JP2006175905A - Brake liquid pressure controlling device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake liquid pressure controlling device which reduces costs and simplifies a liquid pressure circuit by eliminating an expensive pressure sensor of a liquid pressure source. <P>SOLUTION: This brake liquid pressure controlling device is equipped with a gear pump 10, second pressure sensors 16 and 16, and an electronic controller. In this case, the gear pump 10 feeds a liquid pressure to front wheel cylinders 3 and 4 which impart a braking force to respective right and left front wheels through a liquid pressure inside. The second pressure sensors 16 and 16 detect the liquid pressure in respective front wheel cylinders. The electronic controller is equipped with a fed liquid pressure estimating circuit which estimates a discharging pressure of the gear pump by the rotation number and the electric current value of the pump motor 13 of the gear pump. The brake liquid pressure controller device is constituted in a manner to calculate a required braking force for respective right and left front wheels by selecting either one of the liquid pressure in respective front wheel cylinders which is detected by the second pressure sensor, or a fed liquid pressure which is estimated by the fed liquid pressure estimating circuit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a brake fluid pressure control device that controls a braking force for each wheel of a vehicle, for example.

  Recently, as a brake fluid pressure control device for a vehicle, a pump motor as a fluid pressure source in which a normal braking force is provided separately from a master cylinder is electrically detected, for example, an operation amount of a brake pedal is detected. A so-called brake-by-wire (electrically controlled hydraulic brake) control device for controlling based on a detection signal is provided, and one of them is disclosed in Patent Document 1 below.

  In brief, a master cylinder that generates hydraulic pressure in response to a brake operation, an operation amount detection means that detects the brake operation amount, a hydraulic pressure source that includes a pump and an accumulator, and a hydraulic pressure of the hydraulic pressure source A hydraulic pressure source hydraulic pressure detecting means for detecting the pressure, a pump drive control means for controlling the driving of the pump based on a detection amount of the hydraulic pressure source hydraulic pressure detecting means, and a plurality of wheels for controlling the rotation of a plurality of wheels A cylinder, wheel cylinder hydraulic pressure detecting means for detecting hydraulic pressure of each wheel cylinder, a first hydraulic pressure passage connecting the hydraulic pressure source and the plurality of wheel cylinders, and the first hydraulic pressure passage. Provided with a plurality of hydraulic pressure control mechanisms for controlling the hydraulic pressure of the wheel cylinder.

  When an abnormality is detected in the wheel cylinder hydraulic pressure detecting means for detecting the hydraulic pressure of each wheel cylinder, an accumulator hydraulic pressure detecting means for detecting the hydraulic pressure of the accumulator is detected for the wheel cylinder in which the abnormality is detected. Change control is performed so as to determine a command value to the proportional electromagnetic hydraulic pressure control valve so as to coincide with the accumulator pressure.

As a result, even when an abnormality such as a failure occurs in the wheel cylinder hydraulic pressure detecting means (pressure sensor), the electrically controlled hydraulic brake system can be maintained.
JP 2000-71965 A

  However, in the conventional brake fluid pressure control device, the valve opening control of a plurality of solenoid valves, which are a plurality of fluid pressure control mechanisms of each wheel cylinder, is performed by the fluid pressure for each wheel cylinder, each wheel speed, The braking force of each wheel is controlled based on the hydraulic pressure value in the vicinity of the pump detected by the hydraulic pressure source hydraulic pressure detection means (hydraulic pressure sensor).

  As described above, since a hydraulic pressure sensor for detecting the hydraulic pressure in the vicinity of the pump is required, the number of parts is inevitably increased, and the control logic is complicated. As a result, the cost increases, and the degree of freedom in layout of the apparatus may be restricted.

  The present invention has been devised in view of the technical problem of the conventional brake hydraulic pressure control device, and the invention according to claim 1 provides a wheel for applying a braking force to each wheel via an internal hydraulic pressure. The hydraulic pressure supply means for supplying the hydraulic pressure to each wheel cylinder, the hydraulic pressure detection means for detecting the hydraulic pressure of each wheel cylinder, and the parameters relating to the momentum of the hydraulic pressure supply means, Supply hydraulic pressure estimation means for estimating the supply hydraulic pressure of the pressure supply means, the hydraulic pressure in each wheel cylinder detected by the hydraulic pressure detection means, and the supply liquid estimated by the supply hydraulic pressure estimation means It is characterized in that one of the pressures is selected and the required braking force of each wheel is calculated.

  According to the present invention, the braking force of each wheel is calculated based on the hydraulic pressure detected by the hydraulic pressure detecting means or the supplied hydraulic pressure estimated by the supplied hydraulic pressure estimating means, so that the cost can be reduced. .

