JP2015020459A - Vehicle braking force generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain favorable braking operation feeling of a driver even when an electric actuator has some sort of abnormality during automatic control of a fluid pressure automatic control system.SOLUTION: A vehicle braking force generation system 10 comprises: a fluid pressure generation device 14; a motor cylinder device 16; a collision damage alleviation system 19; a first and a second cutoff valves 60a and 60b; an abnormality diagnosis section 153 which performs abnormality diagnosis of the motor cylinder device 16; and a control section 155. The cutoff valves 60a and 60b have: valve bodies 217 which are driven in a direction to close the cutoff valves 60a and 60b with electromagnetic force of exciting coils 227; and coil springs 221 which energize the valve bodies 217 in a direction to open the cutoff valves 60a and 60b. In the vehicle braking force generation device 10, set loads of the coil springs 221 are decided in a manner that allows loads F3 related to the coil springs 221 to exceed a deviation obtained by subtracting force F2 related to primary fluid pressure from the force F1 related to secondary fluid pressure when a slave piston 88 is returned close to an initial position IP.

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 actuator. 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 (hydraulic pressure automatic control system) uses a motor cylinder device to brake fluid regardless of the driver's braking operation when, for example, an object with 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.

Suppose that the by-wire brake system according to Patent Document 1 is applied in combination with a hydraulic automatic control system such as a collision damage reduction system according to Patent Document 2. In this case, it is assumed that, for example, some abnormality occurs in the electric actuator that drives the piston of the motor cylinder device during the operation of the hydraulic pressure automatic control 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 hydraulic automatic control system according to Patent Document 2 is applied in combination with the by-wire brake system according to Patent Document 1, the automatic hydraulic control system is used in the by-wire brake system. During automatic control (not depending on the braking operation by the driver), if any abnormality occurs in the electric actuator that drives the piston of the motor cylinder device 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 if any abnormality occurs in the electric actuator that drives the piston of the motor cylinder device during the automatic control of the hydraulic automatic control 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 brake fluid pressure, a fluid pressure automatic control unit that automatically controls brake fluid pressure using the motor cylinder device regardless of the braking operation, the fluid pressure generator, and the motor cylinder An on-off valve that is provided in a hydraulic pressure path between the devices and that communicates when the hydraulic pressure path is opened and that is shut off when the hydraulic pressure path is closed; an abnormality diagnosis unit that diagnoses an abnormality of the motor cylinder device; and the abnormality A control unit that controls to open the on-off valve when the diagnosis unit diagnoses that the motor cylinder device is abnormal. The on-off valve has a valve body that is driven in a direction to close the on-off valve by an electromagnetic force of an exciting coil, and an elastic member that urges the valve body in a direction to open the on-off valve. The opening / closing valve is controlled to be opened by the unit, and the force related to the secondary hydraulic pressure generated by the automatic control of the hydraulic pressure automatic control unit and the load related to the elastic member are acting on the valve body. However, the most important feature is that an opening pressure that allows the opening / closing valve to be opened is set so that the opening / closing valve is opened when the piston returns to the vicinity of the initial position.

  In the invention according to (1), the control unit performs control to open the on-off valve, and the force related to the secondary hydraulic pressure generated by the automatic control of the hydraulic pressure automatic control unit and the load related to the elastic member are the valve body. The opening pressure that allows the opening / closing valve to be opened is set so that the opening / closing valve is opened when the piston returns to the vicinity of the initial position.

  For example, it is assumed that a relatively large force related to the secondary hydraulic pressure is generated as a result of the automatic braking control having a relatively high degree of emergency performed by the hydraulic pressure automatic control unit. In this case, the current position of the piston is relatively far from the initial position. Further, contrary to the control for opening the on-off valve, the on-off valve maintains a closed state.

  While the on-off valve maintains the closed state, the force relating to the secondary hydraulic pressure for returning the piston to the initial position side is maintained. For this reason, the piston is urged toward the initial position and returns to the vicinity of the initial position. As the piston returns to the vicinity of the initial position, the force related to the secondary hydraulic pressure gradually decreases.

