JP2007230432A - Brake controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid an event that a large current flows at braking operation in a brake controller having a plurality of solenoid valves. <P>SOLUTION: The brake controller 20 gives braking forces to wheels provided at a vehicle according to the braking operation by a driver. The brake controller 20 is provided with the plurality of solenoid valves provided in a flow passage of an operation fluid; and a brake ECU 70 for controlling currents fed to the plurality of solenoid valves. The brake ECU 70 performs control for switching it to a retaining current having a lower current value than an activation current after the activation current is fed relative to each of the plurality of solenoid valves, and after it switches the current fed to one solenoid valve from the activation current to the retaining current, it starts the feeding of the activation current relative to the subsequent solenoid valve. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a brake control device that controls braking force applied to wheels provided in a vehicle.

  2. Description of the Related Art In recent years, many electronically controlled brake systems that control the braking force of each wheel so as to give an optimal braking force to the vehicle according to the traveling state of the vehicle have been adopted as a braking device in the vehicle. Such an electronically controlled brake system includes a plurality of electromagnetic valves in the flow path of the working fluid.

The solenoid valve includes a solenoid coil, and can be switched between an open state and a closed state by controlling a current supplied to the solenoid coil. The solenoid valve requires a starting current having a large current value at the time of starting, but once driven, the driving state can be maintained by supplying a holding current having a current value smaller than the starting current. Patent Document 1 discloses a current circuit that switches a current supplied to a solenoid valve to be large when the solenoid valve is activated and to reduce a current when the solenoid valve is in a holding state.
JP-A-6-188121

  In an electronically controlled brake system having a plurality of solenoid valves, it is necessary to drive these solenoid valves when a brake operation is performed by a driver. As described above, since a solenoid valve requires a starting current having a large current value at the time of starting, when a plurality of solenoid valves are started at the same time, a power supply device that supplies current to these solenoid valves has a large current at a time. Need to be supplied. Therefore, it has been necessary to use a power supply device for driving the solenoid valve having a large current capacity.

  Also, usually, electronic components such as a solenoid relay and a filter are provided downstream of the power supply device. When the current flowing through such electronic components increases, the voltage drop due to the electronic components increases, and the voltage applied to each solenoid valve decreases. On the other hand, since the minimum operating voltage required to operate each solenoid valve is determined, it is necessary to set the voltage of the power supply device high in order to ensure the minimum operating voltage of each solenoid valve.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technology capable of avoiding a situation where a large current flows during a brake operation in a brake control device having a plurality of solenoid valves. It is in.

  In order to solve the above problems, a brake control device according to an aspect of the present invention is provided in a flow path of a working fluid in a brake control device that applies braking force to wheels provided in a vehicle in response to a brake operation by a driver. And a current control unit that controls current supplied to the plurality of solenoid valves. The current control unit controls each of the plurality of solenoid valves to switch to a holding current having a current value lower than the start current after supplying a start current for starting the solenoid valve, and supplies the solenoid valve with one current After switching the starting current from the starting current to the holding current, supply of the starting current to the next solenoid valve is started.

  According to this aspect, when the brake operation is performed by the driver, the startup current does not flow in a superimposed manner, so that a situation in which a large current flows through the device can be avoided. The current control unit may start supplying the starting current to the plurality of solenoid valves in a predetermined order.

  Another aspect of the present invention is also a brake control device. The device includes a first wheel cylinder for applying a braking force to the first wheel, a second wheel cylinder for applying a braking force to a second wheel different from the first wheel, A main flow path that communicates the one wheel cylinder and the second wheel cylinder, a first flow path that communicates the main flow path with the first wheel cylinder, and a second flow path that communicates with the second wheel cylinder; A separation valve that is a normally closed solenoid valve that is separated into a master cylinder, a master cylinder that pressurizes a working fluid in accordance with an operation amount of a brake operation member by a driver, a master passage that communicates the master cylinder and the first passage, A master cut valve, which is a normally open solenoid valve provided in the master flow path, a power hydraulic pressure source capable of generating a high hydraulic pressure by supplying power, and the power hydraulic pressure source and the second flow path communicate with each other. Power hydraulic pressure source flow path and power hydraulic pressure source flow path Provided, comprising a pressure-increasing valve for adjusting the fluid pressure in the first and second wheel cylinders, the separation valve, a current control section for controlling the current supplied to the master cut valve and the pressure increasing valve, the. The current control unit starts supplying current to the separation valve, the master cut valve, and the pressure increasing valve at different timings when the brake operation is performed.

  According to this aspect, when the brake operation is performed, the current control unit starts supplying current to the separation valve, the master cut valve, and the pressure increasing valve at different timings. The current flowing through the apparatus can be made smaller than when the supply is started.

