JP2017094787A - Brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-piston type brake device capable of suppressing power consumption in performing anti-lock control.SOLUTION: A two-piston type brake device is provided with wheel speed estimation means and a vehicle body speed estimation function part 37. A control device 5 includes a normal control part 51 for performing follow-up control of brake force for a brake command, and an anti-lock control function part 36 for detecting a slide of a wheel against a road surface that the wheel contacts, and performing anti-lock control for suppressing an amount of the slide. When the anti-lock control is performed by the anti-lock control function part 36, the anti-lock control function part 36 controls a load generated by one of two actuators 2 at a constant level, and performs control to increase or decrease a load generated by the other actuator 2 so as to suppress an amount of the slide based on a wheel speed estimated by the wheel speed estimation means, and a vehicle body speed estimated by the vehicle body speed estimation function part 37.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a brake device capable of suppressing power consumption during ABS control in a two-piston type brake device.

In the case of a brake that requires a large load on the front wheels when exerting a braking force in a vehicle, a so-called two-piston type brake device in which two actuators are mounted on one caliper in order to apply a load to the friction pad uniformly. Proposed.
Also, ABS control using a reduction in wheel speed (Patent Document 1), ABS control using an estimated value of road surface frictional force (Patent Document 2), ABS control using an electric brake device (Japanese Patent Application No. 2015-180506). ) Etc. are also proposed.

JP-A-2-11450 JP 2010-70142 A

  When performing ABS control with an electric brake device in which two actuators are mounted on one caliper, large power is required if the load of both actuators is controlled to be increased or decreased.

  An object of the present invention is to provide a brake device capable of suppressing power consumption when performing antilock control in a two-piston type brake device.

The brake device of the present invention includes a brake rotor 3 and
A friction pad 4 that contacts the brake rotor 3 to generate a braking force;
Two actuators 2, 2 each including two pistons 18, 18 for driving the friction pad 4 to abut against the brake rotor 3 by the two pistons 18, 18;
A brake device comprising: a control device 5 that controls the two actuators 2 and 2 in accordance with a given brake command;
Wheel speed estimation means for estimating a wheel speed that is a speed of a wheel for performing a braking operation;
A vehicle speed estimation function unit 37 for estimating the vehicle speed, and
The control device 5
A normal control unit 51 for following and controlling the braking force with respect to the brake command;
An anti-lock control function unit 36 for performing anti-lock control for detecting slippage of the wheel with respect to the ground road surface and suppressing slippage,
When the antilock control function unit 36 is executing antilock control, the antilock control function unit 36 controls the load generated by any one of the actuators 2 to be constant, and the wheel speed estimation means Based on the estimated wheel speed and the vehicle body speed estimated by the vehicle body speed estimation function unit 37, control is performed to increase or decrease the load generated by the other actuator 2 so as to suppress the slip amount. Features.
The “constant” load generated by the one actuator 2 can be determined according to, for example, the estimated road friction coefficient. The relationship between the “constant” load and the road surface friction coefficient is determined by results of tests, simulations, and the like.

  According to this configuration, the normal control unit 51 controls the brake force so as to follow the brake command. The anti-lock control function unit 36 performs anti-lock control (ABS control) that detects the slip of the wheel with respect to the ground road surface and suppresses the slip amount. When the antilock control is being executed, the antilock control function unit 36 controls the load generated by one actuator 2 to be constant. At the same time, the anti-lock control function unit 36 controls to increase or decrease the load generated by the other actuator 2 so as to detect the slip of the wheel with respect to the ground road surface from the wheel speed and the vehicle body speed and suppress the slip amount. Do. As a result, the braking behavior can be stabilized. In addition, when the anti-lock control is being executed, the load generated by one actuator 2 is controlled to be constant, and the total amount of control is less than the control of increasing or decreasing the load generated by both actuators 2 and 2. Power consumption can be suppressed.

The anti-lock control function unit 36 includes a friction coefficient estimation unit 43a that estimates a road surface friction coefficient according to a predetermined condition, and a constant load generated by the one actuator 2 is set to the road surface friction coefficient. It is good also as what controls based on an estimated value.
The predetermined conditions are determined by the results of tests, simulations, and the like.

  According to this configuration, when anti-lock control is being executed by the anti-lock control function unit 36, for example, when the road surface friction coefficient increases due to a change in the road surface state, the anti-lock control function unit 36 determines the increased road surface friction coefficient. The constant load is increased according to the estimated value. On the contrary, when the road surface friction coefficient decreases, the antilock control function unit 36 reduces the constant load according to the estimated value of the decreased road surface friction coefficient. Thereby, the minimum required braking force can be ensured.

The other actuator 2 that increases or decreases the load may correspond to the pad portion 4 a located on the upstream side in the rotational direction of the brake rotor 3 in the friction pad 4.
When the friction pad 4 and the brake rotor 3 come into contact with each other, due to mutual friction, the pad portion 4a located on the upstream side in the rotational direction of the brake rotor 3 in the friction pad 4 (hereinafter referred to as "the pad portion 4a on the entry side") Is applied to the brake rotor 3 as compared with the pad portion 4b located on the downstream side in the rotation direction (hereinafter sometimes referred to as “the pad portion 4b on the delivery side”). . As a result, the pad portion 4a on the turn-in side may be unevenly worn away more than the pad portion 4b on the turn-out side.

  In this case, by determining the actuator 2 corresponding to the pad portion 4a on the turn-in side as the other actuator 2 that increases or decreases the load, the wear amount of the pad portions 4a and 4b on the turn-in side and the turn-out side is made uniform. Evenly, uneven wear of the friction pad 4 can be prevented in advance. Therefore, drag torque resulting from the progress of uneven wear of the friction pad 4 can be reduced, and the replacement time of the friction pad 4 can be delayed.

  The other actuator 2 that increases or decreases the load may correspond to the pad portion 4b located on the downstream side in the rotational direction of the brake rotor 3 in the friction pad 4. Considering the phenomenon that the force that is drawn into the brake rotor 3 acts on the pad portion 4a on the turn-in side, the actuator 2 corresponding to the pad portion 4a on the turn-in side is held at a constant load, The load control can be stably performed by increasing or decreasing the load generated by the actuator 2 corresponding to the side pad portion 4b.

The anti-lock control function unit 36 includes a friction coefficient estimation unit 43a that estimates a road surface friction coefficient according to a predetermined condition. The anti-lock control function unit 36 is estimated by the vehicle body speed estimation function unit 37. Considering the vehicle body speed, the road surface friction coefficient estimated by the friction coefficient estimation unit 43a, and the amount of uneven wear in the friction pad 4, the load is increased or decreased by the wheel speed estimated by the wheel speed estimation means. The other actuator 2 may be determined.
The predetermined conditions are determined by the results of tests, simulations, and the like.
In this case, the anti-lock control function unit 36 appropriately controls the actuator 2 to be controlled to increase or decrease the load according to the vehicle state (body speed, road friction coefficient, uneven wear amount, wheel speed) that changes from moment to moment. Can be changed.

