JPH10329676A - Braking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably make a brake effective by providing a pressure intensifier to control the liquid pressure level of a brake cylinder so that a real body deceleration detected by a body deceleration detecting means can be equal to a target body deceleration based on an operating force relative amount detected by a brake operating force relative amount detecting means. SOLUTION: An operating force sensor 302 constitutes a brake operating force relative amount detecting means. Plural wheel speed sensor 306, an estimated speed computing means 326 and a real body deceleration computing means 328 are mutually cooperated to constitute a body deceleration detecting means. A booster negative pressure switch 304, a distribution control valve 60, a pressure intensifier 100, a pump and a pump motor 310, a controller related to effectiveness control out of an ECU constitute a pressure intensifier. A control condition determining means 330 determines the respective control conditions of a valve device and the pump motor 310 to be zero deviation in accordance with the deviation of the determined target body deceleration from the computed real body deceleration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake device for a vehicle, and more particularly to a technique for stabilizing the braking effect of the brake device.

[0002]

2. Description of the Related Art Generally, a brake device for a vehicle includes (a) a brake operating member operated by a driver such as a brake pedal, and (b) a master cylinder which generates a hydraulic pressure based on the operation of the brake operating member. And (c) a brake cylinder that is connected to the master cylinder by a liquid passage, has a brake cylinder that is operated by hydraulic pressure supplied from the liquid passage, and that suppresses rotation of the wheels.
Here, the “master cylinder” is generally configured such that a pressurizing piston is slidably fitted to the master cylinder housing, thereby forming a pressurizing chamber between the master cylinder housing and the pressurizing piston. Is done.

[0003]

Problems to be Solved by the Invention, Means for Solving Problems, Functions and Effects The applicant has previously developed the following brake device. (A) a brake operation force-related amount detection means for detecting an amount related to the operation force of the brake operation member; and (b) the brake cylinder hydraulic pressure is changed to a master cylinder pressure after a pressure increase start condition is satisfied during the brake operation. And a pressure-intensifying device that controls the height of the brake cylinder hydraulic pressure to be equal to a target value based on the operation force-related amount detected by the brake operation force-related amount detection means. Device. Here, the "pressure increase start condition" includes, for example, that the booster provided between the brake operating member and the master cylinder has reached the assisting limit, or that the brake operating force exceeds the reference value or the brake operation is performed. This includes the fact that the sudden braking operation in which the operation speed of the member exceeds the reference value has been started.

[0004] However, it has been found that this developed brake device has a problem that the braking effect cannot be sufficiently stabilized. Hereinafter, this will be specifically described.

[0005] The effectiveness of the brake is determined by the relationship between the brake operating force and the vehicle deceleration. Here, the height of the vehicle body deceleration does not always correspond one-to-one with the height of the brake cylinder hydraulic pressure. The brake cylinder fluid pressure, which is an input to the brake, and the wheel braking force, which is an output, do not always correspond one-to-one. For example, the friction coefficient of the friction material in the brake changes over time, This is because the friction coefficient may vary depending on the heat and moisture of the material, and the friction coefficient may differ between individuals due to manufacturing variations of the friction material. Nevertheless, in the above-described developed brake device, the height of the brake cylinder hydraulic pressure is unilaterally controlled in accordance with the operation force-related amount. Therefore, the developed brake device has a problem that the effectiveness of the brake varies due to the influence of the variation of the friction coefficient of the brake friction material and the like.

The present invention has been made in view of the above circumstances, and an object thereof is to stabilize the braking effect.

[0007] This problem is solved by a brake device of the following mode. In the following description, each aspect of the present invention will be described in the same form as the claims, with the respective items numbered. This is to clarify the possibility of adopting the features described in each section in combination.