  The current control unit may start supplying current to the master cut valve before the pressure increasing valve. If the supply of current to the booster valve is started before the master cut valve, which is a normally open solenoid valve, the working fluid may flow into the master cylinder via the master cut valve, and the driver may feel uncomfortable with the brake operation. . Such a situation can be avoided by starting the supply of current to the master cut valve before the pressure increasing valve.

  According to the present invention, in a brake control device having a plurality of solenoid valves, it is possible to avoid a situation in which a large current flows during a brake operation.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a system diagram showing a brake control device 20 according to an embodiment of the present invention. A brake control device 20 shown in the figure constitutes an electronically controlled brake system (ECB) for a vehicle, and controls braking force applied to four wheels provided on the vehicle.

  As shown in FIG. 1, the brake control device 20 includes disc brake units 21FR, 21FL, 21RR and 21RL as a braking force application mechanism provided for each wheel (not shown), a master cylinder unit 10, A hydraulic pressure source 30 and a hydraulic actuator 40 are included.

  Disc brake units 21FR, 21FL, 21RR, and 21RL apply braking force to the right front wheel, the left front wheel, the right rear wheel, and the left rear wheel of the vehicle, respectively. The master cylinder unit 10 as a manual hydraulic pressure source sends the brake fluid pressurized according to the operation amount by the driver of the brake pedal 24 as a brake operation member to the disc brake units 21FR to 21RL. The power hydraulic pressure source 30 can send brake fluid as working fluid pressurized by supplying power to the disc brake units 21FR to 21RL independently of the operation of the brake pedal 24 by the driver. . The hydraulic actuator 40 appropriately adjusts the hydraulic pressure of the brake fluid supplied from the power hydraulic pressure source 30 or the master cylinder unit 10 and sends it to the disc brake units 21FR to 21RL. Thereby, the braking force with respect to each wheel by hydraulic braking is adjusted. In the present embodiment, a wheel cylinder pressure control system is configured including the power hydraulic pressure source 30 and the hydraulic actuator 40.

  Each of the disc brake units 21FR to 21RL, the master cylinder unit 10, the power hydraulic pressure source 30, and the hydraulic actuator 40 will be described in more detail below. Each of the disc brake units 21FR to 21RL includes a brake disc 22 and wheel cylinders 23FR to 23RL incorporated in the brake caliper, respectively. The wheel cylinders 23FR to 23RL are connected to the hydraulic actuator 40 via different fluid passages. Hereinafter, the wheel cylinders 23FR to 23RL are collectively referred to as “wheel cylinders 23” as appropriate.

  In the disc brake units 21FR to 21RL, when brake fluid is supplied to the wheel cylinder 23 from the hydraulic actuator 40, a brake pad as a friction member is pressed against the brake disc 22 that rotates together with the wheel. Thereby, a braking force is applied to each wheel. In this embodiment, the disc brake units 21FR to 21RL are used, but other braking force applying mechanisms including a wheel cylinder 23 such as a drum brake may be used.

  The master cylinder unit 10 is a master cylinder with a hydraulic booster in this embodiment, and includes a hydraulic booster 31, a master cylinder 32, a regulator 33, and a reservoir 34. The hydraulic booster 31 is connected to the brake pedal 24, amplifies the pedal effort applied to the brake pedal 24, and transmits it to the master cylinder 32. When the brake fluid is supplied from the power hydraulic pressure source 30 to the hydraulic pressure booster 31 via the regulator 33, the pedal effort is amplified. The master cylinder 32 generates a master cylinder pressure having a predetermined boost ratio with respect to the pedal effort.

  A reservoir 34 for storing brake fluid is disposed above the master cylinder 32 and the regulator 33. The master cylinder 32 communicates with the reservoir 34 when the depression of the brake pedal 24 is released. On the other hand, the regulator 33 is in communication with both the reservoir 34 and the accumulator 35 of the power hydraulic pressure source 30, and the reservoir 34 is used as a low pressure source, the accumulator 35 is used as a high pressure source, and the hydraulic pressure is approximately equal to the master cylinder pressure. Is generated. Hereinafter, the hydraulic pressure in the regulator 33 is appropriately referred to as “regulator pressure”.

  The power hydraulic pressure source 30 includes an accumulator 35 and a pump 36. The accumulator 35 converts the pressure energy of the brake fluid boosted by the pump 36 into the pressure energy of an enclosed gas such as nitrogen, for example, about 14 to 22 MPa and stores it. The pump 36 has a motor 36 a as a drive source, and its suction port is connected to the reservoir 34, while its discharge port is connected to the accumulator 35. The accumulator 35 is also connected to a relief valve 35 a provided in the master cylinder unit 10. When the pressure of the brake fluid in the accumulator 35 increases abnormally to about 25 MPa, for example, the relief valve 35 a is opened, and the high-pressure brake fluid is returned to the reservoir 34.

