ANOMALYSES DIAGNOSTIC DEVICE

Abstract

Anomaly diagnosis device applied to a vehicle braking device (A), comprising: a reaction force chamber (R) in which a reaction force hydraulic pressure is generated in response to an operation amount of a brake operating member (10); a low pressure source (171, 172, 173, 434) communicating with the reaction force chamber under a predetermined condition; a master brake cylinder (1) having a main chamber (1D, 1E) in which a main hydraulic pressure is generated by being driven by a main piston (14, 15); a drive section (Y) that generates a drive force for driving the master piston in response to the amount of operation of the brake operating member; and a control section (61) that sets a target value of the actuating force or the main hydraulic pressure based on at least one of the operation amount of the brake operating member and an operation force of the brake operating member, and controls the actuating section to cause an actual value of the actuating force or the main hydraulic pressure with respect to the target value to approach the target value, wherein the abnormality diagnosis device (C) comprises: a diagnosis section (62) that performs an abnormality diagnosis based on at least one parameter selected from a relationship between the operation amount of the brake operating member and the reaction force hydraulic pressure and a relationship between the target value and the actual value; and a judging section (63) which judges whether a state of the reaction force chamber with respect to at least one of a hydraulic pressure and an amount of fluid therein is in a predetermined insufficient state or in a predetermined excess state, wherein the diagnosis section stops execution of the abnormality diagnosis when it is judged by the judgment section that the state of the reaction force chamber with respect to the at least one of the hydraulic pressure and the amount of fluid therein is in the predetermined insufficient state or in the predetermined excess state.

Description

[Technical field]

[0001] The present invention relates to an abnormality diagnosis device suitable for a vehicle braking device. [Background of the invention]

[0002] Generally, a vehicle brake device is equipped with an abnormality diagnosis device (e.g., an ECU) that performs abnormality diagnosis of a system. The abnormality diagnosis is performed based on at least one of "the relationship between the operation amount of the brake operating member and the reaction force hydraulic pressure" and "the relationship between the target hydraulic pressure and the actual hydraulic pressure." For example, the reaction force hydraulic pressure is generated in response to the operation amount of the brake operating member. If the reaction force hydraulic pressure is too large or too small with respect to the operation amount, it can be diagnosed that an abnormality is generated in a system.Further, the ECU executes control to approximate the actual hydraulic pressure to the target hydraulic pressure. When the actual hydraulic pressure is too large or too small compared to the target hydraulic pressure, it can also diagnose that an abnormality is generated in a device. As explained above, in the abnormality diagnosis device, the abnormality diagnosis is performed based on the relationship described above. Note that a vehicle brake device disclosed in, for example, Japanese Patent Publication No. JP 2012-16984 A, in which the reaction force chamber in which the reaction hydraulic pressure is generated and a low-pressure source such as a reservoir or the like establish fluid communication therebetween under a predetermined condition.

[0003] Document DE 11 2011 100 209 T5 describes a braking device and a braking method. The braking device is provided with an operation amount detection means for detecting an operation amount of a pedal; a plurality of systems of hydraulic passages for connecting between a plurality of hydraulic chambers of a tandem-type master cylinder capable of generating hydraulic pressures by operation of the pedal and a plurality of wheel cylinders; a hydraulic pressure source installed in the hydraulic passages and capable of generating hydraulic pressure in the hydraulic passages based on the operation amount; shut-off valves installed in each of the hydraulic passages between the master cylinder and the hydraulic pressure source; and a plurality of hydraulic pressure detection means, each for detecting a hydraulic pressure in each of the hydraulic passages.In the open command state, a first mutual diagnosis is performed based on the hydraulic pressures detected by the hydraulic pressure detecting means and the operation amount detected by the operation amount detecting means, and a second mutual diagnosis is performed based on the hydraulic pressures detected by a plurality of hydraulic pressure detecting means. In the close command state, the first and second mutual diagnoses are performed. The occurrence of a fault is detected in the shut-off valves and a plurality of hydraulic pressure detecting means based on the results of the first and second mutual diagnoses in the open command state and the close command state.

[0004] The document DE 10 2012 221 395 A1 describes a vehicle braking device provided with a master piston which is driven to generate a master cylinder pressure.The device includes a pressure accumulator portion that stores the brake fluid under pressure; a servo pressure generating portion configured to generate the servo pressure using the brake fluid in the pressure accumulator portion regardless of the operation of the brake operating member; brake fluid consumption correlation value detecting means for detecting a brake fluid consumption correlation value related to a consumption of the brake fluid in the pressure accumulator portion; and failure detecting means for driving the master piston only by the servo pressure using the servo pressure generating portion in a state where the brake operating member is not operated, and for detecting a failure of a main system based on a brake fluid consumption correlation value detected by the brake fluid consumption correlation value detecting means at that time. [Summary of the invention][Technical problem / Technical problems]

[0005] However, according to the conventional abnormality diagnosis device disclosed in JP 2012-16984 A, such a fluid connection between the reaction force chamber and the low-pressure source was not considered. Consequently, there is still a need for improvement in diagnostic accuracy in such an abnormality diagnosis device. The inventors of the present application have focused on this point to complete this invention.

[0006] Accordingly, this invention has been made in consideration of the above situation, and an object of the invention is to provide an abnormality diagnosis apparatus that can improve the accuracy of abnormality diagnosis.

[0007] This object is achieved by an anomaly diagnosis device according to claim 1. Advantageous further developments are specified in the appended claims. [Solution to the problem(s)]

[0008] The abnormality diagnosis device according to the invention, which is applied to a vehicle brake device, comprising a reaction force chamber in which a reaction force hydraulic pressure is generated in response to an operation amount of a brake operating member, a low-pressure source that communicates with the reaction force chamber under a predetermined condition, a master cylinder having a main chamber in which a main hydraulic pressure is generated by being driven by a master piston, a driving section that generates a driving force for driving the master piston in response to the operation amount of the brake operating member, and a control section,which sets a target value of the actuating force or the main hydraulic pressure based on at least one parameter from the operation amount of the brake operating element or an operation force of the brake operating element, and controls the actuating section to cause an actual value of the actuating force or the main hydraulic pressure with respect to the target value to approach the target value. The diagnostic device includes a diagnostic section that performs an abnormality diagnosis based on at least one parameter from a relationship between the operation amount of the brake operating element and the reaction force hydraulic pressure and a relationship between the target value and the actual value, and a judging section that judgeswhether a state of the reaction force chamber with respect to at least one parameter of a hydraulic pressure and a fluid amount therein is in a predetermined insufficient state or in a predetermined excess state, wherein the diagnosis section stops execution of the abnormality diagnosis when it is judged by the judgment section that the state of the reaction force chamber with respect to the at least one parameter of the hydraulic pressure and the fluid amount therein is in the predetermined insufficient state or in the predetermined excess state. [Effect of the invention]

[0009] According to the vehicle brake device in which the reaction force chamber and the low-pressure source are in fluid communication under a predetermined condition, an insufficient fluid state or an excess fluid state may be generated in the reaction force chamber, which is derived from the establishment or interruption of the fluid communication therebetween. In such a case, since the various responses to the operation amount of the brake operating member are different from the normal state, such responses may influence the result of the abnormality diagnosis, thereby misjudging that an abnormality exists despite a normal state. However, according to the invention, when the fluid state in the reaction force chamber becomes an insufficient fluid state or an excess fluid state, such a state is detected to stop execution of the abnormality diagnosis.Thus, a false assessment that an abnormality exists despite a normal state is suppressed. In other words, according to the invention, abnormality diagnosis can be performed when the state of the reaction force chamber is normal. This can improve the accuracy of abnormality diagnosis. [Short description of the drawing] Fig. 1 is a structural diagram of a vehicle braking device according to an embodiment of the invention to which the invention is applied; Fig. 2 shows a cross-sectional view of a regulating device to which the embodiment can be applied; Fig. 3 is an explanatory diagram explaining a relationship between the stroke and the reaction force hydraulic pressure; Fig. 4 is an explanatory diagram explaining a relationship between the target servo pressure and the actual servo pressure; Fig. Fig. 5 is an explanatory diagram explaining an example of a fluid amount change in the reaction force chamber; and Fig. 6 is a flowchart explaining a procedure of abnormality diagnosis according to the embodiment. [Embodiments for implementing the invention]

[0010] The embodiments of the invention will be explained below with reference to the accompanying drawings. It should be noted that each drawing used for explanation shows a conceptual drawing, and the shape of a respective portion in the drawings does not necessarily indicate an exact shape in practice. As stated in Fig. As shown in FIG. 1, the vehicle brake device A according to the embodiment is constituted by a hydraulic pressure braking force generating device BF that generates hydraulic pressure braking force at vehicle wheels 5FR, 5FL, 5RR, and 5RL, and a brake ECU 6 that controls the hydraulic pressure braking force generating device BF. The brake ECU 6 corresponds to the abnormality diagnosis device C, and the abnormality diagnosis device C is applied to the vehicle brake device A. (Hydraulic pressure brake force generating device BF)

[0011] The hydraulic pressure braking force generating device BF is, as described in Fig. 1 is constituted by a master cylinder 1, a reaction force generating device 2, a first control valve 22 (corresponding to an electromagnetic valve), a second control valve 23, a servo pressure generating device 4, an actuator 5, wheel cylinders 541 to 544 and various sensors 71 to 76. (Master brake cylinder 1)

[0012] The brake master cylinder 1 is a portion that supplies the operating device 5 with a fluid (an operating fluid) in response to the operation amount of the brake pedal 10 (corresponding to a "brake operating member") and is constituted by a master cylinder 11, a cover cylinder 12, an input piston 13, a first master piston 14, and a second master piston 15, etc. The brake pedal 10 may be any type of brake operating device that can perform a braking operation by a driver of the vehicle.