  Here, the opening pressure (including the opening force) that enables the opening / closing valve to open is set to open the opening / closing valve when the piston returns to the vicinity of the initial position. Therefore, the on-off valve is switched from the closed state to the open state after a predetermined delay time from the start of the control for opening the on-off valve.

According to the invention according to (1), even if any abnormality occurs in the electric actuator during the automatic control of the hydraulic pressure automatic control system, the piston stops at a halfway position where it does not return to the initial position. The situation can be prevented beforehand.
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.

  The invention according to (2) is the vehicle braking force generator according to the invention according to (1), wherein the control unit performs a braking operation by a driver when the vehicle braking force generator is activated. When the primary hydraulic pressure generated by the hydraulic pressure generating device exceeds the opening pressure of the on-off valve, the vehicle braking force generating device is prohibited from starting.

  According to the invention according to (2), in the case where the on-off valve may be in a self-locking state, in order to prohibit the start of the vehicle braking force generator, in addition to the operational effects of the invention according to (1), Occurrence of a situation where the on-off valve cannot be opened can be prevented.

  The invention according to (3) is the vehicular braking force generator according to the invention according to (1), wherein the force related to the secondary hydraulic pressure when the piston returns to the vicinity of the initial position. The set load of the elastic member is set so that the load related to the elastic member exceeds the deviation obtained by subtracting the force related to the primary hydraulic pressure that is the hydraulic pressure upstream of the on-off valve. .

  According to the invention according to (3), in addition to the function and effect of the invention according to (1), the set load of the elastic member is set in consideration that the on-off valve opens when the piston returns to the vicinity of the initial position. Specific design guidelines for setting can be provided.

  According to the vehicle 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 control of the hydraulic pressure automatic control system, 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 explanatory drawing which represents typically the internal structure of the 1st cutoff valve at the time of closure. It is explanatory drawing which represents typically the internal structure of the 1st cutoff valve at the time of open | release. It is a block diagram showing the periphery structure of ESB-ECU which the braking force generator for vehicles concerning the embodiment of the present invention has. It is a time chart figure used for description of 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.

[Outline of Braking Force Generating Device 10 for Vehicle according to 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 vehicular braking force generator 10 includes a hydraulic pressure generator 14 that receives a braking operation by a driver through a brake pedal 12, and a brake hydraulic pressure based on at least an electric signal corresponding to the braking operation by the driver. And a vehicle stability assist device 18 (hereinafter referred to as “VSA device 18”) that assists in stabilizing the behavior of the vehicle (not shown) based on the brake fluid pressure generated by the motor cylinder device 16. 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, and a function to suppress side slip during 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 vehicular braking force generator 10 according to the embodiment of the present invention is equipped with a collision damage reducing system 19 (see FIG. 3: see, for example, Japanese Patent Laid-Open No. 2008-181200). The collision damage reduction system 19 automatically generates brake fluid pressure using the motor cylinder device 16 regardless of the braking operation by the driver when there is an object with high collision risk in the traveling direction of the host vehicle. And has a function of avoiding a collision with an object. The collision damage reduction system 19 has a function of automatically generating a brake fluid pressure using the motor cylinder device 16 and corresponds to a fluid pressure automatic control system (corresponding to the “fluid pressure automatic control unit” of the present invention). Belongs to the category. As the hydraulic pressure automatic control system, in addition to the collision damage reducing system 19, a cruise control system, a hydraulic pressure holding system, a tracking control system, and the like are included.

(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 brake hydraulic 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 brake hydraulic pressure sensor Pm has a function of detecting the primary hydraulic pressure on the master cylinder 34 side of the first cutoff 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 secondary 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 such that the normal position (the position of the valve body when not energized (non-energized)) 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).

(Internal structure of the first shutoff valve 60a)
Here, the internal structure of the first shut-off valve 60a will be described with reference to FIGS. 2A and 2B. FIG. 2A is an explanatory view schematically showing the internal structure of the first shut-off valve 60a at the time of closing. FIG. 2B is an explanatory diagram schematically illustrating the internal structure of the first shutoff valve 60a when opened.
The internal structure of the second cutoff valve 60b is the same as that of the first cutoff valve 60a. Therefore, by describing the internal structure of the first shut-off valve 60a, the description will replace the description of the internal structure of the second shut-off valve 60b.