  As described above, the brake control device 20 includes the master cylinder 32, the regulator 33, and the accumulator 35 as a supply source of brake fluid to the wheel cylinder 23. A master pipe 37 is connected to the master cylinder 32, a regulator pipe 38 is connected to the regulator 33, and an accumulator pipe 39 is connected to the accumulator 35. These master pipe 37, regulator pipe 38 and accumulator pipe 39 are each connected to a hydraulic actuator 40.

  The hydraulic actuator 40 includes an actuator block in which a plurality of flow paths are formed, and a plurality of electromagnetic valves. The flow paths formed in the actuator block include individual flow paths 41, 42, 43 and 44 and a main flow path 45. The individual flow paths 41 to 44 are respectively branched from the main flow path 45 and connected to the wheel cylinders 23FR, 23FL, 23RR, 23RL of the corresponding disc brake units 21FR, 21FL, 21RR, 21RL. Thereby, each wheel cylinder 23 can communicate with the main flow path 45.

  In addition, ABS holding valves 51, 52, 53 and 54 are provided in the middle of the individual flow paths 41, 42, 43 and 44. Each of the ABS holding valves 51 to 54 has a solenoid and a spring that are ON / OFF controlled, and each is a normally open solenoid valve that is opened when the solenoid is in a non-energized state. Each of the ABS holding valves 51 to 54 in the opened state can distribute the brake fluid in both directions. That is, the brake fluid can flow from the main flow path 45 to the wheel cylinder 23, and conversely, the brake fluid can also flow from the wheel cylinder 23 to the main flow path 45. When the solenoid is energized and the ABS holding valves 51 to 54 are closed, the flow of brake fluid in the individual flow paths 41 to 44 is blocked.

  Further, the wheel cylinder 23 is connected to the reservoir channel 55 via pressure reducing channels 46, 47, 48 and 49 connected to the individual channels 41 to 44, respectively. ABS decompression valves 56, 57, 58 and 59 are provided in the middle of the decompression channels 46, 47, 48 and 49. Each of the ABS pressure reducing valves 56 to 59 has a solenoid and a spring that are ON / OFF controlled, and is a normally closed electromagnetic valve that is closed when the solenoid is in a non-energized state. When the ABS pressure reducing valves 56 to 59 are closed, the flow of brake fluid in the pressure reducing flow paths 46 to 49 is blocked. When the solenoid is energized and the ABS pressure reducing valves 56 to 59 are opened, the brake fluid is allowed to flow through the pressure reducing flow paths 46 to 49, and the brake fluid flows from the wheel cylinder 23 to the pressure reducing flow paths 46 to 49 and It returns to the reservoir 34 via the reservoir channel 55. The reservoir channel 55 is connected to the reservoir 34 of the master cylinder unit 10 via a reservoir pipe 77.

  The main channel 45 has a separation valve 60 in the middle. By this separation valve 60, the main channel 45 is divided into a first channel 45 a connected to the individual channels 41 and 42 and a second channel 45 b connected to the individual channels 43 and 44. The first flow path 45a is connected to the front wheel side wheel cylinders 23FR and 23FL via the individual flow paths 41 and 42, and the second flow path 45b is connected to the rear wheel side wheel cylinder via the individual flow paths 43 and 44. Connected to 23RR and 23RL.

  The separation valve 60 is a normally closed solenoid valve that has a solenoid and a spring that are controlled to be turned on and off, and is closed when the solenoid is in a non-energized state. When the separation valve 60 is in the closed state, the flow of brake fluid in the main flow path 45 is blocked. When the solenoid is energized and the separation valve 60 is opened, the brake fluid can be circulated bidirectionally between the first flow path 45a and the second flow path 45b.

  In the hydraulic actuator 40, a master channel 61 and a regulator channel 62 communicating with the main channel 45 are formed. More specifically, the master channel 61 is connected to the first channel 45 a of the main channel 45, and the regulator channel 62 is connected to the second channel 45 b of the main channel 45. The master channel 61 is connected to a master pipe 37 that communicates with the master cylinder 32. The regulator channel 62 is connected to a regulator pipe 38 that communicates with the regulator 33.

  The master channel 61 has a master cut valve 64 in the middle. The master cut valve 64 has a solenoid and a spring that are ON / OFF controlled, and is a normally open solenoid valve that is opened when the solenoid is in a non-energized state. The master cut valve 64 in the opened state can cause the brake fluid to flow in both directions between the master cylinder 32 and the first flow path 45 a of the main flow path 45. When the solenoid is energized and the master cut valve 64 is closed, the flow of brake fluid in the master channel 61 is blocked.

