JP2020104641A - Vehicular braking device - Google Patents

Abstract

To provide a vehicular braking device capable of detecting abnormality, such as air contamination, in a constitution having two systems that are not directly connected to each other.SOLUTION: A vehicular braking device includes: a cylinder unit 2 having a piston 22 which can slide inside a cylinder 21 according to a difference between input pressure and output pressure, and constituted to be capable of forming a differential pressure generation state that is a state in which the output pressure is greater than the input pressure; a first liquid passage 601 connecting an input chamber 211 with first wheel cylinders 53 and 54; a second liquid passage 602 connecting an output chamber 212 with second wheel cylinders 51 and 52; and a detector 92 detecting abnormality of the first liquid passage 601, on the basis of an amount of change in liquid pressure inside the first liquid passage 601 at the time the piston 22 slides from a differential pressure position being a position of the piston 22 in the differential pressure generation state, to a balanced position being a position of the piston 22 in a state that the input pressure and the output pressure are balanced.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle braking device.

The vehicle braking system includes, as a hydraulic circuit, for example, a front system for supplying fluid to the wheel cylinders of the front wheels and a rear system for supplying fluid to the wheel cylinders of the rear wheels. The hydraulic circuit is filled with fluid. Here, if air is mixed in the hydraulic circuit, it may cause a bad feeling and a delay in response. Therefore, it is inspected whether the air is mixed or not at the time of shipping from the factory.

For example, Japanese Unexamined Patent Application Publication No. 2008-30545 describes a method for detecting air mixture in a brake control device. In this method, first, an operator operates the brake pedal to supply fluid to the front system, and determines whether air is mixed in the front system based on the hydraulic pressure of the front system and the amount of pedal stroke. After that, the separation valve is opened to flow the fluid from the front system to the rear system, and it is determined whether or not air is mixed in the rear system based on the amount of decrease in the hydraulic pressure of the front system. As a result, it becomes possible to inspect the front system and the rear system for air mixture.

JP, 2008-30545, A

However, the above method is intended for a configuration in which the front system and the rear system are directly connected, that is, a configuration in which fluid can flow through the systems so as to transmit hydraulic pressure. In other words, the above method is intended for a configuration in which the front system and the rear system are connected by the liquid path that does not pass through the reservoir. Therefore, the above method cannot be applied to a configuration in which the front system and the rear system are not directly connected.

The present invention has been made in view of such circumstances, and provides a vehicle braking device capable of detecting an abnormality such as air mixing in a configuration having two systems that are not directly connected. The purpose is to do.

The vehicle braking device of the present invention is arranged such that a cylinder and the inside of the cylinder are divided into an input chamber and an output chamber, and the input pressure is the hydraulic pressure in the input chamber and the hydraulic pressure in the output chamber. A cylinder unit configured to be capable of forming a differential pressure generation state in which the output pressure is larger than the input pressure, and a piston slidable in the cylinder according to a difference from the output pressure. , A first liquid passage connecting the input chamber and the first wheel cylinder, a second liquid passage connecting the output chamber and the second wheel cylinder, and a fluid supply capable of supplying fluid to the first liquid passage Section, an acquisition section that acquires the hydraulic pressure in the first hydraulic passage, and a differential pressure position that is the position of the piston in the differential pressure generation state, the input pressure and the output pressure are in a balanced state. A detection unit that detects an abnormality in the first liquid passage based on the amount of change in the hydraulic pressure in the first liquid passage when the piston slides to the equilibrium position that is the position of the piston.

According to the present invention, the sliding of the piston from the differential pressure position to the balanced position reduces the volume of the input chamber, and the fluid in the input chamber is supplied to the first liquid passage and the first wheel cylinder. As a result, the liquid pressure in the first liquid passage increases. When there is an abnormality such as air mixture or liquid leakage in the first liquid passage, the amount of increase in the hydraulic pressure in the first liquid passage is smaller than that in the normal case. By detecting this increase amount, it is possible to detect an abnormality in the first liquid passage. Further, the fluid in the output chamber is supplied to the second liquid passage and the second wheel cylinder when the piston slides to the differential pressure position. At this time, the liquid pressure in the second liquid passage increases. By detecting this increase amount, an abnormality in the second liquid passage can also be detected. As described above, according to the present invention, an abnormality such as air mixing can be detected in a configuration having two systems (first liquid passage and second liquid passage) that are not directly connected.

It is a block diagram of the braking device for vehicles of this embodiment. 6 is a time chart for explaining the abnormality detection processing of the present embodiment. 6 is a time chart for explaining the abnormality detection processing of the present embodiment.

Hereinafter, the present embodiment will be described with reference to the drawings. Each drawing used for explanation is a conceptual diagram, and the shape of each part is not exact. As shown in FIG. 1, the vehicle braking device 1 of the present embodiment includes a master cylinder (corresponding to a "cylinder unit") 2, a fluid supply unit 3, an actuator 4, and wheel cylinders 51, 52, 53,. 54, a first liquid passage 601, a second liquid passage 602, a first brake ECU 81, and a second brake ECU 82.

