98b for controlling the output brake hydraulic pressure is provided.

According to this configuration, the second back chamber 94a, the first back chamber 94b, the second hydraulic chamber 98a, and the first hydraulic chamber 98b in which the brake fluid is sealed are brake fluid sealing portions in the cylinder body 82. The guide piston 90c functioning as a seal member is partitioned from the mechanism housing portion 173a of the actuator housing 172 in a liquid tight (air tight) manner.
Note that the method of attaching the guide piston 90c to the cylinder body 82 is not limited. For example, the guide piston 90c may be attached with a circlip (not shown).

  A regulating means for regulating the maximum stroke (maximum displacement distance) and the minimum stroke (minimum displacement distance) of the second slave piston 88a and the first slave piston 88b between the second slave piston 88a and the first slave piston 88b. 100 is provided. Further, the first slave piston 88b is provided with a stopper pin 102 that restricts the sliding range of the first slave piston 88b and prevents an overreturn to the second slave piston 88a side. At the time of backup braking at 34, when one system fails, the other system is prevented from failing.

  The VSA device 18 is a known one, and a second brake system that controls a second hydraulic system 70a connected to the disc brake mechanisms 30a, 30b (wheel cylinders 32FR, 32RL) of the right front wheel WFR and the left rear wheel WRL. 110a and a first brake system 110b for controlling the first hydraulic system 70b connected to the disc brake mechanisms 30c, 30d (wheel cylinders 32RR, 32FL) of the right rear wheel WRR and the left front wheel WFL. The second brake system 110a is composed of a hydraulic system connected to a disc brake mechanism provided on the left front wheel WFL and the right front wheel WFR, and the first brake system 110b is connected to the right rear wheel WRR and the left rear wheel WRL. A hydraulic system connected to the provided disc brake mechanism may be used. Further, the second brake system 110a includes a hydraulic system connected to a disc brake mechanism provided on the right front wheel WFR and the right rear wheel WRR on one side of the vehicle body, and the first brake system 110b includes the left front wheel WFL on the vehicle body side. And a hydraulic system connected to a disc brake mechanism provided on the left rear wheel WRL.

  Since the second brake system 110a and the first brake system 110b have the same structure, the corresponding parts in the second brake system 110a and the first brake system 110b are assigned the same reference numerals, and The description of the first brake system 110b will be added in parentheses with a focus on the description of the two brake system 110a.

  The second brake system 110a (first brake system 110b) has a common pipe line (first common hydraulic pressure path 112 and second common hydraulic pressure path 114) for the wheel cylinders 32FR, 32RL (32RR, 32FL). Have. Among these, the first common hydraulic pressure path 112 is a supply path for supplying brake hydraulic pressure to the wheel cylinders 32FR, 32RL (32RR, 32FL).

  The VSA device 18 includes a first in-valve 120a (120b) composed of a normally open solenoid valve disposed between the first common hydraulic pressure path 112 and the first outlet port 28a (fourth outlet port 28d), The brake fluid is allowed to flow from the first outlet port 28a (fourth outlet port 28d) side to the first common hydraulic pressure passage 112 side, which is arranged in parallel with the one-in valve 120a (120b) (first common hydraulic pressure passage 112). A second check valve 122 that blocks the flow of brake fluid from the side to the first outlet port 28a (fourth outlet port 28d) side, a first common hydraulic path 112, and a second outlet port 28b (third outlet port). 28c), a second in-valve 124a (124b) comprising a normally open type solenoid valve, and a second in-valve 124a 124b) and allows the brake fluid to flow from the second outlet port 28b (third outlet port 28c) side to the first common hydraulic path 112 side (second side from the first common hydraulic path 112 side to the second side). And a third check valve 126 for blocking the flow of brake fluid to the outlet port 28b (third outlet port 28c) side.

  The VSA device 18 of the present embodiment includes a pressure sensor P1 that measures the brake hydraulic pressure in the first common hydraulic pressure path 112, and a measurement signal measured by the pressure sensor P1 is input to the control unit 150. .

The first in-valve 120a (120b) and the second in-valve 124a (124b) are opening / closing means for opening and closing a pipe line (first common hydraulic path 112) for supplying brake hydraulic pressure to the wheel cylinders 32FR, 32RL, 32RR, 32FL. It is.
When the first in valve 120a is closed, the supply of the brake fluid pressure from the first common hydraulic path 112 to the wheel cylinder 32FR is shut off, and when the first in valve 120b is closed, the first common fluid to the wheel cylinder 32FL is closed. The supply of brake fluid pressure from the pressure path 112 is shut off. Further, when the second in-valve 124a is closed, the supply of the brake hydraulic pressure from the first common hydraulic pressure path 112 to the wheel cylinder 32RL is cut off, and when the second in-valve 124b is closed, the first inflow to the wheel cylinder 32RR is performed. The supply of brake fluid pressure from the common fluid pressure path 112 is cut off.

