JP2007091227A - Electric brake device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To certainly transmit master cylinder pressure to a wheel cylinder as brake pressure by sucking a brake liquid into a master cylinder even during stepping on a brake pedal even if air is mixed into a pipe. <P>SOLUTION: When a difference of an actual M/C stroke length L detected by a stroke sensor 9 and a stroke length LS presumed from a current value of a motor 5 is larger than a threshold KS, oil amount compensation control for performing M/C stroke return by a returning current I2 of the motor and a returning period T2 is repeated. Thereby, pumping operation by the electric device is enabled and the M/C pressure can be certainly transmitted to each W/C even if air is mixed into the brake pipe. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle brake device.

  Conventionally, the brake fluid recirculation pump at the time of pressure reduction control of the wheel cylinder in ABS control is abolished, the brake fluid at the time of pressure reduction is temporarily stored in a reservoir provided in the piping system, and the master cylinder of the master cylinder accompanying the return of the brake pedal A so-called closed circuit pumpless brake system is known in which brake fluid is recirculated from a reservoir to a master cylinder during decompression (see Patent Document 1). Patent Document 1 also discloses a so-called open circuit pumpless brake system that directly returns the brake fluid when the wheel cylinder is depressurized to the master reservoir.

On the other hand, Patent Document 2 discloses an electric brake device that generates a master cylinder pressure by linearly moving a piston of a master cylinder according to a depression force of a brake pedal.
Japanese Patent Laid-Open No. 11-20645 JP-A-6-183330

  In the pumpless ABS control device disclosed in Patent Document 1, for example, when the road surface friction coefficient is low (the road surface is slippery), the brake pedal is depressed for a long time by the occupant at a relatively high vehicle speed, and the braking time is increased. When it lasts for a long time, there is a possibility that proper ABS control is not performed.

  In other words, when the above closed circuit is used in a pumpless ABS control device, if the ABS control continues for a long time, the reservoir becomes full and the brake fluid pressure cannot be further reduced. The corresponding master cylinder pressure is directly applied to the wheel cylinder, which may cause a wheel lock state.

  Further, when the above open circuit is used for a pumpless ABS control device, although there is no limit on the recirculation capacity at the time of decompression in the closed circuit, the brake pedal depression limit becomes the master cylinder pressure increase limit as it is. There is a possibility that the bottoming state occurs and the ABS control cannot be continued for a long time.

  On the other hand, in the electric brake device disclosed in Patent Document 2, when the depression of the brake pedal is released, the master cylinder pressure is also released accordingly. Therefore, when ABS control is to be performed with this electric brake device, it is necessary for the occupant to release the depression force of the brake pedal at the time of pressure reduction control, which is not realistic.

  In view of the above points, the present invention ensures that even when the brake pedal is depressed, the master cylinder pressure is reliably applied to the wheel cylinder as the brake pressure even when air is mixed into the piping by sucking the brake fluid into the master cylinder. An object of the present invention is to provide an electric brake device capable of transmitting.

  In order to achieve the above object, according to the first aspect of the present invention, pedal operation amount detection means for detecting an operation amount of a brake pedal, an actuator for moving a rod in accordance with the pedal operation amount, and movement of the rod A master cylinder that draws brake fluid from a master reservoir by generating a stroke to generate a master cylinder pressure, a stroke sensor that detects a stroke of the master cylinder, and a master cylinder that is connected to the master cylinder and adjusts the master cylinder pressure. A pressure increasing valve that outputs the wheel cylinder pressure, a wheel cylinder that is connected to the pressure increasing valve and generates a braking force on the wheel by the wheel cylinder pressure, and is connected to the wheel cylinder and adjusts the wheel cylinder pressure to adjust the wheel cylinder. Brake fluid is discharged according to pressure reduction A pressure valve, a pipe for returning brake fluid discharged from the pressure reducing valve to the master reservoir when the wheel cylinder pressure is reduced, and a control means for outputting drive signals for the actuator, the pressure increasing valve, and the pressure reducing valve. When the master cylinder is being pressurized to the actuator, the control means determines that the difference between the output value of the stroke sensor and the stroke length of the master cylinder estimated from the drive current of the actuator is greater than a threshold value. After returning the stroke for a predetermined time, oil amount compensation control for pressurizing the master cylinder again is performed.

  According to the present invention, the stroke of the master cylinder that generates the brake pressure is generated by the actuator that operates according to the pedal operation amount, and is calculated from the detected value of the actual stroke of the master cylinder and the drive current of the actuator. When the difference from the estimated stroke value is large, oil amount compensation control is performed to return the stroke of the master cylinder only for a predetermined time by driving the actuator, so the brake pedal was depressed even when air entered the brake piping. In this state, the master cylinder can be replenished with brake fluid and the pressure generated by the master cylinder can be reliably transmitted to the wheel cylinder.

  According to the second aspect of the present invention, the pedal operation amount detecting means for detecting the operation amount of the brake pedal, the actuator for moving the rod according to the pedal operation amount, and the stroke by the movement of the rod A master cylinder that generates a master cylinder pressure by sucking brake fluid from a master reservoir, a stroke sensor that detects a stroke of the master cylinder, and a master cylinder pressure that adjusts the master cylinder pressure as a wheel cylinder pressure. An output pressure increasing valve, a wheel cylinder connected to the pressure increasing valve to generate a braking force on the wheel by the wheel cylinder pressure, and connected to the wheel cylinder, adjusting the wheel cylinder pressure and responding to a decrease in the wheel cylinder pressure A pressure reducing valve for discharging brake fluid and the wheel A reservoir for storing brake fluid discharged from the pressure reducing valve when the cylinder pressure is reduced, and a check valve that is interposed between the reservoir and the master cylinder and allows fluid flow from the reservoir to the master cylinder; Control means for outputting respective drive signals of the actuator, the pressure increasing valve and the pressure reducing valve, and the control means outputs the output value of the stroke sensor to the actuator during pressurization of the master cylinder. If the difference between the stroke length of the master cylinder estimated from the drive current of the actuator is larger than the threshold value, the oil amount compensation control for pressurizing the master cylinder again after returning the stroke for a predetermined time may be performed. The same effect as that of the invention described in item 1 can be obtained.

(Reference Embodiment 1)
Reference Embodiment 1 serving as a reference of the present invention will be described with reference to the drawings. The first embodiment is an electric brake device in which the present invention is applied to a pumpless ABS device. In particular, a master cylinder (hereinafter referred to as M / C) is stroked by a motor, and the stroke length is normally used. It is characterized by its longer length. FIG. 1 shows the overall configuration.

  As shown in FIG. 1, the electric brake device according to the first embodiment includes a brake pedal 1, a stroke simulator 2, and a pedal operation amount (stepping force, stroke) sensor 3 that are operated in response to a driver's braking request. It has been. The stroke simulator 2 includes a piston 2a that is depressed by the brake pedal 1, a cylinder 2b that the piston 2a slides, and a spring 2c that is disposed in the cylinder 2b. The brake pedal 1 and the piston 2a are connected. When the brake pedal 1 is depressed, a reaction force and a stroke corresponding to the pedal operation amount are applied to the brake pedal 1 by the spring force from the spring 2c. ing. The stroke simulator 2 is also provided with a pedal operation amount sensor 3 as a pedal operation amount detection means. The pedal operation amount sensor 3 can detect a pedal operation amount, for example, a pedal depression force according to a reaction force of the spring 2c. Hereinafter, the pedal operation amount sensor is simply referred to as a pedaling force sensor.