The control device 5 includes a pad portion remaining amount detecting portion 55 that detects the remaining amounts of the pad portions 4a, 4a and 4b, 4b corresponding to the pistons 18, 18, respectively, and the antilock control function portion 36 is When the difference between the remaining amounts detected by the respective pad portion remaining amount detecting portions 55 is equal to or less than a predetermined value, among the friction pads 4, the pad portions 4a located on the upstream side in the rotation direction of the brake rotor 3; The load of the actuator 2 corresponding to 4a may be controlled to be constant, and the load of the actuator 2 corresponding to the pad portions 4b and 4b located on the downstream side in the rotation direction may be increased or decreased.
The predetermined value is determined by the result of a test or simulation.

  According to this configuration, during the anti-lock control, when the difference between the remaining amounts of the pad portions 4a, 4a and 4b, 4b is equal to or less than a predetermined value, it is considered that the uneven wear of the friction pad 4 has not yet occurred. Can do. When it is considered that such uneven wear of the friction pad 4 has not occurred, considering the phenomenon in which a force that is drawn into the brake rotor 3 acts on the pad portion 4a on the entrance side, the pad portion on the entrance side The load control can be stably performed by holding the actuator 2 corresponding to 4a at a constant load and increasing / decreasing the load generated by the actuator 2 corresponding to the pad portion 4b on the delivery side.

The anti-lock control function unit 36 includes a friction coefficient estimation unit 43a that estimates a road surface friction coefficient according to a predetermined condition.
The anti-lock control function unit 36 calculates the road surface friction coefficient estimated by the friction coefficient estimation unit 43a when the difference between the remaining amounts detected by the pad portion remaining amount detection units 55 is larger than the predetermined value. Corresponds to the pad portions 4b and 4b located on the downstream side in the rotation direction when the vehicle speed estimated by the vehicle speed estimation function unit 37 is smaller than the determined vehicle speed. The load of the actuator 2 may be controlled to be constant, and the load of the actuator 2 corresponding to the pad portions 4a and 4a located on the upstream side in the rotation direction may be increased or decreased.
The predetermined condition and the predetermined vehicle body speed are determined based on the results of tests and simulations, respectively.

  According to this configuration, during the anti-lock control, when the difference between the remaining amounts of the pad portions 4a, 4a and 4b, 4b is larger than a predetermined value, it can be considered that the uneven wear of the friction pad 4 is progressing. . In such a case, when the road surface friction coefficient is larger than a predetermined value and the vehicle body speed is smaller than the predetermined vehicle body speed, by increasing or decreasing the load of the actuator 2 of the pad portion 4a on the turn-in side, The wear amount of the pad portions 4a and 4b on the return side and the return side can be uniformly leveled, and uneven wear of the friction pad 4 can be prevented beforehand. Therefore, drag torque resulting from the progress of uneven wear of the friction pad 4 can be reduced, and the replacement time of the friction pad 4 can be delayed.

  Each of the actuators 2 and 2 may include fluid pressure type driving units 58 and 58 for driving the pistons 56 and 56 using a fluid as a medium. In this case, the pistons 56 and 56 can be independently driven by the fluid pressure type drive units 58 and 58. Therefore, the anti-lock control function unit 36 can easily control to increase or decrease the load generated by the other actuator 2 while controlling the load generated by the one actuator 2 to be constant.

  The actuators 2 and 2 may include electric motors 11 and 11 and linear motion mechanisms 12 and 12 that convert the rotational motion of the electric motors 11 and 11 into linear motion of the pistons 18 and 18. . Thus, in the 2-piston type electric actuator 2, power consumption can be suppressed.

The brake device according to the present invention includes a brake rotor, a friction pad that generates a braking force in contact with the brake rotor, and two pistons, and the two pistons cause the one friction pad to the brake rotor. A wheel speed that is a speed of a wheel that performs a braking operation is estimated in a brake device that includes two actuators that drive to contact and separate and a control device that controls the two actuators according to a given brake command A vehicle speed estimation function unit for estimating the vehicle body speed, and the control device includes a normal control unit for controlling the brake force to follow the brake command, and a ground contact surface of the wheel. An anti-lock control function unit that performs anti-lock control that detects slipping to the surface and suppresses slippage. When the antilock control function unit is executing antilock control, the antilock control function unit controls the load generated by any one of the actuators to be constant, and is estimated by the wheel speed estimation unit. Based on the wheel speed and the vehicle body speed estimated by the vehicle body speed estimation function unit, control is performed to increase or decrease the load generated by the other actuator so as to suppress the slip amount.
For this reason, in the two-piston type brake device, power consumption can be suppressed when performing anti-lock control.

1 is a front view of a brake device according to an embodiment of the present invention. It is a left view of the brake device. It is a right view of the brake device. It is a top view which shows a part of the brake device. It is the VV line end view of FIG. It is the VI-VI sectional view taken on the line of FIG. It is a block diagram of the control system of the brake device. It is a block diagram which shows the detailed structure of the control apparatus of the brake device. It is a figure which shows typically each actuator load in ABS control in the brake device. It is a figure which shows the relationship between a slip ratio and a road surface friction coefficient. It is a figure which shows the example of a road surface pattern. It is a figure which shows an example of the relationship between a road surface pattern and a road surface friction coefficient. It is a figure which shows the relationship between the motor torque and load of the forward drive side of this actuator, and a reverse action side. It is a figure which shows an example of the correlation of the motor rotation angle according to the grade of pad wear in the brake device, and a braking force estimated value. It is a figure which shows the example of detection of the pad wear amount by the correlation of the braking force estimated value of the brake device, and a motor rotation angle. In the brake device, it is a figure which shows the example which estimates the pad part abrasion amount from the change rate of the motor rotation angle at the time of the change of brake force estimated value. In the brake device, it is a figure which shows the example which estimates the pad part abrasion amount from the nonlinear strength of the correlation of a braking force estimated value and a motor rotation angle. It is a flowchart which shows the process which controls each actuator of the brake device. It is sectional drawing of the brake device which concerns on other embodiment of this invention. It is a block diagram of the control system of the brake device.

  A brake device according to an embodiment of the present invention will be described with reference to FIGS. This brake device is mounted on a vehicle. FIG. 1 is a front view of the brake device, and FIGS. 2 and 3 are left and right side views of the brake device. As shown in FIG. 3, this brake device is an electric brake device. As shown in FIG. 1, the brake device includes a caliper 1, two actuators 2 and 2 (FIG. 3), a brake rotor 3, friction pads 4 and 4 (FIG. 4), and a control device 5 (FIG. 1). And have.

  As shown in FIGS. 2 and 3, two actuators 2 and 2 are arranged in parallel with a predetermined interval on one caliper 1. As shown in FIG. 4, these actuators 2 and 2 drive to bring one friction pad 4 (FIG. 5) into contact with and separate from the brake rotor 3 (FIG. 4). The predetermined interval is appropriately determined according to the dimensions of the friction pad 4 and the actuator 2.

  6 is a cross-sectional view taken along line VI-VI in FIG. As shown in FIG. 6, the caliper 1 is provided in the vehicle so as to surround the outer peripheral portion of the brake rotor 3. A claw portion 6 is provided at an end portion of the caliper 1 on the outboard side. The claw portion 6 faces the side surface on the outboard side of the brake rotor 3 in the axial direction. The claw portion 6 supports the friction pad 4 on the outboard side. In this specification, the outboard side refers to the vehicle width direction outer side of the vehicle as the outboard side and the vehicle width direction center side of the vehicle as the inboard side in a state where the brake device is mounted on the vehicle.