  A stroke simulator 69 is connected to the master channel 61 via a simulator cut valve 68 on the upstream side of the master cut valve 64. That is, the simulator cut valve 68 is provided in a flow path connecting the master cylinder 32 and the stroke simulator 69. The simulator cut valve 68 is a normally closed solenoid valve that has a solenoid and a spring that are ON / OFF controlled and is closed when the solenoid is in a non-energized state. When the simulator cut valve 68 is closed, the flow of brake fluid between the master flow path 61 and the stroke simulator 69 is blocked. When the solenoid is energized and the simulator cut valve 68 is opened, the brake fluid can be circulated bidirectionally between the master cylinder 32 and the stroke simulator 69.

  The stroke simulator 69 includes a plurality of pistons and springs, and creates a reaction force according to the depression force of the brake pedal 24 by the driver when the simulator cut valve 68 is opened. As the stroke simulator 69, one having a multi-stage spring characteristic is preferably employed in order to improve the feeling of brake operation by the driver, and the stroke simulator 69 of the present embodiment has a multi-stage spring characteristic.

  The regulator flow path 62 has a regulator cut valve 65 in the middle. The regulator cut valve 65 also has a solenoid and a spring that are ON / OFF controlled, and is a normally open solenoid valve that is opened when the solenoid is in a non-energized state. The regulator cut valve 65 that has been opened can cause the brake fluid to flow in both directions between the regulator 33 and the second flow path 45 b of the main flow path 45. When the solenoid is energized and the regulator cut valve 65 is closed, the flow of brake fluid in the regulator flow path 62 is blocked.

  In the present embodiment, as described above, the master cylinder 32 of the master cylinder unit 10 communicates with the wheel cylinders 23FR and 23FL on the front wheel side by the first system that includes the following elements. The first system includes a master pipe 37, a master channel 61, a master cut valve 64, a first channel 45a of the main channel 45, individual channels 41 and 42, and ABS holding valves 51 and 52. The hydraulic booster 31 and the regulator 33 of the master cylinder unit 10 are communicated with the wheel cylinders 23RR and 23RL on the rear wheel side by a second system that includes the following elements. The second system includes a regulator pipe 38, a regulator channel 62, a regulator cut valve 65, a second channel 45b of the main channel 45, individual channels 43 and 44, and ABS holding valves 53 and 54.

  Therefore, the hydraulic pressure in the master cylinder unit 10 pressurized according to the brake operation amount by the driver is transmitted to the wheel cylinders 23FR and 23FL on the front wheel side through the first system. The hydraulic pressure in the master cylinder unit 10 is transmitted to the wheel cylinders 23RR and 23RL on the rear wheel side through the second system. Thereby, the braking force according to the amount of brake operation of the driver can be generated in each wheel cylinder 23.

  In addition to the master channel 61 and the regulator channel 62, an accumulator channel 63 is also formed in the hydraulic actuator. One end of the accumulator channel 63 is connected to the second channel 45 b of the main channel 45, and the other end is connected to an accumulator pipe 39 that communicates with the accumulator 35.

  The accumulator flow path 63 has a pressure-increasing linear control valve 66 in the middle. Further, the accumulator channel 63 and the second channel 45 b of the main channel 45 are connected to the reservoir channel 55 via the pressure-reducing linear control valve 67. The pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67 each have a linear solenoid and a spring, and both are normally closed solenoid valves that are closed when the solenoid is in a non-energized state. In the pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67, the opening degree of the valve is adjusted in proportion to the current supplied to each solenoid.

  The pressure-increasing linear control valve 66 is provided as a common pressure-increasing control valve for each of the wheel cylinders 23 provided corresponding to each wheel. Similarly, the pressure reducing linear control valve 67 is provided as a pressure reducing control valve common to the wheel cylinders 23. That is, in this embodiment, the pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67 are a pair of common control valves that control the supply and discharge of the working fluid sent from the power hydraulic pressure source 30 to each wheel cylinder 23. It is provided as.

  Here, the differential pressure between the inlet and outlet of the pressure-increasing linear control valve 66 corresponds to the differential pressure between the pressure of the brake fluid in the accumulator 35 and the pressure of the brake fluid in the main flow path 45, and the inlet / outlet of the pressure-reducing linear control valve 67. The pressure difference therebetween corresponds to the pressure difference between the brake fluid pressure in the main flow path 45 and the brake fluid pressure in the reservoir 34. Further, the electromagnetic driving force according to the power supplied to the linear solenoid of the pressure increasing linear control valve 66 and the pressure reducing linear control valve 67 is F1, the spring biasing force is F2, and the pressure increasing linear control valve 66 and the pressure reducing linear control valve are Assuming that the differential pressure acting force according to the differential pressure between the inlet / outlet of 67 is F3, the relationship F1 + F3 = F2 is established. Therefore, the differential pressure between the inlet and outlet of the pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67 is controlled by continuously controlling the power supplied to the linear solenoids of the pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67. can do.