The master cylinder 2 is a hydraulic pressure generator configured to supply fluid to the wheel cylinders 51, 52 of the front wheels Wf. The master cylinder 2 includes an input piston 20, a cylinder 21, a master piston (corresponding to “piston”) 22, a reservoir 23, and a spring 24. The input piston 20 is a piston member and slides in the cylinder 21 in conjunction with the operation of the brake pedal 11 which is a brake operating member. The vehicle braking device 1 is provided with a stroke sensor 12 that detects a stroke of the brake pedal 11.

The cylinder 21 is a cylinder member whose internal space is divided into an input chamber 211 and an output chamber 212 by a master piston 22. More specifically, an input chamber 211, an output chamber 212, a separation chamber 213, and a reaction force chamber 214 are formed inside the cylinder 21. The input chamber 211 and the output chamber 212 will be described later.

The separation chamber 213 is partitioned by the input piston 20 and the master piston 22. The master piston 22 and the input piston 20 are arranged to face each other with a predetermined distance therebetween, that is, via a separation chamber 213. The separation chamber 213 is connected to a stroke simulator 73 via a liquid passage 71 and a normally closed solenoid valve 72. The reaction force with respect to the forward movement of the input piston 20 which is the hydraulic pressure in the separation chamber 213 is formed by the stroke simulator 73 when the solenoid valve 72 is in the open state. The pressure sensor 78 connected to the liquid passage 71 detects the separation pressure (reaction force pressure) that is the liquid pressure in the separation chamber 213 and the driver's pedal force on the brake pedal 11.

The reaction force chamber 214 is partitioned by the master piston 22. The reaction chamber 214 is formed so that the volume decreases as the master piston 22 moves forward, and increases as the master piston 22 retracts. The reaction force chamber 214 is connected to the reservoir 76 via the liquid passage 74 and the normally open type electromagnetic valve 75. A portion of the liquid passage 74 between the electromagnetic valve 75 and the reaction force chamber 214 is connected via a liquid passage 77 to a portion of the liquid passage 71 between the electromagnetic valve 72 and the stroke simulator 73. The pressure sensor 79 connected to the liquid passage 74 detects the liquid pressure in the reaction force chamber 214.

The master piston 22 is a piston member arranged inside the cylinder 21. The master piston 22 slides in the cylinder 21 so as to change the volume of the output chamber 212, is driven by a force corresponding to the hydraulic pressure in the input chamber 211, and the output pressure (hydraulic pressure) in the output chamber 212 ( Hereinafter, also referred to as "master pressure"). The master piston 22 has a large-diameter portion 221 formed to have a larger diameter than other parts so as to partition the input chamber 211 and the reaction force chamber 214.

The input chamber 211 is a so-called servo chamber and is formed on the rear side of the large diameter portion 221 of the master piston 22. The input chamber 211 is formed so as to face the reaction force chamber 214 via the large diameter portion 221. The input pressure (hereinafter also referred to as “servo pressure”), which is the hydraulic pressure of the input chamber 211, serves as a driving force that presses the rear end surface of the large diameter portion 221 and advances the master piston 22. The fluid supply unit 3 is connected to the input chamber 211 via a connection liquid passage 65 described later.

The output chamber 212 is a so-called master chamber and is formed on the bottom surface side of the cylinder 21, that is, in front of the master piston 22. The output chamber 212 is formed so that the volume decreases as the master piston 22 moves forward, and increases as the master piston 22 retracts.
The output chamber 212 is connected to the actuator 4 via the second supply path 62.

In this way, the master cylinder 2 is arranged so as to divide the cylinder 21 into the input chamber 211 and the output chamber 212, and the servo pressure which is the hydraulic pressure in the input chamber 211 and the inside of the output chamber 212. The master piston 22 is slidable in the cylinder 21 according to the difference from the master pressure, which is the hydraulic pressure.

The reservoir 23 is a tank that stores fluid and is kept at atmospheric pressure. The liquid passage that connects the reservoir 23 and the output chamber 212 is communicated when the master piston 22 is in the initial position, and is shut off when the master piston 22 advances a predetermined distance from the initial position. The spring 24 pushes the master piston 22 toward the initial position (that is, backward). The initial position of the master piston 22 is the position where the master piston 22 is stopped in the state where the brake operation is not performed.

For example, when a power failure occurs, the solenoid valves 72, 75, 35, 36 are de-energized, so the solenoid valve 72 is closed and the solenoid valve 75 is opened. As a result, the separation chamber 213 is sealed, the separation distance between the input piston 20 and the master piston 22 is fixed, and the reaction force chamber 214 is communicated with the reservoir 76. In the state in which the separation distance is locked (hereinafter, referred to as “separation lock state”), the master piston 22 also advances in accordance with the advance of the input piston 20. That is, in the separation lock state, the master pressure can be generated only by the pedal effort of the driver. In the separation lock state, the master piston 22 is driven only by the operation driving force by the braking operation of the driver. The separation lock state can be formed not only when the power fails but also under the control of the first brake ECU 81. That is, the first brake ECU 81 can switch between the separation lock state and the normal state.