  In other words, when performing a specific condition that requires monitoring the hydraulic pressure in each wheel cylinder while the vehicle is running, for example, control for applying a braking force to a plurality of wheels, the hydraulic pressure is maintained while ensuring the braking force for each wheel. Without using an expensive hydraulic pressure sensor for detecting the supply pressure of the supply source, for example, a relatively inexpensive rotation speed sensor or current for detecting the rotation speed or supply current of a rotary electric pump motor used for the hydraulic pressure supply source. Since the sensor is used, the cost can be reduced and the apparatus can be simplified.

  The invention according to claim 2 calculates the braking force required by each wheel based on the hydraulic pressure of the wheel cylinder that is performing the maximum pressure increase control among the wheel cylinders of the left and right wheels, When the wheel cylinders are held at the same pressure, the braking force required by each wheel is calculated based on the estimated hydraulic pressure detected by the supply hydraulic pressure estimation means.

  According to this invention, in addition to the function and effect of the invention of claim 1, the wheel performing the maximum pressure increase control is an electric motor that is a hydraulic pressure supply source using the hydraulic pressure of the wheel cylinder of this wheel as a control parameter. While controlling the pump motor of the pump, the braking force is ensured. On the other hand, when the control is infrequent, such as the all-wheel constant pressure holding control in the low friction path of the antilock brake device, the current or the rotational speed of the pump motor Since the hydraulic pressures of all wheels are controlled, independent braking force control can be executed in a stable state for each wheel.

  Embodiments of a vehicle brake fluid pressure control apparatus according to the present invention will be described below in detail with reference to the drawings.

  This brake hydraulic pressure control device has control functions such as normal braking, ABS and VSC as shown in the hydraulic circuit of FIG. 1 showing only the front side of the vehicle for convenience, and according to the depression amount of the brake pedal 1 A master cylinder 2 that generates a high brake pressure is provided, and a fluid that allows the front wheel cylinders 3 and 4 provided on the left and right front wheels (FR and FL) to communicate with the pressurizing chamber of the master cylinder 2. Pressure passages 5 and 5 are connected. Each of the hydraulic pressure passages 5 and 5 is provided with normally open shut-off valves 6 and 6 on the upstream side, and branch passages 7 and 7 are connected to the downstream portions 5a and 5a.

  The branch passages 7 and 7 are provided with pressure-increasing proportional solenoid valves 8 and 8 on the upstream side of the downstream portions 5a and 5a of the hydraulic pressure passages 5 and 5, respectively. Valves 9 and 9 are respectively provided. A gear pump 10 serving as a hydraulic pressure supply means is provided on the upstream side of each of the pressure increasing proportional solenoid valves 8, 8 via a discharge passage 12.

  The pressure-increasing proportional solenoid valves 8 and 8 are normally open type, and are excited by an output current from an electronic controller (not shown) and controlled to be closed. , 9 are normally closed types, and are controlled to open by the output current from the electronic controller.

  The pressure reducing proportional solenoid valves 9 and 9 are connected to a reflux passage 11 communicating with the reservoir 2 a of the master cylinder 2, and the hydraulic pressure in the front wheel cylinders 3 and 4 is changed to the hydraulic pressure passages 5 and 5. 5 is returned from the reflux passage 11 to the reservoir 2a via the downstream portions 5a and 5a.

  The gear pump 10 operates during normal braking control of the left and right front wheels (FL, FR). The gear pump 10 includes a pump body 12 having a pair of external gears provided in a pump housing, and rotates the gears. And an electrically driven brushless pump motor 13 to be driven. By the rotational drive of the pump motor 13, check valves 14 and 14 provided from the discharge passage 12a to the branch passages 7 and 7 and the proportional solenoid valves for pressure increase. The hydraulic pressure is supplied to the front wheel cylinders 3 and 4 via 8 and 8. The discharge pressure is set relatively high and higher than that of the plunger pump.

  The pump motor 13 is driven to rotate by an output current from the electronic controller, and a rotation sensor (not shown) for detecting the rotation speed of the motor shaft is accommodated therein.

  In addition, first pressure sensors 15 and 15 for detecting the fluid pressure supplied from the master cylinder 2 are provided on the upstream side of the fluid pressure passages 5 and 5, and the downstream portions 5 a and 5 a Are provided with second pressure sensors 16 and 16 which are hydraulic pressure detecting means for detecting the hydraulic pressure in each of the front wheel cylinders 3 and 4.