  In the present embodiment, a pressure control mechanism is configured including the power hydraulic pressure source 30, the pressure-increasing linear control valve 66, and the pressure-decreasing linear control valve 67. The hydraulic pressure in the wheel cylinder 23 is controlled by operating the pressure control mechanism. Since the second flow path 45b of the main flow path 45 is communicated between the pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67, the pressure control mechanism can operate the wheel on the rear wheel side regardless of whether the separation valve 60 is opened or closed. The hydraulic pressure of the cylinders 23RR and 23RL can be controlled. If the separation valve 60 is in the open state, the hydraulic pressures of all the wheel cylinders 23 can be controlled by operating the pressure control mechanism.

  In the brake control device 20, the power hydraulic pressure source 30 and the hydraulic actuator 40 are controlled by a brake ECU 70 as control means in the present embodiment. The brake ECU 70 is configured as a microprocessor including a CPU, and includes a ROM that stores various programs, a RAM that temporarily stores data, an input / output port, a communication port, and the like in addition to the CPU. The brake ECU 70 can communicate with a host hybrid ECU (not shown) and the like, and based on control signals from the hybrid ECU and signals from various sensors, the pump 36 of the power hydraulic pressure source 30 and the hydraulic pressure Brake control can be executed by controlling the electromagnetic valves 51 to 54, 56 to 59, 60, and 64 to 68 constituting the actuator 40.

  Further, a regulator pressure sensor 71, an accumulator pressure sensor 72, and a control pressure sensor 73 are connected to the brake ECU 70. The regulator pressure sensor 71 detects the pressure of the brake fluid in the regulator flow path 62 on the upstream side of the regulator cut valve 65, that is, the regulator pressure, and gives a signal indicating the detected value to the brake ECU 70. The accumulator pressure sensor 72 detects the pressure of the brake fluid in the accumulator flow path 63, that is, the accumulator pressure on the upstream side of the pressure increasing linear control valve 66, and gives a signal indicating the detected value to the brake ECU 70. The control pressure sensor 73 detects the pressure of the brake fluid in the first flow path 45a of the main flow path 45, and gives a signal indicating the detected value to the brake ECU 70. The detection values of the pressure sensors 71 to 73 are sequentially given to the brake ECU 70 every predetermined time, and are stored and held in a predetermined storage area of the brake ECU 70 by a predetermined amount.

  When the separation valve 60 is opened and the first flow path 45 a and the second flow path 45 b of the main flow path 45 communicate with each other, the output value of the control pressure sensor 73 is the low pressure of the pressure-increasing linear control valve 66. This indicates the hydraulic pressure on the high pressure side of the pressure-reducing linear control valve 67 and the output value can be used to control the pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67. When the pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67 are closed and the master cut valve 64 is opened, the output value of the control pressure sensor 73 indicates the master cylinder pressure. Further, the separation valve 60 is opened so that the first flow path 45a and the second flow path 45b of the main flow path 45 communicate with each other, and the ABS holding valves 51 to 54 are opened, while the ABS pressure reducing valves 56 are opened. When? 59 is closed, the output value of the control pressure sensor 73 indicates the working fluid pressure acting on each wheel cylinder 23, i.e., the wheel cylinder pressure.

  Further, the sensor connected to the brake ECU 70 includes a stroke sensor 25 provided on the brake pedal 24. The stroke sensor 25 detects a pedal stroke as an operation amount of the brake pedal 24 and gives a signal indicating the detected value to the brake ECU 70. The output value of the stroke sensor 25 is also sequentially given to the brake ECU 70 every predetermined time, and is stored and held in a predetermined storage area of the brake ECU 70 by a predetermined amount. A brake operation state detection unit other than the stroke sensor 25 may be provided in addition to the stroke sensor 25 or in place of the stroke sensor 25 and connected to the brake ECU 70. Examples of the brake operation state detection means include a pedal depression force sensor that detects an operation force of the brake pedal 24 and a brake switch that detects that the brake pedal 24 is depressed.

  When the brake pedal 24 is depressed by the driver, the brake ECU 70 calculates the target deceleration of the vehicle from the pedal stroke and the master cylinder pressure. Then, the brake ECU 70 calculates the target hydraulic pressure of the wheel cylinder 23 based on the calculated target deceleration, and supplies it to the pressure increasing linear control valve 66 and the pressure reducing linear control valve 67 so that the wheel cylinder pressure becomes the target hydraulic pressure. Determine the current value. As a result, in the brake control device 20, the brake fluid is supplied from the power hydraulic pressure source 30 via the pressure-increasing linear control valve 66 to each wheel cylinder 23 and braking force is applied to each wheel. At this time, the brake ECU 70 opens the separation valve 60 so that the brake fluid from the power hydraulic pressure source 30 is supplied to the front wheels, while the master cut valve 64 and the regulator cut valve 65 are closed. The brake fluid sent from the master cylinder 32 and the regulator 33 is prevented from being supplied to the main flow path 45.