(1) A brake operating member operated by a driver, a master cylinder for generating a hydraulic pressure based on the operation of the brake operating member, connected to the master cylinder by a liquid passage, and supplied from the liquid passage. A brake cylinder having a brake cylinder that is actuated by a hydraulic pressure to be applied, and a brake that includes a brake that suppresses the rotation of wheels. Body deceleration detecting means for detecting the actual vehicle deceleration, and after the pressure increase start condition is satisfied during the brake operation, the hydraulic pressure of the brake cylinder is increased from the hydraulic pressure of the master cylinder, and the hydraulic pressure of the brake cylinder is increased. The actual vehicle deceleration detected by the vehicle body deceleration detecting means is detected by the brake operating force related amount detecting means. And a pressure increasing device for controlling the target vehicle body deceleration based on the operated force-related amount to be equal to the target vehicle deceleration. In this brake device, the height of the brake cylinder hydraulic pressure is controlled such that the actual vehicle deceleration is equal to the target vehicle deceleration while monitoring the actual vehicle deceleration. Therefore, according to this brake device, the effect of the brake is stabilized irrespective of the fluctuation of the friction coefficient of the brake friction material and the effect that the braking performance of the vehicle is improved. In this brake device, the “brake operation force-related amount detection means” is, for example, an operation force sensor that detects an operation force of a brake operation member, an operation stroke sensor that detects an operation stroke, or detects a hydraulic pressure of a master cylinder. It may be a master cylinder hydraulic pressure sensor or a booster variable pressure chamber pressure sensor for detecting the pressure of the variable pressure chamber in the booster. Further, in this brake device, the `` vehicle deceleration detecting means '' is, for example, a deceleration sensor that directly detects the actual vehicle deceleration, (a) vehicle speed detecting means that detects the vehicle speed, and (b) the detected And an actual vehicle deceleration calculating means for calculating the actual vehicle deceleration as a time differential value of the vehicle speed. Here, the `` vehicle speed detecting means '' includes, for example, (a) a plurality of wheel speed sensors for detecting each wheel speed of a plurality of wheels in the vehicle, and (b) a plurality of wheel speeds detected for the plurality of wheels. Based on the fact that the largest one is closest to the true vehicle speed, the vehicle may include an estimated vehicle speed calculating means for calculating the estimated vehicle speed based on the wheel speeds of the plurality of wheels. (2) Further, a booster is provided between the brake operating member and the master cylinder, and a booster that assists the operating force and outputs the boosted force to the master cylinder is provided, and the pressure increasing start condition is:
The brake device according to claim 1, which includes that the booster has reached an assisting limit (claim 2). In this brake device, the brake cylinder pressure is increased from the master cylinder pressure after the booster assist limit, and the height of the brake cylinder pressure is set so that the actual vehicle deceleration becomes equal to the target vehicle deceleration. Controlled. Therefore, according to the brake device, in the brake device including the booster, the same braking effect as before the boosting limit is realized even after the boosting limit of the booster, and the braking effect is caused by the fluctuation of the friction coefficient of the brake friction material. And the like, so that a stable braking effect can be achieved. In this brake device, the “booster” can be a vacuum booster using a negative pressure source as a drive source, or a hydraulic booster using a high pressure source as a drive source. (3) The pressure booster pumps up the hydraulic fluid from the suction side and discharges the boosted pressure toward the brake cylinder in a state where the flow of the hydraulic fluid from the brake cylinder to the master cylinder is blocked at least. The brake device according to the above mode (1) or (2), which is a pump pressurizing type pressure intensifying apparatus performed by the above method. (4) the master cylinder, a pressurized piston is slidably fitted to the master cylinder housing, thereby forming a pressurized chamber between the master cylinder housing and the pressurized piston, The suction side is a pressurization chamber of the master cylinder, and further includes a hydraulic fluid introduction passage for introducing the hydraulic fluid in the pressurization chamber to the suction side of the pump so that the hydraulic pressure does not decrease (3). The brake device according to the paragraph. In this brake device, at the time of pressure increase control, the hydraulic pressure of the master cylinder is effectively used to increase the pressure of the brake cylinder. Therefore, according to this brake device, there is obtained an effect that the operation responsiveness of the pump during the pressure increase control is improved. (5) The pressure increasing device is further provided in the middle of the fluid passage, and allows a bi-directional flow of hydraulic fluid between the master cylinder and the brake cylinder. A flow control valve for switching to a second state for preventing a flow of hydraulic fluid toward the cylinder, wherein the pump has a discharge side connected to a portion of the liquid passage between the flow control valve and the brake cylinder, respectively. The brake device according to (3) or (4), wherein the pressure increase device performs the pressure increase by operating the pump with the flow control valve in the second state. In this brake device, the "flow control valve"
An electromagnetic type that has a solenoid and switches to a plurality of states by its magnetic force, or a mechanical type that switches to a plurality of states by a differential pressure between a master cylinder and a brake cylinder can be used. In the case of the mechanical type, the level of the differential pressure between the master cylinder and the brake cylinder may be controlled mechanically, or may be controlled electromagnetically by the magnetic force of a solenoid. (6) the flow control valve is configured to electromagnetically switch to the plurality of states, and the pressure increasing device further includes a connection point between the liquid passage and a discharge side of the pump and the flow control valve. And a pressure control valve that electromagnetically switches between a state in which the brake cylinder communicates with the flow control valve and the pump and a state in which the brake cylinder is shut off therefrom, and the flow control valve, the pressure control valve, and the pump. The brake device according to the mode (5), wherein the hydraulic pressure of the brake cylinder is controlled by the joint operation of the brake device. (7) the pressure intensifier, (a) pump control means for operating the pump, (b) a control valve for switching the flow control valve and the pressure control valve to each of the plurality of states in the operating state of the pump The brake device according to mode (5), including a control unit. (8) the pressure intensifier, (a) a flow control valve control means for setting the flow control valve to the second state, and (b) discharge of the hydraulic fluid from the pump in the second state of the flow control valve. The brake device according to item (5), further comprising: a discharge amount control unit that controls the amount. (9) The brake device according to (8), wherein the discharge amount control means includes a motor duty control means for duty-controlling an excitation current of a motor driving the pump. (10) Further, an inflow control valve provided on the suction side of the pump and electromagnetically switched between a state in which the hydraulic fluid is allowed to flow from the master cylinder to the suction side of the pump and a state in which the hydraulic fluid is blocked, The brake device according to claim 8, wherein the discharge amount control means includes an inflow control valve duty control means for duty-controlling an excitation current of a solenoid that drives the inflow control valve. (11) Further, the brake device includes a wheel torque control device that performs wheel torque control for automatically controlling the wheel torque by the brake, and the pump is driven by the wheel torque control device to cause the brake device to operate in the brake device. The brake device according to any one of (3) to (10), which is used to generate a flow of hydraulic fluid. In this brake device, the same pump is used for both wheel torque control and pressure increase control. Therefore, according to this brake device, it is not necessary to provide a dedicated pump for pressure increase control,
The effect that the cost increase of the apparatus for realizing the pressure increase control is reduced is obtained. In this brake device, "wheel rotational force control" includes, for example, anti-lock control to prevent the tendency of locking the wheels during vehicle braking to be excessive,
Traction control that prevents the spin tendency of the driving wheels from becoming excessive when the vehicle is driven, and control of the braking force or the driving force difference between the left and right wheels, which reduces the running stability of the vehicle while the vehicle is running. There is a vehicle stability control that prevents (12) Further, a booster provided between the brake operating member and a master cylinder, which boosts the operating force and outputs the boosted force to the master cylinder, wherein the pressure booster determines whether the booster has reached a boosting limit. The brake device according to any one of (1) to (11), including an assisting limit determination device that determines whether the brake device is not in use. (13) the booster is a vacuum booster that operates a power piston by a differential pressure between a negative pressure chamber communicating with a negative pressure source and a variable pressure chamber selectively communicated with the negative pressure chamber and the atmosphere; When the limit determination device is (a) a booster pressure sensor that detects the pressure of the transformation chamber, and (b) based on the detected transformation chamber pressure, when the transformation chamber pressure becomes substantially equal to the atmospheric pressure, An assist limit determining means for determining that the vacuum booster has reached an assist limit.
The brake device according to item 2). In this brake device, for example, the “booster pressure sensor” may be configured to output a value that changes continuously as the pressure in the variable pressure chamber changes, or may output a value that changes discretely. it can. One example of the latter type is a booster negative pressure switch that outputs a signal that changes between two states as the pressure in the transformation chamber changes between two states. (14) the pressure intensifier, (a) target vehicle body deceleration determining means for determining a target vehicle body deceleration according to the detected operation force related amount, (b) the determined target vehicle body deceleration and Control state determining means for determining a control state to be realized according to a predetermined relationship between the deviation and a control state of the hydraulic pressure of the brake cylinder based on the detected deviation from the actual vehicle deceleration; c) The brake device according to any one of (1) to (13), further including control means for controlling a hydraulic pressure of the brake cylinder in the determined control state. (15) The pressure-intensifying device, (a) based on the detected operating force-related amount and the detected actual vehicle deceleration, based on the operating force-related amount, the actual vehicle deceleration, and the hydraulic pressure of the brake cylinder. Control state determining means for determining a control state to be realized according to a predetermined relationship with the control state; and (b) control means for controlling the hydraulic pressure of the brake cylinder in the determined control state. The brake device according to any one of (1) to (13). (16) a booster provided between the brake operating member and the master cylinder for assisting the operating force and outputting the boosted force to the master cylinder, wherein the pressure increasing device operates the operating force of the actual vehicle deceleration. (1) The brake device according to any one of (1) to (15), further including control means for controlling the hydraulic pressure of the brake cylinder so that the change gradient with respect to the pressure does not substantially change before and after the boosting limit of the booster.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some specific embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a brake device for a four-wheeled vehicle according to an embodiment of the present invention. This brake device includes a booster between a brake operation member and a master cylinder. The brake device further includes an anti-lock control device and an effectiveness characteristic control device. The anti-lock control device is a device that prevents the locking tendency of each wheel from becoming excessive during vehicle braking. This antilock control device has a pump, and the hydraulic fluid is recirculated in the brake circuit by the pump. In contrast, the effectiveness characteristic control device, because of the boosting limit the booster, as shown graphically in Figure 2, not the master cylinder pressure P _M is increased always by the same gradient with respect to the brake operating force F is As shown in the graph of FIG. 3, the braking operation force is set such that the actual vehicle deceleration G increases at the same gradient with respect to the braking operation force F regardless of before and after the boosting limit of the booster. This is a device for controlling the braking effect characteristic, which is the relationship between F and the actual vehicle deceleration G. This effect characteristics control device controls the effect characteristics using the pump. That is, the pump is shared by the antilock control device and the effectiveness characteristic control device.