  Further, the electric brake device has a configuration separated from the brake pedal 1, and includes an M / C 40, a motor 5 and a gear mechanism 6 as an actuator, an ABS actuator 71, a wheel cylinder corresponding to each wheel (hereinafter referred to as W / C). 8a to 8d).

  The M / C 40 is divided into a primary chamber 40b and a secondary chamber 40c by a master piston 40a, and the primary chamber 40b is connected to the first piping system and the secondary chamber 40c is connected to the second piping system. The first and second piping systems are respectively distributedly connected to the left front wheel (W / C8a), the right rear wheel (W / C8b), the left rear wheel (W / C8c), and the right front wheel (W / C8d). . The combination of each wheel may be two front wheels and two rear wheels.

  Each of the rooms 40b and 40c is longer than the normally used M / C, that is, the stroke amount of the M / C 40 is made longer than the stroke amount of the piston 2a of the stroke simulator 2 according to the depression amount of the brake pedal 1. As a result, the capacity of the pressure chamber of the M / C 40 is increased, and as will be described later, even when the wheel cylinder pressure continues to be reduced and the ABS control takes a long time, the M / C stroke has a margin. The ABS operation can be continued without causing bottoming.

  Then, as the piston rod 40d moves in the axial direction, the master piston 40a is moved to increase the brake fluid pressure (hereinafter referred to as M / C pressure) in each of the rooms 40b and 40c. The hydraulic pressure (hereinafter referred to as W / C pressure) is increased. Further, the M / C 40 is provided with a master reservoir 4e, and each of the rooms 40b and 40c is connected to the master reservoir 4e.

  The motor 5 as an M / C actuator generates a rotational driving force (output) by a pedaling force instruction current value corresponding to a target braking force calculated based on a pedaling force detection value from the pedal operation amount sensor 3 by an ECU 10 described later. To do. The gear mechanism 6 is composed of a ball screw, a rack and pinion, and the like, and converts the rotational driving force of the motor 5 into linear motion. The above-described piston rod 40d is driven by the gear mechanism 6, and when the rotational driving force of the motor 5 is converted into a linear motion by the gear mechanism 6, the piston rod according to the converted force. 40d is driven. That is, the M / C pressure corresponding to the rotational driving force of the motor 5 is generated, and the W / C pressure corresponding to the M / C pressure is generated. The gear mechanism 6 may be provided with a reduction gear and a speed increase gear in order to adjust the required motor torque and the required axial force.

  The ABS actuator 71 is a normal ABS actuator provided with pressure increasing valves 73a to 73d and pressure reducing valves 74a to 74d for each wheel, and reservoirs 751a and 751b and check valves 76a and 76b in the first and second piping systems, respectively. It is. Hereinafter, the left front wheel of the first piping system will be described. In addition, since the same operation | movement is performed also about another wheel, ie, the right rear wheel of a 1st piping system, the right front wheel of a 2nd piping system, and a left rear wheel, description about them is abbreviate | omitted.

  Between the primary chamber 40b of the M / C 40 and the W / C 8a, a pressure increasing valve 73a is connected as a two-position valve that is controlled by the ECU 10 to be in a communication state when non-conducting and shut off when conducting, and M / C 40 is generated. The brake fluid pressure is generated in the W / C 8a when the pressure increasing valve 73a is in communication. Further, on the W / C 8a side (downstream side) of the pressure increasing valve 73a, a pressure reducing valve 74a as a two-position valve controlled by the ECU 10 in a non-conducting state and a communicating state when in a conductive state, and a downstream side of the pressure reducing valve 74a ( A reservoir 751a is connected to the opposite side of W / C 8a. The pressure reducing valve 74a is brought into a communication state at the time of pressure reduction during ABS control, and operates so as to release the brake fluid in the W / C 8a to the reservoir 751a and reduce the W / C pressure. Note that. The capacity of the reservoir 751a is larger than the capacity of the reservoir used in a normal ABS actuator, and corresponds to the capacity of the M / C 40. More specifically, the first piping system includes the capacity of the primary chamber 40b and the capacity of the W / C 8a and 8b. The capacity is obtained by subtracting the capacity of.

  Further, the M / C 40 side (upstream side) of the pressure increasing valve 73a and the reservoir 751a are connected by a check valve 76a. In the process of increasing the M / C pressure during the braking operation, the brake fluid is not sent to the reservoir 751a by the check valve 76a, the braking operation is finished, and the piston rod 40d (that is, the master piston 40a) is returned by the motor 5. When the volume of the primary chamber 40b is increased, the brake fluid stored in the reservoir 751a is sucked out via the check valve 76a and returned to the primary chamber 40b to prepare for the next increase in the M / C pressure. It has become.

  The other pressure increasing valves 73b to 73d and pressure reducing valves 74b to 74d perform the same operation with the same configuration as the pressure increasing valve 73a and pressure reducing valve 74a described above, and the reservoir 751b and check valve 76b of the second piping system also have the above described reservoirs. The same operation is performed with the same configuration as 751a and the check valve 76a. The pressure increasing valves 73a to 73d and the pressure reducing valves 74a to 74d are respectively controlled by the ECU 10 so that the generated pressure is controlled linearly.

  Furthermore, the electric brake device according to the first embodiment includes an ECU 10 for driving the motor 5 and the ABS actuator 71. In addition to the detection signal from the pedal force sensor 3, the ECU 10 is input with wheel speed signals from the wheel speed sensors 11a to 11d provided for each wheel and signals from other various sensors. . The ECU 10 performs various calculations based on the input signals, and outputs command values obtained by the calculations as drive signals to the motor 5 and the ABS actuator 71.

  Next, the operation of the brake device configured as described above will be described with reference to the time chart of FIG.

  First, when the occupant depresses the brake pedal 1, the ECU 10 reads out the target braking force to be generated by the wheel from a preset map in accordance with the pedal pedal force that is an output signal of the pedal force sensor 3, and this target braking force. Thus, a motor drive signal is given to the motor 5. Driving the motor 5 causes the piston rod 40d to generate a stroke proportional to the pedal effort. With this stroke, the pressure in the primary chamber 40a and the secondary chamber 40b, that is, the M / C pressure increases, and the pressure reducing valves 74a to 74d are in a non-conducting state, that is, in a shut-off state. The W / C pressure increases via 73a-d, braking force is generated on each wheel, and the vehicle speed decreases.

  The ECU 10 calculates the slip ratio of the vehicle (= slip speed / body speed = (body speed−wheel speed) / body speed) based on the wheel speed signals from the wheel speed sensors 11a to 11d. ABS control is started when the preset target slip ratio is exceeded.

  The ABS control is repeated with (A) pressure reduction mode, (B) pressure increase control mode, and (C) pulse pressure increase / hold mode as one cycle. FIG. 2 shows a period in which ABS control is performed and periods of modes A, B, and C, respectively.

  (A) In the pressure reducing mode, the pressure increasing valve 73a is shut off (closed) and the pressure reducing valve 74a is in communication, assuming that the wheel is locked when the calculated slip ratio exceeds the target slip ratio by 15%, for example. When the wheel speed starts to increase due to decompression, the decompression valve 74a is shut off (closed) and the decompression mode is terminated. It should be noted that the first decompression mode after the start of the brake operation is further added with a condition that it is executed when the slip speed exceeds a predetermined value. This prevents unnecessary ABS control from entering an instantaneous change in the running state.