  Further, in the pressure-sensitive passage 17 connecting the discharge passage 12a of the gear pump 10 and the reflux passage 11, when the discharge pressure of the gear pump 10 exceeds a predetermined value, the discharge pressure is supplied to the reservoir 2a via the return passage 11. There is provided a relief valve 18 for returning to.

  The shut-off valves 6 and 6 are opened for fail-safe when the pressure sensor 15, 15, 16, 16, etc. fails and the gear pump 10 stops driving, and the brake pedal 1 is depressed. Accordingly, the hydraulic pressure of the master cylinder 2 is supplied to the front wheel cylinders 3 and 4.

  The electronic controller detects the hydraulic pressure detection signal of each part output from the first and second pressure sensors 15, 15, 16, 16, the rotation sensor of the pump motor 13, and the output current amount to the pump motor. On the basis of detection signals from various sensors such as a current sensor, a vehicle speed sensor, a lateral G sensor, etc., in addition to opening / closing control of the pressure-increasing and pressure-reducing proportional solenoid valves 8, 8, 9, 9 The shutoff valves 6 and 6 are controlled to be opened and closed, and the rotational drive and stop of the pump motor 13 are controlled.

The electronic controller also includes a supply hydraulic pressure estimation circuit that estimates the discharge pressure of the gear pump 10 based on the rotation speed signal from the rotation sensor of the pump motor 13 and the current amount signal from the current sensor. Either the supply estimation signal estimated by the hydraulic pressure estimation circuit or the hydraulic pressure signal in each front wheel cylinder 3, 4 output from the second pressure sensor 16, 16 is selected to select the front wheel cylinder 3, An arithmetic circuit that calculates the required braking force of the front wheels via 4 is provided.

  The arithmetic circuit calculates the braking force required by the left and right front wheels based on the hydraulic pressure of the front wheel cylinders 3 and 4 of the left and right front wheels that is performing the maximum pressure increase control. Further, when the front wheel cylinders 3 and 4 are held at the same pressure, the braking force required by each front wheel is calculated based on the estimated hydraulic pressure estimated by the supply hydraulic pressure estimation circuit. It has become.

  Hereinafter, the control action of the braking force by the electronic controller will be described with reference to FIGS.

  First, FIG. 2 is a schematic control flowchart showing normal braking force control and ABS control of the front wheels while the vehicle is running. First, in step 1, normal braking force control is performed on both front wheels at the same pressure. Determine whether it is going.

  Here, if it is determined that the same pressure control is being performed, the routine proceeds to step 2, where it is determined whether or not the pressure-increasing proportional control valves 8 and 8 are in the closed valve holding state. That is, it is determined whether or not a control current is output from the electronic controller to the pressure increasing proportional control valves 8 and 8 and the valve is in a closed state.

  If it is determined that the pressure-increasing proportional control valves 8 and 8 are not fully closed but fully open, the process proceeds to step 3.

  In Step 3, the hydraulic pressures of the front wheel cylinders 3 and 4 are monitored by the second pressure sensors 16 and 16, and based on the hydraulic pressure signal, the braking force required for each front wheel is determined in Step 4. A control current is output to the pump motor 13 to rotate it to operate the gear pump 10 and to control each of the pressure increasing / decreasing proportional electromagnetic valves 8, 8, 9, 9.

  If it is determined in step 2 that the pressure-increasing proportional solenoid valves 8 and 8 are in the closed state, the process proceeds to step 5.

  In step 5, the current hydraulic pressure in each front wheel cylinder 3, 4 is estimated from the current rotation speed and current value of the pump motor 13 detected by the rotation sensor and current sensor.

  Therefore, the electronic controller performs ABS control based on the estimated hydraulic pressure of each front wheel cylinder 3 and 4 based on the pump rotation speed and the current value detection signal.

  Next, when it is determined in step 1 that the same pressure control is not performed, that is, when the vehicle is running, for example, in cornering, the braking force on the other side is controlled to be greater than the braking force on the one front wheel. When this occurs, the routine proceeds to step 6, where the front wheel cylinders 3, 4 on the side of the front wheel cylinders 3, 4 on which maximum pressure increase control is being performed by the second pressure sensors 16, 16. Monitor fluid pressure.

  Thereafter, the process proceeds to step 4 and, based on the maximum hydraulic pressure detection signal, the pump motor 13 is driven to rotate by driving the gear pump 10 with respect to the required braking force of each front wheel to operate the gear pump 10. At the same time, the pressure increasing / decreasing proportional solenoid valves 8, 8, 9, 9 are controlled.