In FIG. 1, reference numeral 10 denotes a master cylinder. The master cylinder 10 is of a tandem type and includes two pressurizing pistons 10 in a master cylinder housing 10a.
The pressurizing chambers 10d and 10e are formed independently of each other in the master cylinder housing 10a in front of the pressurizing pistons 10b and 10c. ing. The master cylinder 10 is linked to a brake pedal 14 as a brake operating member via a vacuum booster (hereinafter simply referred to as “booster”) 12 as a booster. The booster 12 includes a negative pressure chamber 12c in which a space inside the booster housing 12a is communicated by a power piston 12b to an engine intake pipe as a negative pressure source, and a variable pressure chamber in which the negative pressure chamber 12c is selectively communicated with the atmosphere. 12d, the negative pressure chamber 12c and the transformation chamber 1
The master cylinder 10 is actuated by the actuation force of the power piston 12b due to the pressure difference from 2d. Thereby, the operating force F of the brake pedal 14 is assisted by the booster 12 and transmitted to the master cylinder 10, and the hydraulic pressure having a height corresponding to the assisted operating force F is applied to each of the pressurizing chambers 10d and 10e.
Is generated.

One pressurizing chamber 10e of the master cylinder 10
Is connected to a first brake system for the left front wheel FL and the right rear wheel RR, and the other pressurizing chamber 10d is connected to a second brake system for the right front wheel FR and the left rear wheel RL. That is, this brake device is a diagonal two-system type. Since these two brake systems have a common configuration, only the first brake system will be described with text and drawings as a representative, and the description of the second brake system will be omitted.

In the first brake system, the master cylinder 10 uses a main passage 48 (liquid passage) to operate a brake for suppressing the rotation of the left front wheel FL, and a brake cylinder 50 for braking the right rear wheel RR.
And connected to. The brake is of a type (a disk type, a drum type, and the like) that suppresses rotation of the wheel by pressing a friction material against a friction surface of a rotating body that rotates together with the wheel by an operating force based on hydraulic pressure. In addition, main passage 4
Reference numeral 8 denotes a bifurcated branch after extending from the master cylinder 10, and one main passage 54 and two branch passages 56 are connected to each other. Each brake cylinder 50 is connected to the tip of each branch passage 56.

