JP5988926B2 - Braking force generator for vehicle - Google Patents

Description

  The present invention relates to a vehicular braking force generator that generates a braking force on a vehicle.

  For example, in a hybrid vehicle, in addition to an existing brake system that generates braking force through a hydraulic circuit, a By Wire type braking system that generates braking force through an electric circuit is adopted. ing. In such a by-wire type brake system, an operation amount of a driver's brake pedal is converted into an electric signal, which is supplied to an electric actuator that drives a piston of a slave cylinder (hereinafter referred to as “motor cylinder device”). Then, the brake fluid pressure is generated in the motor cylinder device by driving the piston by the electric motor. The brake hydraulic pressure generated in this way operates the wheel cylinder to generate a braking force on the vehicle (see, for example, Patent Document 1).

  On the other hand, recent vehicles are equipped with a device called a collision damage reduction system (see, for example, Patent Document 2). The collision damage mitigation system includes a radar device that detects an object in the traveling direction of a vehicle, a vehicle state detection unit that detects a traveling speed, a determination unit that determines a risk of collision of the vehicle with the object, and another vehicle And a wireless communication unit that performs wireless communication with each other. A collision damage reduction system (automatic hydraulic pressure generation system) uses a motor cylinder device to brake fluid regardless of the braking operation by the driver, for example, when an object having a high collision risk exists in the traveling direction of the host vehicle. It has a function of automatically generating pressure and avoiding collision with an object.

  In the by-wire type brake system according to Patent Document 1, a shut-off valve called a master cut valve is provided in a hydraulic pressure path that connects the master cylinder and the motor cylinder device in communication. This shut-off valve is a normally-open electromagnetic valve, and operates so as to cut off the hydraulic pressure path when closed while communicating the hydraulic pressure path when opened.

Assume that an automatic hydraulic pressure generation system such as a collision damage reduction system according to Patent Document 2 is applied in combination with the by-wire brake system according to Patent Document 1. In this case, it is assumed that some abnormality occurs in the electric actuator that drives the piston of the motor cylinder device during the operation of the automatic hydraulic pressure generation system. Then, the braking control device opens the shut-off valve to switch the brake system from the by-wire system to the backup system, and controls the braking operation by the driver (without mediating the by-wire system). Operates to be directly connected to power.

JP 2009-227023 A JP 2008-181200 A

  As described above, when the automatic hydraulic pressure generating system according to Patent Document 2 is applied in combination to the by-wire type brake system according to Patent Document 1, the automatic hydraulic pressure generating system is used in the by-wire type brake system. If an abnormality occurs in the electric actuator that drives the piston of the motor cylinder device during automatic operation (not depending on the braking operation by the driver) and the shut-off valve is opened, the pressure chamber of the motor cylinder device is stored in the reservoir (atmospheric pressure). Is approximately equal to). Then, the fluid pressure acting on the piston of the motor cylinder device is rapidly reduced to near atmospheric pressure. As a result, since the hydraulic pressure for returning the piston to the initial position side is lost, the piston may not return to the initial position.

  In such a case, if the driver performs a braking operation immediately after the shut-off valve is opened, the brake fluid pressure generated in the master cylinder is consumed to return the piston of the motor cylinder device that has not yet returned to the initial position side. (So-called liquid loss occurs). Then, during the braking operation immediately after the shut-off valve is opened, the braking force corresponding to the braking operation is reduced compared to the normal time (the braking force when the brake pedal is depressed is reduced compared to the normal time). As a result, the driver may feel uncomfortable.

  The present invention has been made in view of the above circumstances, and even when an abnormality occurs in the electric actuator that drives the piston of the motor cylinder device during the automatic operation of the automatic hydraulic pressure generation system, the operation is performed. It is an object of the present invention to provide a vehicular braking force generator that can maintain a feeling of braking operation by a person.

  In order to achieve the above object, the invention according to (1) includes a hydraulic pressure generating device that accepts a braking operation by a driver, and a movement of a piston that accompanies an operation of an electric actuator based on an electrical signal corresponding to at least the braking operation. A motor cylinder device that generates a brake fluid pressure, and a fluid pressure path between the fluid pressure generator and the motor cylinder device, and operates to connect the fluid pressure path when opened and to shut off when closed. When a diagnosis that the motor cylinder device is abnormal is made by the abnormality diagnosis unit, an abnormality diagnosis unit that performs abnormality diagnosis of the on-off valve, the motor cylinder device, and a predetermined waiting time after the abnormality diagnosis And a control unit that controls to open and close the on-off valve.

In the invention according to (1), when the diagnosis that the motor cylinder device is abnormal is made by the abnormality diagnosis unit, the control unit opens the on-off valve after a predetermined waiting time from the abnormality diagnosis. We decided to adopt the configuration.
As the predetermined waiting time, for example, the time required for the piston to be positioned from the current position to the initial position by being pushed back to the hydraulic pressure acting on the piston of the motor cylinder device that has entered an abnormal state is appropriately set. Good.

According to the invention according to (1), even if some abnormality occurs in the electric actuator during the automatic operation of the automatic hydraulic pressure generation system, a situation in which the piston stops at a halfway position where the piston does not return to the initial position has occurred. Can be prevented.
As a result, it is possible to maintain a good feeling of braking operation by the driver even during the first braking operation after the brake system is switched from the by-wire system to the backup system.

  The invention according to (2) is the vehicle braking force generator according to the invention according to (1), further comprising a position information acquisition unit that acquires position information of the piston, and the control unit includes: When the fact that the piston has returned to the initial position is acquired by the position information acquisition unit, the on-off valve is set immediately after the acquisition regardless of whether the elapsed time from the abnormality diagnosis reaches the standby time. It is characterized by performing control to be opened.

  In the invention according to (2), when the fact that the piston has returned to the initial position is acquired by the position information acquisition unit, the control unit regardless of whether the elapsed time from the abnormality diagnosis reaches the standby time, A configuration is adopted in which control is performed to open the on-off valve immediately after the acquisition.

  According to the invention according to (2), compared to the invention according to (1), the brake system can be expected to be accelerated earlier when switching from the by-wire system to the backup system. The feeling of operation can be maintained better.