  Further, the VSA device 18 includes a first out valve 128a (128b) including a normally closed solenoid valve disposed between the first outlet port 28a (fourth outlet port 28d) and the second common hydraulic pressure path 114. A second out valve 130a (130b) composed of a normally closed solenoid valve disposed between the second derivation port 28b (third derivation port 28c) and the second common hydraulic pressure path 114, and a second common The reservoir device 132 connected to the hydraulic pressure path 114, and disposed between the first common hydraulic pressure path 112 and the second common hydraulic pressure path 114, and the first common hydraulic pressure path from the second common hydraulic pressure path 114 side. The fourth check valve 13 allows the brake fluid to flow to the 112 side (blocks the brake fluid from the first common hydraulic pressure passage 112 side to the second common hydraulic pressure passage 114 side). A pump 136 that is disposed between the fourth check valve 134 and the first common hydraulic pressure path 112 and supplies brake fluid from the second common hydraulic pressure path 114 side to the first common hydraulic pressure path 112 side; A normally closed solenoid disposed between the suction valve 138 and the discharge valve 140 provided before and after 136, the motor M for driving the pump 136, the second common hydraulic pressure path 114 and the introduction port 26a (26b). And a suction valve 142 comprising a valve.

In the second brake system 110a, an output port 24a of the motor cylinder device 16 is output on a pipe line (hydraulic pressure passage) adjacent to the introduction port 26a, and the second brake pressure chamber 98a of the motor cylinder device 16 A pressure sensor Ph is provided for measuring the controlled brake fluid pressure. Measurement signals measured by the pressure sensors Pm, Pp, and Ph are input to the control unit 150. In addition to the VSA control, the VSA device 18 can operate an ABS. In this embodiment, the VSA device 18 serves as an ABS operation unit.
Instead of the VSA device 18, the vehicle brake system 10 to which an ABS operation unit having only an ABS function is connected may be used.

The VSA device 18 of the present embodiment is controlled by the ABS control unit 151 included in the control means 150, and the ABS operates. The ABS control unit 151 includes an in-valve (first in-valve 120a, first in-valve 120b, second in-valve 124a, second in-valve 124b) and out-valve (first out-valve 128a, first out-valve 128b, second out-valve 130a, The ABS is operated by controlling the VSA device 18 such as opening and closing of the second out valve 130b). The control means 150 and the ABS control unit 151 may be configured integrally or may be configured separately.
Hereinafter, all of the first in valve 120a, the first in valve 120b, the second in valve 124a, and the second in valve 124b are referred to as in valves. In addition, all of the first out valve 128a, the first out valve 128b, the second out valve 130a, and the second out valve 130b are referred to as out valves.

In the VSA device 18, when the first in-valve 120a (120b) opens with the first out valve 128a (128b) closed, the brake fluid pressure is supplied to the wheel cylinder 32FR (32FL) and the right front wheel WFR (left side). The braking force of the front wheels WFL) increases. When the first out valve 128a (128b) is opened, the brake fluid supplied to the wheel cylinder 32FR (32FL) flows into the reservoir device 132, and the brake fluid pressure of the wheel cylinder 32FR (32FL) decreases. As a result, the braking force of the right front wheel WFR (left front wheel WFL) decreases.
Further, when the second in-valve 124a (124b) opens with the second out valve 130a (130b) closed, the brake fluid pressure is supplied to the wheel cylinder 32RL (32RR), and the left rear wheel WRL (right rear wheel). WRR) braking force increases. When the second out valve 130a (130b) is opened, the brake fluid supplied to the wheel cylinder 32RL (32RR) flows into the reservoir device 132, and the brake fluid pressure of the wheel cylinder 32RL (32RR) decreases. As a result, the braking force of the left rear wheel WRL (right rear wheel WRR) decreases.
The control means 150 drives the pump 136 when the braking force generated in each wheel (WFR, WRL, WRR, WFL) is increased with the in-valve opened.

FIG. 3 is a functional block diagram of the ABS control unit.
The ABS control unit 151 of the present embodiment determines that the vehicle 1 (see FIG. 1) has slipped when the deviation between the slip ratio of at least one wheel and the target slip ratio is greater than a predetermined threshold. The ABS control unit 151 operates the ABS when it is determined that the vehicle 1 has slipped.

  As shown in FIG. 3, the ABS control unit 151 includes wheel speed calculation units 15aa, 15ab, 15ac, and 15ad that calculate the wheel speed of each wheel (WFR, WRL, WRR, WFL). The wheel speed calculation unit 15aa calculates the wheel speed of the right front wheel WFR based on the measurement signal input from the wheel speed sensor 35a. The wheel speed calculation unit 15ab calculates the wheel speed of the left rear wheel WRL based on the measurement signal input from the wheel speed sensor 35b. The wheel speed calculation unit 15ac calculates the wheel speed of the right rear wheel WRR based on the measurement signal input from the wheel speed sensor 35c. The wheel speed calculation unit 15ad calculates the wheel speed of the left front wheel WFL based on the measurement signal input from the wheel speed sensor 35d.

  The ABS control unit 151 includes a vehicle body speed calculation unit 15b. The vehicle body speed calculation unit 15b calculates the vehicle body speed of the vehicle 1 (see FIG. 1) based on the wheel speeds calculated by the wheel speed calculation units 15aa, 15ab, 15ac, and 15ad. The ABS control unit 151 has a low speed selection unit 15c. The low speed selection unit 15c selects one of the wheel speed of the left rear wheel WRL and the wheel speed of the right rear wheel WRR which is lower.