[0013] The master cylinder 11 is formed in a substantially bottomed cylindrical housing having a closed bottom surface at a front end and an opening at a rear end thereof. The master cylinder 11 includes therein an inner wall portion 111 extending inward in a flange shape at a rear side in the inner peripheral side of the master cylinder 11. An inner peripheral surface of the inner wall portion 111 is provided with a through hole 111a at a center portion thereof, which penetrates through the inner wall portion in a front-rear direction.The master cylinder 11 is provided with a small diameter portion 112 (rear) and a small diameter portion 113 (front) at portions closer to the front end than the inner wall portion 111, the inner diameter of each of which is set to be slightly smaller than the inner diameter of the inner wall portion 111. In other words, the small diameter portions 112, 113 protrude from the inner peripheral surface of the master cylinder 11, having an inwardly shaped annular profile. The first master piston 14 is disposed within the master cylinder 11 and slidably movable along the small diameter portion 112 in the axial direction. Similarly, the second master piston 15 is disposed within the master cylinder 11 and slidably movable along the small diameter portion 113 in the axial direction.

[0014] The cover cylinder 12 includes an approximately cylindrical portion 121, a tubular bellows shoe 122, and a plate-shaped compression spring 123. The cylindrical portion 121 is disposed at a rear end side of the main cylinder 11 and coaxially fitted into the rear opening of the main cylinder 11. An inner diameter of a front portion 121a of the cylindrical portion 121 is formed to be larger than an inner diameter of the through hole 111a of the inner wall portion 111. Further, the inner diameter of the rear portion 121b is formed to be smaller than the inner diameter of the front portion 121a.

[0015] The dust protection shoe 122 is shaped like a tubular bellows and is expandable or compressible in the front and rear directions. The front of the shoe 122 is mounted to be in contact with the rear end side opening of the cylindrical portion 121. A through hole 122a is formed at a central portion of the rear of the shoe 122. The compression spring 123 is a spiral biasing member arranged around the shoe 122. The front of the compression spring 123 is in contact with the rear end of the master cylinder 11, and the rear side of the compression spring 123 is arranged with a bias adjacent to the through hole 122a of the shoe 122. The rear end of the shoe 122 and the rear end of the compression spring 123 are connected to an operating rod 10a. The compression spring 123 biases the actuating rod 10a in a rearward direction.

[0016] The input piston 13 is a piston configured to slidably move within the cover cylinder 12 in response to an operation of the brake pedal 10. The input piston 13 is formed in a substantially bottomed cylindrical shape having a bottom surface at a front portion thereof and an opening at a rear portion thereof. A bottom wall 131 forming the bottom surface of the input piston 13 has a larger diameter than the diameters of the other parts of the input piston 13. The input piston 13 is disposed at the rear end portion 121b of the cylindrical portion 121 and is slidably and fluid-tightly movable in an axial direction, with the bottom wall 131 being mounted in an inner peripheral side of the front portion 121a of the cylindrical portion 121.

[0017] The operating rod 10a, which is operable in conjunction with the brake pedal 10, is disposed within the input piston 13. A joint 10b is provided at a tip end of the operating rod 10a such that the joint 10b can push the input piston 13 toward a front side. The rear end of the operating rod 10a protrudes toward an outside through the rear opening of the input piston 13 and the through hole 122a of the shoe 122 and is connected to the brake pedal 10. The operating rod 10a moves in response to the low-pressure operation of the brake pedal 10. More specifically, when the brake pedal 10 is depressed, the operating rod 10a advances in a forward direction while the shoe 122 and the compression spring 123 are compressed in the axial direction. The input piston 13 also advances in response to the forward movement of the actuating rod 10a.

[0018] The first master piston 14 is disposed in the inner wall portion 111 of the master cylinder 11 and is slidably movable in the axial direction. The first master piston 14 includes a pressurizing cylinder portion 141, a flange portion 142, and a protrusion portion 143 in order from the front, with the cylinder portion 141, the flange portion 142, and the protrusion portion 143 being integrally formed as a unit. The pressurizing cylinder portion 141 is formed in a substantially bottomed cylindrical shape having an opening at a front portion thereof and a bottom wall at a rear portion thereof. The pressurizing cylinder portion 141 includes a clearance formed with the inner peripheral surface of the master cylinder 11 and is slidable in contact with the small-diameter portion 112.A coil spring-shaped biasing member 144 is provided in the interior of the pressurizing cylinder portion 141 between the first main piston 14 and the second main piston 15. The first main piston 14 is biased in a rearward direction by the biasing member 144. In other words, the first main piston 14 is biased toward a predetermined initial position by the biasing member 144.

[0019] The flange portion 142 is formed to have a larger diameter than the diameter of the pressurizing cylinder portion 141, and is slidably in contact with the inner peripheral surface of the master cylinder 11. The protrusion portion 143 is formed to have a smaller diameter than the diameter of the flange portion 142, and is slidably in fluid-tight contact with the through-hole 111a of the inner wall portion 111. The rear end of the protrusion portion 143 protrudes into an inner space of the cylindrical portion 121, passes through the through-hole 111a, and is separated from the inner peripheral surface of the cylindrical portion 121. The rear end surface of the protrusion portion 143 is separated from the bottom wall 131 of the input piston 13, and the separation distance is configured to be variable.

[0020] Note that a "first main chamber 1D" is defined by the inner peripheral surface of the master cylinder 11, a front side of the pressurizing cylinder portion 141 of the first master piston 14, and a rear side of the second master piston 15. A rear chamber, located further rearward of the first main chamber 1D, is defined by the inner peripheral surface (inner peripheral portion) of the master cylinder 11, the small diameter portion 112, a front surface of the inner wall portion 111, and the outer peripheral surface of the first master piston 14.The front end portion and the rear end portion of the flange portion 142 of the first master piston 14 separate the rear chamber into a front portion and a rear portion, with a "second hydraulic pressure chamber 1C" defined at the front side of the rear chamber and a "servo chamber (drive chamber) 1A" defined at the rear side of the rear chamber. The master cylinder 11 and the first master piston 14 form a second hydraulic pressure chamber forming portion Z, which defines the second hydraulic pressure chamber 1C. The second hydraulic pressure chamber 1C, formed by the second hydraulic pressure chamber forming portion Z, decreases its volume by the advance movement of the first master piston 14 and increases its volume by the retreat movement of the first master piston 14.Further, a “first hydraulic pressure chamber 1B” is defined by the inner peripheral surface of the master cylinder 11, a rear surface of the inner wall portion 111, an inner peripheral surface (an inner peripheral portion) of the front portion 121a of the cylindrical portion 121, the projection portion 143 (rear end portion) of the first master piston 14, and the front end of the input piston 13.

[0021] The second master piston 15 is coaxially disposed within the master cylinder 11 at a position forward of the first master piston 14 and slidably movable in an axial direction to be in sliding contact with the small-diameter portion 113. The second master piston 15 is formed as a unit including a tubular pressurizing cylinder portion 151 in a substantially bottomed cylindrical shape having an opening at a front portion thereof and a bottom wall 152 closing the rear end of the tubular pressurizing cylinder portion 151. The bottom wall 152 holds the biasing member 144 with the first master piston 14. A coil spring-shaped biasing member 153 is disposed in the interior of the pressurizing cylinder portion 151 between the second piston 15 and a closed inner bottom surface 111d of the master cylinder 11.The second main piston 15 is biased in a rearward direction by the biasing member 153. In other words, the second main piston 15 is biased toward a predetermined initial position by the biasing member 153. A "second main chamber 1E" is defined by the inner peripheral surface of the master cylinder 11, the inner bottom surface 111d, and the second main piston 15.

[0022] Ports 11a to 11i connecting the inside and outside of the master cylinder 1 are formed in the master cylinder 1. The port 11a is formed in the master cylinder 11 at a position located rearward of the inner wall portion 111. The port 11b is formed in the master cylinder 11 opposite to the port 11a in the axial direction at approximately the same position. The port 11a and the port 11b communicate through an annular space formed between the inner peripheral surface of the master cylinder 11 and the outer peripheral surface of the cylindrical portion 121. The port 11a and the port 11b are connected to a conduit 161 and are also connected to a reservoir 171.