  Hereinafter, a specific operation of the hydraulic circuit according to the control flowchart of the electronic controller will be described.

  First, FIG. 3 shows a case where a normal braking force is applied to the front wheel cylinders 3 and 4 of the left and right front wheels in steps 1 to 4 described above during normal traveling of the vehicle. When the pressures 3 and 4 are controlled to the same pressure, the shut-off valves 6 and 6 are maintained in the closed state, and the pressure increasing proportional solenoid valves 8 and 8 are controlled to be fully opened.

  On the other hand, the gear pump 10 is driven to rotate, and the hydraulic pressure corresponding to the required braking force is supplied to the front wheel cylinders 3 and 4 as indicated by arrows in FIG.

  Next, at the time of ABS control shown in steps 1, 2, and 5 and the like, as shown in FIG. 4, the shut-off valves 6 and 6 maintain the closed state and the pressure-increasing proportional control valves 8 and 8 are maintained. Is energized by the electronic controller and temporarily closes to a holding state.

  Therefore, the second pressure sensors 16 and 16 cannot monitor the hydraulic pressures of the front wheel cylinders 3 and 4. However, since the holding control time is instantaneous, the pump motor 13 is rotating. As described above, the hydraulic pressure is estimated from the rotation speed and the current value based on the rotation speed and the current value. The pump motor 13 stops rotating when the holding state reaches a certain time or longer. In addition, all the wheels are controlled to be in a holding state for a very short time on a very low friction road surface during ABS control, and the frequency of such an operating state is low.

  Further, at the time of pressure reduction control of the front wheel cylinders 3 and 4 in the ABS control, the shut-off valves 6 and 6 and the pressure increasing proportional solenoid valves 8 and 8 are kept closed, and the pressure reducing proportional solenoid valves 9 and 9 are While energized from the electronic controller to open the valve, the pump motor 13 stops rotating.

  Next, in cornering traveling or the like, when the braking force of the left and right wheels shown in steps 1, 6, and 4 is controlled independently, as shown in FIG. 5, for example, the front wheel cylinder 3 of the left wheel (FL) is turned on. When performing control to increase the pressure and hold the front wheel cylinder 4 of the right wheel (FR), the shutoff valves 6 and 6 are closed, the pump motor 13 is driven to rotate, and the left wheel side pressure increasing proportionality is used. The solenoid valve 8 is controlled to open, and the right-wheel side pressure increasing proportional solenoid valve 8 is controlled to close.

  Further, for example, when pressure increase control is performed on the front wheel cylinder 3 for the left wheel and pressure reduction control is performed on the front wheel cylinder 4 for the right wheel, the shutoff valves 6 and 6 are closed and the pump motor 13 is driven to rotate. At the same time, the left-wheel-side pressure-increasing proportional solenoid valve 8 is controlled to open, and at the same time, the right-wheel-side pressure-increasing proportional solenoid valve 8 is controlled to close, and the right-side pressure reducing proportional solenoid valve 9 is controlled to open.

  Further, for example, when holding control of the left wheel front wheel cylinder 3 and pressure reducing control of the right wheel front wheel cylinder 4, the shutoff valves 6 and 6 are closed and the pump motor 13 is driven to rotate. At the same time, the left-wheel-side pressure-increasing proportional solenoid valve 8 is controlled to be closed, and at the same time, the right-wheel-side pressure-increasing proportional solenoid valve 8 is controlled to be closed, and the right-side pressure reducing proportional solenoid valve 9 is controlled to be opened.

  For example, when the pressure increase of the front wheel cylinder 3 of the left wheel is controlled to be large and the pressure increase of the front wheel cylinder 4 of the right wheel is controlled to be small, the shutoff valves 6 and 6 are maintained in the closed state, and the pump motor 13 is driven to rotate in accordance with the increase amount side, the left-wheel-side pressure-increasing proportional solenoid valve 8 is fully opened, and the right-wheel-side pressure-increasing proportional solenoid valve 8 is subjected to valve-opening proportional control in accordance with the small pressure increase. .

  Further, when the pressure reduction of the front wheel cylinder 3 of the left wheel is controlled to be large and the pressure reduction of the front wheel cylinder 4 of the right wheel is controlled to be small, the shut-off valves 6 and 6 are kept closed and the pump motor 13 is temporarily turned on. The left and right pressure-increasing proportional solenoid valves 8 and 8 are closed and controlled, and the left and right pressure-reducing proportional solenoid valves 9 and 9 are valve-opened proportionally controlled according to the amount of pressure reduction. Is done.