  The first shut-off valve 60a is configured by accommodating an on-off valve mechanism 213 in an internal section of a hollow housing 211 having a substantially cylindrical appearance. A lid member 215 is fixed to one side of the hollow housing 211. The on-off valve mechanism 213 includes a spherical valve body 217, a mortar-shaped valve seat 219 formed on the lid member 215, a coil spring (corresponding to the “elastic member” of the present invention) 221, a disk-shaped slider 223, and a rod 225 and an exciting coil 227.

  The valve body 217 is supported so as to be able to reciprocate between a closed position (see FIG. 2A) seated on the valve seat 219 and an open position (see FIG. 2B) away from the valve seat 219. The valve body 217 operates to close the first shutoff valve 60a by being seated on the valve seat 219 when the exciting coil 227 is excited. The valve body 217 and the slider 223 are connected via a rod 225. The valve body 217, the rod 225, and the slider 223 constitute a movable iron core 231 that is driven in a direction to close the first shut-off valve 60a by an electromagnetic force of an exciting coil 227 serving as a fixed iron core. A coil spring 221 is provided around the valve body 217 and the rod 225. The coil spring 221 is interposed between the inner wall of the lid member 215 and the inner wall of the slider 223 facing the lid member 215.

  In the vehicular braking force generator 10 according to the embodiment of the present invention, the set load of the coil spring (elastic member) 221 that constitutes a part of the on-off valve mechanism 213 in the first shut-off valve 60a is applied to the collision damage reduction system (liquid Automatic pressure control system) After the operation of the motor 19 is started, the motor cylinder device 16 enters an abnormal state and the first and second shut-off valves 60a and 60b are de-energized. When the force F1 related to the secondary hydraulic pressure (see FIG. 2A, unit: N) and the load F3 related to the coil spring 221 (see FIG. 2A, unit: N) are acting on the valve body 217, the valve body 217 On the other hand, the deviation (F1) obtained by subtracting the force F2 (see FIG. 2A, unit: N) related to the primary hydraulic pressure on the hydraulic pressure generating device 14 side from the force F1 related to the secondary hydraulic pressure on the motor cylinder device 16 side. -F2 And it is set in consideration that the load F3 of the coil spring 221 exceeds. The set load of the coil spring 221 means a load that is initially set in the manufacturing process of the coil spring 221.

  Here, the force F2 related to the primary hydraulic pressure means that the brake hydraulic pressure (primary hydraulic pressure) generated on the hydraulic pressure generating device 14 side (upstream side) with the first cutoff valve 60a as a boundary is that of the first cutoff valve 60a. It means the force generated by acting on the valve body 217. Further, the force F1 related to the secondary hydraulic pressure is the brake hydraulic pressure (secondary hydraulic pressure) generated on the motor cylinder device 16 side (downstream side) with the first cutoff valve 60a as a boundary. It means the force generated by acting on the valve body 217. And the load F3 concerning the coil spring 221 means a load generated in the coil spring 221.

  An excitation coil (fixed iron core) 227 is provided on the inner wall of the body portion 229 of the hollow housing 211 so as to surround the movable iron core 231. When the exciting coil (fixed iron core) 227 is excited, a force in the direction indicated by the arrow 233 in FIG. 2A acts on the movable iron core 231. That is, a force in the direction of closing the first shut-off valve 60a also acts on the valve body 217 constituting a part of the movable iron core 231. As a result, when the exciting coil 227 is excited, the valve element 217 operates to close the first shut-off valve 60a by being seated on the valve seat 219 as shown in FIG. 2A.

  On the other hand, when the exciting coil (fixed iron core) 227 is demagnetized, the force in the direction indicated by the arrow 233 in FIG. 2A acting on the movable iron core 231 disappears. At this time, the coil spring 221 urges the slider 223 connected to the valve body 217 in a direction to open the first cutoff valve 60a. Accordingly, the slider 223 connected to the valve body 217 receives the load (see reference numeral F3 shown in FIGS. 2A and 2B) applied to the coil spring 221 and moves to the open position shown in FIG. 2B. As a result, the valve body 217 operates to open the first shut-off valve 60a by being separated from the valve seat 219.