[0023] The opening 11b communicates with the first hydraulic pressure chamber 1B via a passage 18 formed between the cylindrical portion 121 and the input piston 13. The fluid communication through the passage 18 is interrupted when the input piston 13 advances forward. In other words, when the input piston 13 advances forward, the fluid communication between the first hydraulic pressure chamber 1B and the reservoir 171 is interrupted.

[0024] The opening 11c is formed at a position rearward of the inner wall portion 111 and forward of the opening 11a, wherein the opening 11c connects the first hydraulic pressure chamber 1B to a conduit 162. The opening 11d is formed at a position forward of the opening 11c and connects the servo chamber 1A to a conduit 163. The opening 11e is formed at a position forward of the opening 11d and connects the second hydraulic pressure chamber 1C to a conduit 164.

[0025] The orifice 11f is formed between the sealing members 91 and 92 provided at the small-diameter portion 112, and connects a reservoir 172 to the inside of the master cylinder 11. The orifice 11f communicates with the first main chamber 1D via a passage 145 formed at the first master piston 14. The passage 145 is formed at a position where the orifice 11f and the first main chamber 1D are separated from each other when the first master piston 14 advances forward. The orifice 11g is formed at a position forward of the orifice 11f and connects the first main chamber 1D and a conduit 51.

[0026] The orifice 11h is formed between the sealing members 93 and 94 provided at the small-diameter portion 113 and connects a reservoir 173 to the inside of the master cylinder 11. The orifice 11h communicates with the second main chamber 1E via a passage 154 formed at the pressurizing cylinder portion 151 of the second master piston 15. The passage 154 is formed at a position where the orifice 11h and the second main chamber 1E are separated from each other when the second master piston 15 advances forward. The orifice 11i is formed at a position forward of the orifice 11h and connects the second main chamber 1E to a conduit 52.

[0027] Sealing members such as O-rings and the like (see black circles indicated in the drawing) are suitably provided in the master cylinder 1. The sealing members 91 and 92 are provided at the small diameter portion 112, being in liquid-tight contact with the outer peripheral surface of the first master piston 14. Similarly, the sealing members 93 and 94 are provided at the small diameter portion 113, being in liquid-tight contact with the outer peripheral surface of the second master piston 15. In addition, sealing members 95 and 96 are provided between the input piston 13 and the cylindrical portion 121. These sealing members are an outer ring-shaped seal, each cross section of which is formed to be in a C-shape.

[0028] The stroke sensor 71 is a sensor that detects the amount of operation (stroke) of the brake pedal 10 depressed by a driver of the vehicle, and transmits the detection result to the brake ECU 6. The brake stop switch 72 is a switch that detects whether the brake pedal 10 is depressed or not using a binary signal, and the detected signal is sent to the brake ECU 6. (Reaction force generating device 2)

[0029] The reaction force generating device 2 is a device that generates a reaction force against the operation force generated when the brake pedal 10 is depressed. The reaction force generating device 2 is mainly constituted by a stroke simulator 21. The stroke simulator 21 generates a reaction force hydraulic pressure in the first hydraulic pressure chamber 1B and the second hydraulic pressure chamber 1C in response to the operation of the brake pedal 10. The stroke simulator 21 is configured in such a manner that a piston 212 is fitted into a cylinder 211 while being allowed to slide therein. The piston 212 is biased in the forward direction by a compression spring 213, and a hydraulic pressure chamber 214 is formed at a rear surface side of the piston 212.The hydraulic pressure chamber 214 is connected to the second hydraulic pressure chamber 1C via a line 164 and the orifice 11e, and is further connected to the first control valve 22 and the second control valve 23 via the line 164. At least the second hydraulic pressure chamber 1C forms a reaction force chamber that generates the reaction hydraulic pressure. The first hydraulic pressure chamber 1B can be referred to as a separation chamber that separates the first piston 14 and the input piston 13 from each other. (First control valve 22)

[0030] The first control valve 22 is an electromagnetic valve configured to close in a de-energized state (normally closed type electromagnetic valve), the opening and closing operations of which are controlled by the brake ECU 6. The first control valve 22 is arranged between the conduit 164 and the conduit 162 for communication therebetween. The conduit 164 is connected to the second hydraulic pressure chamber 1C via the orifice 11e, and the conduit 162 is connected to the first hydraulic pressure chamber 1B via the orifice 11c. The first hydraulic pressure chamber 1B enters a hydraulic valve-closing state when the first control valve 22 closes. The conduits 164 and 162 are configured to establish fluid communication between the first hydraulic pressure chamber 1B and the second hydraulic pressure chamber 1C.

[0031] The first control valve 22 is closed in a de-energized state in which no electricity is supplied, in which state communication between the first hydraulic pressure chamber 1B and the second hydraulic pressure chamber 1C is interrupted. Due to the closure of the first hydraulic pressure chamber 1B, the fluid cannot flow anywhere, and the input piston 13 and the first main piston 14 are moved integrally while maintaining a constant separation distance therebetween. The first control valve 22 is open in the energized state in which electricity is supplied, in which state communication between the first hydraulic pressure chamber 1B and the second hydraulic pressure chamber 1C is established.Thus, the volume changes in the first hydraulic pressure chamber 1B and the second hydraulic pressure chamber 1C due to the advance and retraction of the first main piston 14 can be absorbed by transferring the fluid.

[0032] The pressure sensor 73 is a sensor that detects the reaction force hydraulic pressure of the second hydraulic pressure chamber 1C and the first hydraulic pressure chamber 1B and is connected to the line 164. The pressure sensor 73 detects the pressure of the second hydraulic pressure chamber 1C while the first control valve 22 is in a closed state and also detects the pressure of the first hydraulic pressure chamber 1B while the first control valve 22 is in an open state. The pressure sensor 73 sends the detected signal to the brake ECU 6. (Second control valve 23)

[0033] The second control valve 23 is an electromagnetic valve configured to open in a de-energized state, with the associated opening and closing operations controlled by the brake ECU 6. The second control valve 23 is arranged between the conduit 164 and the conduit 161 to establish fluid communication therebetween. The conduit 164 communicates with the second hydraulic pressure chamber 1C via the orifice 11e, and the conduit 161 communicates with the reservoir 171 via the orifice 11a. Accordingly, the second control valve 23 establishes communication between the second hydraulic pressure chamber 1C and the reservoir 171 in the de-energized state, thereby generating no reaction force hydraulic pressure, but the second control valve 23 interrupts communication therebetween in the energized state, thereby generating the reaction force hydraulic pressure.The pressure of vessels 171 to 173 is atmospheric pressure. (Servo pressure generating device 4)

[0034] The servo pressure generating device 4 is constituted by a pressure reducing valve 41, a pressure increasing valve 42, a pressure supply section 43, and a regulator 44. The pressure reducing valve 41 is a valve configured to open in a de-energized state (normally open valve or closed valve), and its flow rate (or pressure) is controlled by the brake ECU 6. One end of the pressure reducing valve 41 is connected to the conduit 161 via the conduit 411, and the other end is connected to the conduit 413. In other words, one end of the pressure reducing valve 41 is connected to the reservoir 171 via the conduits 411 and 161 and the ports 11a and 11b.The pressure-reducing valve 41 prevents the fluid in the first pilot chamber 4D from flowing out through a valve-closing operation, which will be described in detail below. Note that the reservoirs 171 and 434 (or the reservoirs 171 to 173 and 434) are formed by one reservoir.

[0035] The pressure-increasing valve 42 is an electromagnetic valve configured to close in a de-energized state (normally closed valve, or normally closed valve), with its flow rate (or pressure) controlled by the brake ECU 6. One end of the pressure-increasing valve 42 is connected to the conduit 421, and the other end is connected to the conduit 422. The pressure supply section 43 is a section that primarily supplies the regulator 44 with a high-pressure fluid. The pressure supply section 43 includes the accumulator 431 ("high-pressure source"), the pump 432, the motor 433, and the reservoir 434.

[0036] The accumulator 431 is a tank or container in which the highly pressurized fluid is stored. The accumulator 431 is connected to the regulator 44 and the pump 432 through the line 431a. The pump 432 is driven by the motor 433 and supplies the fluid retained in the container 434 to the accumulator 431. The pressure sensor 75 provided in the line 431a detects the accumulator hydraulic pressure in the accumulator 431 and sends the detected signal to the brake ECU 6. The accumulator hydraulic pressure correlates with the amount of fluid stored in the accumulator 431.