  The invention according to (3) is the vehicular braking force generator according to the invention according to (1) or (2), in which the diagnosis that the motor cylinder device is abnormal is performed during the waiting time. It is variably set according to the position of the piston when lowered.

  In the invention according to (3), according to the position of the piston when the diagnosis that the motor cylinder device is abnormal is made, for example, as the piston position is closer to the initial position side, It is variably set to be shorter.

  According to the invention according to (3), compared to the inventions according to (1) and (2), it can be expected that the timing when the brake system is switched from the by-wire system to the backup system is optimized. The feeling of braking operation by the driver can be maintained even better.

  According to the vehicular braking force generator according to the present invention, even if any abnormality occurs in the electric actuator that drives the piston of the motor cylinder device during the automatic operation of the automatic hydraulic pressure generation system, it is determined by the driver. A feeling of braking operation can be maintained well.

It is a block diagram showing the outline | summary of the braking force generator for vehicles which concerns on embodiment of this invention. It is a block diagram showing the periphery structure of ECU which the braking force generator for vehicles concerning the embodiment of the present invention has. It is explanatory drawing showing the time series operation | movement of the braking force generator for vehicles which concerns on a comparative example. It is explanatory drawing showing the time series operation | movement of the braking force generator for vehicles which concerns on embodiment of this invention.

Hereinafter, a vehicle braking force generator according to an embodiment of the present invention will be described in detail with reference to the drawings.
In addition, in the figure shown below, the common referential mark shall be attached | subjected between the members which have a common function, or between the members which have a mutually corresponding function. Further, for convenience of explanation, the size and shape of the member may be schematically represented by being deformed or exaggerated.

[Overview of Braking Force Generating Device 10 for Vehicle According to an Embodiment of the Present Invention]
First, the outline | summary of the braking force generator 10 for vehicles which concerns on embodiment of this invention is demonstrated with reference to FIG. FIG. 1 is a configuration diagram illustrating an outline of a vehicle braking force generator 10 according to an embodiment of the present invention.
A vehicle braking force generator 10 according to an embodiment of the present invention is a by-wire that generates a braking force through an electric circuit in addition to an existing braking system that generates a braking force through a hydraulic circuit. It has a (By Wire) brake system.

  As shown in FIG. 1, the vehicle braking force generator 10 includes a hydraulic pressure generator 14 that receives a braking operation by a driver via a brake pedal 12, and a brake based on at least an electric signal corresponding to the braking operation by the driver. A motor cylinder device 16 that generates hydraulic pressure, and a vehicle stability assist device 18 (hereinafter referred to as “VSA device”) that assists in stabilizing the behavior of the vehicle (not shown) based on the brake hydraulic pressure generated by the motor cylinder device 16. 18 ". However, VSA is a registered trademark).

  As shown in FIG. 1, each of the hydraulic pressure generation device 14, the motor cylinder device 16, and the VSA device 18 is provided so as to be separated from each other via piping tubes 22 a to 22 f. The hydraulic pressure generating device 14 and the motor cylinder device 16 constituting the by-wire type brake system are electrically connected to an ECU (Electronic Control Unit) 111 (see FIG. 2) described later via an electric wire (not shown). ing. The internal configuration of the hydraulic pressure generator 14 and the motor cylinder device 16 will be described later in detail.

The VSA device 18 has an ABS (anti-lock braking system) function to prevent wheel lock during braking operation, a TCS (traction control system) function to prevent wheel slipping during acceleration, etc., and a function to suppress side slip when turning Etc. are provided.
Since the VSA device 18 is not directly related to the present invention, description of its internal configuration is omitted.

  The vehicle braking force generator 10 according to the embodiment of the present invention is equipped with a collision damage reduction system (not shown: see, for example, Japanese Patent Application Laid-Open No. 2008-181200). The collision damage reduction system automatically generates brake fluid pressure using the motor cylinder device 16 regardless of the braking operation by the driver when there is an object having a high collision risk in the traveling direction of the host vehicle. This has the function of avoiding collision with an object. The collision damage alleviating system belongs to the category of an automatic hydraulic pressure generating system in that it has a function of automatically generating a brake hydraulic pressure using the motor cylinder device 16. As an automatic hydraulic pressure generation system, a cruise control system, a hydraulic pressure holding system, a tracking control system, and the like are included in addition to the collision damage reduction system.

(Structure of hydraulic path)
First, the configuration of the hydraulic path will be described. The hydraulic pressure path is roughly divided into a first hydraulic pressure system 70a for connecting the first hydraulic pressure chamber 56a of the master cylinder 34 belonging to the hydraulic pressure generating device 14 and the plurality of wheel cylinders 32FR, 32RL, and the generation of hydraulic pressure. The second hydraulic pressure system 56b connects the second hydraulic pressure chamber 56b of the master cylinder 34 belonging to the device 14 and the plurality of wheel cylinders 32RR, 32FL.

  The first hydraulic system 70 a is connected to the first hydraulic pressure path 58 a that connects the output port 54 a and the connection port 20 a of the master cylinder 34 (cylinder unit 38) belonging to the hydraulic pressure generator 14, and the hydraulic pressure generator 14. The first and second piping tubes 22a and 22b that connect the port 20a and the output port 24a of the motor cylinder device 16 (via the first connection point A1), the output port 24a of the motor cylinder device 16 and the VSA device 18 The second and third piping tubes 22b and 22c connecting the introduction ports 26a (via the first connection point A1), the first and second outlet ports 28a and 28b of the VSA device 18, and the wheel cylinders 32FR and 32RL. 7th and 8th piping tubes 22g and 22h which connect between each.

The second hydraulic pressure system 70 b includes a second hydraulic pressure path 58 b that connects the output port 54 b of the master cylinder 34 (cylinder portion 38) belonging to the hydraulic pressure generator 14 and the other connection port 20 b, and the hydraulic pressure generator 14. 4th and 5th piping tubes 22d and 22e which connect between other connection port 20b and output port 24b of motor cylinder device 16 (via 2nd connection point A2), output port 24b of motor cylinder device 16, and The fifth and sixth piping tubes 22e, 22f that connect the introduction ports 26b of the VSA device 18 (via the second connection point A2), the third and fourth outlet ports 28c, 28d of the VSA device 18, and the wheels. 9th and 10th piping tubes 22i and 22j which connect between cylinders 32RR and 32FL, respectively.
The first hydraulic pressure path 58a and the second hydraulic pressure path 58b correspond to the “hydraulic pressure path” of the present invention.