  In the caliper 1, the friction pad 4 on the inboard side is supported on the outboard side end of the actuator 2. The friction pad 4 faces the inboard side surface of the brake rotor 3 in the axial direction. The actuator 2 drives the friction pad 4 to contact and separate from the brake rotor 3.

  The mount 7 is supported by a knuckle (not shown) in the vehicle. As shown in FIG. 3, pin support pieces 8 and 8 are provided at both ends in the longitudinal direction of the mount 7. Slide pins 9 and 9 extending in parallel with each other in the axial direction are provided at the ends of the pin support pieces 8 and 8, respectively. The caliper 1 is supported by these slide pins 9 and 9 so as to be slidable in the axial direction.

  As shown in FIG. 6, at the time of braking, the friction pad 4 on the inboard side comes into contact with the brake rotor 3 by driving an actuator 2 described later, and presses the brake rotor 3 in the axial direction. The caliper 1 slides to the inboard side by the reaction force of the pressing force. As a result, the friction pad 4 on the outboard side supported by the claw portion 6 of the caliper 1 contacts the brake rotor 3. The braking force is applied to the brake rotor 3 by firmly holding the brake rotor 3 from both sides in the axial direction by the friction pads 4 and 4 on the outboard side and the inboard side.

  Each actuator 2 includes a housing 10, an electric motor 11 (FIG. 3), a linear motion mechanism 12, and a speed reduction mechanism 13. As shown in FIG. 3, cylindrical housings 10 and 10 are fixed to the caliper 1, respectively. An electric motor 11 is supported on each housing 10. As shown in FIG. 6, a linear motion mechanism 12 is incorporated in the housing 10, and the linear motion mechanism 12 applies a braking force to the brake rotor 3 by the output of the electric motor 11 (FIG. 3).

  The linear motion mechanism 12 is a mechanism that converts the rotational motion output from the speed reduction mechanism 13 into a linear motion and causes the friction pad 4 to abut against and separate from the brake rotor 3. The linear motion mechanism 12 includes a rotary shaft 14 that is rotationally driven by the electric motor 11 (FIG. 3), a conversion mechanism portion 15 that converts the rotational motion of the rotary shaft 14 into linear motion, and restraint portions 16 and 17. Have. The conversion mechanism portion 15 includes a linear motion portion 18 that is a piston, a support member 19, a backup plate 20 that is an annular thrust plate, a thrust bearing 21, a rolling bearing 22, a carrier 23, and sliding bearings 24 and 25. And a plurality of planetary rollers 26.

A cylindrical linear motion portion 18 is supported on the inner peripheral surface of the housing 10 so as not to rotate and to be movable in the axial direction. On the inner peripheral surface of the linear motion portion 18, a spiral protrusion is provided that protrudes a predetermined distance radially inward and is formed in a spiral shape. A plurality of planetary rollers 26 are engaged with the spiral protrusions.
A support member 19 is provided on one end side in the axial direction of the linear motion portion 18 in the housing 10. The support member 19 has a boss portion and a flange portion extending radially outward from the boss portion. A plurality of rolling bearings 22 are fitted in the boss portion, and the rotary shaft 14 is fitted to the inner ring inner diameter surface of the rolling bearings 22. The rotary shaft 14 is rotatably supported by the support member 19 via a plurality of rolling bearings 22.

  A carrier 23 that can rotate around the rotation shaft 14 is provided on the inner periphery of the linear motion portion 18. The carrier 23 has a pair of disks that are arranged to face each other in the axial direction. Of these disks, the disk close to the support member 19 is referred to as an inner disk, and the other disk is referred to as an outer disk. A plurality of pillar members are provided on a side surface of the outer side disk facing the inner side disk so as to protrude in an axial direction (inboard side) from an outer peripheral edge portion on the side surface. The outer side disc and the inner side disc are integrally provided by the plurality of column members.

  The inner disk is rotatably supported on the rotary shaft 14 by a slide bearing 24 fitted between the inner disc and the rotary shaft 14. A shaft insertion hole is formed at the center of the outer side disk, and a slide bearing 25 is fitted in the shaft insertion hole. The outer disk is rotatably supported on the rotary shaft 14 by a slide bearing 25. At both ends in the axial direction of the rotating shaft 14, restraining portions 16 and 17 for restraining the axial position of the rotating shaft 14 and the carrier 23 with respect to the support member 19 are provided.

  The carrier 23 is provided with a plurality of roller shafts 27 at intervals in the circumferential direction. Both end portions in the axial direction of each roller shaft 27 are supported across the inner side disk and the outer side disk. Both discs have a plurality of shaft insertion holes. Each shaft insertion hole is composed of a long hole extending a predetermined distance in the radial direction. Both axial ends of each roller shaft 27 are inserted into the respective shaft insertion holes, and these roller shafts 27 are supported so as to be movable in the radial direction within the range of the respective shaft insertion holes. An elastic ring 28 that urges the roller shafts 27 inward in the radial direction is stretched between both axial ends of the plurality of roller shafts 27.

  A planetary roller 26 is rotatably supported on each roller shaft 27. On the outer peripheral surface of each planetary roller 26, a circumferential groove or a spiral groove that meshes with the spiral protrusion of the linear motion portion 18 is formed. Each planetary roller 26 is interposed between the outer peripheral surface of the rotating shaft 14 and the inner peripheral surface of the linear motion portion 18. Each planetary roller 26 is pressed against the outer peripheral surface of the rotating shaft 14 by the urging force of the elastic ring 28. As the rotating shaft 14 rotates, each planetary roller 26 that contacts the outer peripheral surface of the rotating shaft 14 rotates due to contact friction.

  The speed reduction mechanism 13 is a mechanism that transmits the rotation of the electric motor 11 (FIG. 3) at a reduced speed to an output gear 29 fixed to the rotation shaft 14. As shown in FIG. 3, the speed reduction mechanism 13 includes a plurality of gear trains. In this example, the speed reduction mechanism 13 can reduce the rotation of the input gear 30 attached to the rotor shaft (not shown) of the electric motor 11 by the intermediate gear 31 and transmit it to the output gear 29.

  FIG. 7 is a block diagram of a control system of the brake device. The control device 5 of this brake device controls the two actuators 2 and 2 respectively. The control device 5 includes an ECU 32 and two inverter devices 33 and 33 respectively corresponding to the two actuators 2 and 2. For example, an electric control unit that controls the entire vehicle is applied as the ECU 32 that is a higher-level control unit of each inverter device 33.

  The ECU 32 includes a brake force distribution function unit 34, a switching function unit 35, an antilock control function unit 36, and a vehicle body speed estimation function unit 37. The brake force distribution function unit 34 determines the brake force of each wheel according to the vehicle weight distribution, the posture situation, and the like based on the output of the sensor 38a that changes according to the operation amount of the brake pedal that is the brake operation means 38. obtain. The weight distribution of the vehicle is given in advance as, for example, vehicle specifications, and the posture state is determined based on the vehicle specifications, data from the acceleration sensor 39, and the like.

  The vehicle body speed estimation function unit 37 estimates the vehicle body speed of the vehicle using each wheel speed sensor 40 and acceleration sensor 39 provided for each wheel. The vehicle body speed estimation function unit 37 can improve the estimation accuracy of the vehicle body speed using a GPS or the like that can perform other high-speed arithmetic processing. As the acceleration sensor 39, an acceleration sensor capable of measuring three axes orthogonal to each other and moments of each axis is applied.