As described above, the vehicle braking device 1 includes the cutoff mechanism 70 that permits or blocks the transmission of the operation driving force to the master piston 22. The shut-off mechanism 70 includes an input piston 20 that is interlocked with a driver's braking operation, a separation chamber partition 25 that partitions the separation chamber 213 between the input piston 20 and the master piston 22, and an electromagnetic valve that seals or opens the separation chamber 213. And a valve 72. It can be said that the separated chamber partitioning portion 25 of the present embodiment is configured by the front end surface of the input piston 20, the rear end surface of the master piston 22, and the cylinder 21. Further, the vehicle braking device 1 includes a stroke simulator 73 connected to the reaction force chamber 214 whose volume is reduced by the forward movement of the master piston 22, an electromagnetic valve 75 for opening and closing the connection between the reaction force chamber 214 and the reservoir 76, The reaction force generation mechanism 13 having In other words, the vehicle braking device 1 is connected to the stroke simulator 73 that is connected to the separation chamber 213 via the solenoid valve 72, and the fluid path 71 that connects the solenoid valve 72 and the stroke simulator 73 to each other. A reaction force chamber 214 whose volume is reduced by forward movement and an electromagnetic valve 75 which opens and closes the connection between the reaction force chamber 214 and the reservoir 76 are provided. It can be said that the reaction force generation mechanism 13 includes the separation chamber 213, the solenoid valve 72, the stroke simulator 73, the reaction force chamber 214, and the solenoid valve 75.

The fluid supply unit 3 is a device that supplies fluid to the actuator 4 and the connection liquid passage 65. The fluid supply unit 3 supplies the fluid to the first hydraulic circuit 63 in the actuator 4 via the first supply passage 61. The first hydraulic circuit 63 is connected to the wheel cylinders 53 and 54. The connection liquid passage 65 is a liquid passage that connects the first supply passage 61 and the input chamber 211 of the master cylinder 2. When the solenoid valve 36, which will be described later, is in the open state or when the solenoid valve 36 is not present, the fluid supplied by the fluid supply unit 3 to the connection liquid passage 65 is supplied to the first hydraulic circuit 63 and the input chamber 211.

The fluid supply unit 3 includes a motor 31, a pump 32, a reservoir 33, an annular liquid passage 34, a solenoid valve (corresponding to a “valve portion”) 35, and a solenoid valve 36. The motor 31 is an electric motor whose drive is controlled by the first brake ECU 81 and which drives the pump 32. The pump 32 is driven by the driving force of the motor 31. The pump 32 sucks the fluid stored in the reservoir 33 and discharges it to the first supply passage 61 and the connection liquid passage 65 via the annular liquid passage 34. The annular liquid passage 34 is a liquid passage that connects the discharge port and the suction port of the pump 32, and is constituted by liquid passages 341, 342, 343, 344.

The liquid passage 341 connects the discharge port of the pump 32 to the first supply passage 61 and the connection liquid passage 65. The liquid passage 342 connects the connection liquid passage 65 and the reservoir 33. An electromagnetic valve 35 is provided in the liquid passage 342. The liquid passage 343 is a portion of the connection liquid passage 65 that connects the liquid passage 341 and the liquid passage 342. That is, the connection liquid passage 65 is configured by the liquid passage 650 that connects the input chamber 211 and the annular liquid passage 34, and the liquid passage 343 that is a part of the annular liquid passage 34. An electromagnetic valve 36 is provided in a part of the liquid passage 343, that is, the connection liquid passage 65. The liquid path 344 connects the reservoir 33 and the suction port of the pump 32.

The liquid passage 341 is provided with a pressure sensor 37 that detects the liquid pressure of the liquid passage 341 and the first supply passage 61. It can be said that the hydraulic pressure detected by the pressure sensor 37 is the hydraulic pressure supplied by the pump 32 to the first hydraulic circuit 63 and the connection hydraulic passage 65. The servo pressure, which is the hydraulic pressure in the input chamber 211, varies depending on the control state of the solenoid valve 36. Further, the reservoir 33, the reservoir 76, and the reservoir 23 may be configured by one common reservoir (for example, the reservoir 23).

The solenoid valves 35 and 36 are normally open solenoid valves, and are linear valves capable of controlling the differential pressure between upstream and downstream. The solenoid valve 35 and the solenoid valve 36 make the hydraulic pressure on the upstream side higher than the hydraulic pressure on the downstream side based on the magnitude of the control current from the first brake ECU 81. The target differential pressure between the solenoid valve 35 and the solenoid valve 36 is determined by the magnitude of the control current. It can be said that the solenoid valve 35 and the solenoid valve 36 form a throttled state in the liquid passage according to the control current.

The first liquid passage 601 is a passage that connects the input chamber 211 and the wheel cylinders (corresponding to “first wheel cylinders”) 53 and 54. The first liquid passage 601 includes a connecting liquid passage 65, a first supply passage 61, and a first hydraulic circuit 63. The first liquid passage 601 can be said to be a first system or a rear system. The rear system of this embodiment has a so-called by-wire configuration.