  (B) The pressure increase control mode starts simultaneously with the end of the pressure reduction mode. That is, at the end of the pressure reduction mode, if the pressure reducing valve 74a is turned off and shut off, the pressure increasing valve 73a simultaneously changes from the shut-off state to the communication state, and the W / C pressure increases by repeating short-time communication and shut-off. Increase the wheel speed from the locked state. In FIG. 2, the repetition of communication / blocking of the pressure increasing valve is shown in a simplified manner.

  At this time, the ECU 10 calculates acceleration (speed increase rate) as a differential value of the output signal of the wheel speed sensor 11a. This acceleration changes from small to large to small as the wheel speed increases during the pressure increase control mode. When the wheel acceleration is reduced by the ECU 10 or when the increase rate becomes 0, the pressure increase control mode is terminated and the next pulse pressure increase / hold mode is entered.

  (C) In the pulse pressure increasing / holding mode, the pressure increasing valve 73a is pulsed while the pressure reducing valve 74a is kept in the non-conductive state, and the W / C pressure of the W / C 8a is increased when the pressure is turned on. It is repeatedly held at the time of non-conduction. Meanwhile, the W / C pressure increases in steps and approaches the M / C pressure. When the braking force increases as the W / C pressure increases, the wheel speed decreases, and when the slip rate further increases and exceeds the target slip rate by 15%, the pressure increasing valve 73a is shut off and the pressure reducing valve 74a As described above, the decompression mode as described above is started again.

  Thereafter, the ABS control is continued by repeating a series of operation modes of pressure reduction (A), pressure increase control (B), and pulse pressure increase / hold (C).

  By the way, during this time, the M / C stroke does not change because the pressure increasing valve 73a is shut off in the pressure reducing mode, and when the pressure increasing valve 73a is in the communication state during the pressure increasing control mode and the pulse pressure increasing, The stroke increases accordingly. That is, during ABS control, the M / C stroke may increase but not decrease. Therefore, as indicated by SL in FIG. 2, if the maximum stroke of M / C 40 is short, even if the brake pedal 1 is kept depressed, if the stroke cost becomes 0, the bottoming state is reached at that point, and the W / C pressure The pressure cannot be reduced or increased, that is, the ABS control is disabled.

  However, in the first embodiment, the M / C stroke limit can be increased by using a longer stroke (indicated by LL in FIG. 2) than the one that normally uses the stroke of M / C 40, and ABS. Even when the control continues for a long time, bottoming does not occur in the M / C stroke, and it is possible to prevent the control from becoming impossible. The M / C 40 is not directly stroked by depressing the brake pedal 1, but is stroked by the motor 5 controlled based on the signal of the pedal force sensor 3, so that the brake pedal is secured in order to secure the M / C stroke. There is no need to lengthen the stroke of 1 itself.

  Further, if the reservoir capacity is small, as indicated by RL in FIG. 2, it becomes impossible to store the reduced pressure brake fluid earlier, and the W / C pressure cannot be further reduced, that is, the ABS control is disabled. On the other hand, in the first embodiment, since the reservoirs 751a and 751b are increased in capacity according to the volumes of the respective chambers 40b and 40c of the M / C 40, they are repeated while the ABS control is continued. The brake fluid sucked out by reducing the W / C pressure that is performed can be sufficiently stored, and the ABS control can be continued for a long time without being disabled.

(Reference embodiment 2)
Next, a reference embodiment 2 as a reference of the present invention will be described with reference to the drawings. Reference Embodiment 2 is an electric brake device in which the present invention is applied to a pumpless ABS device. In particular, the brake fluid when reducing the W / C pressure is directly returned to the master reservoir connected to the M / C. It is characterized in that a circuit is used. FIG. 3 shows the overall configuration. In addition, the same code | symbol is attached | subjected to the same structure as the said reference Embodiment 1, and description is abbreviate | omitted. Further, even in the case of components having the same reference numerals, if the operation is slightly different, this will be described.

  As shown in FIG. 3, the electric brake device according to the second embodiment includes a brake pedal 1, a stroke simulator 2, a pedaling force sensor 3, a motor 5, and a gear mechanism 6, as in the first embodiment.

  M / C4 has a normal stroke length. Therefore, the stroke length may be shorter than M / C40 of the first embodiment. The master reservoir 4e connected to the primary chamber 4b and the secondary chamber 4c and placed at atmospheric pressure constitutes an open circuit in which the brake fluid discharged from the W / Cs 8a to 8d as it is depressurized is directly returned, as will be described later. So that it is piped.

  The ABS actuator 72 has the same configuration as that of the reference embodiment 1 and is similarly connected by piping, and the pressure reducing valves 74a to 73d having the same configuration as the reference embodiment 1 and having the downstream side connected to the master reservoir 4e. 74d.

  The W / Cs 8a to 8d and the wheel speed sensors 11a to 11d have the same configuration as that of the first embodiment.

  The ECU 10 is slightly different from the reference embodiment 1 in the ABS actuator 72, but the control logic is the same as that in the reference embodiment 1. That is, when ABS control is started, (A) pressure reduction mode, (B) pressure increase control mode, and (C) pulse pressure increase / hold mode are repeated on the basis of the change rate (acceleration) of slip speed and wheel speed. . The difference from the first embodiment is that when the W / C pressure is reduced, the return destination of the brake fluid from the W / C 8a is not the reservoir provided in the ABS actuator but the master reservoir 4e. That is, the brake fluid can be returned from the W / C 8a at a pressure higher than the atmospheric pressure to the master reservoir 4e at the atmospheric pressure by setting the pressure reducing valve 74a in the communicating state while the pressure increasing valve 73a is in the shut-off state. The pumpless ABS control device is realized by the open circuit.

  FIG. 4 is a time chart showing the operation of the second embodiment, and shows that the operation state is the same based on the same control logic as the time chart (FIG. 2) of the first embodiment. However, FIG. 4 shows that the W / C pressure can be increased to the stroke limit of M / C4, and the W / C pressure does not change after reaching the stroke limit.

  As described above, also in the reference embodiment 2, M / C 4 is not directly stroked when the brake pedal 1 is depressed, but is stroked by the motor 5 that is controlled based on the signal of the pedal force sensor 3. Therefore, it is not necessary to lengthen the stroke of the brake pedal 1 itself.

  In addition, in the second embodiment, since an open circuit is used, there is no limit to the amount of liquid accumulated when the W / C pressure is reduced. Therefore, even if the ABS control continues for a long time, the W / C pressure cannot be reduced. The wheel lock can be prevented.

(Reference Embodiment 3)
Next, a reference embodiment 3 as a reference of the present invention will be described with reference to the drawings. The third embodiment is an electric brake device in which the present invention is applied to a pumpless ABS device. In particular, the first embodiment is different from the first embodiment in that the M / C stroke is returned for a short time in the (C) pulse pressure increasing / holding mode. Therefore, the oil amount compensation control for returning the brake fluid to M / C is different. FIG. 5 shows the overall configuration. In addition, the same code | symbol is attached | subjected to the same structure as the said reference embodiment 1 and the reference embodiment 2, and description is abbreviate | omitted. Further, even in the case of components having the same reference numerals, if the operation is slightly different, this will be described.

  As shown in FIG. 5, the electric brake device according to the third embodiment includes a brake pedal 1, a stroke simulator 2, a pedaling force sensor 3, a motor 5, and a gear mechanism 6 as in the first embodiment.