The ABS control unit 151 includes a rear wheel slip ratio calculation unit 15d and a front wheel slip ratio calculation unit 15e.
The rear wheel slip ratio calculation unit 15d calculates the rear wheel slip ratio from the ratio between the wheel speed of the rear wheel selected by the low speed selection unit 15c and the vehicle body speed calculated by the vehicle speed calculation unit 15b.
The front wheel slip ratio calculation unit 15e includes a right front wheel slip ratio calculation unit 15ea and a left front wheel slip ratio calculation unit 15ed. The right front wheel slip ratio calculation unit 15ea calculates the slip ratio of the right front wheel WFR from the ratio of the wheel speed of the right front wheel WFR to the vehicle body speed. The left front wheel slip ratio calculation unit 15ed calculates the slip ratio of the left front wheel WFL from the ratio of the wheel speed of the left front wheel WFL to the vehicle body speed.

  The ABS control unit 151 includes a target slip ratio setting unit 15j, a rear wheel side control amount calculation unit 15f, and a front wheel side control amount calculation unit 15g.

The target slip ratio setting unit 15j sets the target slip ratio based on the vehicle body speed of the vehicle 1 (see FIG. 1) calculated by the vehicle body speed calculation unit 15b.
For example, the target slip ratio setting unit 15j has a map indicating the correlation between the vehicle body speed of the vehicle 1 and the target slip ratio. The target slip ratio setting unit 15j sets the target slip ratio with reference to the map according to the vehicle body speed of the vehicle 1.

The rear wheel side control amount calculation unit 15f sets the braking force of the rear wheels (WRL, WRR) so that the slip ratio of the rear wheels becomes the target slip ratio. Further, the rear wheel side control amount calculation unit 15f calculates a control amount for causing the set braking force to act on the rear wheel.
Specifically, the rear-wheel-side control amount calculation unit 15f operates the in-valve (second in-valve 124a so that a braking force such that the slip ratio of the rear wheel becomes the target slip ratio acts on the left rear wheel WRL and the right rear wheel WRR. , 124b) and the control amount for driving the out valves (second out valves 130a, 130b).

The front wheel side control amount calculation unit 15g includes a right front control amount calculation unit 15ga and a left front control amount calculation unit 15gd.
The right front control amount calculation unit 15ga sets the braking force of the right front wheel WFR so that the slip ratio of the right front wheel WFR becomes the target slip ratio. Further, the right front control amount calculation unit 15ga calculates a control amount for causing the set braking force to act on the right front wheel WFR.
Specifically, the right front control amount calculation unit 15ga drives the first in-valve 120a and the first out valve 128a so that a braking force that causes the slip ratio of the right front wheel WFR to be the target slip ratio acts on the right front wheel WFR. A control amount is calculated.
The left front control amount calculation unit 15gd sets the braking force of the left front wheel WFL so that the slip ratio of the left front wheel WFL becomes the target slip ratio. Further, the left front control amount calculation unit 15gd calculates a control amount for applying the set braking force to the left front wheel WFL.
Specifically, the left front control amount calculation unit 15gd drives the first in-valve 120b and the first out valve 128b so that the braking force that causes the slip ratio of the left front wheel WFL to be the target slip ratio acts on the left front wheel WFL. A control amount is calculated.

  The ABS control unit 151 includes a regeneration control unit 15i. A signal indicating that the battery 202 is in a charge restriction state is input from the regeneration control device 201 to the regeneration control unit 15i. Based on the signal input from the regeneration control device 201, the regeneration control unit 15i determines whether the battery 202 is in a chargeable state or a charge limit state.

  When the regeneration control unit 15i determines that the battery 202 is in a chargeable state, the control amount calculated by the right front control amount calculation unit 15ga and the control amount calculated by the left front control amount calculation unit 15gd are input to the regeneration control unit 15i. The regeneration control unit 15i controls the regeneration control apparatus 201 based on the input control amount. Specifically, the regenerative control unit 15i performs regenerative power generation by the electric motor 200 (see FIG. 1) so that a braking force is generated such that the slip rate of the front wheels (WFL, WFR) becomes the target slip rate. Is generated.

When the battery 202 is in the charge limit state and the regeneration control unit 15i determines, the control amount calculated by the rear wheel side control amount calculation unit 15f is input to the right rear wheel side drive unit 15hc and the left rear wheel side drive unit 15hb. The The right rear wheel side drive unit 15hc drives the second in valve 124b and the second out valve 130b based on the input control amount. The left rear wheel side drive unit 15hb drives the second in valve 124a and the second out valve 130a based on the input control amount.
Further, the control amount calculated by the right front control amount calculation unit 15ga is input to the right front wheel side drive unit 15ha. The right front wheel side drive unit 15ha drives the first in valve 120a and the first out valve 128a based on the input control amount.
Further, the control amount calculated by the left front control amount calculation unit 15gd is input to the left front wheel side drive unit 15hd. The left front wheel drive unit 15hd drives the first in valve 120b and the first out valve 128b based on the input control amount.

The ABS control unit 151 of the present embodiment is configured as shown in FIG. When the battery 202 is in the charge limit state, the ABS is operated by driving the in-valve and the out-valve so that the slip ratio of each wheel becomes the target slip ratio.
The control means 150 drives the pump 136 (see FIG. 2) when the braking force generated on each wheel (WFR, WRL, WRR, WFL) is increased with the in-valve being driven. Specifically, the control means 150 drives the pump 136 to increase the braking force generated at each wheel when the braking force generated at each wheel with the in-valve driven is insufficient for the set braking force. .