[0037] When the pressure sensor 75 detects that the accumulator hydraulic pressure drops to a value equal to or less than a predetermined value, the motor 433 is driven based on a control signal from the brake ECU 6, and the hydraulic pressure pump 432 pumps the fluid to the accumulator 431 to thereby restore the pressure to the value equal to or greater than a predetermined value.

[0038] The regulating device 44 (pressure adjusting device) comprises a cylinder 441, a ball valve 442, a biasing section 443, a valve seat section 444, a control piston 445 and a sub-piston 446, as shown in Fig. 2. The cylinder 441 includes a cylinder housing 441a formed in a substantially bottomed cylindrical shape having a bottom surface at one end thereof (on the right side in the drawing), and a cover member 441b closing an opening of the cylinder housing 441a (on the left side thereof in the drawing). Note that the cylinder housing 441a is provided with a plurality of openings 4a to 4h through which the inside and outside of the cylinder housing 441a communicate. The cover member 441b is formed in a substantially bottomed cylindrical shape having a bottom surface and is provided with a plurality of openings arranged at positions opposite to the respective cylindrical openings 4d to 4h provided in the cylindrical portion.

[0039] Port 4a is connected to line 431a. Port 4b is connected to line 422. Port 4c is connected to a line 163. Line 163 connects servo chamber 1A and exhaust port 4c. Port 4d is connected to line 161 via line 414. Port 4e is connected to line 424 and further to line 422 via a relief valve 423. Port 4f is connected to line 413. Port 4g is connected to line 421. Port 4h is connected to a line 511 branched off from line 51.

[0040] The ball valve 442 is a valve having a spherical shape and is disposed at the bottom surface side (hereinafter also referred to as a cylinder bottom surface side) of the cylinder housing 441a inside the cylinder 441. The biasing portion 443 is formed by a spring member that biases the ball valve 442 toward the opening side (hereinafter also referred to as a cylinder opening side) of the cylinder housing 441a and is provided at the bottom surface of the cylinder housing 441a. The valve seat portion 444 is a wall member provided at the inner peripheral side of the cylinder housing 441a, dividing the cylinder inside into two parts, the cylinder opening side and the cylinder bottom surface side. A passage 444a through which spaces of the cylinder opening side and the cylinder bottom surface side communicate is formed at a central portion of the valve seat portion 444.The valve element 444 holds the ball valve 442 from the cylinder opening side in such a way that the preloaded ball valve 442 closes the passage 444a. A valve seat surface 444b is formed at the opening of the cylinder bottom surface side of the passage 444a, and the ball valve 442 is detachably fitted onto (in contact with) the valve seat surface 444b.

[0041] A space defined by the ball valve 442, the biasing portion 443, the valve seat portion 444, and the inner peripheral surface of the cylinder housing 441a on the cylinder bottom surface side is referred to as a "first chamber 4A." The first chamber 4A is filled with the fluid and is connected to the conduit 431a via the opening 4a and to the conduit 422 via the opening 4b.

[0042] The control piston 445 includes a main body portion 445a formed in a substantially columnar shape and a protrusion portion 445b formed in a substantially columnar shape having a diameter smaller than the diameter of the main body portion 445a. The main body portion 445a is disposed in the cylinder 441 in a coaxial and fluid-tight manner at the cylinder opening side of the valve seat portion 444, and the main body portion 445a is slidably movable in an axial direction. The main body portion 445a is biased toward the cylinder opening side by a biasing member (not shown). A passage 445c is formed at a substantially intermediate portion of the main body portion 445a in a cylinder axis direction.The passage 445c extends in the radial direction (in an up-down direction as viewed in the drawing), with both ends of the passage 445c opening to the peripheral surface of the main body portion 445a. A portion of the inner peripheral surface of the cylinder 441 corresponding to an opening position of the passage 445c is provided with the opening 4d and is recessed. The recessed space portion forms a "third chamber 4C."

[0043] The protrusion portion 445b protrudes toward the cylinder bottom surface side from a central portion of an end surface of the cylinder bottom surface side of the main body portion 445a. The protrusion portion 445b is formed such that its diameter is smaller than the diameter of the passage 444a of the valve seat portion 444. The protrusion portion 445b is provided coaxially with the passage 444a. A tip end of the protrusion portion 445b is spaced from the ball valve 442 toward the cylinder opening side by a predetermined distance. A passage 445d is formed at the protrusion portion 445b such that the passage 445d extends in the cylinder axis direction and opens at a central portion of an end surface of the protrusion portion 445b. The passage 445d extends into the inside of the main body portion 445a and is connected to the passage 445c.

[0044] A space defined by the cylinder bottom surface side end surface of the main body portion 445a, an outer peripheral surface of the protrusion portion 445b, the inner peripheral surface of the cylinder 441, the valve seat portion 444, and the ball valve 442 is referred to as a "second chamber 4B." The second chamber 4B communicates with the ports 4d and 4e via the passages 445d and 445c and the third chamber 4C in a non-contact state.

[0045] The sub-piston 446 includes a sub-main body portion 446a, a first protrusion portion 446b, and a second protrusion portion 446c. The sub-main body portion 446a is formed in a substantially columnar shape. The sub-main body portion 446a is disposed in the cylinder 441 in a coaxial and fluid-tight manner at the cylinder opening side of the main body portion 445a. The sub-main body portion 446a is slidably movable in the axial direction.

[0046] The first protrusion portion 446b is formed in a substantially columnar shape having a diameter smaller than the diameter of the sub-main body portion 446a and protrudes from a central portion of an end surface of the cylinder bottom surface side of the sub-main body portion 446a. The first protrusion portion 446b is in contact with the end surface of the cylinder bottom surface side of the sub-main body portion 446a. The second protrusion portion 446c is formed in the same shape as the first protrusion portion 446b. The second protrusion portion 446c protrudes from a central portion of an end surface of the cylinder opening side of the sub-main body portion 446a. The second protrusion portion 446c is in contact with the cover member 441b.

[0047] A space defined by the cylinder bottom surface side end surface of the lower main body portion 446a, an outer peripheral surface of the first protrusion portion 446b, an end surface of the cylinder opening side of the control piston 445, and the inner peripheral surface of the cylinder 441 is referred to as a "first pilot chamber 4D." The first pilot chamber 4D communicates with the pressure-reducing valve 41 via the orifice 4f and the conduit 413, and is in fluid communication with the pressure-increasing valve 42 via the orifice 4g and the conduit 421.

[0048] A space defined by the cylinder opening side end surface of the sub-main body portion 446a, an outer peripheral surface of the second protrusion portion 446c, the cover member 441b, and the inner peripheral surface of the cylinder 441 is referred to as a "second pilot chamber 4E." The second pilot chamber 4E communicates with the port 11g via the port 4h and the conduits 511 and 51. Each of the chambers 4A to 4E is filled with fluid. The pressure sensor 74 is a sensor that detects the pressure (hydraulic pressure in the servo chamber 1A: servo pressure) to be supplied to the servo chamber 1A, and is connected to the conduit 163. The pressure sensor 74 sends the detected signal to the brake ECU 6. The detected value of the pressure sensor 74 is an actual value of the servo pressure (corresponding to the actuating force), and is referred to as the "actual servo pressure (corresponding to the "actual hydraulic pressure")".

[0049] As explained, the regulator 44 includes the control piston 445, which is driven by the difference between the force corresponding to the pressure (also referred to as "pilot pressure") in the first pilot chamber 4D and the force corresponding to the servo pressure, and the volume of the first pilot chamber 4D changes in response to the movement of the control piston 445. The more the fluid flowing into or out of the first pilot chamber 4D increases, the more the amount of movement of the control piston 445 from the associated reference point increases in the equilibrium state where the force corresponding to the pilot pressure is balanced with the force corresponding to the servo pressure. Thus, the flow rate of the fluid flowing into or out of the servo chamber 1A is structured to be increasing.

[0050] The regulating device 44 is constructed such that the more the flow rate of the liquid flowing into the first pilot chamber 4D from the accumulator 431 increases, the larger the volume of the first pilot chamber 4D becomes, and at the same time the flow rate of the liquid flowing into the servo chamber 1A from the accumulator 431 increases, and further the more the flow rate of the liquid flowing from the first pilot chamber 4D into the reservoir 171 increases, the smaller the volume of the first pilot chamber 4D becomes, and at the same time the flow rate of the liquid flowing from the servo chamber 1A into the reservoir 171 increases.