  As the wheel speed sensor 40, a sensor such as a general ABS sensor that observes a pulse output divided in a predetermined direction in the circumferential direction of the wheel is inexpensive and suitable. Alternatively, in a wheel (not shown) provided with a drive motor (not shown) capable of independent driving of each wheel, a motor angle sensor or a sensorless angle estimation function for driving the drive motor is used as a wheel speed sensor 40. It is possible to use. These ABS sensor, motor angle sensor, and sensorless angle estimation function correspond to wheel speed estimation means.

  As shown in FIG. 8, the anti-lock control function unit 36 causes the wheel to be excessively locked during braking from the vehicle body speed estimated by the vehicle body speed estimation function unit 37 and the wheel speed detected by the wheel speed sensor 40. The braking force for preventing the vehicle can be determined by wheel speed feedback control or brake pressure reduction control accompanying determination of the locking tendency, and can intervene in the control as necessary.

The antilock control function unit 36 includes a wheel slip amount estimation unit 41, an antilock control intervention determination unit 42, and a control calculation unit 43. The wheel slip amount estimation unit 41 estimates the slip amount of the wheel. This wheel slip amount can be defined by the following equation, for example.
Wheel slip amount = (vehicle speed−wheel speed) ÷ vehicle speed In the above equation, the vehicle speed is estimated by the vehicle speed estimation function unit 37. The wheel speed is given from the wheel speed sensor 40.

  The antilock control intervention determination unit 42 determines whether or not to execute the antilock control according to a predetermined condition. Specifically, as the predetermined condition, if the wheel slip amount estimated by the wheel slip amount estimation unit 41 exceeds a predetermined value, the antilock control is started. In addition, the anti-lock control intervention determination unit 42 may additionally include, for example, processing for shifting to anti-lock control when the wheel deceleration exceeds a predetermined value. Each of the predetermined values is determined by a result of a test or simulation.

  The switching function unit 35 receives the command to start the antilock control from the antilock control intervention determination unit 42 and switches the antilock control function unit 36 from the so-called follow-up control by the inverter device 33 without the antilock control function unit 36 interposed. Switch to antilock control to be interposed.

  As shown in FIGS. 8 and 9, when the antilock control (ABS control) is executed by the antilock control function unit 36, the antilock control function unit 36 determines the wheel speed from the wheel speed and the vehicle body speed. Slip on the ground surface is detected and the amount of slip is suppressed. When the anti-lock control is being executed, the control calculation unit 43 frequently repeats ascent and descent with respect to a predetermined braking command to the inverter device 33 (inverter device corresponding to the actuator A in the example of FIG. 9). Therefore, the amount of slip can be suppressed.

  When the antilock control is being executed, the control calculation unit 43 controls the load generated by any one of the actuators 2 (actuator B in the example of FIG. 9) to be constant. At the same time, the control calculation unit 43 increases or decreases the load generated by the other actuator 2 (actuator A in the example of FIG. 9) so as to suppress the slip amount based on the estimated wheel speed and vehicle body speed. Take control.

The control calculation unit 43 includes a friction coefficient estimation unit 43a that estimates a road surface friction coefficient according to a predetermined condition, and a relationship setting unit 43b. The predetermined conditions include formulas (1), (2), and (3) described later, a relationship between a typical road surface slip ratio and a road surface friction coefficient, a road surface pattern, and the like. Expressions (1), (2), and (3) are shown as an example when the road surface friction coefficient μ _i of each wheel is estimated by the friction coefficient estimation unit 43a.

I in equation (1) is the moment of inertia of one driven wheel. In equation (1), ω _i is the rotational speed of each wheel, T _mi is the driving torque of each wheel, r is the tire rotation radius, and X _i is the braking / driving force that is the force in the longitudinal direction of each wheel. I in each parameter is a subscript specifying the i-th (i = 1 to 4) -th wheel (the same applies to the equations (2) and (3)). Z _i in equation (2) is the vertical load on each wheel. In equation (3), λ _i represents a slip ratio at each wheel, and V represents a vehicle body speed. Longitudinal force X _i, the total longitudinal force of the vehicle, i.e., determined from the requested longitudinal acceleration is determined from the accelerator operation or the brake operation of the driver. The vertical load Z _i is the longitudinal acceleration of the vehicle , The lateral acceleration is measured by the acceleration sensor 39, and is calculated as a value considering the influence of load movement caused by each acceleration. Sequential slip ratio λ _i and road surface friction coefficient μ _i are obtained sequentially from equations (1), (2), and (3).
The relationship between the slip ratio λ and the road surface friction coefficient μ is generally represented by a curve as shown in FIG. In the present embodiment, the road surface pattern is preliminarily classified and registered in the relationship setting means 43b (FIG. 8) using the relationship between the representative road surface slip ratio λ and the road surface friction coefficient μ as shown in FIG. .

  As shown in FIG. 8, the friction coefficient estimator 43a compares the plurality of road surface patterns set in the relationship setting means 43b with the estimated slip ratio and the friction coefficient, thereby approximating the road surface most approximated from the plurality of road surface patterns. A pattern is selected, and the road surface friction coefficient set for each road surface pattern is used as the road surface friction coefficient for each wheel.

  Specifically, the friction coefficient estimator 43a determines that the road surface on which the wheel is currently traveling is in a plurality of road surface patterns from the slip ratio obtained by the equation (3) and the road surface friction coefficient obtained by the equation (2). It is determined which road surface pattern is included in the range. In the relationship setting means 43b, the road surface friction coefficient for each road surface pattern is registered as shown in the table of FIG. Therefore, as shown in FIG. 8, the friction coefficient estimation unit 43a selects the current road surface pattern from the relationship between the estimated slip ratio and the road surface friction coefficient, and determines the road surface friction coefficient by illuminating this road surface pattern with the relationship setting means 43b. select. This selected road friction coefficient is used as an estimated value of the road friction coefficient.

  When the anti-lock control is executed, the control calculation unit 43 uses the reference brake force on the reverse operation side described later as a reference for the load generated by one actuator 2 (actuator B in the example of FIG. 9). Control based on the estimated value of the road surface friction coefficient. In this case, for example, the control calculation unit 43 sets the load generated by the one actuator 2 (actuator B in the example of FIG. 9) to increase as the estimated value of the road surface friction coefficient increases. However, it is assumed that the wheels do not slip due to the set load. The relationship between the load and the estimated value of the road surface friction coefficient is determined in advance by results of tests and simulations.

  FIG. 13 is a diagram showing the relationship between the motor torque and the load on the forward drive side and the reverse operation side of the actuator 2 (FIG. 1). The normal efficiency characteristic A1 when increasing the brake load is different from the reverse efficiency characteristic A2 when decreasing the brake load, mainly due to the influence of loss due to friction or the like inside the linear motion mechanism 12 (FIG. 6) or the speed reduction mechanism 13. .

  When the control calculation unit 43 (FIG. 8) performs control to increase or decrease the brake load generated by the actuator 2 (FIG. 7), the motor torque decreases along the arrow L1 while maintaining a certain brake load F1. Go. When the motor torque reaches the reverse efficiency characteristic A2, the brake load decreases along the reverse efficiency characteristic A2 along the arrow L2. When the brake load F2 decreases, the motor torque increases along the arrow L3 while maintaining the brake load F2, and reaches the positive efficiency characteristic A1. Thereafter, the brake load increases along the positive efficiency characteristic A1 along the arrow L4. When the desired motor torque is reached, the motor torque decreases again along the arrow L1 while maintaining the brake load corresponding to the motor torque.