A flow control valve 60 is provided in the main passage 54. The flow control valve 60 includes a solenoid 62
Based on the magnetic force (see FIG. 4), an open state (first state) that allows bidirectional flow of hydraulic fluid between the master cylinder 10 and the brake cylinder 50, and at least the brake cylinder 50 The state is switched to the closed state (second state) in which the flow of the working fluid in the forward direction is blocked. The flow control valve 60 is opened when the solenoid 62 is OFF, and is switched to closed when ON.

The flow control valve 60 has a bypass passage 82
A check valve 84 is provided in the middle of the bypass passage 82. Even if the flow control valve 60 is closed due to the fluid force generated in the movable member in the flow control valve 60 when the brake pedal 14 is depressed, the flow of the hydraulic fluid from the master cylinder 10 to the brake cylinder 50 is ensured. That's why.
The flow control valve 60 further has a relief valve 8 in parallel with it.
6 is also provided. This is to prevent the discharge pressure of the pump 112 described below from becoming excessive.

A pressure-intensifying valve 90, which is a normally open electromagnetic on-off valve, is provided in the middle of each of the branch passages 56. Realize. A bypass passage 92 is connected to each pressure increasing valve 90, and a check valve 94 for returning hydraulic fluid is provided in each bypass passage 92. A reservoir passage 96 extends from a portion of each branch passage 56 between the pressure intensifying valve 90 and the brake cylinder 50 to form a reservoir 98.
Has been reached. A pressure reducing valve 100, which is a normally closed electromagnetic on-off valve, is provided in the middle of each of the reservoir passages 96, and realizes a reduced pressure state in which the flow of hydraulic fluid from the brake cylinder 50 to the reservoir 98 is allowed in an open state. The reservoir 98 is formed by fitting a reservoir piston 104 to the reservoir housing in a substantially airtight and slidable manner, and a spring 108 as a biasing means for urging the hydraulic fluid in a reservoir chamber 106 formed by the fitting. Is stored under pressure.

The reservoir 98 is connected by a suction passage 110 to the suction side of a pump 112, and the discharge side of the pump 112 is connected by a discharge passage 114 to a portion of the main passage 48 between the flow control valve 60 and the pressure increasing valve 90. ing. The suction passage 110 is provided with a suction valve 116 as a check valve, and the discharge passage 114 is provided with a discharge valve 118 as a check valve. The discharge passage 114 is further provided with an orifice 120 as a throttle and a fixed damper 122, respectively, so that pulsation of the pump 112 is reduced.

When the antilock control is not being performed, it is normal that there is no hydraulic fluid to be pumped into the reservoir 98. Therefore, in order to always guarantee the execution of the effect characteristic control, it is necessary to supply the working fluid to the reservoir 98 regardless of whether the antilock control is executed.

Therefore, in the present embodiment, a supply passage 130 extending from a portion of the main passage 54 between the master cylinder 10 and the flow control valve 60 to reach the reservoir 98 is provided. However, since the master cylinder 10 and the reservoir 98 are always communicated with each other through the supply passage 130, even if the brake pedal 14 is operated, the master cylinder 10 is pressurized unless the reservoir piston 104 bottoms in the reservoir 98. And the delay of the braking effect occurs. Further, during the anti-lock control, the pump 112 pumps the hydraulic fluid from the master cylinder 10 instead of the reservoir 98, and the pressure reducing function of the reservoir 98 is hindered.

Therefore, in the present embodiment, an inflow control valve 140 is provided in the middle of the supply passage 130. The inflow control valve 140 is connected to the reservoir 9 from the master cylinder 10.
When it is necessary to replenish the hydraulic fluid to the reservoir 8, it is opened, allowing the flow of the hydraulic fluid from the master cylinder 10 to the reservoir 98, while it is not necessary to replenish the hydraulic fluid from the master cylinder 10 to the reservoir 98. Sometimes, it is closed, and the flow of the hydraulic fluid from the master cylinder 10 to the reservoir 98 is blocked, so that the pressure rise by the master cylinder 10 is enabled. In the present embodiment, the inflow control valve 140 is a normally closed electromagnetic on-off valve. Further, in the present embodiment, it is determined whether or not it is necessary to introduce the hydraulic fluid from the master cylinder 10 during the antilock control, and there is no hydraulic fluid to be pumped by the pump 112 in the reservoir 98 during the antilock control. It is determined whether the hydraulic fluid is present or not, and the integrated value of the time when the pressure increasing valve 90 is in the pressure increasing state and the integrated value of the time when the pressure reducing valve 100 is in the pressure reducing state are calculated respectively. The operation is performed by estimating the remaining amount of the working fluid in the reservoir 98 based on the pressure increasing time and the pressure decreasing time.

During operation of the brake, when the hydraulic fluid in the portion of the main passage 48 upstream of the flow control valve 60 is used to pressurize the hydraulic fluid by the pump 112, the high-pressure operation in the upstream portion is performed. Rather than pumping the liquid with the reservoir 98 at a low pressure by the pump 98 without pumping the liquid to a low pressure, the operation responsiveness of the pump 112 is improved, and the pump 112 is easily reduced in capacity by reducing the load on the pump 112. Becomes

Therefore, in the present embodiment, the flow of the hydraulic fluid from the supply passage 130 toward the reservoir 98 is provided at a portion of the suction passage 110 between the connection point with the supply passage 130 and the connection point with the reservoir passage 96. And a check valve 142 is provided to prevent the flow in the opposite direction.

FIG. 4 shows an electrical configuration of the brake device. The brake device is a CPU, ROM and R
An ECU (electronic control unit) 300 mainly including a computer including an AM is provided. Various routines including a braking effect characteristic control routine (shown in flowcharts in FIGS. 5 and 6) and an antilock control routine (not shown) are stored in the ROM.
When these routines are executed by the CPU while using the RAM, the effect characteristic control and the antilock control are respectively executed.