[0051] Furthermore, the control piston 445 is provided with a damping device (not shown) at the wall portion facing the first pilot chamber 4D. The damping device is configured as a stroke simulator and is provided with a piston portion biased toward the first pilot chamber 4D by a biasing member. By providing this damping device, the rigidity of the first pilot chamber 4D is variable in response to the pilot pressure. (Actuating device 5)

[0052] The actuator 5 is provided between the first master chamber 1D and the second master chamber 1E, which generate the master cylinder hydraulic pressure, and the wheel cylinders 541 to 544. The actuator 5 and the first master chamber 1D are connected through the conduit 51, and the actuator 5 and the second master chamber 1E are connected through the conduit 52. The actuator 5 adjusts the brake hydraulic pressure to be supplied to the wheel cylinders 541 to 544 based on instructions from the brake ECU 6. The actuator 5 according to the embodiment constitutes an anti-lock brake system (ABS). The actuator 5 is formed with a four-channel system (dual circuit system) corresponding to the respective wheel cylinders 541 to 544. The structure of the actuator 5 is of a well-known type, and a detailed explanation thereof will be omitted. (Brake ECU 6)

[0053] The brake ECU 6 is an electronic control unit and includes a microprocessor. The microprocessor includes an input / output interface, a CPU, a RAM, a ROM, and a storage section such as a non-volatile memory, which are connected to each other via a bus connection. The brake ECU 6 is connected to various sensors 71 to 76 for controlling each of the electromagnetic valves 22, 23, 41, and 42, the motor 433, and the actuator 5, etc.The operation amount (stroke amount) information of the brake pedal 10 is input to the brake ECU 6 from the stroke sensor 71, information showing whether or not the operation of the brake pedal 10 is input to the brake ECU 6 from the brake stop switch 72, the reaction force hydraulic pressure information is input to the brake ECU 6 from the pressure sensor 73, the servo pressure information is input to the brake ECU 6 from the pressure sensor 74, the accumulator hydraulic pressure information is input to the brake ECU 6 from the pressure sensor 75, and respective wheel speed information of the respective vehicle wheels 5FR, 5FL, 5RR, and 5RL is input to the brake ECU 6 from each of the wheel speed sensors 76. (brake control)

[0054] The braking control by the brake ECU 6 (normal braking control) is explained below. Normal braking control is performed by normally controlling the hydraulic pressure braking force. In braking control (normal operation mode), the brake ECU 6 energizes the first control valve 22 and opens the first control valve 22, and energizes the second control valve 23 and closes the second control valve 23. By closing the second control valve 23, the communication between the second hydraulic pressure chamber 1B and the reservoir 171 is interrupted, and the opening of the first control valve 22 establishes communication between the first hydraulic pressure chamber 1B and the second hydraulic pressure chamber 1C.Thus, the brake control is a mode for controlling the servo pressure of the servo chamber 1A by controlling the pressure-reducing and pressure-increasing valves 41 and 42, opening the first control valve 22 and closing the second control valve 23. The pressure-reducing valve 41 and the pressure-increasing valve 42 constitute a "valve section" that adjusts the flow rate of the fluid flowing into or out of the first pilot chamber 4D. In this brake control, the brake ECU 6 calculates a required braking force requested by the driver of the vehicle according to a situation based on the operation amount of the brake pedal 10 detected by the stroke sensor 71 (displacement amount of the input piston 13) or the operation force of the brake pedal 10 (for example, the hydraulic pressure detected at the pressure sensor 73).Then, based on the calculated required braking force, the brake ECU 6 sets a target servo pressure (corresponding to a "target hydraulic pressure"), which is the target value of the servo pressure. The pressure-reducing valve 41 and the pressure-increasing valve 42 are controlled so that the actual servo pressure approaches the target servo pressure.

[0055] More specifically, in the state that the brake pedal 10 is not depressed, the brake control state becomes the state as explained above, that is, it becomes the state that the ball valve 442 closes the passage 444a of the valve seat portion 444. In this state, the pressure-reducing valve 41 is in an open state, and the pressure-increasing valve 42 is in a closed state. In other words, the fluid communication between the first chamber 4A and the second chamber 4B is interrupted. The second chamber 4B communicates with the servo chamber 1A via the conduit 163 to maintain the hydraulic pressures in the two chambers 4B and 1A mutually at the same level. The second chamber 4B communicates with the third chamber 4C via the passages 445c and 445d of the control piston 445.Accordingly, the second chamber 4B and the third chamber 4C communicate with the reservoir 171 via lines 414 and 161. One side of the first pilot chamber 4D is closed by the pressure-increasing valve 42, while the corresponding other side is connected to the reservoir 171 via the pressure-reducing valve 41. The pressures of the first pilot chamber 4D and the second chamber 4B are maintained at the same pressure level. The second pilot chamber 4E communicates with the first main chamber 1D via lines 511 and 51, thereby maintaining the pressure levels of the two chambers 4E and 1D mutually equal to each other.

[0056] From this state, when the brake pedal 10 is depressed, the brake ECU 6 controls the pressure reducing valve 41 and the pressure increasing valve 42 based on the actual servo pressure and the target servo pressure. Upon pressure increase, the brake ECU 6 controls the pressure reducing valve 41 to close and the pressure increasing valve 42 to open. When the pressure increasing valve 42 is opened, communication is established between the accumulator 431 and the first pilot chamber 4D. When the pressure reducing valve 41 is closed, communication between the first pilot chamber 4D and the reservoir 171 is interrupted. The pressure in the first pilot chamber 4D can be increased by the high-pressure fluid supplied from the accumulator 431.As the pressure in the first pilot chamber 4D increases, the control piston 445 slides toward the cylinder bottom surface side. Then, the tip end of the protruding portion 445b of the control piston 445 is brought into contact with the ball valve 442 to close the passage 445d through the ball valve 442. Thus, the fluid communication between the second chamber 4B and the reservoir 171 is interrupted.

[0057] By further sliding the control piston 445 toward the cylinder bottom surface side, the ball valve 442 is pushed toward the cylinder bottom surface side by the protrusion portion 445b, thereby separating the ball valve 442 from the valve seat surface 444b. This will enable fluid communication to be established between the first chamber 4A and the second chamber 4B through the passage 444a of the valve seat portion 444. Since the highly pressurized fluid is supplied to the first chamber 4A from the accumulator 431, the hydraulic pressure in the second chamber 4B is also increased by the communication therebetween.It should be noted that the more the separation distance of the ball valve 442 from the valve seat surface 444b increases, the more the fluid passage for the fluid increases, and accordingly the flow rate of the fluid in the fluid passage downstream of the ball valve 442 becomes high.

[0058] The brake ECU 6 controls the pressure increase valve 42 and simultaneously closes the pressure decrease valve 41, so that the larger the displacement amount of the input piston 13 (the operation amount of the brake pedal 10) detected by the stroke sensor 71, the higher the pilot pressure in the first pilot chamber 4D becomes. In other words, the larger the displacement amount of the input piston 13 (the operation amount of the brake pedal 10), the higher the pilot pressure becomes, and accordingly, the higher the actual servo pressure becomes. The actual servo pressure can be obtained from the pressure sensor 74 and can be converted into the pilot pressure.

[0059] As the pressure of the second chamber 4B increases, the pressure (actual servo pressure) in the servo chamber 1A, which is in fluid communication with the second chamber 4B, increases. Due to the pressure increase in the servo chamber 1A, the first master piston 14 advances, increasing the pressure (master pressure) in the first master chamber 1D. Then, the second master piston 15 also advances, increasing the pressure (master pressure) in the second master chamber 1E. Due to the increase in the pressure (master pressure) in the first master chamber 1D, a highly pressurized fluid (master pressure) is supplied to the actuator 5 and the second pilot chamber 4E. The pressure in the second pilot chamber 4E increases, but since the pressure in the first pilot chamber 4D also increases, the sub-piston 446 does not move.Thus, the high-pressure (main pressure) fluid is supplied to the actuator 5, operating friction braking to control braking of the vehicle. When the braking operation is released, unlike what was described above, the pressure-reducing valve 41 is open and the pressure-increasing valve 42 is closed to establish fluid communication between the reservoir 171 and the first pilot chamber 4D. Then, the control piston 445 retracts, and the vehicle returns to the state before the brake pedal 10 was depressed. (Reaction force chamber opening mode)

[0060] In contrast, when the first control valve 22 is in a closed state (de-energized state) and the second control valve 23 is in an open state, the first hydraulic pressure chamber 1B becomes sealed, and the second hydraulic pressure chamber 1C communicates with the reservoir 171. In this state, when the brake pedal 10 is depressed, the first master piston 10 is actuated along with the advancement of the input piston 13 and advances integrally with the input piston 13 (in a mutually non-contact state). At this time, since the second hydraulic pressure chamber 1C communicates with the reservoir 171, substantially no reaction force hydraulic pressure is generated. The fluid corresponding to the volume corresponding to the reduction in the second hydraulic pressure chamber 1C flows out and into the reservoir 171 via the second control valve 23.Then, the master pressure generated by the advancement of the first master piston 14 is supplied to the actuator 5 and the second pilot chamber 4E via the conduits 51, 52, and 511. Thus, it is possible to generate braking force only by operating the brake pedal 10. This state (or control) is referred to as the "reaction force chamber opening mode," and the mode in which the braking control is performed by the brake ECU 6 is referred to as the "normal mode." It should be noted that in this reaction force chamber opening mode, when the first control valve 22 is in the open state or when the first control valve 22 is not present (provided), the first master piston 14 does not advance forward until the input piston 13 is brought into contact with the first master piston 14 and pushes the first master piston 14.The stroke until the input piston 13 is brought into contact with the first main piston 14 is defined to be the “invalid stroke”.