  The hysteresis loss when the unit braking force is increased or decreased is an area S surrounded by the hysteresis lines L1 to L4. One cycle from the hysteresis lines L1 to L4 is one fluctuation cycle, and the total hysteresis loss increases as the number of fluctuation cycles per unit time of the brake load increases. The increase in hysteresis loss increases the power consumption of the brake device. When antilock control is performed in a two-piston type brake device, hysteresis loss increases in each of the two actuators, resulting in a further increase in power consumption.

  Therefore, in the brake device according to the present embodiment, when the anti-lock control is being performed, as described above, as shown in FIG. 8, the control calculation unit 43 has one actuator 2 (actuator B in the example of FIG. 9). ) Is controlled at a constant level. As a result, when antilock control is performed, hysteresis loss in the one actuator 2 (actuator B in FIG. 9) can be suppressed. Therefore, it is possible to suppress the total power consumption rather than performing control to increase or decrease the loads generated by the actuators 2 and 2 respectively.

  The anti-lock control intervention determination unit 42 executes the anti-lock control, for example, when the brake force in the anti-lock control becomes equal to or exceeds the required brake force (brake command), or the vehicle speed. When becomes below a predetermined value, the antilock control is terminated. For example, when the road surface friction coefficient increases due to a change in the road surface state, or when the required brake force decreases during the antilock control, the target brake force by the antilock control becomes the current braking operation means 38 by the operator. Is constantly equal to or exceeds the required braking force according to the operation amount. In that case, since the wheel is not locked even if the antilock control is not performed, the antilock control intervention determination unit 42 ends the antilock control.

In addition, since the antilock control is not important in extremely low speed or in a stopped state, when the vehicle speed estimated by the vehicle speed estimation function unit 37 falls below a predetermined value, the antilock control intervention determination unit 42 End anti-lock control.
The switching function unit 35 receives the command to end the antilock control, and switches to the follow-up control by the inverter device 33 without the antilock control function unit 36 interposed.

Each inverter device 33 includes a brake force estimating unit 44, a power circuit unit 45 provided for each electric motor 11, a motor control unit 46 for controlling the power circuit unit 45, a warning signal output unit 47, Current detection means 48.
The brake force estimation means 44 is a means for obtaining an estimated value of the brake force that presses the friction pad 4 (FIG. 4) against the brake rotor 3 (FIG. 4). In the brake force estimating means 44, the relationship among the output of the sensor 38a, the motor current, and the brake force estimated value is determined by the results of tests and simulations, and is recorded in the recording means 49 so as to be rewritable.

  In addition to this, the brake force estimating means 44 may include a load sensor (not shown) for detecting the axial load of the linear motion mechanism 12 (FIG. 6). In this case, the control device 5 advances the brake from the position where the linear motion portion 18 (FIG. 6) is separated from the brake rotor 3 (FIG. 6) to the outboard side, and the brake is the minimum detection value that can be detected by this load sensor Get power.

  The brake force, which is a detection value detected by the load sensor, gradually increases in accordance with the operation amount that further depresses the brake operation means 38. By using the detection value of the load sensor, the braking force can be detected with high accuracy. In addition, torque estimating means 50 for estimating the motor torque from the motor current detected by the current detecting means 48 may be provided, and the braking force may be estimated using the torque estimated by the torque estimating means 50.

  The motor control unit 46 includes a computer, a program executed on the computer, and an electronic circuit. The motor control unit 46 converts it into a current command based on a voltage value in accordance with a brake force command value (brake force command) given from the brake force distribution function unit 34 and a brake force estimated value estimated by the brake force estimating means 44. Then, this current command is given to the power circuit unit 45. The motor control unit 46 has a function of outputting information such as detection values and control values related to the electric motor 11 to the ECU 32.

  The power circuit unit 45 includes an inverter 45b that converts DC power of a power source (not shown) into three-phase AC power used for driving the electric motor 11, and a PWM control unit 45a that controls the inverter 45b. The electric motor 11 is composed of a three-phase synchronous motor or the like. The electric motor 11 is provided with motor rotation angle detection means Sm for detecting the rotation angle of a rotor (not shown). The inverter 45b is composed of a plurality of semiconductor switching elements (not shown), and the PWM controller 45a performs pulse width modulation on the input current command and gives an on / off command to each of the semiconductor switching elements.

  The motor control unit 46 includes a motor drive control unit 51 as a normal control unit. In principle, the motor drive control unit 51 converts the current command based on the voltage value according to the aforementioned required brake force and the estimated value of the brake force, and gives a motor operation command value including the current command to the PWM control unit 45a. The motor drive control unit 51 obtains a motor current flowing from the inverter 45b to the electric motor 11 from the current detection means 48 with respect to the required brake force, and performs current feedback control. Therefore, the brake force can be controlled to follow the required brake force. Further, the motor drive control unit 51 obtains the motor rotation angle from the motor rotation angle detection means Sm, and gives a current command to the PWM control unit 45a so that efficient motor driving according to the motor rotation angle can be performed.

  The motor control unit 46 is provided with a pad wear amount estimation unit 52, a recording unit 49, and the like. As shown in FIGS. 4 and 5, the pad wear amount estimation means 52 is a combined wear of the pad portions 4 a, 4 a and 4 b, 4 b corresponding to the two linear motion mechanisms 12, 12 (FIG. 6) in the friction pad 4. Estimate each quantity. Pad portions 4a and 4a corresponding to one of the linear motion mechanisms 12 (FIG. 6) in the friction pad 4 are substantially half of the friction pads 4 corresponding to the one of the linear motion mechanisms 12 (FIG. 6) (brake rotor). 3 upstream of the rotation direction). Pad portions 4b and 4b corresponding to the other linear motion mechanism 12 (FIG. 6) in the friction pad 4 are substantially half of the friction pad 4 corresponding to the other linear motion mechanism 12 (FIG. 6) (brake rotor). Part on the downstream side in the rotational direction).

  As shown in FIG. 8, each pad portion wear amount estimation means 52 calculates the friction between the motor rotation angle detected by the motor rotation angle detection means Sm and the brake force estimation value obtained by the brake force estimation means 44 by friction. The pad portions 4a, 4a and 4b, 4b (FIG. 4) of the pad 4 are compared with the predetermined correlation between the motor rotation angle and the estimated brake force when not worn, and the respective pad portions of the current friction pad 4 are compared. The total wear amount of 4a, 4a and 4b, 4b (FIG. 4) is estimated. The amount of wear is determined by subtracting the current remaining amount from the thickness of each pad portion 4a, 4a and 4b, 4b (FIG. 4) when not worn.

  The warning signal output means 47 warns the ECU 32 when the total wear amount of at least one of the pad portions 4a, 4a or 4b, 4b (FIG. 4) estimated by each pad portion wear amount estimation means 52 is equal to or greater than a threshold value. Output a signal. The threshold value is recorded in the recording means 49 so as to be rewritable. For example, an output means 53 (FIG. 7) such as a warning display such as a display, a warning light, or an audio output device is provided on a console panel or the like in the vehicle. When the warning signal is input from the warning signal output means 47, the ECU 32 causes the warning display output means 53 (FIG. 7) to output a warning display or the like. The driver of the vehicle can recognize that the wear limit of the friction pad 4 (FIG. 4) is close based on the warning display that is output.