  FIG. 2 shows an electromagnetic valve drive circuit of the brake control device 20 according to the present embodiment. The DC power supply device 96 is a power supply device for driving a plurality of electromagnetic valves of the brake control device 20. The DC power supply device 96 supplies current to a plurality of solenoid valve drive circuits via electronic components such as a solenoid relay 94 and a filter 92. The current that has passed through the filter 92 and from which the noise component has been removed flows to a plurality of solenoid valve drive circuits connected in parallel via the power line 99. In FIG. 2, one electromagnetic valve driving circuit 88 is shown, and the other electromagnetic valve driving circuits are not shown.

  The solenoid valve drive circuit 88 controls the current supplied to the solenoid coil 90 of the solenoid valve by a control signal from the brake ECU 70. The solenoid valve drive circuit 88 includes a P-channel type FET 80, an N-channel type FET 82, a flywheel diode 84, and a current detection resistor 86.

  The source terminal of the FET 80 is connected to the power supply line 99. The gate terminal of the FET 80 is connected to the brake ECU 70 via the control signal line 97. A solenoid coil 90 is connected between the drain terminal of the FET 80 and the drain terminal of the FET 82. The cathode terminal of the flywheel diode 84 is connected to the drain terminal of the FET 80, and the anode terminal of the flywheel diode 84 is grounded. The gate terminal of the FET 82 is connected to the brake ECU 70 via the control signal line 98. One terminal of the current detection resistor 86 is connected to the source terminal of the FET 82, and the other terminal of the current detection resistor 86 is grounded. The source terminal of the FET 82 is connected to the brake ECU 70 via the current monitor line 95.

  The solenoid valve requires a starting current having a large current value at the time of starting, but once driven, the driving state can be maintained by supplying a holding current having a current value smaller than the starting current. By changing the current supplied according to the state of the solenoid valve, current consumption and heat generation can be reduced. In the present embodiment, the brake ECU 70 can control the current I supplied to the solenoid coil 90 of the solenoid valve by changing the duty ratio of the control signal supplied to the gate terminal of the FET 80 by PWM control.

FIG. 3 is a timing chart showing a current supply state to a plurality of solenoid valves during a brake operation. In the brake control device 20 according to the present embodiment, the brake ECU 70 starts supplying current to the plurality of electromagnetic valves at different timings when a brake operation is performed. The brake ECU 70 controls each of the plurality of solenoid valves to switch to a holding current having a current value lower than the startup current after supplying a startup current for starting the solenoid valve, and supplies the solenoid valve with one of the solenoid valves. After switching the current from the starting current to the holding current, supply of the starting current to the next solenoid valve is started. In Figure 3, the brake operation by the driver at time t ₀ is started, brake operation by the driver is assumed that ends at time t _5.

First, when a brake operation is performed by the driver at time t ₀ , the brake ECU 70 starts supplying current to the master cut valve 64. The brake ECU 70 performs PWM control so that the current supplied to the master cut valve 64 at this time is a current I ₁ sufficient to drive the master cut valve 64, that is, to close the master cut valve 64. Do. This current I ₁ is referred to as a starting current of the master cut valve 64. The start-up current I ₁ is supplied during a time T ₁ from time t ₀ to time t ₁ . The time T ₁ is set from the start of the supply of the starting current I ₁ to the master cut valve 64 so that the drive of the master cut valve 64 is time or more to complete. Whether or not the driving of the master cut valve 64 is completed may be detected by using a sensor for determining the driving state of the electromagnetic valve, or a time required for completing the driving of the master cut valve 64 in advance. You may measure it.

At time t ₁ , the brake ECU 70 performs PWM control so that the current supplied to the master cut valve 64 has a current value lower than the starting current I ₁ and is sufficient to maintain the drive state of the master cut valve 64. switch to a holding current _{I 2.}

The brake ECU 70 starts supplying current to the separation valve 60 after time t ₁ when the current supplied to the master cut valve 64 is switched from the drive current I ₁ to the holding current I ₂ . The brake ECU 70 performs PWM control so that the current supplied to the separation valve 60 at this time is a current I ₃ sufficient to drive the separation valve 60, that is, to open the separation valve 60. The current _{I 3,} referred to as the starting current of the separate valve 60. The supply of starting current _{I 3} is carried out during the time _{T 2} of the from time _{t 1} to time _{t 2.} The time T ₂ are set from the start of the supply of the starting current I ₃ to the separation valve 60 so that the driving of the separation valve 60 is equal to or greater than the time to complete. Whether or not the driving of the separation valve 60 is completed may be detected by using a sensor for determining the driving state of the electromagnetic valve, or a time required for completing the driving of the separation valve 60 is measured in advance. You may keep it.