  The vehicle brake system 10 according to the present embodiment is basically configured as described above. Next, the operation and effect will be described.

  When the vehicle brake system 10 is functioning normally, the second shut-off valve 60a and the first shut-off valve 60b, which are normally open type solenoid valves, are energized to be closed, and the first shut-off valve, which is composed of a normally close type solenoid valve. The three shut-off valve 62 is excited and the valve is opened. Accordingly, since the second hydraulic system 70a and the first hydraulic system 70b are shut off by the second shut-off valve 60a and the first shut-off valve 60b, the hydraulic pressure generated in the master cylinder 34 of the input device 14 is disc brake mechanism. It is not transmitted to the wheel cylinders 32FR, 32RL, 32RR, 32FL of 30a to 30d.

  At this time, the hydraulic pressure generated in the first pressure chamber 56b of the master cylinder 34 is transmitted to the hydraulic pressure chamber 65 of the stroke simulator 64 via the branch hydraulic pressure path 58c and the third shut-off valve 62 in the valve open state. The The simulator piston 68 is displaced against the spring force of the first and second return springs 66a and 66b by the hydraulic pressure supplied to the hydraulic pressure chamber 65, so that the stroke of the brake pedal 12 is allowed, and the simulation is performed. A typical pedal reaction force is generated and applied to the brake pedal 12. As a result, it is possible to obtain a brake feeling that is comfortable for the driver.

  In such a system state, the control means 150 determines that the braking is being performed when detecting the depression of the brake pedal 12 by the driver, drives the electric motor 72 of the motor cylinder device 16 to energize the actuator mechanism 74, and 2 The second slave piston 88a and the first slave piston 88b are displaced in the direction of the arrow X1 in FIG. 2 against the spring force of the return spring 96a and the first return spring 96b. Due to the displacement of the second slave piston 88a and the first slave piston 88b, the brake fluid in the second fluid pressure chamber 98a and the first fluid pressure chamber 98b is pressurized so as to be balanced to generate a desired brake fluid pressure.

  Specifically, the control means 150 calculates a depression operation amount of the brake pedal 12 (hereinafter referred to as “brake operation amount” as appropriate) according to a measured value of the pedal stroke sensor St, and based on the brake operation amount, The target brake fluid pressure is set in consideration of the regenerative braking force, and the set brake fluid pressure is generated in the motor cylinder device 16.

The control means 150 of the present embodiment includes, for example, a microcomputer and peripheral devices that are configured by a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., not shown. The control means 150 is configured to control the vehicle brake system 10 by executing a program stored in the ROM in advance by the CPU.
Moreover, the electrical signal in this embodiment is a control signal for controlling the electric power which drives the electric motor 72, and the electric motor 72, for example.

  Further, the operation amount measuring means for measuring the depression operation amount (brake operation amount) of the brake pedal 12 is not limited to the pedal stroke sensor St, and any sensor that can measure the depression operation amount of the brake pedal 12 may be used. . For example, the operation amount measuring means may be a pressure sensor Pm, and the hydraulic pressure measured by the pressure sensor Pm may be converted into a depression operation amount of the brake pedal 12, or the depression operation of the brake pedal 12 may be performed by a depression force sensor (not shown). It may be configured to measure the amount (brake operation amount).

  The brake hydraulic pressure in the second hydraulic pressure chamber 98a and the first hydraulic pressure chamber 98b in the motor cylinder device 16 is passed through the first in valves 120a and 120b and the second in valves 124a and 124b in the valve open state of the VSA device 18. Is transmitted to the wheel cylinders 32FR, 32RL, 32RR, and 32FL of the disc brake mechanism 30a to 30d, and the wheel cylinders 32FR, 32RL, 32RR, and 32FL are operated, so that each wheel (WFR, WRL, WRR, WFL) has a desired control. Power is applied.

  In other words, in the vehicle brake system 10 according to the present embodiment, when the motor cylinder device 16 that functions as a power hydraulic pressure source, the control means 150 that performs by-wire control, and the like are operable, the driver can use the brake pedal 12. The communication between the master cylinder 34 that generates hydraulic pressure by stepping on and the disc brake mechanisms 30a to 30d (wheel cylinders 32FR, 32RL, 32RR, and 32FL) that brake each wheel is connected to the second cutoff valve 60a and the first cutoff valve 60b. In this state, the so-called brake-by-wire type brake system in which the disc brake mechanisms 30a to 30d are operated with the brake fluid pressure generated by the motor cylinder device 16 becomes active.

  On the other hand, when the motor cylinder device 16 or the like becomes inoperable, the liquid generated in the master cylinder 34 with the second shut-off valve 60a and the first shut-off valve 60b opened and the third shut-off valve 62 closed respectively. The pressure is transmitted to the disc brake mechanisms 30a to 30d (wheel cylinders 32FR, 32RL, 32RR, 32FL) as brake fluid pressure, and the disc brake mechanisms 30a to 30d (wheel cylinders 32FR, 32RL, 32RR, 32FL) are operated. The old hydraulic brake system becomes active.

  FIG. 4 is a schematic diagram of the braking force generated in the vehicle, (a) is a schematic diagram showing the braking force generated when the battery is in a chargeable state, and (b) is generated when the battery is in a charge limit state. It is a schematic diagram which shows braking force. The vertical axes in FIGS. 4A and 4B indicate the braking force.