The second liquid passage 602 is a passage that connects the output chamber 212 and the wheel cylinders (corresponding to “second wheel cylinders”) 51 and 52. The second liquid passage 602 can be said to be a second system or a front system. The second liquid passage 602 includes a second supply passage 62 and a second hydraulic circuit 64. The second supply passage 62 is a passage that connects the output chamber 212 and the second hydraulic circuit 64. The second hydraulic circuit 64 is a passage that connects the second supply passage 62 and the wheel cylinders 51 and 52.

The first liquid passage 601 and the second liquid passage 602 are not directly connected. That is, the first liquid passage 601 and the second liquid passage 602 are not configured to allow fluid to flow between the two systems (liquid passages) so as to transmit the hydraulic pressure. The first liquid passage 601 and the second liquid passage 602 can be connected, for example, via the reservoir 23, but in this case, the fluid pressure of the flowing fluid is reset by the reservoir 23 and is not transmitted.

As described above, the fluid supply unit 3 is configured to be able to supply the fluid to the first liquid passage 601. In detail, the fluid supply unit 3 includes a motor 31 and a pump 32 that supplies the first fluid passage 601 with fluid at a discharge amount according to the rotation speed of the motor 31. The master cylinder 2 includes a master piston 22 driven by a servo driving force generated by the operation of the motor 31 and an operation driving force generated by a driver's braking operation, and a cylinder 21 in which the master piston 22 is slidably housed. The output chamber 212 is defined by the master piston 22 and the cylinder 21 and is connected to the wheel cylinders 51 and 52.

When the target wheel pressure is set for the stroke, the first brake ECU 81 controls the target differential pressure of the solenoid valve 35 to drive the pump 32. As a result, the hydraulic pressure on the upstream side (pump 32 side) of the electromagnetic valve 35 is increased by the target differential pressure with respect to the hydraulic pressure of the reservoir 33 (here, atmospheric pressure) which is the hydraulic pressure on the downstream side of the electromagnetic valve 35. can do. Further, the first brake ECU 81 controls the target differential pressure of the solenoid valve 36 to drive the pump 32 when different hydraulic pressures are generated in the first hydraulic passage 601 and the second hydraulic passage 602 without using the actuator 4. To do. As a result, the hydraulic pressure on the upstream side (pump 32 side) of the electromagnetic valve 36 is targeted with respect to the hydraulic pressure in the hydraulic path between the electromagnetic valves 36 and 35, which is the downstream side of the electromagnetic valve 36, that is, the servo pressure. It can be increased by the pressure difference.

The first brake ECU 81 controls the solenoid valve 35 and does not control the solenoid valve 36 when similar wheel pressures are generated in the front and rear wheels Wf and Wr. The solenoid valve 36 controls the hydraulic pressure of the wheel cylinders 51 and 52 of the front wheel Wf to be lower than the hydraulic pressure of the wheel cylinders 53 and 54 of the rear wheel Wr in consideration of the regenerative braking force generated in the front wheel Wf, for example. Used.

The actuator 4 is a so-called ESC actuator configured to be able to pressurize each wheel pressure. The actuator 4 includes a first hydraulic pressure circuit 63 and a second hydraulic pressure circuit 64 that is configured so that fluid cannot flow through the first hydraulic pressure circuit 63. Each hydraulic circuit 63, 64 is provided with a solenoid valve, a pump, a pressure adjusting reservoir, etc., which are not shown. The second brake ECU 82 controls the solenoid valves and pumps arranged in the hydraulic circuits 63 and 64 to increase, decrease, or maintain the wheel pressure. Further, the actuator 4 can execute anti-skid control and skid prevention control based on a command from the second brake ECU 82. A pressure sensor 641 that detects the master pressure is provided in the second hydraulic circuit 64 or the second supply passage 62.

The first brake ECU 81 and the second brake ECU 82 are electronic control units each including a CPU, a memory, and the like. The first brake ECU 81 is a device that mainly controls the fluid supply unit 3 based on information from various sensors such as the stroke sensor 12 and the pressure sensors 37 and 78. The second brake ECU 82 is a device that mainly controls the actuator 4 based on information from various sensors such as the stroke sensor 12 and the pressure sensor 641. When the brake pedal 11 is operated, the first brake ECU 81 and the second brake ECU 82 set the target deceleration and the target wheel pressure according to the stroke and/or the pedal effort. The first brake ECU 81 normally opens the solenoid valve 72 and closes the solenoid valve 75. As a result, the reaction chamber 214 and the reservoir 76 are disconnected from each other, and the separation chamber 213 and the reaction chamber 214 are connected to the stroke simulator 73. A hydraulic pressure (separation pressure) corresponding to the operation of the brake pedal 11 is generated in the separation chamber 213 and the reaction force chamber 214.

When the regenerative braking force is not generated, the first brake ECU 81 controls the pump 32 and the solenoid valve 35 of the fluid supply unit 3 according to the target wheel pressure. In this case, the solenoid valve 36 is not controlled, and the open state due to non-energization is maintained. The first brake ECU 81 drives the pump 32, sets the target differential pressure of the solenoid valve 35 in correspondence with the target wheel pressure, and applies a control current corresponding to the target differential pressure to the solenoid valve 35.