In time t _2, the brake ECU70, by performing the PWM control, the current supplied to the separation valve 60, the starting current I ₃ from the current value is low, sufficient holding current to maintain the driving state of the separation valve 60 switch to I _4.

Brake ECU70 is the time _{t 2} after switching the current supplied to the holding current _{I 4} from the driving current _{I 3} to the separation valve 60, starts the supply of current to the regulator cut valve 65. The brake ECU 70 performs PWM control so that the current supplied to the regulator cut valve 65 at this time is a current I ₅ sufficient to drive the regulator cut valve 65, that is, to close the regulator cut valve 65. Do. The current I _5, referred to as the starting current of the regulator cut valve 65. The start-up current I ₅ is supplied during a time T ₃ from time t ₂ to time t ₃ . The time T ₃ is set from the start of the supply of the starting current I ₅ in the regulator cut valve 65 so that the drive of the regulator cut valve 65 is time or more to complete. Whether or not the driving of the regulator cut valve 65 is completed may be detected by using a sensor for determining the driving state of the electromagnetic valve, or a time required for completing the driving of the regulator cut valve 65 in advance. You may measure it.

At time t ₃ , the brake ECU 70 performs PWM control so that the current supplied to the regulator cut valve 65 has a current value lower than the starting current I ₅ and is sufficient to maintain the drive state of the regulator cut valve 65. switch to a holding current _{I 6.}

Brake ECU70 is the current supplied to the time _{t 3} after switching to the holding current _{I 6} from the driving current _{I 5} in the regulator cut valve 65, starts to supply current to the pressure-increasing linear control valve 66. As described above, when the brake pedal 24 is depressed by the driver, the brake ECU 70 calculates the target hydraulic pressure of the wheel cylinder 23 and applies the pressure increase linear control valve 66 so that the wheel cylinder pressure becomes the target hydraulic pressure. Determine the value of the current to be supplied. The brake ECU 70 performs PWM control on the drive circuit of the pressure increasing linear control valve 66 so that the determined current is supplied to the pressure increasing linear control valve 66. After the wheel cylinder pressure reaches the target hydraulic pressure, the brake ECU 70 sets the current supplied to the pressure-increasing linear control valve 66 to zero and closes the pressure-increasing linear control valve 66 (time t ₄ ).

Thereafter, when the driver finishes the brake operation at time t ₅ , the brake ECU 70 starts supplying current to the pressure-reducing linear control valve 67. The brake ECU 70 calculates a target hydraulic pressure of the wheel cylinder 23 and determines a current value to be supplied to the pressure-reducing linear control valve 67 so that the wheel cylinder pressure becomes the target hydraulic pressure. The brake ECU 70 performs PWM control so that the determined current is supplied to the pressure-reducing linear control valve 67. After the wheel cylinder pressure reaches the target hydraulic pressure, the brake ECU 70 sets the current supplied to the pressure-reducing linear control valve 67 to zero and closes the pressure-reducing linear control valve 67 (time t ₆ ).

Pressure reducing linear control valve 67 time t ₆ after the current to be supplied becomes zero, the brake ECU70 the master cut valve 64, so that the retention current supplied to the separation valve 60 and the regulator cut valve 65 is zero Each solenoid valve drive circuit is controlled. As a result, the master cut valve 64 and the regulator cut valve 65 are opened, the separation valve 60 is closed, and the operation of the electromagnetic valve during brake operation is completed.

FIG. 4 is a flowchart showing control of a plurality of solenoid valves during a brake operation. When there is a brake operation (Y in S10), the brake ECU 70 supplies a starting current to the master cut valve 64 (S12). If there is no brake operation, the system waits until the brake operation is performed (N in S10). The supply of starting current is conducted until the time _{T 1} is elapsed (S14 of N). Time T _1, as described above, driving from the start of the supply of the starting current to the master cut valve 64 of the master cut valve 64 is a time or longer to complete. If the time _{T 1} is elapsed (S14 of Y), the brake ECU70 is the current supplied to the master cut valve 64 is switched to the holding current from the starting current (S16).

Thereafter, the brake ECU 70 supplies a starting current to the separation valve 60 (S18). The supply of starting current is conducted until the time _{T 2} has elapsed (S20 of N). Time T ₂ are, as described above, the drive of the separating valve 60 from the start of the supply of the starting current to the partition valve 60 is a time or longer to complete. If the time _{T 2} has elapsed (S20 of Y), the brake ECU70 switches the current supplied to the separation valve 60, the holding current from the starting current (S22).