[0061] As explained above, the vehicle brake device A according to the embodiment includes a reaction force chamber R (1B, 1C, 214, 164, 162) in which a reaction force hydraulic pressure is generated in response to an operation amount of a brake operating member 10, a low-pressure source 171 that communicates with the reaction force chamber R under a predetermined condition, a master cylinder 1 having a main chamber 1D, 1E in which a main hydraulic pressure (master pressure) is generated by being driven by a master piston 14, 15, a drive chamber 1A (servo chamber according to this embodiment) that generates a drive hydraulic pressure (servo pressure according to this embodiment) for driving the master piston 14, 15 in response to the operation amount of the brake operating member 10, a valve portion 41, 42 that controls an inflow and outflow amount of the fluid in relation to the control chamber 1A,a control section 6 (61) that sets a target hydraulic pressure, which is a target value of the control hydraulic pressure or the main hydraulic pressure, based on at least one parameter from the operation amount and an operation force of the brake operating member 10, and controls the valve section 41, 42 to approximate an actual hydraulic pressure, which is an actual value of the control hydraulic pressure or the main hydraulic pressure with respect to the target hydraulic pressure, to the target hydraulic pressure, a stroke sensor 71 that detects the operation amount of the brake operating member 10, a pressure sensor 73 that detects the reaction force hydraulic pressure, and an electromagnetic valve 23,which is arranged between the reaction force chamber R and a reservoir 173. According to this embodiment, at least one of the actuating chamber (servo chamber 1A) and the valve section (pressure-reducing valve 41 and pressure-increasing valve 42) forms an actuating section Y, which generates an actuating force for actuating the master piston. In other words, the control section 6 (61) sets a target value for the actuating force or the main hydraulic pressure based on at least one of the operating amount and the operating force of the brake operating member 10, controlling the actuating section Y to cause the actual value of the actuating force or the main hydraulic pressure with respect to the target value to approach the target value. (Anomaly diagnosis)

[0062] The brake ECU 6 includes, as one function, the control section 61 that executes the above-explained brake control, a diagnostic section 62 that performs abnormality diagnosis, and a judgment section 63 that judges the state of the reaction force chamber R. The control section 61, as explained above, sets the target servo pressure and controls the pressure-reducing valve 41 and the pressure-increasing valve 42 to cause the actual servo pressure to approach the target servo pressure. The control section 61 executes feedback control. The diagnostic section 62 and the judgment section 63 constitute the abnormality diagnosis device C.

[0063] The diagnostic section 62 performs an abnormality diagnosis based on at least one of "a relationship between the operation amount of the brake pedal 10 (hereinafter also simply referred to as "stroke") and the reaction force hydraulic pressure" and "a relationship between the target servo pressure and the actual servo pressure." More specifically, the diagnostic section 62 diagnoses, as shown in Fig. 3, an abnormality is diagnosed when the detection result (reaction force hydraulic pressure) of the pressure sensor 73 with respect to the detection result (stroke) of the stroke sensor 71 indicates a value outside a normal range set per each stroke for a predetermined period of time or more. That is, the diagnosis section 62 diagnoses an abnormality when the detected value of the pressure sensor 73 with respect to the detected value of the stroke sensor 71 exceeds an allowable upper limit set per each stroke for a predetermined period of time or more, or falls below an allowable lower limit set per each stroke for a predetermined period of time. The normal range is a range between the allowable lower limit and the allowable upper limit.

[0064] Furthermore, the diagnostic section 62 diagnoses, as in Fig. 4, an abnormality is detected when the actual servo pressure (the detected value of the pressure sensor 74) indicates a value outside a normal range (from the allowable lower limit to the allowable upper limit) with respect to the target servo pressure, which is set in response to an inclination of the target servo pressure for a predetermined period of time or more. As an alternative, the diagnostic section 62 may diagnose an abnormality when the difference between the target servo pressure and the actual servo pressure indicates a value greater than or equal to an allowable value for a predetermined period of time or more. The diagnostic section 62 performs an abnormality diagnosis at every predetermined time interval. The diagnostic section 62 notifies the driver of the vehicle that an abnormality has occurred by means of an informing device (not shown) when it is judged that an abnormality has occurred.

[0065] The judging section 63 judges whether the state of the reaction force chamber R is in a predetermined insufficient state or a predetermined excess state with respect to at least one of the hydraulic pressure and the fluid amount. The "predetermined insufficient state" means the state that the fluid amount in the reaction force chamber R is less than a predetermined lower limit value, or the state that the reaction force hydraulic pressure in the reaction force chamber is less than a predetermined lower limit pressure. The "predetermined insufficient state" can be expressed as a state that the fluid amount in the reaction force chamber R is less than the amount in an initial state (steady state).The "predetermined excess state" means the state that the fluid amount in the reaction force chamber R is greater than a predetermined upper limit value, or the state that the reaction force hydraulic pressure in the reaction force chamber R is greater than a predetermined upper limit pressure. The "predetermined excess state" can be expressed as a state that the fluid amount in the reaction force chamber R is greater than the amount in an initial state (steady state). Note that, according to this embodiment, the state of the reaction force chamber R is judged mainly based on the fluid amount in the reaction force chamber R, whether the state is the insufficient state or the excess state.

[0066] More specifically, the judging section 63 obtains the fluid communication information between the reaction force chamber R and the reservoirs 171 to 173, and the judging section 63 judges the state of the reaction force chamber R based on the obtained fluid communication information and at least one of the detection result (stroke) of the stroke sensor 71 and the detection result (reaction force hydraulic pressure) of the stroke sensor 73. Further, in detail, the judging section 63 obtains the opening and closing record (history) of the second control valve 23 as the fluid communication information, and the judging section 63 judges the state of the reaction force chamber R based on the obtained opening and closing record and at least one of the stroke and the reaction force hydraulic pressure.When the second control valve 23 is opened, fluid communication is established between the reaction force chamber R and the reservoir 171. In other words, in the state that the second control valve 23 is opened (under the predetermined condition), the reaction force chamber R and the reservoir 171 are fluidly connected to each other. The opening and closing of the second control valve 23 is controlled by the instructions (control flow) of the control section 61, and the corresponding record (instruction information) is stored in the storage section of the brake ECU 6.

[0067] The judging section 63 obtains the information on establishing / disrupting fluid communication between the reaction force chamber R and the reservoir 173 from the stored opening and closing record of the second control valve 23. Note that hereinafter, the state that the second control valve 23 is open is referred to as the "reservoir communication establishment state," and the state that the second control valve 23 is closed is referred to as the "reservoir communication interruption state." The brake ECU 6 according to this embodiment closes the first control valve 22 in the reservoir connection establishment state and opens the first control valve 22 in the reservoir connection interruption state.In the tank connection interruption state, the judging section 63 according to this embodiment judges the state of the reaction force chamber R at a current state (here, in the tank connection interruption state) based on the opening and closing record, a stroke in the tank connection establishment state, and the reaction force hydraulic pressure in the tank connection establishment state.

[0068] The judging section 63 calculates (assumes) the outflow amount of fluid to the reservoir 173 from the reaction force chamber R based on the forward stroke (pressing operation amount) and the reaction force hydraulic pressure during the reservoir connection establishment period. Specifically, the judging section 63 considers (excludes) the consumption amount of fluid in the stroke simulator 21 caused by the forward stroke and calculates the outflow amount of fluid based on the pressure difference between the reaction force hydraulic pressure and the pressure (atmospheric pressure) in the reservoir 173.

[0069] Further, the judging section 63 calculates (assumes) the inflow amount of the fluid into the reaction force chamber R from the reservoir 173 based on the rearward stroke (return operation amount) and the reaction force hydraulic pressure in the period of the reservoir connection establishment state. The judging section 63 calculates the inflow amount of the fluid based on the rearward stroke and the pressure difference between the reaction force hydraulic pressure and the pressure (atmospheric pressure) in the reservoir 173. The judging section 63 judges whether or not the state of the reaction force chamber R is in a predetermined insufficient state based on the calculated outflow and inflow amounts of the fluid. The judging section 63 considers at least one parameter from the fluid passage (opening effect).The valve 173 calculates the inflow and outflow amount of the fluid in the reaction force chamber R based on the orifice effect of the second control valve 23 between the reaction force chamber R and the reservoir 173, a pressure difference, and the viscosity of the fluid, and calculates the inflow and outflow amount of the fluid in the reaction force chamber R. Note that the inflow and outflow amount of the fluid in the reaction force chamber R can be calculated from the database obtained in advance, for example, through experimental work or the like, from the stroke change amount, a reaction force hydraulic pressure change amount, and the duration of the reservoir connection establishment state. It should also be noted that the outflow amount of the fluid can be calculated by taking into account the opening and closing state (opening and closing record) of the first control valve 22 when the first control valve 22 is subjected to opening / closing control in the reservoir connection establishment state.