The pump 32 sucks the fluid from the reservoir 33 and supplies the fluid to the first liquid passage 601. The fluid discharged from the pump 32 is supplied to the first hydraulic circuit 63 and also to the input chamber 211 via the connection liquid passage 65. A hydraulic pressure corresponding to the target differential pressure of the solenoid valve 35 is generated in the input chamber 211 and the first hydraulic passage 601.

When the servo pressure is increased by the above control, the master piston 22 moves forward and the output chamber 212 is contracted, so that the master pressure increases. That is, the hydraulic pressure of the second liquid passage 602 connected to the output chamber 212 also rises. By the control of the pump 32 and the solenoid valve 35, a hydraulic pressure corresponding to the servo pressure (upstream pressure) is generated in the wheel cylinders 53 and 54 via the first hydraulic passage 601 and via the second hydraulic passage 602. It occurs at 51 and 52.

In this way, the first brake ECU 81 executes the brake control so as to achieve the target wheel pressure and the target deceleration. Strictly speaking, the hydraulic pressure in the second hydraulic passage 602 becomes slightly lower than the hydraulic pressure in the first hydraulic passage 601 due to the sliding resistance of the master piston 22 and the like. Further, in a vehicle including a regenerative braking device such as a hybrid vehicle, the target difference of the solenoid valve 36 is set so that the target deceleration (target braking force) of the front wheels Wf is achieved by the sum of the regenerative braking force and the hydraulic braking force. The pressure is controlled. The second brake ECU 82 also estimates each wheel pressure based on the detection value of the pressure sensor 641. The first brake ECU 81 also estimates each wheel pressure based on the detection value of the pressure sensor 37. The second brake ECU 82 estimates each wheel pressure in consideration of the control status of the actuator.

(Abnormality detection process)
Here, the master cylinder 2 is configured to be capable of forming a differential pressure generation state in which the master pressure (input pressure) is larger than the servo pressure (output pressure). In the separation lock state in which each solenoid valve is in the non-energized state, the solenoid valves 72, 35, 36 are closed and the solenoid valve 75 is opened. Moreover, the fluid supply unit 3 is stopped. When the brake pedal 11 is operated in this state, the master piston 22 moves forward only by the pedaling force (operation driving force) of the operator. When the master piston 22 moves forward, the input pressure becomes a negative pressure as the volume of the input chamber 211 increases, and fluid is supplied from the reservoir 33 to the input chamber 211 via the liquid passage 342 and the first liquid passage 601. .. The liquid passage 342 corresponds to a branch passage branched from the first liquid passage 601.

The supply of fluid from the reservoir 33 causes the input chamber 211 to expand while maintaining the servo pressure at atmospheric pressure. On the other hand, the volume of the output chamber 212 is reduced by the forward movement of the master piston 22, and the master pressure is increased. As a result, the differential pressure generation state is formed in the master cylinder 2. The position of the master piston 22 in this differential pressure generation state is referred to as a "differential pressure position". The differential pressure generation state can be said to be a state in which the master piston 22 slides toward the initial position when the brake operation is released. Further, the differential pressure position is an arbitrary position where the increase of the master pressure can be confirmed under normal conditions. Further, in the differential pressure generation state of this embodiment, the servo pressure is equal to or higher than the atmospheric pressure.

The first brake ECU 81 includes an acquisition unit 91 and a detection unit 92. The acquisition unit 91 acquires the hydraulic pressure (fluid pressure information) in the first hydraulic passage 601. The acquisition unit 91 further acquires the fluid pressure (fluid pressure information) in the second fluid passage 602. The acquisition unit 91 can estimate the master pressure based on the detection value of the pressure sensor 78 in the separation lock state. Further, the acquisition unit 91 can estimate the servo pressure based on the detection value of the pressure sensor 37. Therefore, the acquisition unit 91 can acquire the hydraulic pressure in the first hydraulic passage 601 corresponding to the servo pressure and the hydraulic pressure in the second hydraulic passage 602 corresponding to the master pressure.

The detection unit 92 detects an abnormality in the first liquid passage 601 based on the hydraulic pressure of the first liquid passage 601 (hereinafter also referred to as “first hydraulic pressure”) acquired by the acquisition unit 91. Further, the detection unit 92 detects an abnormality in the second liquid passage 602 based on the hydraulic pressure of the second liquid passage 602 (hereinafter also referred to as “second hydraulic pressure”) acquired by the acquisition unit 91. The detection unit 92 determines whether there is an abnormality in the first hydraulic passage 601 based on the hydraulic pressure change amount of the first hydraulic pressure, and determines whether the second hydraulic passage 602 has an abnormality based on the hydraulic pressure change amount of the second hydraulic pressure. Determine the presence or absence.