  Each of the wheel cylinders 32FR, 32RL, 32RR, 32FL constituting the disc brake mechanism 30a-30d receives brake fluid (brake fluid) via piping tubes 22g-22j connected to the outlet ports 28a-28d. Supplied. When the brake fluid is supplied, the fluid pressure in each wheel cylinder 32FR, 32RL, 32RR, 32FL increases. Thereby, each wheel cylinder 32FR, 32RL, 32RR, 32FL operates, and braking force is applied to the corresponding wheel (right front wheel, left rear wheel, right rear wheel, left front wheel).

(Configuration of hydraulic pressure generator 14)
The hydraulic pressure generator 14 includes a tandem master cylinder 34 that generates hydraulic pressure according to the amount of operation of the brake pedal 12 by the driver, and a first reservoir 36 attached to the master cylinder 34. The first reservoir 36 is a container that stores brake fluid. The first reservoir 36 is connected to a second reservoir 84, which will be described later, attached to the motor cylinder device 16 via a piping tube 86. The internal pressures of the first and second reservoirs 36 and 84 are substantially equal to the atmospheric pressure.

In the cylinder portion 38 of the master cylinder 34, a first master piston 40a and a second master piston 40b are slidably provided in a state of being spaced apart by a predetermined distance along the axial direction of the cylinder portion 38. The first master piston 40 a is disposed close to the brake pedal 12 side and is connected to the brake pedal 12 via the push rod 42. Further, the second master piston 40b is disposed farther from the brake pedal 12 than the first master piston 40a.
The first master piston 40a and the second master piston 40b are sometimes collectively referred to as “master pistons 40a, 40b”.

  A pair of piston packings 44a and 44b are provided on the outer peripheral surfaces of the master pistons 40a and 40b via annular stepped portions, respectively. Back chambers 48a and 48b communicating with supply ports 46a and 46b described later are formed between the pair of piston packings 44a and 44b, respectively. Between the 1st master piston 40a and the 2nd master piston 40b, the 1st spring member 50a which connects between master piston 40a, 40b is provided. Between the 2nd master piston 40b and the inner wall part of the cylinder part 38, the 2nd spring member 50b which connects between the 2nd master piston 40b and the inner wall part of the cylinder part 38 is provided.

  The cylinder portion 38 of the master cylinder 34 is provided with two supply ports 46a and 46b, two relief ports 52a and 52b, and two output ports 54a and 54b. The supply ports 46a and 46b and the relief ports 52a and 52b are joined to communicate with a reservoir chamber (not shown) in the first reservoir 36.

  Further, in the cylinder portion 38 of the master cylinder 34, a first hydraulic pressure chamber 56a and a second hydraulic pressure chamber 56b for generating brake hydraulic pressure corresponding to the depression force (depression force) of the brake pedal 12 by the driver are provided, respectively. It has been. The first hydraulic pressure chamber 56a communicates with the connection port 20a via the first hydraulic pressure path 58a. Further, the second hydraulic pressure chamber 56b communicates with the other connection port 20b via the second hydraulic pressure path 58b.

  A pressure sensor Pm is provided between the master cylinder 34 and the connection port 20a and upstream of the first hydraulic pressure path 58a. A first shut-off valve 60a composed of a normally open type (normally open type) solenoid valve is provided downstream of the first hydraulic pressure path 58a. The pressure sensor Pm has a function of detecting the upstream hydraulic pressure on the master cylinder 34 side of the first shutoff valve 60a on the first hydraulic pressure path 58a.

Between the master cylinder 34 and the other connection port 20b, on the upstream side of the second hydraulic pressure path 58b, a second shut-off valve 60b composed of a normally open type (normally open type) solenoid valve is provided. Yes. Further, a pressure sensor Pp is provided on the downstream side of the second hydraulic pressure path 58b. The pressure sensor Pp has a function of detecting the downstream hydraulic pressure on the wheel cylinders 32FR, 32RL, 32RR, 32FL side of the second shutoff valve 60b on the second hydraulic pressure path 58b.
The first cutoff valve 60a and the second cutoff valve 60b correspond to the “open / close valve” of the present invention.

  The normal open in the first shut-off valve 60a and the second shut-off valve 60b is a valve configured so that the normal position (the position of the valve body at the time of demagnetization (non-energization)) is in the open position (normally open). Say. In FIG. 1, a first cutoff valve 60a and a second cutoff valve 60b show a state during excitation (the same applies to a third cutoff valve 62 described later).

  A branch hydraulic pressure path 58c branched from the second hydraulic pressure path 58b is provided in the second hydraulic pressure path 58b between the master cylinder 34 and the second shutoff valve 60b. A third shut-off valve 62 composed of a normally closed type (normally closed type) solenoid valve and a stroke simulator 64 are connected in series to the branch hydraulic pressure path 58c. The normal close in the third shut-off valve 62 refers to a valve configured such that the normal position (the position of the valve body at the time of demagnetization (non-energization)) is in the closed position (normally closed).

  A stroke simulator 64 is connected to the second hydraulic pressure path 58b connected to the output port 54b of the master cylinder 34 (cylinder portion 38) via a branch hydraulic pressure path 58c. The stroke simulator 64 has a reaction force hydraulic chamber 65 communicating with the branch hydraulic pressure path 58c. The brake fluid pressure generated in the second fluid pressure chamber 56 b of the master cylinder 34 is applied to the reaction force fluid pressure chamber 65. The stroke simulator 64 includes a simulator piston 67, a first return spring 68a, and a second return spring 68b in its housing.

[Configuration of Motor Cylinder Device 16]
Next, the configuration of the motor cylinder device 16 will be described with reference to FIG.
As shown in FIG. 1, the motor cylinder device 16 includes a first slave piston 88 a and a second slave piston 88 b (“piston of the present invention”) by the rotational driving force of an electric motor (corresponding to “electric actuator” of the present invention) 72. (Corresponding to “)” is driven in the axial direction, and this has the function of generating brake fluid pressure.
In the following description, the first slave piston 88a and the second slave piston 88b may be collectively referred to as “slave pistons 88a and 88b”.