FIG. 14 is a diagram illustrating an example of the correlation between the motor rotation angle and the estimated brake force value according to the degree of pad wear in the brake device.
The correlation between the motor rotation angle and the estimated braking force is mainly governed by the caliper 1 stiffness, the friction pad 4 compression stiffness, and the actuator 2 stiffness, as shown in FIG. Among these, the rigidity of the caliper 1 and the actuator 2 is substantially linear, and is almost known without changing during continuous use of the brake. In general, the amount of wear of the brake rotor 3 is small with respect to the amount of wear of the friction pad 4 and the amount of compressive deformation of the brake rotor 3 is extremely small with respect to the rigidity of the entire brake. There is almost no impact on the rigidity of the machine.

On the other hand, the compression rigidity of the friction pad 4 is very low compared to the brake rotor 3 and the like, and the influence on the rigidity of the entire brake is large. Therefore, as the friction pad 4 is worn and the rigidity of the friction pad 4 increases, Increases the overall rigidity of the brake.
Therefore, as shown in FIG. 8, the pad wear amount estimation means 52 determines the correlation between the motor rotation angle and the brake force estimated value at the time of non-wear and the current motor rotation angle and the brake force estimated value. From the change in the correlation, the total wear amount of each pad portion 4a, 4a and 4b, 4b (FIG. 4) of the friction pad 4 can be estimated.

  As shown by the solid line in FIG. 14, the friction pad 4 (FIG. 4) exhibits strong non-linearity with respect to the correlation between the motor rotation angle and the estimated brake force when the friction pad 4 (FIG. 6) is not worn. As shown by the dotted line in FIG. 14, in the state where the wear amount of the pad portion is “medium”, the correlation is closer to linear than in the non-wear state. As indicated by the alternate long and short dash line in FIG. 14, in the state where the wear limit of the pad portion wear amount is large, the correlation becomes more linear than the state where the pad portion wear amount is “medium”.

  FIG. 15 is a diagram illustrating a detection example of the wear amount of the pad portion based on the correlation between the estimated brake force value of the brake device and the motor rotation angle. The motor rotation angle θ necessary for exerting a constant braking force F changes to a motor rotation angle θ ′ in a state after the friction pad 4 (FIG. 6) is worn. As shown in FIGS. 8 and 15, the brake force F is estimated by the brake force estimating means 44. The motor rotation angle θ (θ ′) is detected by the motor rotation angle detection means Sm. The pad wear amount estimation means 52 calculates the total wear of the pad portions 4a, 4a and 4b, 4b (FIG. 4) of the friction pad 4 from a map or the like that defines the relationship between the change amount of the motor rotation angle and the pad wear amount. The quantity can be estimated accurately.

FIG. 16 is a diagram showing an example in which the pad wear amount is estimated from the rate of change of the motor rotation angle when the brake force estimated value changes in this brake device. As described above, as the pad wear progresses, the correlation between the motor rotation angle and the brake force estimated value approaches linear. Then, one value either braking force estimated value and the motor rotation angle, in a defined value or more growing or decreasing continue conditions, when the change braking force estimated value from, for example, F ₁ to F _2, the motor rotation By detecting the angle change rate Δθ (Δθ ′), it is possible to determine whether the correlation between the motor rotation angle and the estimated brake force value is maintained non-linear or close to linear, that is, the progress of pad wear.
When estimating the pad wear amount, the correlation between the motor rotation angle θ and the rate of change of each of the brake force estimation bodies F may be used. That is, a value of df / dθ at a predetermined motor rotation angle θ or a value of dθ / dF in a predetermined brake force estimation value F may be used.

  FIG. 17 is a diagram showing an example in which the pad wear amount is estimated based on the strength of the nonlinearity of the correlation between the brake force estimated value and the motor rotation angle in this brake device. As shown in FIGS. 8 and 17, the pad portion wear amount estimating means 52 in this brake device includes a linearity determining portion 54 and a pad portion remaining amount detecting portion 55. The linearity determination unit 54 determines the strength of the linearity of the correlation between the brake force estimated value and the motor rotation angle. The pad portion remaining amount detecting portion 55 determines each pad portion 4a of the friction pad 4 from a brake force estimated value or a motor rotation angle at which the linearity of the correlation determined by the linearity determining portion 54 is equal to or greater than a threshold value. , 4a and 4b, 4b (FIG. 4).

  The linearity determination unit 54 shown in FIG. 8 obtains the change of the other change rate with respect to either the brake force estimated value or the motor rotation angle by, for example, differentiating each parameter twice, and calculates the linearity of the correlation. Detect strength. At this time, in the region where the estimated brake force value is extremely low, the detection accuracy may not be stable. Therefore, a condition more than a predetermined brake force estimate value or a predetermined motor rotation angle may be separately provided. The determined brake force estimated value and the determined motor rotation angle are the minimum value of the estimated brake force value that stabilizes the detection accuracy, or the motor rotation angle that stabilizes the detection accuracy. It is determined based on the minimum angle.

FIG. 18 is a flowchart showing a process for controlling each actuator 2 (FIG. 7) of the brake device. As shown in FIGS. 8 and 18, for example, this processing is started under the condition that the ignition of the vehicle is turned on, and the brake force estimating means 44 acquires the brake force estimated value Fb (step S < _b > 1). The ECU 32 acquires the wheel speed from the wheel speed sensor 40 (step S2), and estimates the vehicle body speed in this vehicle (step S3).

Next, the control calculation unit 43 of the antilock control function unit 36 estimates the slip ratio (step S4). Thereafter, the antilock control intervention determining unit 42 determines whether or not the antilock control is being performed (step S5). If it is determined that the antilock control is being performed (step S5: yes), the antilock control intervention determination unit 42 obtains a reference brake load _Fra for the purpose of wheel speed control (step S6).

The reference brake load _Fra can be obtained from, for example, a feedback control system in which the braking force is an operation amount and the wheel speed is a control amount. Alternatively, a table or the like for deriving the reference brake load _Fra from the wheel speed, the current braking force, the estimated road surface condition, and the wheel deceleration for reaching the target wheel speed using a test or simulation in advance. May be created. In this case, the antilock control intervention determination unit 42 derives the reference brake load F _ra from the table or the like, and determines the target brake force F _r ′ by filtering the reference brake load F _ra (step S7).

  Next, the pad wear amount estimation means 52 estimates the total wear amount of each pad portion 4a, 4a and 4b, 4b (FIG. 4) (step S8). Next, the pad wear amount estimation means 52 subtracts the total wear amount of the pad portions 4a, 4a (FIG. 4) on the entry side from the total wear amount of the pad portions 4b, 4b (FIG. 4) on the delivery side. It is determined whether or not the value is greater than a predetermined value (step S9). The predetermined value is determined by a result of a test or simulation.