Specifically, the operator operates the brake pedal 11 in the separation lock state to slide the master piston 22 from the initial position to the differential pressure position. At this time, as described above, the master pressure increases while the servo pressure is maintained at the atmospheric pressure. The detection unit 92, based on the stroke that is the detection value of the stroke sensor 12 when the master piston 22 slides from the initial position to the differential pressure position, and the increase amount of the second hydraulic pressure, the second hydraulic passage 602. To detect abnormalities.

If the second liquid passage 602 is normal, the second stroke is increased in accordance with the increase of the stroke, that is, the fluid inflow amount so as to correspond to the PV characteristics (relationship between pressure and volume) of the wheel cylinders 51 and 52 stored in advance. The hydraulic pressure increases. When the second liquid passage 602 is abnormal, for example, when air is mixed in the second liquid passage 602 or a liquid leakage occurs, the increase amount of the second liquid pressure with respect to the increase of the fluid inflow amount becomes small. .. For example, when air is mixed, it becomes difficult for the second hydraulic pressure to increase at the beginning of the stroke increase, and the final increase amount of the second hydraulic pressure also decreases. The detection unit 92 determines that the second liquid passage 602 is abnormal when the increase amount of the second liquid pressure is less than the second threshold value. In this way, the detection unit 92 detects an abnormality in the second liquid passage 602.

When the second liquid passage 602 is normal, the detection unit 92 subsequently determines whether or not there is an abnormality in the first liquid passage 601. Specifically, as shown in FIG. 2, the detection unit 92 closes the solenoid valve 35 and shuts off the liquid passage 342 when the master piston 22 is at the differential pressure position. Subsequently, the operator releases the operation of the brake pedal 11 to slide the master piston 22 from the differential pressure position toward the initial position due to the difference between the servo pressure and the master pressure. Then, the master piston 22 stops when the servo pressure and the master pressure are in equilibrium. The state in which the servo pressure and the master pressure are in equilibrium is a state in which the servo pressure and the master pressure have the same level value and the master piston 22 is stopped. In this state, the servo pressure and the master pressure are constant. The position of the master piston 22 in a state where the servo pressure and the master pressure are in balance with each other is referred to as a “balanced position”.

The volume of the input chamber 211 is reduced while the master piston 22 slides from the differential pressure position to the balanced position. Along with this, the fluid in the input chamber 211 is not supplied to the reservoir 33 due to the closing of the electromagnetic valve 35, but is supplied to the wheel cylinders 53 and 54 via the first liquid passage 601. If the first hydraulic passage 601 is normal, the first hydraulic pressure increases in accordance with a change in stroke, that is, an increase in the fluid inflow amount, so as to correspond to the PV characteristics of the wheel cylinders 53 and 54 stored in advance. The master piston 22 stops at the equilibrium position and the input piston 20 returns to the initial position. Further, the separation pressure, which is the hydraulic pressure in the separation chamber 213, becomes the atmospheric pressure.

On the other hand, as shown in FIG. 3, when the first hydraulic passage 601 is abnormal, the increase amount of the first hydraulic pressure becomes smaller than that in the normal state. When the first hydraulic passage 601 is abnormal, for example, the first hydraulic pressure may not increase, the master piston 22 may return to the initial position, and the first hydraulic pressure and the second hydraulic pressure may balance at atmospheric pressure. 2 and 3 are conceptual diagrams for explanation. Further, times T1, T2, T3, T4, and T5 represent the same timing in FIGS. 2 and 3.

When the increase amount of the first hydraulic pressure is less than the first threshold value, the detection unit 92 determines that the first hydraulic passage 601 is abnormal. In this way, the detection unit 92 detects an abnormality in the first liquid passage 601 based on the amount of increase in the first hydraulic pressure when the master piston 22 slides from the differential pressure position to the balanced position. Further, the detection unit 92 closes the solenoid valve 35 in the differential pressure generation state, and based on the increase amount of the first hydraulic pressure when the master piston 22 slides from the differential pressure position to the balanced position, the first liquid pressure is increased. It can be said that the abnormality determination control for determining whether or not there is an abnormality on the road 601 is executed. Since the increase amount of the first hydraulic pressure corresponds to the decrease amount of the second hydraulic pressure, the detection unit 92 acquires the increase amount of the first hydraulic pressure by acquiring the decrease amount of the second hydraulic pressure. Can also Further, since the abnormality can be detected by comparing the amount of change in hydraulic pressure with the threshold value, it is not necessary to detect the stroke by stepping on with a constant stepping force.

It can be said that the abnormality detection process (abnormality determination method) of the present embodiment includes a differential pressure forming step, a first determination step, a valve closing step, a differential pressure releasing step, and a second determination step. The differential pressure forming step is a step of sliding the master piston 22 from an initial position to a differential pressure position by operating the brake pedal 11 to form a differential pressure generation state in the master cylinder 2. The first determination step is a step of determining whether or not there is an abnormality in the second fluid passage 602 based on the amount of increase in the second fluid pressure during the execution of the differential pressure formation step. The valve closing step is a step of closing the electromagnetic valve 35 in the differential pressure generation state when the second liquid passage 602 is normal. The differential pressure releasing step is a step of releasing the operation of the brake pedal 11 and sliding the master piston 22 from the differential pressure position to the balanced position after the valve closing step. The second determination step is a step of determining whether or not there is an abnormality in the first liquid passage 601 based on the increase amount of the first hydraulic pressure during the execution of the differential pressure releasing step. It can be said that the vehicle braking device 1 that executes the abnormality detection process is an abnormality detection device.