  Returning to FIG. 1 and continuing the description, 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. ing. 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 when de-energized (non-energized)) 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. 3) 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. 3) 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. 3) 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. The third shut-off valve 62 composed of a normally closed solenoid valve is excited and opened (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 a 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 shut-off valve 62 in the open state to the stroke simulator 64. The reaction force is transmitted to the hydraulic pressure chamber 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 ESB-ECU 111 (see FIG. 3) detects the depression of the brake pedal 12 by the driver, the ESB-ECU 111 drives the electric motor 72 of the motor cylinder device 16 and uses the driving force of the electric motor 72 as power. 1 is transmitted via the transmission mechanism 74, and 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 generation device 10, when the driver steps on the brake pedal 12 during normal operation of the ESB-ECU 111 (see FIG. 3) that controls the motor cylinder device 16 and the by-wire, a so-called buy-by.・ The wire brake system 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 an abnormal state, 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. 62 is closed, and the brake hydraulic 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 cylinders 32FR, 32RL). , 32RR, 32FL).

[Peripheral configuration of ESB-ECU 111 included in vehicle braking force generator 10 according to an embodiment of the present invention]
Next, a peripheral configuration of the ESB-ECU 111 included in the vehicle braking force generation device 10 according to the embodiment of the present invention will be described with reference to FIG. FIG. 3 is an explanatory diagram illustrating a peripheral configuration of the ESB-ECU 111 included in the vehicle braking force generation device 10 according to the embodiment of the present invention.

  As shown in FIG. 3, an ESB-ECU 111 of an ESB (electric servo brake) included in the vehicular braking force generator 10 according to the embodiment of the present invention has an ignition key switch (hereinafter referred to 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 ESB-ECU 111 so that the ESB-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 ESB-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 ESB-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 ESB-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 ESB-ECU 111.

  On the other hand, as shown in FIG. 3, the electric motor 72 and the first to third shut-off valves 60 a, 60 b, 62 are connected to the ESB-ECU 111 as an output system. Further, the ESB-ECU 111 is connected with a VSA device 18 and a collision damage reduction system 19 as an input / output system.

  As shown in FIG. 3, the ESB-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 ESB-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 ESB-ECU 111 has a current position information acquisition function in the axial direction of the slave pistons 88a and 88b, the motor cylinder device 16 (the hydraulic system and It operates so as to perform execution control related to various functions including an abnormality diagnosis function (including an electric system) 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 in the axial direction of the slave pistons 88a and 88b, the strokes of the slave pistons 88a and 88b themselves are used in place 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 abnormality diagnosis unit 153 diagnoses that the motor cylinder device 16 is abnormal, the control unit 155 directly connects the braking operation by the driver to the braking force (without mediating the by-wire system). The first and second shutoff valves 60a and 60b have a function of performing control to open.

[Time-series operation of vehicle braking force generator 10 according to an embodiment of the present invention]
Next, the time-series operation of the vehicle braking force generator 10 according to the embodiment of the present invention will be described with reference to FIGS. 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 illustrating the transition of the torque of the electric motor 72 in time series, and FIG. 4 (b) illustrates the transition of the opening / closing control signals of the first and second shutoff valves 60a and 60b. FIG. 4C is a time chart illustrating time series of the current position of the slave pistons 88a and 88b, and FIG. 4D is a time chart illustrating the internal pressure of the motor cylinder device 16. FIG. FIG. 4E is a time chart illustrating changes in the opening / closing states of the first and second shut-off valves 60a and 60b in time series.
However, as a premise, it is assumed that the IG key switch (121) of the vehicle is turned on and the vehicle is traveling slowly at a constant speed.

  At times t0 to t1 shown in FIG. 4, the torque of the electric motor 72 is zero (see FIG. 4A). At this time, the controller 155 outputs an opening control signal for the first and second shutoff valves 60a and 60b (for example, shuts off the energization of the first and second shutoff valves 60a and 60b) (see FIG. 4B). ). During normal operation of the vehicle braking force generator 10 according to the embodiment of the present invention (no braking operation or no automatic braking control by the collision damage reduction system 19), the first and second shutoff valves 60a and 60b are provided. This is because the principle is to control to open state. The current positions of the slave pistons 88a and 88b are at the initial position IP (see FIG. 4C). The internal pressure of the motor cylinder device 16 is zero (see FIG. 4D). The open / close state of the first and second shut-off valves 60a, 60b is in an open state according to the open control signal (see FIG. 4 (e)).