When the value is equal to or smaller than the predetermined value (step S9: no), the control calculation unit 43 holds the control target value of the actuator 2 corresponding to the pad portion 4a (FIG. 4) on the turn-in side at a constant value of F _ral. To do. At the same time, the control calculation unit 43 increases or decreases the control target value of the actuator 2 corresponding to the pad portion 4b (FIG. 4) on the delivery side (step S10). When the value is equal to or less than the predetermined value during the anti-lock control, it can be considered that uneven wear of the friction pad 4 (FIG. 4) has not yet occurred. When it is considered that such uneven wear of the friction pad 4 (FIG. 4) has not occurred, a force that is drawn into the brake rotor 3 (FIG. 4) acts on the pad portion 4a (FIG. 4) on the turn-in side. In consideration of this phenomenon, the actuator 2 corresponding to the pad portion 4a (FIG. 4) on the entry side is held at a constant load and is generated by the actuator 2 corresponding to the pad portion 4b (FIG. 4) on the extraction side. The load control can be stably performed by increasing or decreasing the load.

  Next, the control device 5 executes brake force control based on the control target value (step S11), and thereafter ends this processing. In step S9, when the value is larger than the predetermined value (step S9: yes), the anti-lock control function unit 36 determines whether or not the road surface friction coefficient estimated by the friction coefficient estimation unit 43a is larger than the predetermined value. Determination is made (step S12). The predetermined value is determined by a result of a test or simulation.

  If it is determined that the road surface friction coefficient is equal to or less than a predetermined value (step S12: no), the process proceeds to step S10. When it is determined that the road surface friction coefficient is greater than the predetermined value (step S12: yes), the antilock control function unit 36 determines whether the vehicle body speed estimated by the vehicle body speed estimation function unit 37 is smaller than the predetermined value. (Step S13). The predetermined value is determined by a result of a test or simulation. When the vehicle body speed is equal to or higher than the predetermined value (step S13: no), the process proceeds to step S10.

When the vehicle body speed is smaller than the predetermined value (step S13: yes), the control calculation unit 43 holds the control target value of the actuator 2 corresponding to the pad portion 4b (FIG. 4) on the _{delivery side at} a constant value of F _ral. To do. At the same time, the control calculation unit 43 increases or decreases the control target value of the actuator 2 corresponding to the pad portion 4a (FIG. 4) on the entry side (step S14). Thereafter, the process proceeds to step S11. As described above, when the pad remaining amount difference is larger than the predetermined value during the antilock control, it can be considered that the partial wear of the friction pad 4 (FIG. 4) is progressing. In such a case, when the road surface friction coefficient is larger than a predetermined value and the vehicle body speed is smaller than the predetermined vehicle body speed, the load of the actuator 2 of the pad portion 4a (FIG. 4) on the entry side is increased or decreased. By doing so, the wear amount of the pad portions 4a and 4b (FIG. 4) on the entrance side and the exit side can be uniformly leveled, and uneven wear of the friction pad 4 (FIG. 4) can be prevented in advance. Therefore, drag torque resulting from the progression of uneven wear of the friction pad 4 (FIG. 4) can be reduced, and the replacement time of the friction pad 4 (FIG. 4) can be delayed.

  If it is determined in step S5 that the antilock control is not being performed (step S5: no), the control calculation unit 43 sets the control target value of each actuator 2 to the required brake force (step S15). Next, the control calculation unit 43 determines whether or not the estimated slip ratio is greater than a predetermined value (step S16). The predetermined value is determined by a result of a test or simulation. When the slip ratio is less than or equal to the predetermined value (step S16: no), the process proceeds to step S11. When it is determined that the slip ratio is greater than the predetermined value (step S16: yes), the process proceeds to antilock control by the antilock control function unit 36 (step S17). Thereafter, the process proceeds to step S11.

  According to the brake device described above, the motor drive control unit 51 controls the brake force so as to follow the brake command. The antilock control function unit 36 performs antilock control. When the antilock control is being executed, the antilock control function unit 36 controls the load generated by one actuator 2 to be constant. At the same time, the antilock control function unit 36 performs control to increase or decrease the load generated by the other actuator 2 so as to suppress the slip amount of the wheel. As a result, the braking behavior can be stabilized. Further, when the anti-lock control is being executed, the load generated by the one actuator 2 is controlled to be constant, and the total amount of control is less than the control of increasing or decreasing the load generated by both the actuators 2 and 2. Power consumption can be suppressed.

  When the anti-lock control is executed by the anti-lock control function unit 36, for example, when the road surface friction coefficient increases due to a change in the road surface state, the anti-lock control function unit 36 responds to the estimated value of the increased road surface friction coefficient. Increase the constant load. On the contrary, when the road surface friction coefficient decreases, the antilock control function unit 36 reduces the constant load according to the estimated value of the decreased road surface friction coefficient. Thereby, the minimum required braking force can be ensured.

  When the friction pad 4 and the brake rotor 3 come into contact with each other, a force that is drawn into the brake rotor acts on the pad portion on the turn-in side compared to the pad portion on the turn-out side due to mutual friction. As a result, there are cases where uneven wear occurs such that the pad portions 4a, 4a on the entry side are more worn than the pad portions 4b, 4b on the delivery side. In this case, by determining the actuator 2 corresponding to the pad portions 4a, 4a on the turn-in side as an actuator for increasing / decreasing the load, the wear amount of the pad portions 4a, 4b on the turn-in side and the turn-out side is uniformly uniformed. In addition, uneven wear of the friction pad 4 can be prevented in advance. Therefore, drag torque resulting from the progress of uneven wear of the friction pad 4 can be reduced, and the replacement time of the friction pad 4 can be delayed.

Another embodiment will be described.
In the following description, the same reference numerals are assigned to the portions corresponding to the matters described in the preceding forms in each embodiment, and overlapping descriptions are omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in advance unless otherwise specified. The same effect is obtained from the same configuration. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

  FIG. 19 is a cross-sectional view of a brake device according to another embodiment, and FIG. 20 is a block diagram of a control system of the brake device. As shown in FIG. 19, each actuator 2 may include a fluid pressure type drive unit 58 that drives each piston 56 using fluid as a medium. Each drive unit 58 includes a hydraulic cylinder having a wheel cylinder 60 in which a hydraulic chamber 57 (59) is formed and a piston 56. Two pistons 56 and 56 are arranged in parallel to each other in one wheel cylinder 60. These pistons 56 and 56 are configured to be freely advanced and retracted by independent oil passages (1) and (2), respectively.

As shown in FIGS. 19 and 20, a fluid pressure type drive source 61 is provided in a vehicle body (not shown) of a vehicle on which the brake device is mounted. The drive source 61 includes a hydraulic pump 61a and a motor 61b that drives the hydraulic pump 61a.
The discharge port of the hydraulic pump 61a is branched into oil passages (1) and (2). Intensified linear valves 62 and 62 are interposed in the middle of the piping of the oil passages (1) and (2), respectively. The oil passages (1) and (2) are connected to the hydraulic chambers 57 and 59 of the wheel cylinder 60 by piping.

  The control device 5A changes the magnitude of the drive signal according to the output of the sensor 38a that changes according to the operation amount of the brake operation means 38. The pressure-increasing linear valve 62 is a so-called normally closed valve whose normal state is “closed”, and when the drive signal is given from the control device 5A, the opening degree is changed according to the magnitude of the drive signal. As a result, the hydraulic pressure in each of the hydraulic chambers 57 and 59 of the wheel cylinder 60 changes according to the opening degree of the corresponding pressure-increasing linear valve 62. Therefore, the friction pad 4 comes into contact with the brake rotor 3 to generate a braking force.