[0070] The judging section 63 continues to calculate the inflow and outflow amount of the fluid, including the time until the calculated fluid amount in the reaction force chamber R returns to the value within the normal range (the range between the predetermined lower limit and the predetermined upper limit) after the second control valve 23 is closed. Even in the state that the second control valve 23 has been closed, if the reaction force chamber R is in a negative pressure state, the fluid flows into the reaction force chamber R from the reservoir 173 via, for example, the passage 18. In such a situation, the inflow amount is limited due to the orifice effect of the passage 18 and the first control valve 22, and it may take a long time to return to the normal state.For example, the judging section 63 calculates the fluid amount of the reaction force chamber R after the second control valve 23 closes, based on the pressure difference between the reaction force chamber R and the reservoir 173 and the inflow amount (inflow amount of fluid via the passage 18) per unit time caused by the pressure difference. The judging section 63 may consider the fluid flowing therein via the seal members 91, 95 from the reservoir 171 to 173 when calculating the inflow and outflow amount of fluid. The judging section 63 may calculate the inflow and outflow amount of fluid at every different time regardless of the opening and closing state of the second control valve 23, and may judge the state of the reaction force chamber R each time the inflow and outflow amount of fluid is calculated.It should be noted that the judging section 63 may calculate (assume) the time in which the fluid amount in the reaction force chamber R returns to a value within the normal range when the second control valve 23 is closed.

[0071] The judging section 63 sends the signal prohibiting the execution of an abnormality diagnosis to the diagnostic section 62 when the judging section 63 judges that the state of the reaction force chamber R is in the predetermined insufficient state in the reservoir connection interruption state. Conversely, the judging section 63 sends the signal permitting the execution of an abnormality diagnosis to the diagnostic section 62 when the judging section 63 does not judge that the state of the reaction force chamber R is in the predetermined insufficient state in the reservoir connection interruption state. The diagnostic section 62 executes or stops the abnormality diagnosis based on the permission / prohibition signal from the judging section 63.In other words, the diagnosis section 62 stops the abnormality diagnosis when the judgment section 63 judges that the state of the reaction force chamber R is in the predetermined insufficient state.

[0072] It should be noted that an example in which the state of the reaction force chamber R becomes the predetermined insufficient state will be described with reference to Fig. 5 is explained. As it is in Fig. As shown in Fig. 5, in the reservoir connection establishment state (the state that the second control valve 23 is open and the first control valve 22 is closed), when the brake pedal 10 is depressed and the input piston 13 advances forward, the fluid is discharged to the reservoir 173 via the second control valve 23 in response to the stroke. In other words, in the reservoir connection establishment state, when the brake pedal 10 is deeply depressed, the first master piston 14 advances forward in cooperation with the advance movement of the input piston 13. Thus, the volume of the second hydraulic pressure chamber 1C decreases due to the advance movement thereof (the space of the reaction force chamber R is reduced), and then the fluid in the reaction force chamber R is discharged to the reservoir 173 via the second control valve 23.

[0073] In turn, when the brake pedal 10 is suddenly returned (when the brake pedal 10 is quickly released), the first master piston 14 retracts. Due to such retraction of the first master piston 14, the volume of the second hydraulic pressure chamber 1C increases toward the initial state (expands the reaction force chamber R), thereby reducing the pressure in the reaction force chamber R (here, it becomes a negative pressure state). Then, due to the pressure difference between the reaction force chamber R and the reservoir 173, the fluid in the reservoir 173 flows into the reaction force chamber R via the second control valve 23. Note that an orifice effect is generated at the second control valve 23 due to the difference in a width of the fluid path between the second control valve 23 and the conduit 161.Thus, the amount of fluid flowing into the reaction force chamber R is limited, and a timing delay occurs for eliminating the pressure difference (negative pressure in the reaction force chamber R) between the reaction force chamber R and the reservoir 173 with respect to the return operation of the brake pedal 10.

[0074] Then, in the situation that the pressure difference exists, when the second control valve 23 is closed and the state is shifted to the tank communication cutoff state (the state that the second control valve 23 is closed and the first control valve 22 is opened), due to the above-mentioned pressure difference (the state that the fluid in the reaction force chamber R is insufficient), the fluid in the tank 173 flows into the reaction force chamber R via the passage 18. Even in this situation, however, since the amount of fluid flowing into the reaction force chamber R is limited by the orifice effect at the passage 18 and the first control valve 22, it takes time to resolve the pressure difference.In other words, according to the vehicle brake device A, a period in which the pressure difference is not resolved, that is, a period in which the fluid in the reaction force chamber R is less than the fluid in the normal situation, occurs. The second control valve 23 is controlled to be closed from the open state at the time when the brake pedal 10 is depressed again after a sudden return operation of the brake pedal 10, for example, when the operation mode is switched from the reaction force chamber opening mode (operation mode that the braking force is generated without opening the pressure increase valve 42) to the normal operation mode (operation mode that performs the above-described brake control).Before the fluid completely returns to the reaction force chamber R, when the control mode is switched (when the second control valve 23 is controlled to be closed from the opening state), the period of insufficient fluid state occurs at the reaction force chamber R.

[0075] During the period when the fluid in the reaction force chamber R is insufficient, when the brake pedal 10 is depressed, the input piston 13 advances relatively smoothly due to the lack of fluid in the reaction force chamber R, consuming more stroke than in a normal situation. In other words, with the same operation of the brake pedal 10, the stroke becomes larger than the normal operation of the brake pedal 10. Consequently, even if no malfunction occurs, the "relationship between the stroke and the reaction force hydraulic pressure" changes greatly compared to the relationship at a normal time. Furthermore, when the brake pedal 10 is depressed in the insufficient fluid state, the reaction force hydraulic pressure is not increased, but the stroke increases greatly.In such a situation, the input piston 13 and the first master piston 14 may be brought into contact with each other, and when such contact occurs, the first piston 14 advances by the pushing of the input piston 13 (a pushing-down force by the vehicle driver). Then, the master pressure increased by the advance of the first master piston 14 is supplied to the second pilot chamber 4E, and the actual servo pressure increases regardless of the control. Accordingly, even if no malfunction occurs, it may be diagnosed as being in an abnormal pressure increase state. In other words, even in such a case, the "relationship between the target servo pressure and the actual servo pressure" changes greatly compared to the relationship in normal time. The "relationship between the target master pressure and the actual master pressure" also changes in a similar manner.As explained, in the insufficient fluid condition, the diagnosis section 62 may possibly make a misdiagnosis.

[0076] Here, the judging section 63 considers the opening and closing of the second control valve 23 and the opening effect, and calculates the inflowing and outflowing fluid with respect to the reaction force chamber R with the above consideration. The judging section 63 judges that the state of the reaction force chamber R is in a "predetermined insufficient state" when the fluid amount in the reaction force chamber R is less than the predetermined lower limit value. Furthermore, the judging section 63 calculates the fluid amount in the reaction force chamber R at a current time based on the decreased fluid amount (insufficient fluid amount) in the reaction force chamber R, the pressure difference, and the opening effect at the passage 18 or the like in the tank communication cutoff state.The judging section 63 judges that the state of the reaction force chamber R is in the "predetermined insufficient state" until the fluid amount in the reaction force chamber R returns to a value within a normal range. In other words, the judging section 63 judges for the period of time T1 shown in . Fig. 5 that the state of the reaction force chamber R is in the predetermined insufficient state. Thus, an abnormality diagnosis stops in the insufficient fluid state of the reaction force chamber R. It should be noted that the judging section 63 may calculate the fluid amount of the reaction force chamber R in a valve opening state of the second control valve 23, and accordingly, the judging section 63 may judge that the state of the reaction force chamber R is in the predetermined insufficient state for the time period T2 shown in Fig. 5, which includes the duration of an opening state of the second control valve 23 (in the reservoir connection establishment state). However, when the subject of the abnormality diagnosis is the normal brake control (normal operation mode), it is sufficient for the judging section 63 to judge the state of the predetermined insufficient condition only for the time period T1. It should be noted that the amount of fluid that is Fig. 5 is a conceptual set (image) illustrated for the purpose of explanation.