  At times t1 to t2 shown in FIG. 4, the torque of the electric motor 72 gradually rises from zero to the vicinity of the braking torque (torque during braking) (see FIG. 4A). This is because the collision damage reduction system (hydraulic pressure automatic control system) 19 starts automatic control (not depending on the braking operation by the driver) after time t1 shown in FIG. At this time, the controller 155 outputs a closing control signal for the first and second shutoff valves 60a and 60b (see FIG. 4B). The current positions of the slave pistons 88a and 88b gradually rise from the initial position IP to the vicinity of the braking position (braking position) BP (see FIG. 4C). 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. 4D). The open / close state of the first and second shutoff valves 60a, 60b is switched to a closed state in accordance with a closing control signal (see FIG. 4 (e)).

  At times t2 to t3 shown in FIG. 4, the torque of the electric motor 72 maintains the braking torque (see FIG. 4A). That is, the collision damage reduction system (hydraulic pressure automatic control system) of the vehicle braking force generator 10 according to the embodiment of the present invention continues the automatic control. At this time, the controller 155 outputs a closing control signal for the first and second shutoff valves 60a and 60b (see FIG. 4B). The current positions of the slave pistons 88a and 88b maintain the braking position BP (see FIG. 4C). The internal pressure of the motor cylinder device 16 also maintains the vicinity of the braking pressure (pressure during braking) (see FIG. 4D). The open / close state of the first and second shut-off valves 60a and 60b maintains a closed state according to the close control signal (see FIG. 4 (e)).

  It is assumed that some abnormality has occurred in the electric motor 72 at time t3 shown in FIG. Then, at the same time t3, the abnormality diagnosis unit 153 of the ESB-ECU 111 makes a diagnosis that an abnormality has occurred in the electric motor 72. In response to this, the control unit 155 stops the drive control of the electric motor 72 (stops the power supply to the electric motor 72) and outputs an opening control signal for the first and second shutoff valves 60a and 60b (see FIG. 4 (b)). As a result, at time t3 shown in FIG. 4, the torque of the electric motor 72 suddenly drops from the braking torque to zero (see FIG. 4A).

At the same time t3 to t4, the current positions of the slave pistons 88a and 88b gradually return from the braking position BP to the vicinity of the initial position IP, even though power supply to the electric motor 72 is stopped. (See FIG. 4 (c)). The reason is as follows.
That is, at the same time t3, the open / close state of the first and second shut-off valves 60a and 60b still maintains the closed state, regardless of whether the opening control of the first and second shut-off valves 60a and 60b is performed. doing. This is because the force F1 related to the secondary hydraulic pressure on the side of the motor cylinder device 16 is the resultant force of the force F2 related to the primary hydraulic pressure on the side of the hydraulic pressure generator 14 and the load F3 related to the coil spring (elastic member) 221 ( (F2 + F3) is exceeded (F1> (F2 + F3)), and the valve body 217 is kept pressed against the valve seat 219 (see FIG. 2A). For this reason, the force F1 related to the secondary hydraulic pressure acting on the slave pistons 88a and 88b of the motor cylinder device 16 is also maintained in the state immediately before the time t3.

  In short, the current positions of the slave pistons 88a and 88b gradually return from the braking position BP to the vicinity of the initial position IP at times t3 to t4, because the force F1 related to the secondary hydraulic pressure on the motor cylinder device 16 side. Exceeds the resultant force (F2 + F3) of the force F2 related to the primary hydraulic pressure on the side of the hydraulic pressure generator 14 and the load F3 related to the coil spring (elastic member) 221 (F1> (F2 + F3)), and therefore, the slave piston 88a. , 88b, the force F1 related to the secondary hydraulic pressure for returning to the initial position IP side is maintained, and the slave pistons 88a, 88b are urged to the initial position IP side.