An operation force sensor 302, a booster negative pressure switch 304 and a wheel speed sensor 306 are connected to the input side of the ECU 300. The operation force sensor 302 detects the operation force of the brake pedal 14 and outputs an operation force signal that defines the operation force. The booster negative pressure switch 304 is
When the pressure in the transformation chamber 12d of the booster 12 is lower than the atmospheric pressure, the booster 12 outputs a booster negative pressure signal (first signal) in an OFF state, and when the pressure is higher than the atmospheric pressure, the booster negative pressure signal (second signal) in an ON state. Is output. Wheel speed sensor 306
Is provided for each wheel and outputs a wheel speed signal that defines the wheel speed of each wheel.

On the other hand, a pump motor 310 for driving the pump 112 is connected to the output side of the ECU 300.
A motor drive signal is output to the pump motor 310. On the output side of the ECU 300, a solenoid 62 of the flow control valve 60 and solenoids 312, 31 of the inflow control valve 140, the pressure increasing valve 90, and the pressure reducing valve 100 are further provided.
4,316 are also connected. Each solenoid 62, 31
ON / OFF drive signals for ON / OFF drive are output to 2, 314 and 316, respectively.

Here, the effect characteristic control by the ECU 300 will be described, but first, it will be described schematically.

FIG. 11 is a functional block diagram showing the configuration of the effectiveness characteristic control device. The portion of the ECU 300 relating to the effectiveness characteristic control device is shown in the frame of the broken line in the figure. The effectiveness characteristic control device includes an assist limit determination unit 320 connected to the booster negative pressure switch 304. The boosting limit judging means 320 determines the negative pressure chamber 12 of the booster 12 based on the output signal of the booster negative pressure switch 304.
When the pressure d rises to the atmospheric pressure, it is determined that the booster 12 has reached the assisting limit. This assist limit determination means 3
20 is connected to pressure increase control start means 322 for instructing the start of pressure increase control of the brake cylinder 50 when it is determined that the booster 12 has reached the assisting limit. That is, in the present embodiment, the booster 12 reaching the assisting limit is the “pressure increase start condition”. The effectiveness characteristic control device further includes target vehicle deceleration determining means 324 connected to the operation force sensor 302. The target vehicle deceleration determining means 324 determines a predetermined relationship between the operating force F and the target vehicle deceleration G ^* according to the operating force F detected by the operating force sensor 302 (see the solid line graph in FIG. 9). The target vehicle deceleration G ^* is determined this time.

FIG. 7 shows the estimated vehicle speed calculating means 326 connected to the plurality of wheel speed sensors 306. The estimated vehicle speed calculating means 326 is constituted by the antilock control routine, and includes a plurality of wheel speed sensors 306.
Based on the wheel speeds of a plurality of wheels detected by the above, the estimated vehicle speed VS0 is calculated by utilizing the fact that the maximum wheel speed of the four wheels is closest to the true vehicle speed during vehicle braking. The effectiveness characteristic control device includes an estimated vehicle speed calculating means 32.
6 is provided with an actual vehicle deceleration calculating means 328 connected to the vehicle. The actual vehicle deceleration calculating means 328 calculates the actual vehicle deceleration G as a time differential value of the calculated estimated vehicle speed VS0.

The effectiveness characteristic control device further includes a control state determining means 330. This control state determining means 33
0 is based on the deviation δ of the determined target vehicle deceleration G ^* from the calculated actual vehicle deceleration G, and is based on the flow control valve 60, the pressure increasing valve 90, and the pressure reducing valve 100 (hereinafter referred to as “valve”). And the control state of the pump motor 310 is determined such that the deviation δ becomes zero.

[0030] pressure control mode valve device 60,90,100 includes a rapid increase mode pressure increase the brake cylinder pressure P _B with steep slopes, and slow increase mode which applies increasing in shelving, hold mode for holding And a rapid pressure reduction mode in which pressure is reduced at a steep gradient, and a gentle pressure reduction mode in which pressure is reduced at a gentle slope.
The deviation δ is positive when the actual vehicle deceleration G is smaller than the target vehicle deceleration G ^* and is insufficient.
Is larger than the target vehicle body deceleration G ^* and becomes negative when it is excessive, and the control mode of this time is determined in accordance with such a deviation δ as shown in a table form in FIG.

Specifically, (1) a rapid pressure increase mode when the deviation δ is larger than a reference value + δ ₁ ;
Slow pressure increase mode when δ ₁ or less and greater than reference value + δ ₂ (<+ δ ₁ ), (3) Hold mode when deviation δ is greater than or equal to reference value −δ ₃ and less than reference value + δ ₂ , (4) Deviation δ Is less than or equal to the reference value −δ ₄ (<−δ ₃ ) and smaller than the reference value −δ _3.
rapid pressure is determined when δ less than _4.

Therefore, the relationship among the operating force F, the actual vehicle deceleration G, the target vehicle deceleration G ^*, and the pressure control mode is shown in FIG.
Is shown in the graph.

When the current pressure control mode is determined as described above, the control of each of the flow control valve 60, the pressure increasing valve 90, the pressure reducing valve 100, and the pump motor 310 is performed according to the determined pressure control mode. The states are determined as shown in table form in FIG.

Hereinafter, a specific description will be given. First, the basic pressure control modes, ie, the rapid pressure increasing mode, the holding mode, and the rapid pressure decreasing mode will be described.