  M / C4 is provided with a normal stroke length as in the second embodiment, and therefore, the stroke length may be shorter than M / C40 in the first embodiment. The piping system of the primary chamber 4b and the secondary chamber 4c is the same as that of the first embodiment.

  The ABS actuator 71 has the same configuration as that of the first embodiment, but the reservoirs 75a and 75b may have a normal capacity in accordance with the volume of the M / C4.

  The W / Cs 8a to 8d and the wheel speed sensors 11a to 11d have the same configurations as those in the first and second embodiments.

  The control logic performed by the ECU 10 in the present embodiment 3 is the basic ABS control logic in the above embodiment 1 and 2 (A) pressure reduction mode, (B) pressure increase control mode, (C) pulse pressure increase. The point in which the holding mode is repeated is the same, except that the oil amount compensation control for returning the M / C stroke for a short time during the pulse pressure increasing / holding mode is performed. Hereinafter, a description will be given with reference to the flowchart of FIG.

  When the ignition of the vehicle is turned on, the ECU 10 starts processing of this flowchart, and the following routine is repeated at a predetermined calculation cycle (for example, 10 to 20 ms).

  In step S100, it is determined whether ABS control is currently being performed. This is to determine that the ABS control is being performed when the slip ratio calculated by the ECU 10 exceeds the preset target slip ratio, as in the first and second embodiments. If NO, the process moves to step S190, and if YES, the process moves to step S110.

  In step S110, it is determined whether all four wheels are in the pulse pressure increasing / holding mode. This determination is performed by determining whether or not the slip ratio has not reached the target slip ratio after the pressure increase control mode ends. If NO, the process proceeds to step S190, and if YES, the process proceeds to step S120.

  In step S120, it is determined whether or not the pressure increase control mode is set. This determination is made based on whether the increase rate of each wheel speed, that is, whether the wheel acceleration is equal to or greater than a predetermined value. In the case of YES, it is a pressure increase control mode and the oil amount compensation control is not performed, so the process proceeds to step S190, and in the case of NO, the process proceeds to step S130. By this step, it is possible to prevent the W / C pressure from becoming unable to be increased due to the decrease in the M / C pressure due to the return of the M / C stroke during the pressure increase control.

  In step S130, it is determined whether or not the elapsed elapsed time k from the previous execution of the oil amount compensation control has exceeded a predetermined value T1. This predetermined time T1 is set so that the following oil amount compensation control can be started after at least the pulse pressure increasing / holding mode and the pressure reducing mode are executed after the previous oil amount compensating control is finished during the ABS control. In consideration of the amount of brake fluid stored in the W / C 8a and the reservoir 75a due to the reduction of the C pressure, it is set in advance. By this time setting, in the pulse pressure increasing / holding mode for recovering the braking force, In addition, the oil amount compensation control can be performed before the storage amount of the reservoir or the like is exhausted. As a result of the determination in step S130, if NO, ie, k ≦ T1, the process proceeds to step S190, and if YES, ie, k> T1, the process proceeds to step S140.

  In step S140, the execution time t of the oil amount compensation control is incremented as the oil amount compensation control. Next, in step S150, it is determined whether or not the elapsed time t as the compensation control execution time exceeds a predetermined value T2, and if NO, that is, if t ≧ T2, it is determined that the oil amount compensation control has ended, and the process proceeds to step S190. , YES, that is, if t <T2, the process proceeds to step S160 and the oil amount compensation control is continued.

  In step S160, the four-wheel pressure increasing valves 73a to 73d are fixed in the shut-off state, that is, in the holding state, and in step S170, the current instruction value of the motor 5 is set to -I2. For example, if the instruction value I2 is about 10 [A], the motor 5 is reversely rotated with a current of -10 [A] to return the M / C stroke, so that the reservoirs 75a and 75b are in the decompression mode. The stored brake fluid can be returned to the primary chamber 4b and the secondary chamber 4c via the check valves 76a and 76b.

  In step S180, the oil amount compensation control end elapsed time k is reset to 0, and the processes in and after step S100 are repeated.

  On the other hand, in step S190 executed while the W / C pressure is increased, the oil amount compensation control end elapsed time k is incremented, and in step S200, the four-wheel pressure increase valves 73a to 73d are held and fixed. Is released, that is, the communication can be cut off. In step S210, the current command value of the motor 5 is set to the pedal force command current value I1 determined according to the detected pedal force value. In step S220, the execution time t of the oil amount compensation control is reset to 0. Repeat the process.

  The operation progress of the third embodiment executed by the above processing will be described based on the time chart of FIG. In FIG. 7, the modes during ABS control are represented as A, B, and C, and the oil amount compensation control period is represented as D.

  Before the brake pedal 1 is depressed, the pressure-increasing valves 73a to 73d are in communication and the pressure-reducing valves 74a to 74d are in a shut-off state, and the oil amount compensation control end elapsed time k is sequentially incremented by the processing after step S190. As long as the oil amount compensation control does not start, the value continues to increase even if T1 is exceeded. When the brake pedal 1 is depressed, the motor 5 is driven by the pedaling force command current value corresponding to the pedaling force detection value, the M / C4 strokes, and the M / C pressure increases.

  As the M / C pressure increases, the W / C pressure of each wheel also increases, braking force is generated on the wheels, and ABS control is started by decreasing the wheel speed and increasing the slip ratio. Along with the start of the ABS control, the transition is made to the above-described (A) pressure reduction mode, (B) pressure increase control mode, and (C) pulse pressure increase / hold mode. If the end elapsed time k exceeds the predetermined value T1 during the pulse pressure increasing / holding mode, the oil amount compensation control is started. In the example of FIG. 7, since the time counter k greatly exceeds T1 at the time when the pressure increase control mode is completed after the ABS control is started, the first oil amount compensation control is slightly on the diagram according to the control timing. However, the oil amount compensation control is started immediately, and the second and subsequent times indicate that the oil amount compensation control is started when the time counter k reaches T1.

  When the oil amount compensation control is started, a reverse rotation command value I2 (= −10 A), which is a current value for reverse rotation, is given to the motor 5 during the period of compensation execution time t = T2. As a result, the M / C stroke returns, that is, the M / C stroke amount decreases, and the M / C pressure decreases for a short time with a slight time delay.

  Due to the return of the M / C stroke, the brake fluid stored in the decompression mode is returned from the reservoirs 75a and 75b to the primary chamber 4b and the secondary chamber 4c of the M / C 4 through the check valves 76a and 76b, respectively. The amount of oil in each room can be replenished.

  When the time counter t exceeds T2, the oil amount compensation control is terminated, the motor current value is switched to the pedal effort command current value corresponding to the pedal effort, and the brake pedal 1 remains depressed, that is, the pedal effort is the maximum value. The motor 5 is driven by returning to the current value I1 before the start of the oil amount compensation control. As a result, the piston rod 4d is pushed in the direction in which the amount of M / C stroke increases to generate M / C pressure.

  Along with the end of the oil amount compensation control, the counter value of the compensation end time k is incremented to 1 (S190), and the counter value of the compensation execution time t is reset to 0 (S220). Thereafter, the routine after step S190 is repeated, and the next oil amount compensation control is performed when the time counter value k exceeds T1.