  In the motor cylinder device 16, among the moving directions of the slave piston 88, the X1 direction indicated by the arrow in FIG. 1 is defined as the forward direction (hydraulic pressure generating direction), which is opposite to the forward direction (hydraulic pressure generating direction). The X2 direction indicated by the middle arrow is defined as the backward direction.

  As shown in FIG. 1, the motor cylinder device 16 includes a cylinder portion 76, an electric motor 72, and a driving force transmission portion 73 for transmitting the driving force of the electric motor 72 to the slave piston 88.

  As shown in FIG. 1, the cylinder portion 76 includes a substantially cylindrical cylinder body 82 and a second reservoir 84 attached to the cylinder body 82. The second reservoir 84 is connected to the first reservoir 36 attached to the master cylinder 34 of the hydraulic pressure generator 14 via the piping tube 86. Thus, the brake fluid stored in the first reservoir 36 is configured to be supplied into the second reservoir 84 via the piping tube 86.

  In the cylinder main body 82, slave pistons 88a and 88b are slidably provided along the axial direction in a state of being spaced apart by a predetermined distance in the axial direction of the cylinder main body 82. The first slave piston 88a is disposed on the ball screw structure 80 side, while the second slave piston 88b is disposed farther from the ball screw structure 80 side than the first slave piston 88a.

  The electric motor 72 is connected to a slave piston via a power transmission mechanism 74 described below in accordance with an operation amount (stroke amount) of the brake pedal 12 by a driver detected by a brake pedal sensor 125 (see FIG. 2) described later. It has a function of driving 88a and 88b. As the electric motor 72, for example, a permanent magnet synchronous motor such as a brushless DC motor or an AC servo motor can be employed. In the following description, as the electric motor 72 used in the present embodiment, a three-phase AC motor excited by an embedded permanent magnet (a paramagnetic material having a gap in which a permanent magnet is embedded) is exemplified. explain.

  The electric motor 72 has a stator coil and a rotor (not shown). In the electric motor 72, when a three-phase alternating current flows through the three-phase winding of the stator coil, a rotating magnetic field is generated. By controlling this rotating magnetic field in accordance with the rotation angle of the rotor, a permanent magnet attached to the rotor acts on the rotating magnetic field to generate torque. The electric motor 72 incorporates a hall sensor 133 (see FIG. 2) described later. The hall sensor 133 has a function of detecting the rotation angle of the electric motor 72 (current position information in the axial direction of the slave pistons 88a and 88b).

  As shown in FIG. 1, the driving force transmission unit 73 includes a speed reduction mechanism 78 that transmits the rotational driving force of the electric motor 72, and a linear motion along the axial direction of the ball screw shaft portion 80a. A power transmission mechanism 74 including a ball screw structure 80 that converts to a directional driving force is provided.

  The end of the first slave piston 88a in the reverse direction receives the spring force of first and second return springs 96a and 96b described later in a state where the driver does not operate the brake pedal 12, and the cylinder body It is located so as to abut against an annular step formed in 82. In short, the first slave piston 88a is biased in the backward direction.

As shown in FIG. 1, a substantially cylindrical hole is provided at the end of the first slave piston 88a in the backward direction. A substantially cylindrical front end portion of the ball screw shaft portion 80a is accommodated in the hole portion. The ball screw shaft portion 80a is positioned at the initial position IP shown in FIG. 1 in a state where the driver does not operate the brake pedal 12.
In order to position the ball screw shaft portion 80a at the initial position IP (see FIG. 1) in a state where the driver does not operate the brake pedal 12, the rotation angle information of the electric motor 72 corresponding to the initial position IP. Is stored in a control unit 155 (see FIG. 2) described later.

  As shown in FIG. 1, a slave piston packing 90a is provided on the outer peripheral surface on the front end side of the first slave piston 88a via an annular step portion. Moreover, the 1st back chamber 94a by the annular recessed part is formed in the outer peripheral surface in the middle of the front-end side and rear-end side in the 1st slave piston 88a. The first back chamber 94a communicates with a reservoir port 92a described later. A slave piston packing 90b is provided on the rear end side of the first back chamber 94a. The slave piston packing 90b has a function of sealing between the first back chamber 94a and the power transmission mechanism 74 in a liquid-tight state.

  A first return spring 96a is provided between the first and second slave pistons 88a and 88b.

  On the other hand, as shown in FIG. 1, a pair of slave piston packings 90c and 90d are provided on the outer peripheral surface of the second slave piston 88b via an annular step portion. A second back chamber 94b communicating with a reservoir port 92b described later is formed between the pair of slave piston packings 90c and 90d. A second return spring 96 b is provided between the second slave piston 88 b and the front end portion of the cylinder body 82.

  The cylinder body 82 of the cylinder portion 76 is provided with two reservoir ports 92a and 92b and two output ports 24a and 24b. The reservoir ports 92 a and 92 b communicate with the reservoir chamber in the second reservoir 84.

  Further, in the cylinder main body 82, the first hydraulic pressure chamber 98a for generating the brake hydraulic pressure output from the output port 24a to the wheel cylinders 32FR and 32RL side, and the wheel cylinders 32RR and 32FL side from the other output port 24b are provided. The second hydraulic pressure chambers 98b for generating the brake hydraulic pressure output to are respectively provided.

  Between the first slave piston 88a and the second slave piston 88b, a regulating member 100 that regulates the maximum separation section and the minimum separation section between these 88a and 88b is provided. The second slave piston 88b is provided with a stopper pin 102 that restricts the sliding range of the second slave piston 88b and prevents overreturn to the first slave piston 88a. Thereby, for example, even when a failure occurs in a certain system at the time of backup when braking with the brake fluid pressure generated in the master cylinder 34, it does not affect the other systems.

  A pressure sensor Ph that detects the brake fluid pressure generated in the first fluid pressure chamber 98a of the motor cylinder device 16 is provided on the fluid pressure path close to the introduction port 26a of the VSA device 18. The pressure detection signal of the pressure sensor Ph is sent to a VSA-ECU (not shown) that performs overall control of the VSA device 18.