(1) In the rapid pressure increase mode, the flow control valve 60 is turned on (closed state), the pressure increase valve 90 is turned off (opened), the pressure reducing valve 100 is turned off (closed), and the pump motor 310 is turned on. The ON state is determined. Pump 11
All of the hydraulic fluid discharged from the brake cylinder 50
To the brake cylinder hydraulic pressure P _B
Is rapidly increased.

(2) In the holding mode, the flow control valve 6
0 is set to the ON state (closed state), the pressure increasing valve 90 is set to the ON state (closed state), the pressure reducing valve 100 is set to the OFF state (closed state), and the pump motor 310 is set to the OFF state. Pump motor 3
10 may be in the ON state because the brake cylinder 50 is shut off from the pump 112 when the pressure increasing valve 90 is turned on. In this holding mode, the pressure increasing valve 90 can be turned off (opened) and the pump motor 310 can be turned off.

(3) In the rapid pressure reduction mode, the flow control valve 60 is in the OFF state (open state), the pressure increasing valve 90 is in the OFF state (open state), the pressure reducing valve 100 is in the OFF state (closed state), and the pump motor 310 is in the OFF state. It is determined to be in the OFF state. Hydraulic fluid of the brake cylinder 50 is released to the master cylinder 10 via the pressure increasing valve 90 and flow control valve 60 in their order, whereby the brake cylinder pressure P _B is rapid decompression. In this rapid pressure reduction mode, the pump motor 310 can be turned on. Pump 112
Is supplied to the master cylinder 10 but is not supplied to the brake cylinder 50.

Next, the slow pressure increasing mode and the slow pressure reducing mode as auxiliary pressure control modes will be described.

(4) The gradual pressure increase mode is realized by alternately realizing a control state similar to the rapid pressure increase mode and a control state similar to the holding mode during one control cycle. Therefore, in the slow pressure increase mode, the flow control valve 60 is ON.
State (closed state), the booster valve 90 is in the ON state (closed state) and
Duty control state with FF state (open state), pressure reducing valve 1
00 is OFF state (closed state), pump motor 310 is O
The state is determined to be N. In this gradual pressure increase mode, as shown in FIG. 11, the brake cylinder hydraulic pressure P during the gradual pressure increase is changed by changing the duty ratio, which is the ratio of the ON continuation time to the duty control cycle of the pressure increase valve 90. The change gradient of _B can be changed.

(5) The slow pressure reduction mode is realized by alternately realizing a control state similar to the holding mode and a control state similar to the rapid pressure reduction mode in one control cycle. Therefore, in the slow pressure reduction mode, the flow control valve 60 is turned off.
The duty control state between the F state (open state) and the ON state (closed state), the pressure increasing valve 90 is OFF state (open state), the pressure reducing valve 100 is OFF state (closed state), and the pump motor 310 is determined to be OFF state. You. Note that, in the slow pressure reduction mode, as in the slow pressure increase mode, as shown in FIG. 12, by changing the duty ratio, which is the ratio of the ON duration to the duty control cycle of the flow control valve 60, It may alter the change gradient of the brake cylinder pressure P _B of the gentle reduced pressure in.

In the above description, the pump 11
It is described that the pump motor 310 is turned off in order to make the discharge amount of the working fluid from 2 zero.
With the pump motor 310 turned on, the inflow control valve 140
Can also be realized by turning OFF (closed state). This is because in the OFF state of the inflow control valve 140, the supply of the hydraulic fluid from the master cylinder 10 to the pump 112 is cut off, and the pump 112 runs idle.

As described above, the control state determining means 330 shown in FIG.
However, the effectiveness characteristic control device further includes a control unit 332 connected to the control state determination unit 330. The control means 332 is also connected to the pressure increase control start means 322, and when the start of the pressure increase control is instructed, the valve devices 60, 90, and so on are realized so that the determined control state is realized. 100 and the pump motor 310 are controlled.

The effect characteristic control schematically described above is shown in FIG.
And a brake effectiveness characteristic control routine shown in the flowchart of FIG.

This routine is repeatedly executed after the driver turns on the ignition switch of the vehicle. At the time of each execution, first, in step S1 (hereinafter simply referred to as “S1”; the same applies to other steps), an operation force signal is taken in from the operation force sensor 302, and then, in step S2, the booster negative signal is input. A booster negative pressure signal is taken in from the pressure switch 304. Then, in S3, based on the booster negative pressure signal,
As described above, it is determined whether or not the booster 12 has reached the assisting limit. This time, if it is assumed that the booster 12 has not reached the assisting limit, the determination is NO,
In S4, a signal for turning off each of the solenoids 62, 312, 314 of the valve devices 60, 90, 100 is output, whereby the flow control valve 60 is opened, the pressure increasing valve 90 is opened, and the pressure reducing valve 100 is closed. State. Subsequently, in S5, the solenoid 31 of the inflow control valve 140
A signal for turning it off is output to 6 so that the inflow control valve 140 is closed. Thereafter, in S6, a signal for turning it off is output to the pump motor 310. This completes one execution of this routine.

On the other hand, if it is assumed that the booster 12 has reached the assisting limit, the determination in S3 becomes YES, and
At 7, the estimated vehicle speed VS0 is fetched from the RAM. The antilock control routine is designed to calculate the estimated vehicle speed VS0 at regular time intervals, and to store the latest value and the previous value of the calculated values in the RAM. Then, in S8, the actual vehicle deceleration G is obtained by subtracting the previous value from the latest value of the estimated vehicle speed VS0.
Is calculated this time. Subsequently, in S9, the current value of the target vehicle body deceleration G ^* is determined as described above according to the operating force F defined by the fetched operating force signal. Thereafter, in S10, the valve devices 60, 9
The control states of 0 and 100 are determined as described above, and subsequently, in S11, the control state of the pump motor 310 is also determined as described above. Then, in S12, the valve devices 60, 90, and 100 are controlled so that the determined control state is realized. Subsequently, in S13, the inflow control valve 140 is controlled.