  When the anti-lock control is executed by the anti-lock control function unit 36, the anti-lock control function unit 36 controls the hydraulic pressure generated by any one of the actuators 2 to be constant and based on the wheel speed and the vehicle body speed. Then, control to increase or decrease the hydraulic pressure generated by the other actuator 2 is performed. Hydraulic pressure sensors 63 and 64 for detecting the hydraulic pressures of the hydraulic chambers 57 and 59 are provided at the lower stages of the pressure-increasing linear valves 62 and 62, respectively. The detection values of these hydraulic sensors 63 and 64 are respectively input to the control device 5A.

  Further, flow meters Sb1 and Sb2 are installed on the oil passages (1) and (2), respectively, and the flow rate of the fluid is detected by these flow meters Sb1 and Sb2, and each detected value is input to the control device 5A. The Furthermore, stroke sensors Sa1 and Sa2 are provided in each drive unit 58, and the movement amounts of the pistons 56 and 56 are input to the control device 5A by the stroke sensors Sa1 and Sa2, respectively.

  The control device 5A uses the detected values of the hydraulic sensors 63 and 64 and the movement amounts of the pistons 56 and 56 calculated from the detected values of the flow meters Sb1 and Sb2 or the stroke sensors Sa1 and Sa2 to each pad portion 4a, 4a and 4b, 4b. The difference in the total wear amount is calculated. Specifically, the total wear amount of the pad portions 4a, 4a on the entry side is subtracted from the total wear amount of the pad portions 4b, 4b on the delivery side. The control device 5A determines whether or not the calculated difference in the total wear amount is larger than a predetermined value (see step S9 in FIG. 18). The wear amount of the pad portions 4a, 4a and 4b, 4b may be detected using the horizontal axis in FIGS.

The relationship between the difference between these detected values and the difference in the amount of wear of each pad portion 4a, 4a is determined by the results of tests, simulations, and the like. Note that the piston movement amount may be calculated using only one of the flow meters Sb1 and Sb2 and the stroke sensors Sa1 and Sa2.
During the anti-lock control, the control device 5A specifies one actuator 2 that controls the oil pressure to be constant and increases / decreases the oil pressure according to the determination result of whether or not the difference in the total wear amount is larger than a predetermined value. The other actuator 2 to be controlled is specified (see steps S10 and S14 in FIG. 18). The configurations of FIGS. 19 and 20 also have the same operational effects as the above-described embodiment.

  The actuator that increases or decreases the load may be an actuator corresponding to the pad portion on the delivery side. In consideration of the phenomenon that the force that is pulled into the brake rotor acts on the pad portion on the return side, the actuator corresponding to the pad portion on the return side is held at a constant load, and the pad portion on the return side The load control can be stably performed by increasing or decreasing the load generated by the actuator corresponding to.

  The anti-lock control function unit 36 determines the actuator 2 that increases or decreases the load according to the wheel speed estimated by the wheel speed estimation means, taking into account the vehicle body speed, the road surface friction coefficient, and the amount of uneven wear on the friction pad 4. good. In this case, the antilock control function unit 36 can appropriately change the actuator 2 to be controlled to increase or decrease the load according to the state of the vehicle that changes from moment to moment. The vehicle state includes a vehicle body speed, a road surface friction coefficient, a partial wear amount, and a wheel speed.

  As mentioned above, although the form for implementing this invention based on embodiment was demonstrated, embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

2 ... Actuator 4 ... Friction pads 4a, 4b ... Pad portions 5, 5A ... Control device 11 ... Electric motor 12 ... Linear motion mechanism 18 ... Linear motion portion (piston)
36 ... Anti-lock control function unit 37 ... Vehicle speed estimation function unit 43a ... Friction coefficient estimation unit 51 ... Motor drive control unit (normal control unit)
55 ... Pad part remaining amount detection part 56 ... Piston 58 ... Drive part

Claims (9)

A brake rotor,
A friction pad that contacts the brake rotor and generates a braking force;
Two actuators each including two pistons, and two actuators for driving the one friction pad against and separating from the brake rotor by the two pistons;
A brake device comprising: a control device that controls the two actuators according to a given brake command;
Wheel speed estimation means for estimating a wheel speed that is a speed of a wheel for performing a braking operation;
A vehicle body speed estimation function unit for estimating the vehicle body speed,
The controller is
A normal control unit for controlling the brake force to follow the brake command;
An anti-lock control function unit that performs anti-lock control that detects slippage of the wheel with respect to the ground road surface and suppresses the slip amount; and
When antilock control is being executed by the antilock control function unit, the antilock control function unit controls the load generated by any one of the actuators to be constant and is estimated by the wheel speed estimation means. A brake device that performs control to increase or decrease a load generated by the other actuator so as to suppress the slippage based on the wheel speed and the vehicle body speed estimated by the vehicle body speed estimation function unit. .   2. The brake device according to claim 1, wherein the anti-lock control function unit includes a friction coefficient estimation unit that estimates a road surface friction coefficient according to a predetermined condition, and a constant load generated by the one actuator. 3. Is controlled based on the estimated value of the road surface friction coefficient.   3. The brake device according to claim 1, wherein the other actuator that increases or decreases the load corresponds to a pad portion of the friction pad that is positioned upstream in the rotational direction of the brake rotor. 4. apparatus.   3. The brake device according to claim 1, wherein the other actuator that increases or decreases the load corresponds to a pad portion of the friction pad that is located downstream in the rotational direction of the brake rotor. 4. apparatus.   3. The brake device according to claim 1, wherein the anti-lock control function unit includes a friction coefficient estimation unit that estimates a road surface friction coefficient according to a predetermined condition, and the anti-lock control function unit includes the anti-lock control function unit. The wheel estimated by the wheel speed estimation means in consideration of the vehicle body speed estimated by the vehicle body speed estimation function unit, the road surface friction coefficient estimated by the friction coefficient estimation unit, and the amount of uneven wear in the friction pad A brake device that determines the other actuator that increases or decreases the load according to speed.   The brake device according to any one of claims 1 to 5, wherein the control device includes a pad portion remaining amount detection unit that detects a remaining amount of a pad portion corresponding to each piston, The anti-lock control function unit is a pad located on the upstream side in the rotational direction of the brake rotor among the friction pads when the difference between the remaining amounts detected by the respective pad unit remaining amount detecting units is equal to or less than a predetermined value. The brake device which controls the load of the actuator corresponding to the portion to be constant, and increases or decreases the load of the actuator corresponding to the pad portion located on the downstream side in the rotation direction. The brake device according to claim 6, wherein the anti-lock control function unit includes a friction coefficient estimation unit that estimates a road surface friction coefficient according to a predetermined condition.
The anti-lock control function unit determines a road surface friction coefficient estimated by the friction coefficient estimation unit when a difference between the remaining amounts detected by the pad portion remaining amount detection units is larger than the predetermined value. When the vehicle body speed estimated by the vehicle body speed estimation function unit is smaller than a predetermined vehicle body speed, the load of the actuator corresponding to the pad portion located downstream in the rotational direction is controlled to be constant. And the brake device which increases / decreases the load of the actuator corresponding to the pad part located in the said rotation direction upstream.   8. The brake device according to claim 1, wherein each of the actuators includes a fluid pressure type drive unit that drives each of the pistons using fluid as a medium. 9. 8. The brake device according to claim 1, wherein each actuator includes an electric motor and a linear motion mechanism that converts a rotational motion of the electric motor into a linear motion of each piston. 9. Brake device.

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