[Basic operation of vehicle braking force generator 10]
Next, the basic operation of the vehicle braking force generator 10 will be described.
During normal operation of the vehicular braking force generator 10, the first shut-off valve 60a and the second shut-off valve 60b, which are normally open solenoid valves, are used regardless of whether or not the brake fluid pressure is generated in the master cylinder 34. While being excited, the valve is closed, and at the same time, the third shut-off valve 62, which is a normally closed solenoid valve, is excited to open the valve (see FIG. 1).

  Accordingly, since the first hydraulic pressure system 70a and the second hydraulic pressure system 70b are shut off by the first shutoff valve 60a and the second shutoff valve 60b, the brake fluid pressure generated in the master cylinder 34 of the fluid pressure generator 14 is applied to the disc. It is not transmitted to the wheel cylinders 32FR, 32RL, 32RR, 32FL of the brake mechanisms 30a-30d. This is because when the vehicle braking force generator 10 is normally operated, an electric brake system by the motor cylinder device 16 is actually operated.

  At this time, when brake fluid pressure is generated in the second fluid pressure chamber 56b of the master cylinder 34, the generated brake fluid pressure is transmitted through the branch fluid pressure path 58c and the third shutoff valve 62 in the valve open state to the stroke simulator. It is transmitted to 64 reaction force hydraulic chambers 65. When the simulator piston 67 is displaced against the spring force of the return springs 68a and 68b by the brake hydraulic pressure supplied to the reaction force hydraulic pressure chamber 65, the stroke of the brake pedal 12 is allowed, and the pseudo A pedal reaction force is created and fed back to the brake pedal 12. As a result, it is possible to obtain a braking operation feeling that is comfortable for the driver.

  In such a system state, when the ECU 111 (see FIG. 2) detects that the driver depresses the brake pedal 12, the ECU 111 drives the electric motor 72 of the motor cylinder device 16 and uses the driving force of the electric motor 72 as a power transmission mechanism. 74, the slave pistons 88a and 88b are displaced in the direction of the arrow X1 in FIG. 1 against the spring force of the first return spring 96a and the second return spring 96b. Due to the displacement of the slave pistons 88a and 88b, the brake fluid in the first fluid pressure chamber 98a and the second fluid pressure chamber 98b is pressurized so as to be balanced to generate a desired brake fluid pressure.

  The brake hydraulic pressure generated in this way is transmitted to the wheel cylinders 32FR, 32RL, 32RR, 32FL of the disc brake mechanisms 30a-30d via the VSA device 18, and each wheel cylinder 32FR, 32RL, 32RR, 32FL is operated to operate each wheel cylinder 32FR, 32RL, 32RR, 32FL. A desired braking force is applied to the wheel.

  In other words, in the vehicular braking force generator 10, when the driver steps on the brake pedal 12 during normal operation of the ECU 111 (see FIG. 2) that controls the motor cylinder device 16 and the by-wire, a so-called by-wire is achieved. The brake system of the type is activated. Specifically, in the vehicle braking force generator 10 during normal operation, when the driver steps on the brake pedal 12, the first cutoff valve 60a and the second cutoff valve 60b brake the master cylinder 34 and each wheel. In a state where communication with the disc brake mechanisms 30a to 30d (wheel cylinders 32FR, 32RL, 32RR, and 32FL) is cut off, the disc brake mechanisms 30a to 30d are operated using the brake hydraulic pressure generated by the motor cylinder device 16.

  On the other hand, in the vehicular braking force generator 10, when the driver steps on the brake pedal 12 when the motor cylinder device 16 or the controller 155 is abnormal, the existing hydraulic brake system becomes active. Specifically, in the vehicular braking force generator 10 in the event of an abnormality, when the driver steps on the brake pedal 12, the first shut-off valve 60a and the second shut-off valve 60b are opened, and the third shut-off valve is set. With the valve 62 closed, the brake fluid pressure generated in the master cylinder 34 is transmitted to the disc brake mechanisms 30a to 30d (wheel cylinders 32FR, 32RL, 32RR, 32FL), and the disc brake mechanisms 30a to 30d (wheel cylinder 32FR) are transmitted. , 32RL, 32RR, 32FL).

[A Peripheral Configuration of ECU 111 of Vehicle Braking Force Generating Device 10 According to an Embodiment of the Present Invention]
Next, a peripheral configuration of the ECU 111 included in the vehicle braking force generator 10 according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is an explanatory diagram illustrating a peripheral configuration of the ECU 111 included in the vehicle braking force generation device 10 according to the embodiment of the present invention.

  As shown in FIG. 2, the ECU 111 of the ESB (electric servo brake) included in the vehicle braking force generator 10 according to the embodiment of the present invention has an ignition key switch (hereinafter abbreviated as “IG key switch”) as an input system. 121, wheel speed sensor 123, brake pedal sensor 125, hall sensor 133, and brake fluid pressure sensors Pm and Pp are connected.

  The IG key switch 121 is a switch operated when power is supplied to each part of the vehicle from an in-vehicle battery (not shown). When the IG key switch 121 is turned on, power is supplied to the ECU 111 and the ECU 111 is activated.

  The wheel speed sensor 123 has a function of detecting the rotational speed (wheel speed) of each wheel. The wheel speed signal for each wheel detected by the wheel speed sensor 123 is sent to the ECU 111.

The brake pedal sensor 125 has a function of detecting an operation amount (stroke amount) of the brake pedal 12 by the driver. A signal related to the operation amount (stroke amount) of the brake pedal 12 detected by the brake pedal sensor 125 is sent to the ECU 111.
The brake pedal sensor 125 may be a brake SW having a function of simply detecting ON (depressed) / OFF (not depressed).

  The hall sensor 133 has a function of detecting the rotation angle of the electric motor 72 (current position information in the axial direction of the slave pistons 88a and 88b). A signal related to the rotation angle of the electric motor 72 detected by the hall sensor 133 is sent to the ECU 111.

  The brake fluid pressure sensors Pm and Pp have a function of detecting the pressure of each part in the brake fluid pressure system. The pressure signal of each part in the brake fluid pressure system detected by the brake fluid pressure sensors Pm and Pp is sent to the ECU 111.

  On the other hand, as shown in FIG. 2, the electric motor 72 and the first to third cutoff valves 60 a, 60 b, 62 are connected to the ECU 111 as an output system.