FIG. 6 is a flowchart showing the details of step S13 as an inflow control valve control routine.

First, in S61, it is determined whether or not the antilock control is currently being executed. If it is assumed that it is not being executed, the determination is NO, and in S62, a signal for turning on the solenoid 316 of the inflow control valve 140, that is, a signal for opening the inflow control valve 140 is output. As a result, the hydraulic fluid is transferred to the master cylinder 1
From 0, the pump can be introduced into the pump 112 via the supply passage 130. This completes one execution of this routine.

On the other hand, if it is assumed that the antilock control is currently being executed, the determination in S61 is YES, and the determination in S61 is YES.
At 63, an operation of estimating the amount of the operating fluid existing as the operating fluid to be pumped by the pump 112 in the reservoir 98, that is, an operation of estimating the remaining amount of the reservoir is performed. Subsequently, in S64, it is determined whether or not the estimated remaining amount of the reservoir is 0, that is, whether or not there is any hydraulic fluid to be pumped by the pump 112 in the reservoir 98. Assuming that the remaining amount of the reservoir is not 0 this time, the determination is NO, and in S65, a signal for turning off the solenoid 316 of the inflow control valve 140, that is, a signal for closing the inflow control valve 140 is output. Is done. On the other hand, if it is assumed that the remaining amount of the reservoir is 0 this time, the determination in S64 becomes YES, and in S62, a signal for causing the inflow control valve 140 to open it is output. In any case, one execution of this routine is completed as described above, and the process shifts to S14 in FIG.

In S14, the pump motor 31
0 is controlled so that the determined control state is realized. When the pump motor 310 is turned on, the hydraulic fluid is pumped from the reservoir 98 by the pump 112, and the hydraulic fluid is discharged to each brake cylinder 50. Thus, higher fluid pressure than the master cylinder pressure P _M is generated in the brake cylinder 50. This completes one execution of this routine.

In the antilock control routine, while the wheel speed sensor 306 monitors the wheel speed of each wheel and the running speed of the vehicle body, the pressure increasing valve 90 is opened, and the pressure reducing valve 100 is closed. The holding state in which both the pressure valve 90 and the pressure reducing valve 100 are closed, the pressure increasing valve 90 in the closed state, and the pressure reducing valve 1
00 selectively prevents the wheels from locking during braking of the vehicle by selectively realizing the depressurized state of opening.
Further, in the antilock control routine, the pump motor 310 is operated during the antilock control, and the hydraulic fluid is pumped from the reservoir 98 by the pump 112 and returned to the main passage 48.

This antilock control routine is executed regardless of whether the brake effect characteristic control routine is executed. Therefore, if the lock tendency of each wheel becomes excessive due to the pressure increase of each brake cylinder 50 by the pump 112 during the execution of the effectiveness characteristic control, the anti-lock control routine is executed, and as a result, the braking of each wheel is performed. The operating force does not need to be excessive.

As is clear from the above description, the ECU 3
5 corresponds to the assisting limit determining means 320 and the pressure increase control starting means 322, the part executing S1 and S9 corresponds to the target vehicle body deceleration determining means 324, and S7 And S8 correspond to the actual vehicle deceleration calculation means 328, S10 and S11 correspond to the control state determining means 330, and S12 and S14 correspond to the control means 3
32.

In this embodiment, the operating force sensor 302 constitutes "brake operating force related amount detecting means", and a plurality of wheel speed sensors 306, an estimated vehicle speed calculating means 326, and an actual vehicle deceleration calculating means. 328 together form a "vehicle deceleration detecting means", and include a booster negative pressure switch 304 (sensor section), a flow control valve 60,
The pressure increasing valve 90, the pressure reducing valve 100, the pump 112, the pump motor 310 (actuator unit), and the part (control unit) of the ECU 300 related to the effective characteristic control constitute a "pressure increasing device".

It should be noted that the flow control valve control routine shown in FIG. 6 can be improved by directly detecting the remaining amount of the working fluid in the reservoir 98 by a sensor. The remaining amount is, for example, the reservoir piston 1 in the reservoir 98.
04 can be detected by providing a permanent magnet integrally movably and providing a reed switch as a sensor in proximity to the permanent magnet.

Another embodiment will be described. However, this embodiment has many configurations in common with the previous embodiment, and differs only in the electrical configuration related to the effective characteristic control. Therefore, the common configurations are described in detail by using the same reference numerals. Are omitted, and only different configurations will be described in detail.

FIG. 13 is a functional block diagram showing the configuration of the effectiveness characteristic control device according to this embodiment. In this embodiment, unlike in the previous embodiment,
The height of the brake cylinder pressure P _B is controlled by duty control of the pump motor 310. Therefore, instead of the control state determining means 330, the valve devices 60, 9 are determined based on the target vehicle deceleration G ^* and the actual vehicle deceleration G.
A control state determining means 400 for determining the control states of 0 and 100 and the duty ratio for duty-controlling the pump motor 310 is provided. The control means 3
32, the valve devices 60, 90, and 100 are controlled such that the determined control state is realized, and the pump motor 310 is controlled in accordance with the determined duty ratio.
Is provided.

In this embodiment, as in the previous embodiment, the target vehicle deceleration G ^* is actually used to determine the control state of the valve devices 60, 90, 100 and the like. Force F, actual vehicle deceleration G, and valve devices 60, 9
If the relationship between 0, 100 and the duty ratio is stored in the ROM as a map, a table, or the like, the actual use of the target vehicle deceleration G ^* is not necessary for determining the control state.