After the same time t3 to t4, the internal pressure of the motor cylinder device 16 gradually decreases from the braking pressure. 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 toward the initial position IP as described above. 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.

  The “near the initial position IP” in the present invention means that the first and second shut-off valves are used because the motor cylinder device 16 falls into an abnormal state and generates a braking force directly in response to the driver's braking operation. Immediately after opening 60a, 60b, when the driver performs a braking operation, the degree of liquid loss generated in the motor cylinder device 16 is permissible in accordance with safety standards (a sufficient braking force can be generated). This means the return position of the slave pistons 88a, 88b that is close to the initial position IP (including the initial position IP itself).

  At time t4 shown in FIG. 4, the first and second shut-off valves 60a and 60b are moved from the closed state to the open state after a delay time DT (see FIG. 4 (e)) from the output time point (time t3) of the open control signal. Switch to. The force F1 related to the secondary hydraulic pressure on the side of the motor cylinder device 16 is the force F2 related to the primary hydraulic pressure on the side of the hydraulic pressure generator 14 and the resultant force (F2 + F3) of the load F3 related to the coil spring (elastic member) 221. This is because it was lower (F1> F2 + F3) (see FIG. 2B). In other words, the deviation (F1-F2) obtained by subtracting the force F2 related to the primary hydraulic pressure on the hydraulic pressure generating device 14 side from the force F1 related to the secondary hydraulic pressure on the motor cylinder device 16 side is the coil spring (elasticity). This is because (F1−F2 <F3) which is less than the load F3 related to the member 221. Thereafter, after the same time t4, the first and second shut-off valves 60a, 60b maintain the open state (see FIG. 4 (e)).

[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 vehicle braking force generator 10 according to the first aspect (Claim 1), the control unit 155 performs control to open the first and second shut-off valves (open / close valves) 60a and 60b, and collision damage. When the force F1 related to the secondary hydraulic pressure generated by the automatic control of the reduction system (hydraulic pressure automatic control system) and the load F3 related to the coil spring (elastic member) 221 are acting on the valve body 217, the slave A configuration is adopted in which an opening pressure is set to open the on-off valve so that the on-off valve is opened when the pistons 88a, 88b return to the vicinity of the initial position IP.

In the vehicle braking force generator 10 according to the first aspect (claim 1), the first and second shut-off valves (open / close valves) 60a and 60b are controlled to be opened, and the collision damage reducing system (liquid When the force F1 related to the secondary hydraulic pressure generated by the automatic control of the automatic pressure control system) and the load F3 related to the coil spring (elastic member) 221 are acting on the valve body 217, the slave piston (piston) An opening pressure that allows the opening and closing valves to be opened is set so that the first and second shutoff valves (opening and closing valves) 60a and 60b are opened when 88a and 88b return to the vicinity of the initial position IP.
Here, the opening pressure enabling opening of the first and second shutoff valves (open / close valves) 60a, 60b is a concept including an opening force derived from the opening pressure. Specifically, the opening pressure (including the opening force) of the first and second shutoff valves (open / close valves) 60a and 60b corresponds to, for example, “a set load of the elastic member 221”.

  Suppose that a relatively large force F1 related to the secondary hydraulic pressure is generated as a result of automatic braking control with a relatively high degree of urgency performed by the collision damage reduction system (hydraulic pressure automatic control system). In this case, the current positions of the slave pistons (pistons) 88a, 88b are relatively far from the initial position IP. Contrary to the control for opening the first and second shutoff valves (open / close valves) 60a, 60b, the first and second shutoff valves 60a, 60b maintain the closed state.

  While the first and second shut-off valves (open / close valves) 60a, 60b are kept closed, the force F1 related to the secondary hydraulic pressure for returning the slave pistons (pistons) 88a, 88b to the initial position IP side. Is maintained. Therefore, the slave pistons 88a and 88b are biased toward the initial position IP and return to the vicinity of the initial position IP. As the slave pistons 88a and 88b return to the vicinity of the initial position IP, the force F1 related to the secondary hydraulic pressure gradually decreases.