  As shown in FIG. 2, the ECU 111 includes a position information acquisition unit 151, an abnormality diagnosis unit 153, and a control unit 155 which will be described later.

  The ECU 111 is configured by a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. This microcomputer reads out and executes programs and data stored in the ROM, and the ECU 111 has a current position information function in the axial direction of the slave pistons 88a and 88b, the motor cylinder device 16 (the hydraulic system and the electrical system). (Including an abnormality diagnosis function) and a braking force control function.

The position information acquisition unit 151 receives the current position information in the axial direction of the slave pistons 88a and 88b based on the rotation angle from the initial position IP (see FIG. 1) of the electric motor 72, which is input via the hall sensor 133. Has a function to acquire.
When acquiring the current position information of the slave pistons 88a and 88b in the axial direction, the strokes of the slave pistons 88a and 88b themselves are used instead of the hall sensor 133 that detects the rotation angle of the electric motor 72 from the initial position IP. You may use the sensor which detects this.
The current position information in the axial direction of the slave pistons 88 a and 88 b acquired by the position information acquisition unit 151 is sent to the abnormality diagnosis unit 153.

  The abnormality diagnosis unit 153 has a function of performing abnormality diagnosis of the motor cylinder device 16 (including a hydraulic system and an electrical system). More specifically, the abnormality diagnosis unit 153, for example, the current position information in the axial direction of the slave pistons 88a and 88b sent from the position information acquisition unit 151 and the target positions of the slave pistons 88a and 88b obtained by the control unit 155. The information is compared from time to time, and when the position deviation between the current position and the target position of the slave pistons 88a and 88b exceeds a predetermined position deviation threshold, there is an abnormality in the motor cylinder device 16. Operates to make a diagnosis.

  As the position deviation threshold value, for example, a value suitable for considering that the position deviation of the current position with respect to the target position of the slave pistons 88a and 88b has occurred based on the result of an experiment with an actual vehicle or a computer simulation. You only have to set it.

  However, the abnormality diagnosis method performed by the abnormality diagnosis unit 153 is not limited to the above example. For example, the abnormality diagnosis unit 153 estimates the current operating state of the electric motor 72 and the driving force transmission unit 73 based on detection values of various sensors (including estimation by numerical calculation), and thus estimates the electric motor 72 and the drive thus estimated. The abnormality diagnosis of the motor cylinder device 16 may be performed by comparing the current operating state and the target state regarding the force transmission unit 73.

  When the diagnosis that the motor cylinder device 16 is abnormal is made by the abnormality diagnosis unit 153, the control unit 155 waits for a predetermined waiting time wt (see FIG. 4) from the time of the diagnosis and performs the first and second cutoffs. It has a function of performing control to open the valves 60a and 60b.

  Here, the predetermined waiting time wt is pushed back to the hydraulic pressure acting on the slave pistons 88a and 88b of the motor cylinder device 16 which has entered an abnormal state, so that the slave pistons 88a and 88b are moved from the current position in the axial direction to the initial position. A time length required to be positioned in the IP is appropriately set. The standby time wt may be variably set according to the current positions of the slave pistons 88a and 88b when the diagnosis that the motor cylinder device 16 is abnormal is made.

  Further, when the position information acquisition unit 151 acquires that the slave pistons 88a and 88b are positioned at the initial position IP, the control unit 155 determines whether or not the elapsed time from the abnormality diagnosis reaches the standby time wt. Regardless of this, immediately after acquisition that the slave pistons 88a and 88b are positioned at the initial position IP, the first and second shutoff valves 60a and 60b are controlled to open.

[Time Series Operation of Vehicle Braking Force Generating Device According to Comparative Example]
Next, the time-series operation of the vehicle braking force generator according to the comparative example will be described with reference to FIGS. FIG. 3 is a time chart for explaining time-series operations of the vehicle braking force generator according to the comparative example. In describing the configuration of the vehicular braking force generator according to the comparative example, the same reference numerals as in the vehicular braking force generator 10 according to the embodiment of the present invention are given in parentheses for convenience.
FIG. 3 (a) is a time chart showing the transition of torque of the electric motor (72) in time series, and FIG. 3 (b) shows the change in the open / close state of the first and second shut-off valves (60a, 60b). FIG. 3C is a time chart drawn in time series, FIG. 3C is a time chart drawing time-series changes in the current position of the slave pistons 88a and 88b, and FIG. 3D is a motor cylinder device (16 FIG. 6 is a time chart illustrating the transition of the internal pressure in chronological order.
However, it is assumed that the IG key switch (121) of the vehicle is turned on and the vehicle is traveling at a constant speed.

  The structural differences between the vehicle braking force generator 10 according to the embodiment of the present invention and the vehicle braking force generator 10 according to the comparative example are as follows. That is, in the vehicular braking force generator 10 according to the embodiment of the present invention, the control unit 155 of the ECU 111 will be described later when the abnormality diagnosis unit 153 diagnoses that the motor cylinder device 16 is abnormal. As described above, control is performed to open the first and second shutoff valves 60a and 60b after a predetermined waiting time wt from the diagnosis.

  On the other hand, in the vehicular braking force generator (10) according to the comparative example, the controller (155) of the ECU (111) indicates that the motor cylinder device (16) is abnormal by the abnormality diagnosis unit (153). When the diagnosis is made, control is performed to open the first and second shutoff valves (60a, 60b) immediately after the diagnosis without placing a predetermined waiting time (wt) from the time of the diagnosis.

  At times t0 to t1 shown in FIG. 3, the torque of the electric motor (72) is zero as shown in FIG. 3 (a). At this time, the first and second shut-off valves (60a, 60b) are in a closed state (see FIG. 3B). This is because, in principle, the first and second shutoff valves 60a and 60b are controlled to be closed during normal operation of the vehicle braking force generator (10). The current position of the slave piston (88a, 88b) is at the initial position (see FIG. 3C). The internal pressure of the motor cylinder device (16) is zero (see FIG. 3 (d)).