  As described above, in the third embodiment, during the ABS control, braking (W / C pressure increase) → slip rate increase → pressure reduction mode (A) → pressure increase control mode (B) → pulse pressure increase / hold mode ( C) → Oil amount compensation control (D) → Pulse pressure increase / hold mode (C) → Slip rate increase → Depressurization mode (A) →... By returning the C stroke for a short time, it is possible to prevent the storage amount of the reservoirs 75a and 75b from reaching the capacity limit due to the decrease in the W / C pressure, thereby preventing the ABS control from being disabled.

  During this time, the brake pedal 1 and the stroke of the M / C 4 are separated from each other by the electric brake system, so that even if the occupant keeps pressing the brake pedal 1 to continue generating braking force on the wheels, the M / C The ABS control can be continued by appropriately returning the C stroke and returning the brake fluid from the reservoirs 75a and 75b to the M / C4.

(Reference Embodiment 4)
Next, a reference embodiment 4 as a reference of the present invention will be described with reference to the drawings. The fourth embodiment is an electric brake device in which the present invention is applied to a pumpless ABS device. In particular, the second embodiment is different from the second embodiment in that the M / C stroke is returned for a short time in the pulse pressure increasing / holding mode. The difference is that oil amount compensation control for replenishment by returning the liquid to M / C is performed. Further, the control logic of the oil amount compensation control is the same as that of the reference embodiment 3.

  Therefore, only the control logic is different from the reference embodiment 2, and the entire configuration is the same as that of FIG. 3 described above. Therefore, the same reference numerals are given to the same configuration as the reference embodiment 2, and the description is omitted.

  As shown in FIG. 3, the fourth embodiment is similar to the second embodiment described above. The brake pedal 1, the stroke simulator 2, the pedal force sensor 3, the M / C 4, the motor 5, the gear mechanism 6, the ABS actuator 72, W / C 8a-8d, ECU10 and wheel speed sensors 11a-11d are provided. However, the point that the ECU 10 performs the same oil amount compensation control as in the reference embodiment 3 is different from the reference embodiment 2. The ABS control operation is the same as that in the first to third embodiments described above, and a description thereof will be omitted.

  Next, the operation of the fourth embodiment will be described with reference to the flowchart of FIG. 6 and the time chart of FIG. 7 with a focus on differences from the third embodiment.

  Since the control logic of the ABS control in the fourth embodiment is the same as that in the above embodiment, the description is omitted. Similar to the second embodiment, the W / C pressure is reduced by bringing the pressure reducing valve 74a into communication and returning the brake fluid to the master reservoir 4e.

  The oil amount compensation control (D) is processed according to the flowchart shown in FIG. 6 as in the third embodiment, and the four pressure increasing valves 43a to 43d are held during the pulse pressure increasing / holding mode (C). (Closed) is performed by rotating the motor 5 reversely for a predetermined time T2 to reduce the M / C stroke amount. However, the difference from the third embodiment is that when the M / C stroke amount is reduced by the oil amount compensation control, the replenishment of the brake fluid to the primary chamber 4b and the secondary chamber 4c of the M / C 4 4e.

  The oil amount compensation control (D) ends, and the motor 5 pushes the piston rod 4d in a direction in which the M / C stroke amount increases according to the pedaling force command current value, thereby generating M / C pressure.

  As described above, in the fourth embodiment, during the ABS control, braking (W / C pressure increase) → slip rate increase → pressure reduction mode (A) → pressure increase control mode (B) → pulse pressure increase / hold mode ( C) → Oil amount compensation control (D) → Pulse pressure increase / hold mode (C) → Slip rate increase → Depressurization mode (A) →... By returning the C stroke for a short time, the occurrence of bottoming of M / C4 can be prevented, and it can be avoided that ABS control becomes impossible.

  In addition, the fourth embodiment is a so-called open circuit in which brake fluid due to W / C pressure reduction is returned to the master reservoir 4e, which is at atmospheric pressure, so there is no restriction on pressure reduction, and the ABS control is long. Even if performed over time, it is possible to prevent the ABS control from being disabled due to the inability to reduce the W / C pressure.

  During this time, the brake pedal 1 and the stroke of the M / C 4 are separated from each other by the electric brake system, so that even if the occupant keeps pressing the brake pedal 1 to continue generating braking force on the wheels, the M / C The ABS stroke can be continued by appropriately returning the C stroke.

(Reference embodiment 5)
Next, a reference embodiment 5 serving as a reference of the present invention will be described with reference to the drawings. The reference embodiment 5 is an electric brake device in which the present invention is applied to a pumpless ABS device. In particular, the reference embodiment 3 is different from the reference embodiment 3 in the execution period T2 of the M / C stroke return in the oil amount compensation control and the motor current instruction value I2. Is different in that it is variably controlled in accordance with the magnitude of the M / C stroke. Therefore, the overall configuration is the same as that of FIG.

  In the fifth embodiment, when the M / C stroke L during braking becomes a predetermined value or more, the return amount of the M / C stroke (corresponding to the motor current I2) and the return time (T2) according to the magnitude. The oil amount compensation control is performed.

  First, the principle of estimating the M / C stroke amount L during braking by calculation will be described.

  That is, the output hydraulic pressure of M / C is estimated from the motor thrust obtained based on the current value I1 of the motor 5, and the acceleration of the M / C piston 4a calculated from the difference between this estimated hydraulic pressure and the actual M / C pressure P. M / C stroke is calculated from the above.

  This is represented by the equation of motion of Equation 1 for the M / C piston 4a.

(Equation 1)
[(I1 × K−M) − (J + j) × α / R] × η / R− (P × A + f)
= Mp × α
However,

(Equation 2)
I1: Motor current value (variable)
K: Motor torque constant J: Motor inertia moment (constant)
M: Motor friction torque (constant)
R: Reduction ratio = piston stroke / motor rotation angle (constant)
η: Reducer efficiency (constant)
j: Reducer inertia moment (constant)
P: M / C output hydraulic pressure (variable)
A: M / C cylinder cross section (constant)
mp: M / C piston mass (constant)
f: M / C piston friction resistance + M / C return spring return force (constant)
α: M / C piston acceleration. Therefore, the left side of Formula 1 is the difference between the output thrust of the motor and the actual output hydraulic pressure of M / C.

  The motor current I1 and the M / C output hydraulic pressure P are detected, and the acceleration α is calculated from Equation 1. Under the initial condition of this acceleration α at time τ = 0 and stroke L = 0, the stroke L of the M / C piston during operation of the brake is calculated by performing time-related integration twice as shown in Equation 3 below. can do.

(Equation 3)
L = ∫∫αdτ (however, the pedal start is set to τ = 0, L = 0)
Note that the actual M / C output hydraulic pressure P is generated by driving the motor 5 with the pedaling force command current value determined according to the pedaling force detection value of the pedaling force sensor 3, and can be calculated from the pedaling force detection value. . Moreover, you may use as the M / C pressure P by directly detecting the output pressure of the primary chamber 4b of the M / C4 and the secondary chamber 4c with the pressure sensor which is not illustrated.

  Next, a control flow executed by the ECU 10 will be described with reference to FIG.

  This control flow starts when the ignition is turned on and is repeatedly executed at a predetermined calculation cycle (10 to 20 ms). First, it is determined in step S300 whether braking is in progress. This is determined by a signal from the pedal force sensor 3. If NO, L = 0 is set in step S460, and the process returns to step S300. If YES, the process moves to step S310.

  In step S310, it is determined whether ABS control is currently being performed. This is to determine that the ABS control is being performed when the slip ratio calculated by the ECU 10 exceeds the preset target slip ratio, as in the first to fourth embodiments. If NO, the process moves to step S400, and if YES, the process moves to step S320.