[0077] The procedure of a condition assessment of the reaction force chamber R for anomaly diagnosis is described with reference to Fig.6. First, the judging section 63 confirms (judges) the opening and closing state of the second control valve 23 at the current time based on the control situation of the control section 61 or the opening and closing record (S101). The judging section 63 obtains the stroke information from the stroke sensor 71 (S102) and obtains the reaction force hydraulic pressure information from the pressure sensor 73 (S103). Then, the judging section 63 calculates or assumes the inflow and outflow amount of the fluid with respect to the reaction force chamber R at the current time based on the opening and closing record, the stroke, and the reaction force hydraulic pressure (S104).The judging section 63 judges whether the state of the reaction force chamber R is in a state smaller than a predetermined state or larger than a predetermined state based on the calculation result (S105). If the judging section 63 judges that the state of the reaction force chamber R is in the predetermined insufficient state or the predetermined excess state (S105: Yes), it sends a diagnosis prohibition signal to the diagnosing section 62, and the diagnosing section 62 stops abnormality diagnosis (S106). On the other hand, if the judging section 63 does not judge that the state of the reaction force chamber R is in the predetermined insufficient state or the predetermined excess state (S105: No), it sends a diagnosis permission signal to the diagnosing section 62, and the diagnosing section 62 performs abnormality diagnosis (S107).This processing is repeated on a stable basis (every predetermined time).

[0078] According to the embodiment, in a system in which the reaction force chamber R and the reservoir 173 are hydraulically connected, the abnormality diagnosis stops when the fluid state of the reaction force chamber R becomes an insufficient fluid state (less fluid state). Accordingly, erroneous detection (erroneous diagnosis, erroneous diagnosis) in the execution of abnormality diagnosis caused by excessive depression of the brake pedal 10 in the insufficient fluid state, rather than the occurrence of a malfunction, can be suppressed. By suppressing the erroneous detection in this way, the accuracy of the abnormality diagnosis can be improved. Furthermore, when the insufficient state of the reaction force chamber R is released, the abnormality diagnosis can be allowed to quickly restart the abnormality diagnosis, thereby improving the safety of the system.As explained above, according to the embodiment, the decision as to whether or not to perform the abnormality diagnosis is made in consideration of the fluid communication state between the reaction force chamber R and the reservoir 173, and accordingly, more reliable abnormality diagnosis can be realized.

[0079] Furthermore, according to the embodiment, the establishment and interruption of the fluid connection between the reaction force chamber R and the container 173 is controlled by opening and closing the second control valve 23.

[0080] Consequently, by referring to the opening and closing record of the second control valve 23, the fluid inflow and outflow amount with respect to the reaction force chamber R can be calculated. By using the opening and closing record as the calculation element, the accuracy of calculating the inflow and outflow amount of the fluid can be improved.

[0081] According to the embodiment, the judgment of the predetermined insufficient state has been mainly explained. The judgment regarding the "predetermined excess state" will be explained below. As explained above, the predetermined excess state means the state that the fluid state of the reaction force chamber R is in a fluid excess state. For example, such a fluid excess state may occur by successively depressing the brake pedal 10, performing a so-called pumping operation (in a case where the input piston 13 repeats an advancing movement and a retracting movement in a very short period of time without returning to the initial position) during normal brake control (normal operation mode: first control valve 22 is open and second control valve 23 is closed).

[0082] Specifically, in this situation, during the sequential actuation, at least one of the first hydraulic pressure chamber 1B and the second hydraulic pressure chamber 1C temporarily enters a negative pressure state, and in this temporary negative pressure state, fluid can flow out of the reservoir 171 to 173 and into the reaction force chamber R via the sealing members 91, 95, etc. In other words, when the reaction force chamber R is in a negative pressure state (corresponding to the "predetermined condition"), the reaction force chamber R and the reservoir 171 to 173 are in fluid communication with each other via the sealing members 91, 95. Thus, the amount of fluid in the reaction force chamber R is increased, and despite a small stroke, the reaction force hydraulic pressure becomes large.The judging section 63 assumes the duration of a negative pressure state and calculates the amount of fluid flowing in via the sealing elements 91, 95 for the period of time (connection establishment period). The amount flowing in through the sealing elements 91, 95 can be set in advance through experimental work or the like. The judging section 63 uses, for example, the "communication information concerning the connection state" as the judgment of whether or not the reaction force chamber R is in a negative pressure state based on the detection result from the pressure sensor 73, and judges that the valium state is the state that the reaction force chamber R and the containers 171 to 173 are in fluid communication, thereby calculating the inflow and outflow amounts of the fluid.The judging section 63 calculates the inflow and outflow amount of the fluid, assuming that the duration of a negative pressure state is the connection establishment period. The judging section 63 judges whether the state of the reaction force chamber R is in the predetermined excess state or not based on the calculation result. (Other)

[0083] The invention is not limited to the embodiment explained above. For example, the reaction force hydraulic pressure may be assumed (calculated) from the stroke. In such a case, the pressure sensor 73 may be omitted from the structure. Further, in the hydraulic braking force generating device BF, the first control valve 22 may be omitted from the structure. Furthermore, the judgment of the abnormality diagnosis, or whether or not the execution of the abnormality diagnosis is permitted, may be performed at another ECU other than the brake ECU 6. The judging section 63 may judge whether or not the abnormality diagnosis can be executed based on the reaction force hydraulic pressure (detected value of the pressure sensor 73) without using the stroke. Further, the regulator 44 may be a type that uses a spool valve.

[0084] According to the above-explained embodiment, as the drive portion Y for generating a drive force of the master piston (14), a drive chamber 1A in which the drive hydraulic pressure is generated and a valve portion 41, 42 that adjusts the inflow and outflow amount of the fluid with respect to the drive chamber 1A are employed. However, the drive portion Y is not limited to this structure, and an electric drive portion including an electromagnetic actuator such as an electric motor that applies the drive force to the master piston (14) in response to the operation amount of the brake operating member 10 may be employed as the drive portion Y. [List of reference symbols]

[0085] 1; master cylinder, 11; master cylinder, 12; cover cylinder, 13; input piston, 14; first master piston, 15; second master piston, 1A; servo chamber, 1B; first hydraulic pressure chamber (reaction force chamber), 1C; second hydraulic pressure chamber (reaction force chamber), 1D; first master chamber, 1E; second master chamber, 10; brake pedal (brake operating member), 171, 172, 173, 434; reservoir (low pressure source), 2; reaction force generating device, 22; first control valve, 23; second control valve, (electromagnetic valve), 4; servo pressure generating device, 41; pressure reducing valve, 42; pressure increasing valve, 431; accumulator (high pressure source), 44; regulating device, 445; control piston, 4D; first pilot chamber, 5; actuator, 541, 542, 543, 544; wheel cylinders, 5FR, 5FL, 5RR and 5RL; wheel, BF; hydraulic pressure braking force generating device, 6; brake ECU, 61; control section, 62; diagnosis section, 63; judgment section, 71;Stroke sensor, 73, 74, 75; pressure sensor, 76; wheel speed sensor, A; vehicle braking device, C; abnormality diagnosis device, R; reaction force chamber, Y: driving section.;

Claims

[1] Anomaly diagnosis device applied to a vehicle braking device (A) comprising: a reaction force chamber (R) in which a reaction force hydraulic pressure is generated in response to an operation amount of a brake operating member (10); a low pressure source (171, 172, 173, 434) communicating with the reaction force chamber under a predetermined condition; a master brake cylinder (1) having a main chamber (1D, 1E) in which a main hydraulic pressure is generated by being driven by a main piston (14, 15); a drive section (Y) that generates a drive force for driving the master piston in response to the amount of operation of the brake operating member; and a control section (61) that sets a target value of the actuating force or the main hydraulic pressure based on at least one of the operation amount of the brake operating member and an operation force of the brake operating member, and controls the actuating section to cause an actual value of the actuating force or the main hydraulic pressure with respect to the target value to approach the target value, wherein the abnormality diagnosis device (C) comprises: a diagnosis section (62) that performs an abnormality diagnosis based on at least one parameter selected from a relationship between the operation amount of the brake operating member and the reaction force hydraulic pressure and a relationship between the target value and the actual value; and a judging section (63) which judges whether a state of the reaction force chamber with respect to at least one of a hydraulic pressure and an amount of fluid therein is in a predetermined insufficient state or in a predetermined excess state, wherein the diagnosis section stops execution of the abnormality diagnosis when it is judged by the judgment section that the state of the reaction force chamber with respect to the at least one of the hydraulic pressure and the amount of fluid therein is in the predetermined insufficient state or in the predetermined excess state. [2] An abnormality diagnosis device according to claim 1, wherein: the vehicle brake device comprises at least one of a stroke sensor (71) which detects the operation amount of the brake operating element and a pressure sensor (73, 74, 75) which detects the reaction force hydraulic pressure; and wherein the judging section receives information about a connection state between the reaction force chamber and the low-pressure source, and judges the state of the reaction force chamber based on the information about the connection state and at least one of a detection result from the stroke sensor and a detection result from the pressure sensor. [3] Anomaly diagnosis device according to claim 2, wherein the vehicle braking device (A) comprises an electromagnetic valve arranged between the reaction force chamber and the low-pressure source, and wherein the judging section (63) uses an opening and closing record of the electromagnetic valve (23) as the connection state information.

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