FIG. 14 is a flowchart showing a brake effect characteristic control routine. This routine is basically the same as the brake effect characteristic control routine (FIG. 5) in the previous embodiment, so that the common parts will be briefly described, and only the different parts will be described in detail.

If it is assumed that the booster 12 has reached the assisting limit, the determination in S103 becomes YES, and the actual vehicle deceleration G is calculated in S107 and S108. The target vehicle deceleration G ^* is determined according to the specified operation force F. Subsequently, in S110, the control state of the valve devices 60, 90, 100 is determined based on the deviation δ between the determined target vehicle body deceleration G ^* and the calculated actual vehicle body deceleration G. The relationship between the deviation δ and the control state is shown in a table form in FIG. Thereafter, in S111, the current duty ratio of the pump motor 310 is determined based on the deviation δ and in accordance with the relationship between the deviation δ and the duty ratio of the pump motor 310. In the present embodiment, as shown in FIG.
ON state duration T _ON for ten control cycles T _cycle
Is defined as the ratio of The relationship between the deviation δ and the duty ratio of the pump motor 310 is shown in a table in FIG. That is, in the present embodiment, unlike the previous embodiment, the change gradient of the brake cylinder hydraulic pressure P _B during pressure increase is optimized by the duty control of the pump motor 310, while the brake cylinder hydraulic pressure P _B during pressure decrease is different. as well as changes in the gradient of pressure P _B is definitive in the previous embodiment, it has become to be optimized by the duty control of the flow control valve 60.

Thereafter, in S112, the valve device 60,
90 and 100 are controlled such that the determined control state is realized. Subsequently, in S113, the inflow control valve 140 is controlled. Thereafter, in S114, the pump motor 310 is controlled according to the determined duty ratio. This completes one execution of this routine.

As is apparent from the above description, the ECU 3
14 corresponds to the assisting limit determining means 320 and the pressure increase control starting means 322, the part executing S101 and S109 corresponds to the target vehicle body deceleration determining means 324, and S107.
The part executing S108 corresponds to the actual vehicle deceleration calculating means 328, the part executing S110 and S111 corresponds to the control state determining means 400, and the part executing S112 and S114 corresponds to the control means 402. It is.

Although some embodiments of the present invention have been described in detail with reference to the drawings, various modifications may be made based on the knowledge of those skilled in the art without departing from the scope of the claims. Of course, the present invention can be implemented in an improved form.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a brake device according to an embodiment of the present invention.

2 is a graph showing the relationship between the operating force F and the master cylinder pressure P _M in the above embodiment.

FIG. 3 is a graph showing a relationship between an operation force F and an actual vehicle deceleration G in the embodiment.

FIG. 4 is a block diagram showing an electrical configuration of the embodiment.

FIG. 5 is a flowchart showing a braking effect characteristic control routine stored in a ROM of a computer of the ECU in FIG. 4;

FIG. 6 is a flowchart showing details of S13 in FIG. 5 as an inflow control valve control routine.

FIG. 7 is a functional block diagram showing a configuration of the embodiment.

FIG. 8 is a table showing a relationship between a deviation δ and a pressure control mode in the embodiment.

FIG. 9 is a graph showing a relationship among an operating force F, an actual vehicle deceleration G, a target vehicle deceleration G ^*, and a pressure control mode in the embodiment.

FIG. 10 is a diagram showing, in a table form, a relationship between a pressure control mode, a control state of each control valve, and a control state of a pump motor in the embodiment.

FIG. 11 is a time chart showing a modification of the slow pressure increase mode in FIG. 10;

FIG. 12 is a time chart showing a modification of the slow pressure reduction mode in FIG. 10;

FIG. 13 is a functional block diagram showing a configuration of a brake device according to another embodiment of the present invention.

FIG. 14 is a flowchart showing a braking effect characteristic control routine stored in a ROM of a computer of the ECU in the embodiment.

FIG. 15 is a time chart for explaining the definition of the duty ratio of the pump motor in the embodiment.

FIG. 16 is a table showing a relationship between a deviation δ, a duty ratio of a pump motor, and a control state of each control valve in the embodiment.

[Explanation of symbols]

 Reference Signs List 10 master cylinder 12 vacuum booster 14 brake pedal 60 flow control valve 90 booster valve 100 pressure reducing valve 112 pump 300 ECU 302 operating force sensor 306 wheel speed sensor 326 estimated vehicle speed calculating means 328 actual vehicle deceleration calculating means

Claims (2)

[Claims] 1. A brake operating member operated by a driver, a master cylinder for generating a hydraulic pressure based on an operation of the brake operating member, connected to the master cylinder by a liquid passage, and supplied from the liquid passage. A brake device having a brake cylinder that is operated by hydraulic pressure, and a brake that suppresses rotation of a wheel. A brake operation force-related amount detection unit that detects an amount related to an operation force of the brake operation member; A vehicle deceleration detecting means for detecting a vehicle deceleration; and after the pressure increase start condition is satisfied during a brake operation, the hydraulic pressure of the brake cylinder is increased from the hydraulic pressure of the master cylinder. The actual vehicle deceleration detected by the vehicle deceleration detecting means is detected by the brake operating force related amount detecting means. Braking device is characterized by providing a pressure increasing device for controlling so as to be equal to the target vehicle deceleration based on the operation-force-related quantity is. A booster provided between the brake operating member and a master cylinder for assisting the operating force and outputting the boosted force to a master cylinder, wherein the pressure increasing start condition is such that the booster is at an assist limit. The brake device according to claim 1, wherein the brake device includes reaching.