  In step S320, it is determined whether all four wheels are in the pulse pressure increasing / holding mode. This determination is performed by determining whether or not the slip ratio has not reached the target slip ratio after the pressure increase control mode ends. If NO, the process proceeds to step S400, and if YES, the process proceeds to step S330.

  In step S330, it is determined whether or not the pressure increase control mode is set. This determination is made based on whether the increase rate of each wheel speed, that is, whether the wheel acceleration is equal to or greater than a predetermined value. In the case of YES, the pressure increase control mode is in effect and the oil amount compensation control is not performed, so the process proceeds to step S400, and in the case of NO, the process proceeds to step S340. By this step, it is possible to prevent the W / C pressure from becoming unable to be increased due to the occurrence of a decrease in the M / C pressure due to the return of the M / C stroke during the pressure increase control mode.

  In step S340, it is determined whether the execution time t of the oil amount compensation control is 0, that is, it is reset. If NO, the process proceeds to step S360, and if YES, the process proceeds to step S350.

  In step S350, it is determined whether the M / C stroke L calculated by Equation 3 exceeds a threshold KL. This threshold value KL can be set in advance as an amount corresponding to 60% of the M / C stroke limit (maximum stroke amount), for example. As a result of the determination, if NO, the oil amount compensation control is unnecessary, so the process proceeds to step S400. If YES, the process proceeds to step S360 in order to perform the oil amount compensation control.

  In step S400, with respect to the M / C stroke L, the oil amount compensation control execution time T2 and the motor current I2 for returning the stroke during the oil amount compensation control are read out and temporarily stored. Keep it. Thereby, these memory values are updated for each calculation cycle.

  In the next step S410, since the oil amount compensation control is not performed, the holding of the four-wheel pressure increasing valves 73a to 73d, that is, the cutoff state is released, and the current instruction value of the motor 5 is obtained from the pedal force sensor 3 in step S420. The pedaling instruction current value I1 calculated by the ECU 10 based on the pedaling force detection value is set. As a result, the motor 5 is driven and the M / C piston 4a strokes to generate an M / C pressure corresponding to the pedal effort. In step S430, the compensation control execution time t is reset.

  On the other hand, in step S360, since the oil amount compensation control is performed, the compensation control execution time t is incremented. In step S370, it is determined whether or not the compensation control execution time t is smaller than the predetermined time T2. The predetermined time T2 uses the value calculated and stored immediately before in step S400. As a result of the determination, if NO, that is, t ≧ T2, the process proceeds to step S410, and normal ABS control is executed. If YES, that is, if t <T2, the oil amount compensation control is continued, and the process proceeds to step S380.

  In step S380, the four-wheel pressure boosting valves 73a to 73d are fixed in the shut-off state, that is, in the holding state, and in step S390, the current instruction value of the motor 5 is set to -I2. As the instruction value I2, the value calculated and stored immediately before at step S400 is used. As a result, the motor 5 is reversely rotated with a current of -I2 [A] to return the M / C stroke, so that the brake fluid stored in the reservoirs 75a and 75b is supplied to the primary chamber via the check valves 76a and 76b. 4b and the secondary chamber 4c can be returned.

  Next, in step S440, variables (motor current, M / C output hydraulic pressure) and constants (motor / reduction gear constant, mechanical loss, M / C characteristic data) necessary for the calculation of equation 1 are read. 3, the M / C stroke L is calculated, and the routines after step S300 are repeated.

  Through the above processing, the current stroke length L of M / C4 is estimated from the difference between the thrust of the motor 5 and the actual output hydraulic pressure of M / C for each calculation cycle, and the oil amount compensation is performed for this stroke length. Oil return compensation control can be performed by calculating a return current of the motor for control and its period.

  In the reference embodiment 5, the current stroke amount L of the master piston 4a of the M / C 4 is estimated and calculated from the motor current and the M / C pressure. However, from FIG. A stroke sensor 9 that detects the M / C stroke by measuring the displacement up to the gear mechanism 6 is provided, and the detection value by the stroke sensor 9 is input to the ECU 10, and the stroke amount L is directly used instead of Equation 3. It may be used.

  Accordingly, the control flow in this case can omit steps S440 and S450 in FIG. Further, the accuracy of the M / C stroke amount L, that is, the accuracy of the oil amount compensation control can be increased.

(Reference Embodiment 6)
Next, a reference embodiment 6 serving as a reference of the present invention will be described with reference to the drawings. Reference Embodiment 6 is an electric brake device in which the present invention is applied to a pumpless ABS device that returns the reduced brake fluid from the pressure reducing valve directly to the master reservoir placed at atmospheric pressure, as in Reference Embodiment 4 above. In particular, the reference embodiment 4 is the amount of oil consumed by the ABS estimated from the stroke return execution time T2 and the motor current instruction value I2 in the oil amount compensation control based on the communication state information of the pressure reducing valves 74a to 74d. , The point which carries out variable control according to the oil quantity which flowed out from W / C8a-d differs. Therefore, the overall configuration is the same as that of FIG. 3 of the reference embodiment 4 (and reference embodiment 2), and the description thereof is omitted.

  In the sixth embodiment, the amount of oil consumed from the W / C (hereinafter referred to as the amount of oil consumed or the amount released) is calculated from the average oil pressure of the four wheels estimated from the deceleration of the vehicle body and the communication time of the pressure reducing valve during braking. When the oil amount exceeds a predetermined value, the M / C stroke return amount (motor return current) and return time are determined according to the oil amount to compensate for the oil amount. Control is performed.

  First, a method for estimating the amount of oil consumed during ABS control will be described.

  The equation of motion shown in Equation 4 is established for each wheel during the ABS control decompression.

(Equation 4)
G × W × S−K × PW = m × g
However,

(Equation 5)
G: Body deceleration (variable)
W: Body weight (constant or variable)
g: Wheel acceleration of each wheel (variable)
S: Braking force distribution for each wheel (for example, equal to 1/4 for all four wheels) (constant)
K: Each wheel braking force coefficient (braking force / hydraulic pressure) (constant)
PW: W / C pressure of each wheel m: Inertial mass of wheel system R: Flow velocity coefficient (flow velocity / differential pressure) (constant) of pressure reducing valve
T: Opening (communication) time (variable) of the pressure reducing valve. The vehicle body deceleration G and the wheel acceleration g of each wheel are detected, and the W / C pressure PW of each wheel is calculated from the above equation of motion.

  Next, the communication time T of the pressure reducing valve is integrated, and the discharge flow rate Q due to the opening of the pressure reducing valve is calculated by Equation 6.

(Equation 6)
Q = RΣ (T × PW)
From the idea of compensating the released oil amount Q by oil amount compensation control for returning the M / C stroke, the return stroke amount ΔL is calculated by Equation 7 where A is the cylinder cross-sectional area of M / C.

(Equation 7)
ΔL = Q / A
Next, a control flow executed by the ECU 10 will be described with reference to FIG.

  This control flow starts when the ignition is turned on and is repeatedly executed at a predetermined calculation cycle. First, in step S500, it is determined whether braking is in progress. This is determined by a signal from the pedal force sensor 3. In the case of NO, Q = 0 is set in step S710, and the process returns to step S500. If YES, the process moves to step S510.

  In step S510, it is determined whether ABS control is currently being performed. This is to determine that the ABS control is being performed when the slip ratio calculated by the ECU 10 exceeds the preset target slip ratio, as in the first to fifth embodiments. If NO, the process moves to step S680, and if YES, the process moves to step S520.