2 when the accelerator pedal 13 (see FIG. 1) is released (the driver releases the accelerator pedal 13) and the accelerator operation is released, the control means 150 shown in FIG. As shown in FIG. 2, a braking force (ApOff braking force BP1) equivalent to the engine brake is generated. In this case, the ApOff braking force BP1 is a target braking force that is set when the driver releases the accelerator operation. Therefore, in this embodiment, the ApOFF braking force is included in the target braking force set from the braking force requested by the driver.
As a result, the vehicle 1 generates a braking force (braking force requested by the driver) corresponding to the engine brake of the vehicle using the engine as a power source.
The target braking force generated by the control means 150 when the accelerator operation is released is not limited to the ApOff braking force BP1. For example, the configuration may be such that the braking force for maintaining the vehicle speed of the vehicle 1 (see FIG. 1) constant becomes the target braking force. The target braking force that is set in this way is a braking force that is required by the driver to maintain the vehicle speed constant. In this embodiment, the target braking force is set from the braking force that the driver requests. It is included in the target braking force.

The magnitude of the ApOff braking force BP1 is appropriately determined according to a travel range set by a shift device (not shown) of the vehicle 1 (see FIG. 1).
For example, the magnitude of the ApOff braking force BP1 corresponding to the travel range is preferably set in advance as the characteristic value of the vehicle 1. The control means 150 (see FIG. 1) determines the magnitude of the ApOff braking force BP1 according to the travel range of the vehicle 1, and generates the ApOff braking force BP1 with the decided magnitude.

At this time, if the battery 202 (see FIG. 1) is in a chargeable state, the control means 150 (see FIG. 1) operates the accelerator pedal 13 (see FIG. 1) as shown in FIG. At the time when the engine is released (AP-OFF), regenerative power generation is performed by the electric motor 200 (see FIG. 1) to generate the regenerative braking force Bgen on the drive wheels. As a result, a regenerative braking force Bgen corresponding to the target braking force is generated in the vehicle 1 (see FIG. 1).
Further, when the driver depresses the brake pedal 12 (see FIG. 1) (BP-ON), the control means 150 generates a braking force (BPdl braking force BP2) corresponding to the depressing operation amount of the brake pedal 12. To do. The BPdl braking force BP2 is added to the ApOff braking force BP1. The resultant force of the BPdl braking force BP2 and the ApOff braking force BP1 becomes the required braking force Breq corresponding to the depression operation amount of the brake pedal 12 (required braking force Breq = ApOff braking force BP1 + BPdl braking force BP2). In this case, the required braking force Breq becomes the target braking force (target braking force set from the braking force requested by the driver).

  When the regenerative braking force Bgen is insufficient for the required braking force Breq when the brake pedal 12 is depressed, the control means 150 generates brake fluid pressure by the motor cylinder device 16 (see FIG. 2) to frictionally control each wheel. Power Bfrq is generated. That is, when the regenerative braking force Bgen is insufficient for the target braking force (required braking force Breq), the friction braking force Bfrq that is insufficient for the target braking force is the wheel cylinders 32FR, 32RL, 32RR, and 32FL (see FIG. 2). Occurs.

On the other hand, when the accelerator pedal 13 (see FIG. 1) is released and the accelerator operation is released (AP-OFF) when the battery 202 (see FIG. 1) is in the charge limit state, the control means 150 (see FIG. 1). Generates a brake fluid pressure in the motor cylinder device 16 (see FIG. 2), and generates a friction braking force Bfrq on each wheel, as shown in FIG. 4 (b). In this case, the regenerative braking force Bgen is not generated. That is, in the vehicle 1 (see FIG. 1), the ApOff braking force BP1 is generated with the friction braking force Bfrq. As a result, when the battery 202 is in the charge limit state, a friction braking force Bfrq corresponding to the target braking force is generated in the wheel cylinders 32FR, 32RL, 32RR, 32FL (see FIG. 2). When the battery 202 is in the charge limited state, the regenerative braking force Bgen is not generated (the generation is limited). For this reason, the control means 150 generates a shortage (actually all of the target braking force) of the regenerative braking force Bgen (actually zero) with respect to the target braking force by the friction braking force Bfrq.
Further, when the driver depresses the brake pedal 12 (BP-ON), the control means 150 increases the brake fluid pressure generated in the motor cylinder device 16 to increase the friction braking force Bfrq and generate the BPdl braking force BP2. As a result, a friction braking force Bfrq corresponding to the required braking force Breq is generated.
Note that a configuration in which a minute regenerative braking force Bgen is generated when the battery 202 is in a charge limited state may be employed. In this case, the control means 150 generates a deficiency of the regenerative braking force Bgen with respect to the target braking force (difference between the target braking force and the minute regenerative braking force Bgen) with the friction braking force Bfrq.

  Thus, the control means 150 (see FIG. 1) generates the regenerative braking force Bgen and the friction braking force Bfrq as shown in FIG. 4A when the battery 202 (see FIG. 1) is in a chargeable state. . Further, when the battery 202 is in the charge restriction state, the control means 150 generates a friction braking force Bfrq as shown in FIG.