  At time t1 to t2 shown in FIG. 3, as shown in FIG. 3A, the torque of the electric motor (72) gradually rises from zero to braking torque (torque during braking). This is because, after time t1 shown in FIG. 3, the automatic hydraulic pressure generation system of the vehicle braking force generator (10) according to the comparative example has started automatic operation (not depending on the braking operation by the driver) control. At this time, the first and second shut-off valves (60a, 60b) are in a closed state (see FIG. 3B). The current position of the slave piston (88a, 88b) rises gently from the initial position IP to the braking position (braking position) BP (see FIG. 3C). The internal pressure of the motor cylinder device (16) also rises gently from zero to the vicinity of the braking pressure (pressure during braking) (see FIG. 3D).

  At times t2 to t3a shown in FIG. 3, as shown in FIG. 3A, the torque of the electric motor (72) maintains the braking torque. That is, the automatic hydraulic pressure generation system of the vehicle braking force generation device (10) according to the comparative example continues the automatic operation control. At this time, the first and second shut-off valves (60a, 60b) are kept closed (see FIG. 3 (b)). The current position of the slave piston (88a, 88b) maintains the braking position BP (see FIG. 3C). The internal pressure of the motor cylinder device (16) also maintains the braking pressure (pressure during braking) (see FIG. 3 (d)).

  It is assumed that some abnormality has occurred in the electric motor (72) at time t3a shown in FIG. Then, at the same time t3a, the abnormality diagnosis unit 153 of the ECU 111 makes a diagnosis that an abnormality has occurred in the electric motor (72). In response, the control unit 155 stops the drive control of the electric motor (72). Thereby, as shown to Fig.3 (a), the torque of the electric motor (72) has fallen rapidly from the braking torque to zero.

  At the same time t3a, the first and second shutoff valves (60a, 60b) are switched from the closed state to the open state. When the abnormality diagnosis unit (153) makes a diagnosis that an abnormality has occurred in the electric motor (72), in response to this, the control unit (155) moves the brake system from the bi-wire system to the backup system side. Because it switches to. When the brake system is switched from the by-wire system to the backup system, the braking operation by the driver is directly linked to the braking force of the vehicle (without mediating the by-wire system).

  After the same time t3a to t3a, the current position of the slave piston (88a, 88b) maintains the braking position BP (see FIG. 3C). The reason is as follows. That is, as will be described below, the fluid pressure acting on the slave pistons (88a, 88b) of the motor cylinder device (16) rapidly decreases to near atmospheric pressure. As a result, the hydraulic pressure for returning the slave piston (88a, 88b) to the initial position IP side is lost. For this reason, the slave pistons (88a, 88b) are not biased toward the initial position IP.

  After the same time t3a to t3a, the internal pressure of the motor cylinder device (16) is rapidly reduced from the braking pressure to zero. When an abnormality occurs in the electric motor (72) and the first and second shut-off valves (60a, 60b) are opened, the first and second hydraulic chambers (98a, 98b) of the motor cylinder device (16) are opened. This is because the first and second reservoirs (approximately equal to the atmospheric pressure) (36, 84) communicate with each other.

  Further, after time t3a shown in FIG. 3, the torque of the electric motor (72) continues to be zero as shown in FIG. 3 (a). This is because the control unit 155 continues to stop the drive control of the electric motor (72).

  After the same time t3a, the first and second shutoff valves (60a, 60b) continue to maintain the open state. This is because the brake system is switched from the by-wire system to the backup system by the operation of the control unit (155).

Therefore, in the vehicular braking force generator (10) according to the comparative example, for example, during the operation of the VSA device 18, some abnormality occurs in the electric motor (72), so that the first and second shutoff valves (60a, 60b). ) Is released, the brake system is switched from the by-wire system to the backup system. When the driver performs a braking operation immediately after this switching, the slave pistons (88a, 88b) in which the brake hydraulic pressure generated by the hydraulic pressure generator (14) has not returned to the initial position IP are moved to the initial position IP side. Consumed to return.
As a result, at the time of the first braking operation immediately after the brake system is switched from the by-wire system to the backup system, the braking force corresponding to the braking operation is reduced compared to the normal operation (depressing the brake pedal (12)). As a result, the braking force at that time is lower than that at normal time), which may make the driver feel uncomfortable.

[Time-series operation of vehicle braking force generator 10 according to an embodiment of the present invention]
Next, a time series operation of the vehicle braking force generator 10 according to the embodiment of the present invention will be described with reference to FIG. FIG. 4 is a time chart for explaining time-series operations of the vehicular braking force generator 10 according to the embodiment of the present invention. 4 (a) is a time chart showing the transition of the torque of the electric motor 72 in time series, and FIG. 4 (b) shows the change in the open / close state of the first and second shut-off valves 60a, 60b. FIG. 4 (c) is a time chart illustrating the current position of the slave pistons 88a and 88b. FIG. 4 (d) is a time chart illustrating the internal pressure of the motor cylinder device 16. FIG. It is a time chart figure which drew chronologically.
However, as a premise, it is assumed that the IG key switch 121 of the vehicle is on and the vehicle is traveling at a constant speed.

  The vehicular braking force generator (10) according to the comparative example and the vehicular braking force generator 10 according to the embodiment of the present invention have a common part in time-series operation. Therefore, the description of the portion of the time series operation that overlaps between the two (see immediately before time t0 to t3b in FIG. 4) is omitted, and the portion of the time series operation that differs between the two (time t3b to time in FIG. 4). The description will proceed with a focus on t4).

  It is assumed that some abnormality has occurred in the electric motor 72 at time t3b shown in FIG. Then, at the same time t3b, the abnormality diagnosis unit 153 of the ECU 111 makes a diagnosis that an abnormality has occurred in the electric motor (72). In response, the control unit 155 stops the drive control of the electric motor (72). Thereby, as shown to Fig.4 (a), the torque of the electric motor 72 has fallen rapidly from the braking torque to zero.

  At the same time t3b to t4, the first and second shut-off valves 60a, 253a, and 630b have a predetermined standby time wt from the time (time t3b) when the abnormality diagnosis unit 153 makes a diagnosis that an abnormality has occurred in the motor cylinder device 16. 60b is maintaining the closed state continuously (refer FIG.4 (b)).