Thereafter, the brake ECU 70 supplies a starting current to the regulator cut valve 65 (S24). The supply of starting current is continued until the elapse of the time _{T 3} (S26 of N). Time T _3, as described above, driving from the start of the supply of the starting current to the regulator cut valve 65 of the regulator cut valve 65 is a time or longer to complete. If the time _{T 3} has elapsed (S26 of Y), the brake ECU70 is the current supplied to the regulator cut valve 65 is switched to the holding current from the starting current (S28). Thereafter, the brake ECU 70 supplies current to the pressure-increasing linear control valve 66 (S30), increases the hydraulic pressure in the wheel cylinder 23, and generates braking force on the wheels. This completes the control of the plurality of solenoid valves during the brake operation.

  As described above, in the brake control device 20 according to the present embodiment, when a brake operation is performed by the driver, the current value is kept lower than the start current after supplying the start current to each of the plurality of solenoid valves. The control to switch to the current was performed, and the current supplied to one solenoid valve was switched from the startup current to the holding current, and then the supply of the startup current to the next solenoid valve was started. By configuring the brake control device in this way, the startup current does not flow in a superimposed manner, and a situation where a large current flows through the device can be avoided. As a result, it is not necessary to use a power supply device for driving the solenoid valve that has a large current capacity, and the degree of freedom in selecting the power supply device is increased.

  Further, by avoiding a situation where a large current flows through the apparatus, a voltage drop due to electronic components such as a solenoid relay 94 and a filter 92 provided in the current supply line is reduced. As a result, the minimum operating voltage of the solenoid valve can be secured without setting the voltage of the power supply device so high.

  In the brake control device 20 according to the present embodiment, it is preferable to start supplying the starting current to the plurality of solenoid valves in a predetermined order. In particular, as described above, it is preferable to start supplying current to the master cut valve 64 before the pressure-increasing linear control valve 66. When the supply of current to the pressure-increasing linear control valve 66 is started before the master cut valve 64 that is a normally open solenoid valve, the brake fluid flows into the master cylinder 32 via the master cut valve 64, and the driver operates the brake. You may feel uncomfortable. Such a situation can be avoided by starting the supply of current to the master cut valve 64 before the pressure-increasing linear control valve 66.

  The present invention has been described above based on the embodiment. It should be understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention.

It is a distribution diagram showing a brake control device concerning one embodiment of the present invention. It is a figure which shows the solenoid valve drive circuit of the brake control apparatus which concerns on this embodiment. It is a timing chart which shows the supply state of the electric current with respect to several solenoid valves at the time of brake operation. It is a flowchart which shows control of the some solenoid valve at the time of brake operation.

Explanation of symbols

  20 brake control device, 23 wheel cylinder, 24 brake pedal, 30 power hydraulic pressure source, 32 master cylinder, 45 main flow path, 60 separation valve, 61 master flow path, 64 master cut valve, 65 regulator cut valve, 66 pressure increase linear Control valve, 67 decompression linear control valve, 70 brake ECU.

Claims (4)

In a brake control device that applies braking force to wheels provided in a vehicle in response to a brake operation by a driver,
A plurality of solenoid valves provided in the flow path of the working fluid;
A current control unit for controlling a current supplied to the plurality of solenoid valves;
With
The current control unit performs control for switching to a holding current having a current value lower than the starting current after supplying a starting current for starting the solenoid valve to each of the plurality of solenoid valves. A brake control device characterized in that, after the current supplied to is switched from the starting current to the holding current, the supply of the starting current to the next solenoid valve is started.   2. The brake control device according to claim 1, wherein the current control unit starts supplying a starting current to the plurality of electromagnetic valves in a predetermined order. A first wheel cylinder for applying braking force to the first wheel;
A second wheel cylinder for applying a braking force to a second wheel different from the first wheel;
A main flow path communicating the first wheel cylinder and the second wheel cylinder;
A separation valve that is a normally closed solenoid valve that separates the main flow path into a first flow path that communicates with the first wheel cylinder and a second flow path that communicates with the second wheel cylinder;
A master cylinder that pressurizes the working fluid according to the amount of operation of the brake operating member by the driver;
A master channel communicating the master cylinder and the first channel;
A master cut valve which is a normally open solenoid valve provided in the master flow path;
A power hydraulic pressure source capable of generating a high hydraulic pressure by supplying power; and
A power hydraulic pressure source channel communicating the power hydraulic pressure source and the second channel;
A pressure increasing valve provided in the power hydraulic pressure source flow path for adjusting the hydraulic pressure of the first and second wheel cylinders;
A current control unit for controlling a current supplied to the separation valve, the master cut valve and the pressure increasing valve;
With
The brake control device according to claim 1, wherein the current control unit starts supplying current to the separation valve, the master cut valve, and the pressure increasing valve at different timings when a brake operation is performed.   The brake control device according to claim 3, wherein the current control unit starts supplying current to the master cut valve before the pressure increasing valve.

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