(effect)
The vehicle braking device 1 of the present embodiment has a cylinder 21 and a master piston 22, and is configured to form a differential pressure generation state in which the master pressure is larger than the servo pressure, and a first cylinder 2 Liquid passage 601, second liquid passage 602, fluid supply unit 3 capable of supplying fluid to the first liquid passage 601, acquisition unit 91 for obtaining the liquid pressure in the first liquid passage 601, and differential pressure generation state In the first fluid passage 601 when the master piston 22 slides from the differential pressure position which is the position of the master piston 22 in the above to the balance position which is the position of the master piston 22 in the state where the input pressure and the output pressure are balanced. A detection unit 92 that detects an abnormality in the first liquid passage 601 based on the amount of change in hydraulic pressure.

According to this configuration, the volume of the input chamber 211 is reduced by the sliding of the master piston 22 from the differential pressure position to the balanced position, and the fluid in the input chamber 211 is supplied to the first liquid passage 601 and the wheel cylinders 53, 54. To be done. As a result, the liquid pressure in the first liquid passage 601 increases. When the first liquid passage 601 has an abnormality such as air mixture or liquid leakage, the increase amount of the first liquid pressure is smaller than that in the normal case. By detecting this increase amount, it is possible to accurately detect an abnormality in the first liquid passage 601. Further, the fluid in the output chamber 212 is supplied to the second liquid passage 602 and the wheel cylinders 51 and 52 when the master piston 22 slides from the initial position to the differential pressure position. At this time, the second hydraulic pressure increases. By detecting this increase amount, it is possible to accurately detect an abnormality in the second liquid passage 602. As described above, according to the present embodiment, an abnormality such as air mixing can be detected in a configuration having two systems (first liquid passage 601 and second liquid passage 602) that are not directly connected. ..

Further, in the present embodiment, the master cylinder 2 is configured so that the master pressure changes according to the operation of the brake pedal 11. That is, the master cylinder 2 is configured to be able to form the separation lock state. Then, the master piston 22 slides from the initial position to the differential pressure position according to the operation of the brake pedal 11, and slides from the differential pressure position to the balanced position according to the release of the operation of the brake pedal 11. With this configuration, the operator can easily adjust the operation speed of the brake pedal 11. Therefore, the brake pedal 11 can be depressed slowly, and the stroke and the amount of increase in hydraulic pressure can be easily adjusted.

Further, by slowing the brake operation speed, the relationship between the hydraulic pressure and the fluid inflow amount can be accurately detected, and the abnormality of the second liquid passage 602 can be accurately detected. Further, by slowing the brake operation speed, it is possible to improve the learning function of the learning unit 93 described later. Further, the abnormality detection process for both the first liquid passage 601 and the second liquid passage 602 can be executed by one operation of the brake pedal 11, that is, by a simple operation.

Further, the vehicle braking device 1 according to the present embodiment has the reservoir 33 included in the fluid supply unit 3 for storing the fluid, the liquid passage 342 connecting the first liquid passage 601 and the reservoir 33, and the liquid passage 342. And a solenoid valve 35 which is provided and closed so as to shut off the liquid passage 342 in the differential pressure generation state. With this configuration, the abnormality detection of the first liquid passage 601 can be executed only by closing the electromagnetic valve 35 and releasing the operation of the brake pedal 11 from the differential pressure generation state.

Further, in the present embodiment, the acquisition unit 91 acquires the hydraulic pressure in the second liquid passage 602, and the detection unit 92 causes the second liquid passage 602 when the master piston 22 slides from the initial position to the differential pressure position. An abnormality in the second liquid passage 602 is detected based on the amount of change in the hydraulic pressure inside. With this configuration, it is possible to detect an abnormality in each of the liquid paths 601 and 602.

The first brake ECU 81 further includes a learning unit 93. The learning unit 93 uses the amount of change in hydraulic pressure in the first liquid passage 601 used for determining abnormality in the first liquid passage 601, and the amount of change in hydraulic pressure in the second liquid passage 602 used for detecting abnormality in the second liquid passage 601. Based on the above, the characteristics (for example, PV characteristics) of the wheel cylinders 51 to 54 are acquired and stored. The learning unit 93 can calculate and update the characteristics of the wheel cylinders 51 to 54 each time the abnormality detection process (abnormality determination process) is performed. The abnormality detection process is executed, for example, when the vehicle is shipped from the factory or when the vehicle is maintained. The characteristics of the wheel cylinders 51 to 54 may change as the period of use increases. Further, there may be an error in the characteristics stored in the initial stage. By having the learning unit 93, the characteristics of the wheel cylinders 51 to 54 can be updated to the latest state.