  In step S520, the wheel speed reading and the vehicle body deceleration necessary for the calculations of the above formulas 4 and 6 and the average value PW of the W / C pressure of the four wheels according to the formula 4 are calculated. Next, in step S530, it is determined whether or not the pressure is being reduced from the energized states of the pressure reducing valves 74a to 74d. In the case of YES, the communication time (pressure reduction time) T of the pressure reducing valves 74a to 74d is incremented in Step S540, and in the case of NO, the process proceeds to Step S550.

  In step S550, the amount of consumed oil q consumed so far is read from a preset map based on the pressure reduction time T thus far and the average value PW of the W / C pressures of the four wheels. This map is stored in advance in the form of a map instead of calculating Formula 6.

  In step S560, the pressure reduction time T is reset to 0. In step S570, the accumulated oil amount Q is added by the consumed oil amount q (Q = Q + q), and then the consumed oil amount q is reset in step S580. .

  Next, in step S590, it is determined whether all four wheels are in the pulse pressure increasing / holding mode. This determination is performed by determining whether or not the slip ratio has not reached the target slip ratio after the pressure increase control mode ends. If NO, the process moves to step S680, and if YES, the process moves to step S600.

  In step S600, it is determined whether or not the pressure increase control mode is set. This determination is made based on whether the increase rate of each wheel speed, that is, whether the wheel acceleration is equal to or greater than a predetermined value. In the case of YES, since it is the pressure increase control mode, the process proceeds to step S680, and in the case of NO, the process proceeds to step S610. By this step S600, it is possible to prevent the W / C pressure from being increased due to the decrease in the M / C pressure due to the return of the M / C stroke during the pressure increase control mode.

  In step S610, it is determined whether the integrated oil consumption Q calculated in step S570 exceeds a preset threshold value KQ. As a result of the determination, if NO, the oil amount compensation control is unnecessary, so the process proceeds to step S680. If YES, the process proceeds to step S620 in order to perform the oil amount compensation control.

  In step S620, the execution time T2 of the oil amount compensation control and the motor current I2 for returning the stroke in the oil amount compensation control are read out from the map set in advance for the accumulated oil consumption Q and temporarily stored. Keep it. In step S630, the execution time t of the oil amount compensation control is incremented. In step S640, it is determined whether or not the execution time t is smaller than T2 obtained from the map in step S620. As a result of the determination, if NO, that is, t ≧ T2, the process proceeds to step S650, and if YES, that is, t <T2, the oil amount compensation control is continued, and the process proceeds to step S660.

  In step S660, the four-wheel pressure increase valves 73a to 73d are fixed in the shut-off state, that is, in the holding state, and in step S670, the current instruction value of the motor 5 is set to -I2 during the execution time T2. As the instruction value I2, the value calculated and stored immediately before in step S620 is used. As a result, the motor 5 is reversely rotated at a current of −I2 [A] for a period of T2 to return the M / C stroke, whereby the brake fluid is supplied from the master reservoir 4e to the primary chamber 4b and the secondary chamber 4c. Can be replenished for Q minutes.

  On the other hand, when the compensation control execution time t exceeds T2, the accumulated oil consumption Q is reset in step S650, and the process proceeds to step S680.

  Steps S680 to S700 are the ABS control flow when the oil amount compensation control is not executed. Like steps S200 to S220 (FIG. 6) in the above-described embodiments, the four-wheel pressure increase valves 73a to 73d are held in step S680. The fixed state is released, that is, the communication can be disconnected, and the current instruction value of the motor 5 is set to the pedaling force instruction current value I1 determined according to the pedaling force detection value in step S690, and the oil amount compensation control is performed in step S700. The execution time t is reset to 0, and the processing after step S500 is repeated.

  With the above processing, the vehicle body deceleration G and the wheel acceleration g are calculated from the output values of the wheel speed sensors 11a to 11d for each calculation cycle, and the average W / C of each wheel is calculated from Equation 4 based on these calculated values. The pressure PW is estimated, and the oil amount Q of the brake fluid discharged and consumed from the W / C of each wheel at the time of pressure reduction is calculated based on the pressure reduction time. When the oil consumption Q exceeds a predetermined value KQ, the motor 5 is reversely rotated by the motor return current value I2 and the return time T2 determined according to the oil consumption to return the M / C stroke. Thus, the amount of oil consumed in the M / C primary chamber and the secondary chamber can be compensated by the master reservoir.

(First embodiment)
Next, a first embodiment of the present invention will be described with reference to the drawings. The first embodiment is an electric brake device to which the present invention is applied. In particular, the reference embodiment 4 detects an actual M / C stroke, and air is mixed in the M / C according to the detected value. In the case where it is determined, the oil amount compensation control similar to that of the above-described reference embodiment 4, that is, the M / C stroke return is performed, and the M / C pressure is increased to obtain an appropriate W / C pressure. The point is different.

  As shown in FIG. 10, the first embodiment is different from FIG. 3 showing the above-described reference embodiments 2 and 4 in that a stroke sensor 9 that detects the stroke of M / C4 is provided. Other than that, the same reference numerals are assigned to the same components, and the description is omitted. In the first embodiment, since the oil amount compensation control is performed independently of the ABS control, the description regarding the ABS control is omitted.

  The stroke sensor 9 detects the M / C stroke by measuring the displacement from the M / C 4 to the gear mechanism 6 and inputs the detected value to the ECU 10.

  Next, a flowchart for returning the M / C stroke in the oil amount compensation control of the first embodiment will be described with reference to FIG.

  When the ignition of the vehicle is turned on, the ECU 10 starts processing of this flowchart, and the following routine is repeated at a predetermined calculation cycle (for example, 10 to 20 ms).

  First, in step S800, it is determined whether braking is in progress. This is determined by a signal from the pedal force sensor 3. If NO, the process moves to step S890, and if YES, the process moves to step S810.

  In step S810, the actual current value of the motor 5 is read, and the estimated value LS of the M / C stroke is read from the relationship between the current value stored in advance as a map and the stroke.

  In step S820, the actual stroke length L of M / C4 is input from the stroke sensor 9, and in step S830, it is determined whether or not the actual stroke length L is greater than the sum of the estimated value LS and the threshold value KS. The threshold value KS is such that the difference between the actual stroke length L and the estimated value LS increases according to the amount of air mixed in the piping of the ABS actuator 72, and the M / C pressure sufficiently acts on the W / Cs 8a to d. It is determined according to the state where it stops and is set in advance. If the result of determination is NO, the difference between the actual stroke length L and the estimated value LS is small. Therefore, the routine proceeds to step S890 to perform normal braking and ABS control. If YES, the difference between the two is greater than the threshold KS. Since it has become larger, it is assumed that air has been mixed, and the process proceeds to step S840 in order to return the M / C stroke by reversely rotating the motor 5 for a short time in the same manner as in each of the reference embodiments described above.

  In step S840, since the oil amount compensation control continues, the compensation control execution time t is incremented.

  Steps S850 to S880 are similar to Steps S150 to S180 in Reference Embodiments 3 and 4 described above. In Step S850, it is determined whether the compensation control execution time t has exceeded a predetermined value T2, and NO, that is, t ≧ T2. If so, it is determined that the oil amount compensation control has ended, and the process proceeds to step S890. If YES, that is, if t <T2, the process proceeds to step S860, and the oil amount compensation control is continued.