  Here, the opening pressure (including the opening force) that can open the first and second shut-off valves (open / close valves) 60a, 60b is the first and second when the pistons 88a, 88b return to the vicinity of the initial position IP. The second shutoff valves (open / close valves) 60a and 60b are set to open. Therefore, the first and second shut-off valves (open / close valves) 60a and 60b are switched from the closed state to the open state after a predetermined delay time (see, for example, FIG. 4E) from the start time of the open control.

According to the vehicle braking force generator 10 based on the first aspect (claim 1), during the automatic control of the collision damage reduction system (hydraulic pressure automatic control system) 19, there is some abnormality in the electric motor (electric actuator) 72. Even if this occurs, it is possible to prevent the slave pistons (pistons) 88a and 88b from stopping at a halfway position where they do not return to the initial position IP.
As a result, even during the first braking operation immediately after the brake system is switched from the by-wire system to the backup system, there is almost no liquid loss (invalid stroke), so the driver feels comfortable in braking operation. Can be maintained.

Further, in the vehicle braking force generation device 10 based on the second aspect (claim 2), when the vehicle braking force generation device 10 is started, the hydraulic pressure generation device 14 generates the braking force according to the braking operation by the driver. In a case where the primary hydraulic pressure exceeds the open pressure of the first and second shutoff valves (open / close valves) 60a and 60b, the first and second shutoff valves 60a and 60b are prevented from falling into a so-called self-lock state. ing.
For example, the case where the IG key switch 121 is turned on or the motor cylinder device 16 is driven in a state where the braking operation by the driver is strongly performed (the brake pedal is depressed deeply). It can be assumed that the motor cylinder device 16 is switched from the abnormal state to the normal state by returning from the abnormal state in which the voltage of the power source (not shown) is reduced to the normal state.

In the case described above, the first and second shut-off valves (open / close valves) 60a and 60b fall into a self-locked state while being closed. Opening that allows the first and second shutoff valves 60a and 60b to be opened even after the driver releases the braking operation (turns off the brake pedal) (even after the slave pistons 88a and 88b return to the initial position IP). This is because the secondary hydraulic pressure exceeding the pressure remains on the motor cylinder device 16 side and hinders the opening operation of the first and second shutoff valves 60a and 60b (for example, refer to paragraphs of JP2012-131393A). 0007 to paragraph 0010).
If the first and second shut-off valves 60a and 60b fall into such a self-locking state, it becomes a factor that causes braking abnormality such as brake dragging.

  Therefore, in the vehicle braking force generator 10 based on the second aspect (claim 2), the controller 155 generates hydraulic pressure in response to a braking operation by the driver when the vehicle braking force generator 10 is activated. Prohibiting the start of the vehicle braking force generator 10 when the primary hydraulic pressure generated in the device 14 exceeds the opening pressure enabling the first and second shut-off valves (open / close valves) 60a, 60b to open; did.

  According to the vehicle braking force generator 10 based on the second aspect (Claim 2), the first and second shut-off valves (open / close valves) 60a, 60b are used in a case where there is a concern that the self-lock state may occur. In order to prohibit the activation of the braking force generator 10 for a vehicle, in addition to the effect of the invention according to the first aspect (Claim 1), the first and second shut-off valves (open / close valves) 60a, 60b cannot be opened Can be prevented.

  Further, in the vehicle braking force generator 10 based on the third aspect (claim 3), the force F1 related to the secondary hydraulic pressure when the slave pistons (pistons) 88a and 88b return to the vicinity of the initial position IP. The load F3 associated with the elastic member 221 exceeds the deviation (F1-F2) obtained by subtracting the force F2 associated with the primary fluid pressure that is the fluid pressure upstream of the first and second shutoff valves (open / close valves) 60a, 60b. Thus, the set load of the elastic member 221 is set.

  Suppose that a relatively large force F1 related to the secondary hydraulic pressure is generated as a result of automatic braking control with a relatively high degree of urgency performed by the collision damage reduction system (hydraulic pressure automatic control system). In this case, the deviation (F 1 -F 2) takes a relatively large value that greatly exceeds the load F 3 related to the coil spring (elastic member) 221. Further, the current positions of the slave pistons (pistons) 88a and 88b are relatively far from the initial position IP. In such a case, the first and second cutoff valves 60a and 60b maintain a closed state, contrary to the control for opening the first and second cutoff valves (open / close valves) 60a and 60b. This is because the opening condition (F1 <(F2 + F3)) related to the first and second shutoff valves 60a and 60b is not satisfied.