  FIG. 5 is a schematic diagram of the braking force generated when the ABS is operated, (a) is a schematic diagram showing when the battery is in a chargeable state, and (b) is a schematic diagram showing when the battery is in a charge limit state. It is.

  The control means 150 shown in FIG. 2 operates the ABS when it is determined that the vehicle 1 has slipped. As described above, the control means 150 includes the ABS control unit 151. The ABS control unit 151 determines that the vehicle 1 has slipped based on the slip rate of each wheel (WFR, WRL, WRR, WFL).

  When the accelerator operation is canceled and the ApOff braking force BP1 is generated while the battery 202 is in the charge limited state, the control means 150 operates the ABS when it is determined that the vehicle 1 has slipped (SLIP-ON) (ABS -ON), as shown in FIG. 5A, the regenerative braking force Bgen is increased or decreased by controlling the regenerative control device 201 (see FIG. 1). As the regenerative braking force Bgen increases or decreases, the ApOff braking force BP1 generated in the vehicle 1 decreases. By reducing the ApOff braking force BP1, the wheel lock is avoided and the slip of the vehicle 1 is eliminated. The control unit 150 adjusts the duty ratio at which the regenerative braking force Bgen increases or decreases to increase or decrease the ApOff braking force BP1 generated in the vehicle 1.

  When the accelerator operation is released while the battery 202 shown in FIG. 1 is in the charge-restricted state and the ApOff braking force BP1 is generated with the friction braking force Bfrq, the control means 150 is configured to operate the vehicle 1 as shown in FIG. When it is determined that the vehicle has slipped (SLIP-ON), the ApOff braking force BP1 is reduced to avoid wheel locking.

Conventionally, when the battery 202 (see FIG. 1) is in a charge limit state, the control means 150 (see FIG. 1) reduces the ApOff braking force BP1 by increasing or decreasing the friction braking force Bfrq as shown in FIG. 5 (b). The slip of the vehicle 1 is eliminated. At this time, the control means 150 controls the VSA device 18 by the ABS control unit 151 shown in FIG. 3 to increase or decrease the friction braking force Bfrq.
The ABS control unit 151 operates the ABS by opening and closing the in-valve and the out-valve of the VSA device 18 in a state where the ApOff braking force BP1 is generated by the friction braking force Bfrq (ABS-ON). The ABS control unit 151 increases or decreases the ApOff braking force BP1 by adjusting the duty ratio at which the friction braking force Bfrq increases or decreases.

  When the ABS control unit 151 operates the ABS (ABS-ON), when the battery 202 (see FIG. 1) is in a charge limit state, the in-valve and the out-valve are opened and closed, and the wheel cylinders 32FR, 32RL, 32RR, 32FL (FIG. 2). The brake hydraulic pressure supplied to the wheel is increased or decreased to increase or decrease the friction braking force Bfrq (ApOff braking force BP1) generated in each wheel.

  As shown in FIG. 5B, the ABS control unit 151 opens the out valve and closes the in valve when the friction braking force Bfrq is reduced during the operation of the ABS. When the friction braking force Bfrq is increased, the ABS control unit 151 closes the out valve and opens the in valve. Further, the ABS control unit 151 drives the pump 136 (see FIG. 2) when opening the in-valve in order to increase the friction braking force Bfrq. When maintaining the friction braking force Bfrq, the ABS control unit 151 opens the out valve and the in valve.

  When the ABS operates in this way, the in-valve and the out-valve frequently open and close. Further, the pump 136 (see FIG. 2) is driven when the in-valve opens. Since the in-valve and the out-valve generate an operation noise when opening and closing, the operation noise increases when each valve is frequently opened and closed, resulting in unpleasant noise for the driver of the vehicle 1 (see FIG. 1). Further, since noise is generated by driving the pump 136, unpleasant noise for the driver or the like increases.

  When it is determined that the vehicle 1 has slipped (SLIP-ON), the ABS control unit 151 of the control means 150 reduces the friction braking force Bfrq to avoid locking of each wheel. At this time, when the ABS control unit 151 opens and closes the in-valve and the out-valve to reduce the friction braking force Bfrq, noise generated by the operation of each valve and the pump 136 (see FIG. 2) increases.

  Therefore, the control unit 150 (see FIG. 2) of the present embodiment operates the ABS when the battery 202 (see FIG. 1) is in a charge-limited state and the ApOff braking force BP1 is generated with the friction braking force Bfrq. First, the brake hydraulic pressure generated in the motor cylinder device 16 (see FIG. 2) is reduced to reduce the ApOff braking force BP1. Specifically, the control means 150 controls the motor cylinder device 16 when the ABS control unit 151 (see FIG. 3) operates the ABS to reduce the brake hydraulic pressure output from the motor cylinder device 16 and generate it on each wheel. The friction braking force Bfrq is reduced.

As described above, the control unit 150 (see FIG. 1) is calculated by the ABS control unit 151 (see FIG. 3) from the measurement signals input from the wheel speed sensors 35a, 35b, 35c, and 35d (see FIG. 2). The ABS is operated based on the wheel speed.
When the ABS control unit 151 (see FIG. 3) operates the ABS, the control means 150 (see FIG. 1) of the present embodiment controls the friction braking force Bfrq so that the slip ratio of each wheel becomes the target slip ratio by the ApOff control. Generated as power BP1. That is, the control means 150 adjusts the braking force (ApOff braking force BP1) corresponding to the engine brake so that the slip rate of each wheel becomes the target slip rate. That is, the control means 150 adjusts the brake pressure generated in the motor cylinder device 16 so that the slip ratio of each wheel becomes the target slip ratio.