  Thus, when controlling the braking force of the left and right wheels independently, the pump motor 13 is driven in accordance with the required braking force of the wheel whose pressure is increased to the maximum, and the other low-pressure wheels are proportional solenoid valves. Therefore, it is possible to monitor the discharge pressure of the gear pump 10 by detecting the hydraulic pressure of the first pressure sensor 16 or 16 on the one of the front wheel cylinders 3 or 4 on the maximum pressure increasing side.

  For example, even when liquid leakage occurs on one side of the front wheel cylinders 3 and 4 and a sufficient braking force cannot be obtained, the discharge passage 12a of the gear pump 10 and the proportional solenoid valves 8 and 8 for pressure increase are used. Since the check valves 14 and 14 are provided between the front wheel cylinder 3 and the other front wheel cylinder 3 or 4, sufficient hydraulic pressure is supplied to the other front wheel cylinder 3 or 4, so that the braking force on the other wheel side can be secured. become.

  As described above, in this embodiment, when the electronic controller controls the braking force of the left and right front wheels, it does not use an expensive hydraulic pressure sensor that detects the supply pressure of the hydraulic pressure source as in the past. Further, the current front speed is determined by the hydraulic pressure detected by the second pressure sensors 16 and 16 of the front wheel cylinders 3 and 4 or the current rotational speed and current value of the pump motor 13 detected by the rotation sensor and current sensor. Since the braking force is controlled by calculating based on the hydraulic pressure obtained by estimating the hydraulic pressure in the wheel cylinders 3 and 4, the use of such a relatively inexpensive rotational speed sensor and current sensor reduces the cost. Reduction and simplification of the hydraulic circuit can be achieved. In addition, the freedom of layout is improved by simplifying the hydraulic circuit.

  Further, as described above, when the braking force of the left and right front wheels is controlled independently, one of the front wheels performing the maximum pressure increase control uses the hydraulic pressure of the front wheel cylinder 3 or 4 of this wheel as a control parameter. The braking force is ensured by controlling the pump motor 13 of the gear pump 10 while the current or rotation of the pump motor 13 is controlled at a low frequency such as the all-wheel same-pressure holding control in the ABS low friction path. Since the hydraulic pressure of the left and right front wheels is controlled by the number and the like, independent braking force control can be executed in a stable state for each wheel.

  In the above embodiment, the braking force control for only the front wheels has been described, but the same control is performed for the rear wheels.

  The present invention is not limited to the configuration of the above-described embodiment, and each component can be arbitrarily changed according to the spirit of the invention.

It is the schematic which shows the hydraulic circuit with which embodiment of the brake fluid pressure control apparatus of the vehicle which concerns on this invention is provided. It is a control flowchart figure of the electronic controller of this embodiment. It is a hydraulic circuit diagram showing the flow of hydraulic pressure at the time of both-wheels same-pressure increase control in this embodiment. It is a hydraulic circuit diagram showing the flow of hydraulic pressure at the time of both wheel same pressure maintenance control in this embodiment. It is a hydraulic circuit diagram showing the flow of hydraulic pressure when the pressure increase of the left and right wheels in this embodiment is varied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Brake pedal 2 ... Master cylinder 3.4 ... Front wheel cylinder 5 ... Fluid pressure passage 7 ... Branch passage 8 ... Proportional solenoid valve for pressure increase 9 ... Proportional solenoid valve for pressure reduction 10 ... Gear pump (hydraulic pressure source)
13 ... Pump motor 16 ... Second pressure sensor (hydraulic pressure detecting means)

Claims (2)

A wheel cylinder that applies a braking force to each wheel via the internal hydraulic pressure;
Hydraulic pressure supply means for supplying hydraulic pressure to each wheel cylinder;
Hydraulic pressure detecting means for detecting the hydraulic pressure of each wheel cylinder;
Supply hydraulic pressure estimation means for estimating the supply hydraulic pressure of the hydraulic pressure supply means according to a parameter related to the momentum of the hydraulic pressure supply means,
The required braking force of each wheel is calculated by selecting either the hydraulic pressure in each wheel cylinder detected by the hydraulic pressure detecting means or the supplied hydraulic pressure estimated by the supplied hydraulic pressure estimating means. A brake fluid pressure control device for a vehicle, characterized in that it is configured as follows. While each wheel cylinder of the left and right wheels calculates the braking force required by each wheel based on the hydraulic pressure of the wheel cylinder that is performing maximum pressure increase control, the wheel cylinders are held at the same pressure. 2. The vehicle brake fluid pressure according to claim 1, wherein the braking force required by each wheel is calculated based on the estimated fluid pressure detected by the supply fluid pressure estimating means. Control device.

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