(Other)
The present invention is not limited to the above embodiment. For example, instead of the configuration including the pump 32, the fluid supply unit 3 may be an electric cylinder that drives a piston with a motor to discharge the fluid in the cylinder. It can be said that the fluid supply unit 3 can electrically supply the fluid to the first liquid passage 601 (by driving the motor). Further, instead of the solenoid valve 35, a valve mechanism that can be manually opened and closed can be provided.

The acquisition unit 91 and the detection unit 92 may be provided in the second brake ECU 82. In this case, the acquisition unit 91 acquires the first hydraulic pressure and the second hydraulic pressure based on the detection value of the pressure sensor 641. This is because the increase amount of the first hydraulic pressure corresponds to the decrease amount of the second hydraulic pressure. Similarly, the learning unit 93 may be provided in any ECU. Further, the first brake ECU 81 and the second brake ECU 82 may be configured by one ECU. Further, the operation of the brake pedal 11 may be performed by a machine (for example, a device that can adjust the pedal effort) instead of the operator. Further, as a term, the liquid passage or the hydraulic circuit can be replaced with a flow passage, an oil passage, a pipe, a hydraulic passage, a pipe, or the like.

The sliding of the master piston 22 from the initial position to the differential pressure position may be performed by the fluid supply of the fluid supply unit 3 instead of the operation of the brake pedal 11. For example, the solenoid valve provided in a portion of the first hydraulic circuit 63 that connects the wheel cylinders 53 and 54 to the first supply passage 61 is closed, and the solenoid valve 35 is closed, so that the pump 32 moves to the first liquid passage. Fluid is supplied to 601. When the servo pressure and the master pressure are increased to a predetermined pressure, the pump 32 is stopped and the solenoid valve of the first hydraulic circuit 63 is opened, so that the fluid in the input chamber 211 flows into the wheel cylinders 53 and 54. .. As a result, the servo pressure decreases, a differential pressure generation state is formed, and the master piston 22 retracts to the equilibrium position. The abnormality may be detected based on the amount of change in the first hydraulic pressure at this time. However, the abnormality detection processing using the operation of the brake pedal 11 is easier to estimate the amount of fluid flowing out from the input chamber 211 and the characteristic detection accuracy is higher than in this case because the stroke can be grasped.

DESCRIPTION OF SYMBOLS 1... Vehicle braking device, 2... Master cylinder (cylinder unit), 21... Cylinder, 211... Input chamber, 212... Output chamber, 22... Master piston (piston), 3... Fluid supply part, 33... Reservoir, 342... Liquid path (branch path), 35... Electromagnetic valve (valve part), 51, 52... Wheel cylinder (second wheel cylinder), 53, 54... Wheel cylinder (first wheel cylinder), 601... First liquid path, 602 ...Second liquid path, 91...Acquisition unit, 92...Detection unit.

Claims (5)

A cylinder, and the cylinder is arranged so as to divide the inside of the cylinder into an input chamber and an output chamber, and the cylinder is arranged in accordance with a difference between an input pressure which is a hydraulic pressure in the input chamber and an output pressure which is a hydraulic pressure in the output chamber. A piston slidable in the cylinder, and a cylinder unit configured to be capable of forming a differential pressure generation state in which the output pressure is larger than the input pressure,
A first liquid passage connecting the input chamber and the first wheel cylinder;
A second liquid passage connecting the output chamber and the second wheel cylinder;
A fluid supply unit capable of supplying fluid to the first liquid passage,
An acquisition unit for acquiring the hydraulic pressure in the first liquid passage,
When the piston slides from a differential pressure position that is the position of the piston in the differential pressure generation state to a balance position that is the position of the piston in the state where the input pressure and the output pressure are in balance A detection unit that detects an abnormality in the first liquid path based on the amount of change in hydraulic pressure in the liquid path;
A braking device for a vehicle including the. The cylinder unit is a master cylinder configured to change the hydraulic pressure in the output chamber according to the operation of a brake operating member,
The piston slides from the initial position to the differential pressure position according to the operation of the brake operating member, and the piston moves from the differential pressure position to the differential pressure position when the operation of the brake operating member is released at the differential pressure position. The vehicle braking device according to claim 1, which slides to a balance position. A reservoir that is included in the fluid supply unit and stores the fluid;
A branch passage connecting the first liquid passage and the reservoir;
A valve portion provided in the branch passage and closed to shut off the branch passage in the differential pressure generation state;
The vehicle braking device according to claim 2, further comprising: The acquisition unit acquires the liquid pressure of the second liquid passage in addition to the liquid pressure of the first liquid passage,
The detection unit detects an abnormality in the second liquid passage based on a hydraulic pressure change amount in the second liquid passage when the piston slides from the initial position to the differential pressure position. Alternatively, the vehicle braking device according to item 3. Based on the amount of change in hydraulic pressure in the first liquid passage used for detecting abnormality in the first liquid passage and the amount of change in hydraulic pressure in the second liquid passage used for detecting abnormality in the second liquid passage, The vehicle braking device according to claim 4, further comprising a learning unit that acquires and stores the characteristics of the first wheel cylinder and the characteristics of the second wheel cylinder.

Images