  At the same time t3b to t4, the current positions of the slave pistons 88a and 88b gradually return from the braking position BP to the initial position IP (see FIG. 4C). The reason is as follows. That is, since the first and second shut-off valves 60a and 60b are kept closed, the hydraulic pressure acting on the slave pistons 88a and 88b of the motor cylinder device 16 is also maintained in the state immediately before time t3b. That is, since the fluid pressure for returning the slave pistons 88a and 88b to the initial position IP side is maintained, the slave pistons 88a and 88b are biased to the initial position IP side.

From the same time t3b to t4, the internal pressure of the motor cylinder device 16 gradually decreases from the braking pressure to zero. The reason is as follows. That is, since the first and second shutoff valves 60a and 60b are kept closed, the first and second hydraulic pressure chambers 98a and 98b of the motor cylinder device 16 are kept almost sealed.
Here, the slave pistons 88a and 88b of the motor cylinder device 16 are gradually returned to the initial position IP side. Therefore, the internal pressure of the motor cylinder device 16 (pressure in the first and second hydraulic pressure chambers 98a and 98b) also gradually decreases as the slave pistons 88a and 88b return to the initial position IP side. Become.

  At time t4 shown in FIG. 4, the first and second shutoff valves 60a and 60b are switched from the closed state to the open state. Thereafter, after the same time t4, the first and second shut-off valves 60a and 60b are kept open (see FIG. 4B).

Therefore, in the vehicle braking force generator 10 according to the embodiment of the present invention, for example, some abnormality has occurred in the electric motor 72 during automatic operation of the automatic hydraulic pressure generation system (not depending on the braking operation by the driver). However, it is possible to prevent a situation where the slave pistons 88a and 88b stop at a halfway position where they do not return to the initial position IP.
As a result, the feeling of braking operation by the driver can be favorably maintained during the first braking operation immediately after the brake system is switched from the by-wire system to the backup system.

[Effects of vehicle braking force generator 10 according to an embodiment of the present invention]
Next, the effect of the vehicle braking force generator 10 according to the embodiment of the present invention will be described.
In the vehicular braking force generation device 10 based on the first aspect (claim 1), the control unit 155 performs the abnormality diagnosis when the abnormality diagnosis unit 153 makes a diagnosis that the motor cylinder device 16 is abnormal. A configuration is adopted in which control is performed to open the first and second shut-off valves (open / close valves) 60a, 60b after a predetermined waiting time wt from time.

According to the vehicle braking force generator 10 based on the first aspect (claim 1), even if any abnormality occurs in the electric motor (electric actuator) 72 during automatic operation of the automatic hydraulic pressure generation system, the slave It is possible to prevent a situation where the pistons (pistons) 88a and 88b stop at a halfway position where they do not return to the initial position IP.
As a result, the feeling of braking operation by the driver can be favorably maintained even during the first braking operation immediately after the brake system is switched from the by-wire system to the backup system.

  In the vehicular braking force generator 10 based on the second aspect (claim 2), the control unit 155 indicates that the position information acquisition unit 151 has returned the slave pistons (pistons) 88a and 88b to the initial position IP. When acquired, regardless of whether or not the elapsed time from the abnormality diagnosis reaches the standby time wt, the first and second shut-off valves (open / close valves) 60a and 60b are controlled immediately after the acquisition, The configuration was adopted.

  According to the vehicular braking force generator 10 based on the second aspect (Claim 2), the brake system is changed from the by-wire system to the backup system as compared with the invention according to the first aspect (Claim 1). Since the switching timing can be expected to be accelerated, the driver's feeling of braking operation can be maintained better.

  In the vehicular braking force generator 10 according to the third aspect (Claim 3), the standby time wt is a slave piston (piston) when a diagnosis that the motor cylinder device 16 is abnormal is made. A configuration that is variably set according to the positions of 88a and 88b is adopted. Specifically, the waiting time wt becomes shorter as the positions of the slave pistons (pistons) 88a and 88b when the diagnosis that the motor cylinder device 16 is abnormal is made closer to the initial position IP side. Is variably set.

  According to the braking force generator 10 for a vehicle based on the third aspect (Claim 3), the brake system is a buy-and-squeeze compared to the inventions related to the first and second aspects (Claims 1 and 2). Since it is possible to expect an appropriate timing for switching from the wire system to the backup system, it is possible to better maintain the driver's feeling of braking operation.

[Other Embodiments]
The plurality of embodiments described above show examples of realization of the present invention. Therefore, the technical scope of the present invention should not be limitedly interpreted by these. This is because the present invention can be implemented in various forms without departing from the gist or main features thereof.

DESCRIPTION OF SYMBOLS 10 Vehicle braking force generator 14 Hydraulic pressure generator 16 Motor cylinder apparatus 58a 1st hydraulic pressure path (hydraulic pressure path)
58b Second hydraulic pressure path (hydraulic pressure path)
60a First shut-off valve (open / close valve)
60b Second shut-off valve (open / close valve)
72 Electric motor (electric actuator)
88a First slave piston (piston)
88b Second slave piston (piston)
151 Position Information Acquisition Unit 153 Abnormality Diagnosis Unit 155 Control Unit

Claims (3)

A hydraulic pressure generator for receiving a braking operation by the driver;
A motor cylinder device that generates a brake fluid pressure by movement of a piston associated with an operation of an electric actuator based on at least an electric signal corresponding to the braking operation;
An on-off valve that is provided in a hydraulic pressure path between the hydraulic pressure generating device and the motor cylinder device and operates to shut off the hydraulic pressure path while closing the hydraulic pressure path;
An abnormality diagnosis unit for performing abnormality diagnosis of the motor cylinder device;
A controller that performs control to open the on-off valve after a predetermined waiting time from the time of diagnosis when the diagnosis that the motor cylinder device is abnormal is made by the abnormality diagnosis unit;
A vehicular braking force generator. The vehicle braking force generator according to claim 1,
A position information acquisition unit for acquiring position information of the piston;
The control unit, when the fact that the piston has returned to the initial position is acquired by the position information acquisition unit, whether or not the elapsed time from the abnormality diagnosis reaches the standby time immediately after the acquisition Control to open the on-off valve
A braking force generator for a vehicle. A braking force generator for a vehicle according to claim 1 or claim 2,
The waiting time is variably set according to the position of the piston when the diagnosis that the motor cylinder device is abnormal is made.
A braking force generator for a vehicle.

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