  Further, the control means 150 (see FIG. 1) calculates (estimates) the friction coefficient μ of the road surface when the ABS is operated. For example, if the correlation between the wheel slip ratio and the road surface friction coefficient μ is obtained in advance, the control means 150 can calculate the road surface friction coefficient μ based on the slip ratio. The method by which the control means 150 calculates the road surface friction coefficient μ is not limited.

  When the road surface friction coefficient μ changes, the control means 150 (see FIG. 1) adjusts the ApOff braking force BP1 so as to correspond to the changed road surface friction coefficient μ. The control means 150 increases or decreases the ApOff braking force BP1 by increasing or decreasing the brake hydraulic pressure generated by the motor cylinder device 16 (see FIG. 2), and generates the ApOff braking force BP1 corresponding to the road surface friction coefficient μ.

  For example, if a suitable ApOff braking force BP1 corresponding to the road surface friction coefficient μ is set in advance by experimental measurement or the like, the control means 150 easily generates the ApOff braking force BP1 corresponding to the road surface friction coefficient μ. Can be made.

FIG. 6 is a diagram showing a change in friction braking force and an operating state of the ABS. The vertical axis in FIG. 6 represents the friction braking force. A one-dot chain line indicates a change in the friction coefficient μ of the road surface.
As shown in FIG. 6, when the accelerator operation is released (AP-OFF) when the battery 202 (see FIG. 1) is in the charge restriction state, the control means 150 (see FIG. 1) is operated with the friction braking force Bfrq. ApOff braking force BP1 is generated.
As the road friction coefficient μ decreases, the slip ratio of each wheel increases. When the ABS control unit 151 (see FIG. 3) determines that the slip ratio of each wheel has increased and the vehicle 1 (see FIG. 1) has slipped (SLIP-ON), the ABS control unit 151 (see FIG. 2) Control and operate ABS (ABS-ON). Further, the control means 150 adjusts (reduces) the brake hydraulic pressure generated in the motor cylinder device 16 (see FIG. 2) so as to reduce the ApOff braking force BP1 so that the slip rate of each wheel becomes the target slip rate. .
The control means 150 controls the motor cylinder device 16 to reduce the brake hydraulic pressure generated in the motor cylinder device 16 and reduce the ApOff braking force BP1.

  When the ABS is operated, the ABS control unit 151 (see FIG. 3) of the control means 150 opens and closes the in-valve and the out-valve of the VSA device 18 (see FIG. 2) to reduce the friction braking force Bfrq and avoid the wheel lock. To do. In the present embodiment, when the ABS control unit 151 controls the VSA device 18 to operate the ABS, the motor cylinder device 16 (see FIG. 2) is driven to reduce the brake fluid pressure and the ApOff braking force BP1. Therefore, the friction braking force Bfrq is quickly reduced, and the slip ratio of each wheel becomes the target slip ratio. For this reason, the ABS control unit 151 can quickly stop the ABS (ABS-OFF), and the opening and closing of the in-valve and the out-valve are quickly stopped. The ABS control unit 151 also stops the pump 136 (see FIG. 2) of the VSA device 18 when stopping the ABS.

  As described above, the vehicle brake system 10 of the present embodiment shown in FIG. 2 is operated when the ABS is activated when the battery 202 is charged and the ApOff braking force BP1 is generated as shown in FIG. ABS-ON), the motor cylinder device 16 is driven, and the ApOff braking force BP1 decreases. Then, the ABS control unit 151 promptly stops the ABS (ABS-OFF). As a result, the opening and closing of the in-valve and the out-valve are quickly stopped. Further, the pump 136 (see FIG. 2) is also quickly stopped. Therefore, the generation of the operation sound of the in-valve and the out-valve and the operation sound of the pump 136 is suppressed, and unpleasant noise for the driver of the vehicle 1 (see FIG. 1) is reduced.

  Further, when it is determined that the calculated road friction coefficient μ has increased, the control means 150 increases the ApOff braking force BP1. Therefore, the ApOff braking force BP1 is generated so as to correspond to the changed friction coefficient μ. While the state where the slip rate of each wheel is the target slip rate is maintained, the braking force corresponding to the engine brake generated in the vehicle 1 (see FIG. 1) is changed (increased) in a recovery direction.

FIG. 7 is a diagram showing a state in which the friction braking force is changed to the regenerative braking force during the operation of the ABS.
As shown in FIG. 7, the control means 150 (see FIG. 1) is configured so that the battery is turned off when the in-valve and out-valve of the VSA device 18 (see FIG. 2) are opened and the ApOff braking force BP1 is maintained constant. A configuration may be adopted in which the friction braking force Bfrq is switched to the regenerative braking force Bgen when 202 (see FIG. 1) is in a chargeable state (CHG-ON).