  While the first and second shut-off valves (open / close valves) 60a, 60b are kept closed, the force F1 related to the secondary hydraulic pressure for returning the slave pistons (pistons) 88a, 88b to the initial position IP side. Is maintained. For this reason, the slave pistons 88a and 88b are biased toward the initial position IP, and return to the vicinity of the initial position IP. As the slave pistons 88a and 88b move back to the vicinity of the initial position IP, the force F1 related to the secondary hydraulic pressure gradually decreases.

  As a result of the reduction of the force F1 related to the secondary hydraulic pressure, the load F3 related to the elastic member 221 is calculated as a deviation (F1-F2) obtained by subtracting the force F2 related to the primary hydraulic pressure from the force F1 related to the secondary hydraulic pressure. In other words, if the opening condition (F1 <(F2 + F3)) relating to the first and second shutoff valves (open / close valves) 60a, 60b is satisfied, the first and second shutoff valves 60a, 60b start the opening control. After a predetermined delay time (for example, refer to FIG. 4E) from the time, the closed state is switched to the open state.

  Incidentally, in the example of this embodiment, since it is premised on the automatic control by the collision damage reduction system (hydraulic pressure automatic control system) 19 (not depending on the braking operation by the driver), the force F2 related to the primary hydraulic pressure is It can be regarded as substantially zero. Then, the opening condition (F1 <(F2 + F3)) can be replaced with the fact that the force F1 related to the secondary hydraulic pressure is smaller than the load F3 related to the coil spring 221 (F1 <F3).

  According to the vehicle braking force generator 10 based on the third aspect (Claim 1), in addition to the operational effects of the invention according to the first aspect (Claim 1), the slave pistons (pistons) 88a, 88b include Provides specific design guidelines for setting the set load of the elastic member 221 in consideration of the opening of the first and second shut-off valves (open / close valves) 60a, 60b when returning to the vicinity of the initial position IP. can do.

[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 device 19 Collision damage reduction system (hydraulic pressure automatic control system; hydraulic pressure automatic controller)
58a First 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)
153 Abnormality diagnosis unit 155 Control unit 217 Valve element 221 Coil spring (elastic member)
227 Excitation coil F1 Force related to secondary hydraulic pressure F2 Force related to primary hydraulic pressure F3 Load related to coil spring (elastic member)

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;
Regardless of the braking operation, a hydraulic pressure automatic control unit that automatically controls the brake hydraulic pressure using the motor cylinder device;
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 when the abnormality diagnosis unit diagnoses that the motor cylinder device is abnormal; and
With
The on-off valve has a valve body that is driven in a direction to close the on-off valve by electromagnetic force of an excitation coil, and an elastic member that urges the valve body in a direction to open the on-off valve,
Control for opening the on-off valve is performed by the control unit, and the force F1 related to the secondary hydraulic pressure generated by the automatic control of the hydraulic pressure automatic control unit and the load related to the elastic member act on the valve body. Setting an opening pressure that allows the on-off valve to be opened so that the on-off valve is opened when the piston returns to the vicinity of the initial position.
A braking force generator for a vehicle. The vehicle braking force generator according to claim 1,
When the primary hydraulic pressure generated in the hydraulic pressure generator in response to a braking operation by a driver exceeds the opening pressure of the on-off valve when the vehicle braking force generator is activated, Prohibiting activation of the braking force generator for the vehicle,
A braking force generator for a vehicle. The vehicle braking force generator according to claim 1,
When the pistons 88a and 88b return to the vicinity of the initial position IP, the force F2 related to the primary hydraulic pressure that is the hydraulic pressure upstream of the on-off valves 60a and 60b is subtracted from the force F1 related to the secondary hydraulic pressure. The set load of the elastic member 221 is set so that the load F3 related to the elastic member 221 exceeds the deviation (F1-F2).
A braking force generator for a vehicle.

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