  In step S860, the four-wheel pressure increasing valves 73a to 73d are fixed in the shut-off state, that is, in the holding state, and in step S870, the current instruction value of the motor 5 is set to -I2. For example, if the instruction value I2 is about 10 [A], the motor 5 is reversely rotated by a current of −10 [A] to return the M / C stroke, whereby the brake fluid stored in the master reservoir 4e is recovered. The M / C pressure can be reliably transmitted to each W / C by sucking into the primary chamber 4b and the secondary chamber 4c and replenishing the amount of brake fluid in the piping. This operation usually achieves the same effect as the pumping operation of the brake pedal when air is mixed with the electric brake device.

  In step S880, the oil amount compensation control end elapsed time k is reset to 0, and the processes in and after step S800 are repeated.

  On the other hand, in step S890 executed while the oil amount compensation control is not operating, the oil amount compensation control end elapsed time k is incremented, and in step S900, the four-wheel pressure increase valves 73a to 73d are held and fixed. Is released, that is, the communication can be cut off. In step S910, the current command value of the motor 5 is set to the pedal force command current value I1 determined according to the pedal force detection value. In step S920, the oil amount compensation control execution time t is reset to 0. Repeat the process.

  Thus, when the difference between the actual M / C stroke length L detected by the stroke sensor 9 and the stroke length LS estimated from the current value of the motor 5 is larger than the threshold KS, the motor return current I2 and the return period T2 By repeating the oil amount compensation control that performs the M / C stroke return by, pumping operation in the electric brake device is made possible, and even when air enters the brake pipe, the M / C pressure is reliably set to each W / C. Can be communicated to.

(Other embodiments)
In the electric brake device that performs pumpless ABS control using a closed circuit, the reference embodiment 5 is a motor return current and return period in oil amount compensation control, an estimated value obtained by calculating an M / C stroke length, or The value detected by the sensor is variably controlled according to the stroke length. However, the present invention is not limited to this, and in the same closed circuit shown in FIG. 5, the pressure is reduced from the pressure reducing valves 74a to 74d in the same manner as in the sixth embodiment. The amount of oil consumed at the time may be calculated, and the return current and return period of the motor in the oil amount compensation control may be variably controlled so as to compensate for the amount of oil consumed.

  Further, in the above-described Reference Embodiment 6, in the electric brake device that performs pumpless ABS control using an open circuit, the return current and return period of the motor at the time of oil amount compensation control are set as follows: Although the variable control is performed so as to compensate for the amount of oil consumption according to the calculated value of the amount, the present invention is not limited to this, and in the same open circuit shown in FIG. The stroke length may be obtained as an estimated value by calculation or a detection value by a sensor, and the return current and return period of the motor during oil amount compensation control may be variably controlled according to the stroke length.

  Furthermore, in the first embodiment, in the open circuit electric brake device, the oil amount compensation is performed when the difference between the actual detected value of the M / C stroke and the estimated value of the M / C stroke calculated from the motor current is large. The brake fluid is replenished to the M / C by control so that the M / C pressure can be reliably transmitted to the W / C even when air is mixed in the brake pipe. As in the first embodiment, the closed circuit shown in FIG. 5 may perform oil amount compensation control for air contamination according to the difference between the detected value of the M / C stroke and the estimated value.

It is a figure which shows the whole structure of the reference embodiment 1 of this invention. 3 is a time chart showing the operation of the reference embodiment 1; It is a figure which shows the whole structure of reference embodiment 2, 4, 6 of this invention. It is a time chart which shows operation | movement of the reference embodiment 2 of this invention. It is a figure which shows the whole structure of reference embodiment 3 and 5 of this invention. It is a flowchart which shows the process of Reference Embodiment 3 and 4 of this invention. It is a time chart which shows operation | movement of reference Embodiment 3 and 4 of this invention. It is a flowchart which shows the process of Reference Embodiment 5 of this invention. It is a flowchart which shows the process of Reference Embodiment 6 of this invention. It is a figure which shows the whole structure of 1st Embodiment of this invention. It is a flowchart which shows the process of 1st Embodiment.

Explanation of symbols

1 ... Brake pedal, 2 ... Stroke simulator, 2a ... Piston,
2b ... Cylinder, 2c ... Spring, 3 ... Treading force sensor, 4,40 ... M / C,
4a, 40a ... master piston, 4b, 40b ... primary chamber,
4c, 40c ... secondary chamber, 4d, 40d ... piston rod,
4e ... master reservoir, 5 ... motor, 6 ... gear mechanism,
71, 72... ABS actuator, 73a to 73d.
74a-74d ... pressure reducing valve, 75a, 751a, 75b, 751b ... reservoir,
76a, 76b ... check valve, 8a-8d ... W / C, 9 ... stroke sensor,
10 ... ECU, 11a-11d ... wheel speed sensor.

Claims (2)

Pedal operation amount detection means for detecting the operation amount of the brake pedal;
An actuator for moving the rod in accordance with the pedal operation amount;
A master cylinder that draws in brake fluid from a master reservoir and generates a master cylinder pressure by stroking by the movement of the rod; and
A stroke sensor for detecting a stroke of the master cylinder;
A pressure increasing valve that is connected to the master cylinder and outputs the wheel cylinder pressure by adjusting the master cylinder pressure;
A wheel cylinder connected to the pressure increasing valve and generating a braking force on a wheel by the wheel cylinder pressure;
A pressure reducing valve that is connected to the wheel cylinder, adjusts the wheel cylinder pressure, and discharges brake fluid in accordance with a decrease in the wheel cylinder pressure;
A pipe for returning the brake fluid discharged from the pressure reducing valve to the master reservoir when the wheel cylinder pressure is reduced;
Control means for outputting each drive signal of the actuator, the pressure increasing valve and the pressure reducing valve, and
The control means applies a predetermined time to the actuator when the difference between the output value of the stroke sensor and the stroke length of the master cylinder estimated from the drive current of the actuator is greater than a threshold during pressurization of the master cylinder. An electric brake device for a vehicle that performs oil amount compensation control for pressurizing the master cylinder again after returning the stroke. Pedal operation amount detection means for detecting the operation amount of the brake pedal;
An actuator for moving the rod in accordance with the pedal operation amount;
A master cylinder that draws in brake fluid from a master reservoir and generates a master cylinder pressure by stroking by the movement of the rod; and
A stroke sensor for detecting a stroke of the master cylinder;
A pressure increasing valve that is connected to the master cylinder and outputs the wheel cylinder pressure by adjusting the master cylinder pressure;
A wheel cylinder connected to the pressure increasing valve and generating a braking force on a wheel by the wheel cylinder pressure;
A pressure reducing valve that is connected to the wheel cylinder, adjusts the wheel cylinder pressure, and discharges brake fluid in accordance with a decrease in the wheel cylinder pressure;
A reservoir for storing brake fluid discharged from the pressure reducing valve when the wheel cylinder pressure is reduced;
A check valve interposed between the reservoir and the master cylinder and allowing a liquid flow from the reservoir to the master cylinder;
Control means for outputting each drive signal of the actuator, the pressure increasing valve, and the pressure reducing valve,
The control means applies a predetermined time when the difference between the output value of the stroke sensor and the stroke length of the master cylinder estimated from the drive current of the actuator is greater than a threshold during pressurization of the master cylinder. An electric brake device for a vehicle that performs oil amount compensation control for pressurizing the master cylinder again after returning the stroke.

Images