  The control means 150 (see FIG. 1) stops the generation of brake fluid pressure in the motor cylinder device 16 (see FIG. 2) when the battery 202 (see FIG. 1) is in a chargeable state (CHG-ON). To do. As a result, the generation of the friction braking force Bfrq is stopped. In addition, the control means 150 gives a command to the regenerative control device 201 (see FIG. 1) to generate regenerative power with the electric motor 200 (see FIG. 1) to generate a regenerative braking force Bgen. At this time, the control means 150 generates a regenerative braking force Bgen having a magnitude corresponding to the ApOff braking force BP1 determined according to the travel range set by the shift device (not shown) of the vehicle 1 (see FIG. 1). Occur.

Further, the ABS control unit 151 (see FIG. 3) of the control means 150 operates the ABS (ABS-ON), controls the regeneration control device 201 (see FIG. 1), and regenerative power generation of the electric motor 200 (see FIG. 1). Adjust the amount to increase or decrease the regenerative braking force Bgen. The vehicle 1 (see FIG. 1) generates the same braking force as before the regenerative braking force Bgen is generated.
That is, the control means 150 adjusts the ApOff braking force BP1 (braking force equivalent to engine braking) by adjusting the regenerative power generation amount of the electric motor 200 so that the slip rate of each wheel becomes the target slip rate.

  With such a configuration, when the battery 202 (see FIG. 1) is in a chargeable state, the opening and closing of the in-valve and the out-valve and the driving of the pump 136 (see FIG. 2) are stopped even when the ABS is activated. Therefore, noise due to operation sounds of the valves and the pump 136 is not generated.

The present invention is not limited to the above-described embodiment, and can be appropriately changed in design without departing from the spirit of the invention.
As shown in FIG. 1, the vehicle brake system 10 of this embodiment is provided in a vehicle 1 (electric vehicle) that uses an electric motor 200 as a power source.
In addition, the present invention can also be applied to the vehicle brake system 10 provided in a hybrid vehicle including the electric motor 200 and an internal combustion engine (not shown) as power sources.
When the vehicle 1 is a hybrid vehicle, the ApOff braking force BP1 that is a braking force equivalent to the engine brake at the time when the ABS is activated when the battery 202 is in a charge-restricted state while traveling with the power output from the electric motor 200. What is necessary is just to set it as the structure which falls.

In addition, the regeneration control device 201 (see FIG. 1) of the present embodiment is configured to input a signal indicating that the battery 202 (see FIG. 1) is in a charge-limited state to the control unit 150 when the battery 202 (see FIG. 1) is in a fully charged state. Has been.
Furthermore, the regenerative control device 201 may be configured to input a signal indicating that the battery is in a charge restriction state to the control unit 150 when an abnormality of the battery 202 is detected.

  Further, when the vehicle 1 (see FIG. 1) is a hybrid vehicle and the battery 202 (see FIG. 1) is in a charge limit state when the accelerator operation is released, an internal combustion engine (not shown) is generated by a generator (not shown). ) To generate an engine brake, and a braking force insufficient for the target braking force may be generated by the friction braking force Bfrq.

DESCRIPTION OF SYMBOLS 1 Vehicle 10 Brake system for vehicles 12 Brake pedal 16 Motor cylinder device (friction braking force generation part, hydraulic pressure generation part)
18 VSA device (ABS operation unit)
32FR, 32RL, 32RR, 32FL Wheel cylinder (friction braking force generator)
72 Electric motor (actuator, friction braking force generator)
150 Control means 200 Electric motor 202 Battery (power storage device)
Bfrq Friction braking force Bgen Regenerative braking force

Claims (4)

Provided in vehicles that run with the power output from the electric motor according to the accelerator operation,
A friction braking force generator for generating a friction braking force on the wheel by generating a brake fluid pressure according to the amount of depression of the brake pedal by the operation of the actuator;
Control means for setting the braking force requested by the driver as the target braking force and generating the target braking force;
In a brake system for a vehicle having an ABS operation unit that avoids wheel lock by increasing or decreasing the brake fluid pressure by driving a solenoid valve and a pump ,
The control means includes
The target braking force is generated by the regenerative braking force generated by the regenerative power generation of the motor when the power storage device that stores the power to be supplied to the motor is in a chargeable state, and the friction control is performed when the power storage device is in a charge limit state. By generating the brake hydraulic pressure at the hydraulic pressure generation unit of the power generation unit, an insufficient amount of the regenerative braking force with respect to the target braking force is generated by the friction braking force,
When it is determined that the vehicle has slipped when the power storage device is in a charge limit state when the accelerator operation and the brake pedal depression operation are released , the slip ratio of the wheels becomes the target slip ratio. A brake system for a vehicle, wherein the brake hydraulic pressure generated by a hydraulic pressure generating unit is reduced so as to reduce the friction braking force . The control means includes
After adjusting to reduce the friction braking force, when it is determined that the friction coefficient of the road surface has increased, the brake hydraulic pressure generated at the hydraulic pressure generating unit is increased to increase the friction braking force. The vehicle brake system according to claim 1, wherein the vehicle brake system is adjusted. The control means includes
When the power storage device is changed from a charge restriction state to a chargeable state when the brake fluid pressure is reduced so that the slip ratio of the wheel becomes the target slip ratio,
2. The regenerative power generation amount of the motor is adjusted so that the target braking force is generated by the regenerative braking force, and the slip rate of the wheel becomes the target slip rate. 2. The vehicle brake system according to 2. The control means includes
4. The vehicle brake system according to claim 1, wherein when the power storage device is in a fully charged state, it is determined that the battery is in a charge limited state. 5.

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