JP3536569B2 - Brake equipment - Google Patents

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 improving braking performance in a sudden braking operation state.

[0002]

BACKGROUND ART A brake device for a vehicle generally includes (a) a brake operating member, (b) a brake for suppressing wheel rotation, and (c) an operating state amount (operating force, operating stroke, etc.) of the brake operating member. And a brake driving device that operates the brake with a force according to the following. In one conventional example of the brake device, as is well known, a brake operation member is a brake pedal, and a brake driving device is provided with a booster for assisting a pedaling force which is an operation force of the brake pedal, and a booster for the booster. A master cylinder that mechanically generates a hydraulic pressure at a height corresponding to the output of the master cylinder, and a brake cylinder that is connected to the master cylinder by a liquid passage and operates based on the hydraulic pressure generated in the master cylinder to operate a brake And a configuration including

In this type of brake device, the amount of operation of the brake operating member is input as reflecting the driver's intention, and the brake is operated with a magnitude corresponding to the input amount of operation.

[0004] However, the present applicant has studied the operating characteristics of a brake operating member by a driver.
It has been found through experiments that the following operating characteristics are obtained in a sudden braking operation state. That is, in general, the driver first performs an operation for increasing the brake operation force (increase stage), and then performs an operation for maintaining the brake operation force constant (holding stage). In spite of the fact that the driver operates the brake operating member with the intention of holding the brake operating force constant, the operating state amount of the brake operating member actually increases with time against the driver's will at the beginning of the holding stage. He discovered that it had an operating characteristic that decreased and eventually remained constant.

The discovered operating characteristics will be specifically described with reference to the graph of FIG. 11 in relation to the above-mentioned conventional brake device.

As shown in FIG. 1 (a), in the increasing stage, the depression force F (an example of the operation state amount) of the brake pedal increases with time t as the driver intends. With the increase of the pedaling force, as shown in FIG.
_M also increased, as shown in (c) of FIG, also increases the brake cylinder pressure P _B.

On the other hand, in the subsequent holding stage, as shown in FIG. 1A, at the beginning, the pedaling force F decreases with time t against the driver's will. Therefore, as shown in (b) of FIG, master cylinder pressure P _M also decreases, as shown in (c) of FIG, decreases also the brake cylinder pressure P _B.

As described above, the driver's operation characteristics in the sudden braking operation state include the operation characteristic that the brake operation state amount is reduced against the driver's intention at the beginning of the holding stage. Therefore, if such braking characteristics are actively considered on the brake device side and improper operation of the brake device based on a decrease in the amount of operation state contrary to the driver's intention is avoided, the driver's will will always be satisfied. The brakes can be actuated by the applied force, and as a result, the safety of the vehicle is improved.

[0009]

Based on these findings, the present invention is based on the above findings, and in the case of a sudden braking operation state, the present invention relates to a failure of a braking device based on a mismatch between a driver's intention and an operation state amount. The object of the present invention is to improve vehicle safety by avoiding proper operation.

According to the present invention, the object is to provide (1) a brake operating member, (2) a brake for suppressing wheel rotation, and (3)
A brake driving device that operates the brake with a force having a magnitude corresponding to an operation state amount of the brake operation member, (4)
(5) a sudden brake operation detecting means for detecting a sudden brake operation of the brake operating member by a driver, and (5) after the sudden brake operation is detected by the sudden brake operation detecting means, the operating force of the brake is changed to the operation state amount. Brake actuation force decrease suppressing means for suppressing a decrease according to
(6) (a) (i) Operation state amount detection for detecting the operation state amount
And (ii) a sudden braking operation by the sudden braking operation detecting means.
The brake operation is detected and the reduction of the brake operation force is suppressed.
Means for suppressing a decrease in the brake operating force.
The operation state detected by the operation state amount detection means.
When the amount of reduction in the operation state amount exceeds the set value, the driver
Reducing the operating force of the brake operating member
Determined that a matching reduction operation consistent with the driver's intention was performed.
(B) a matching reduction operation detecting means including a determining means for determining
The operation to reduce the alignment is detected by the alignment reduction operation detecting means.
After that, the operation of the brake operating force reduction suppressing means is activated.
By terminating, the operating force is reduced to the operation state quantity.
This is solved by providing a brake device (claim 1) that includes a brake operating force reduction permitting unit that permits a reduction in response .

[0011] In this brake device, in the case of a sudden braking operation state, even if the operation state amount decreases contrary to the driver's intention, the brake operating force may fall below a value corresponding to the operation state amount. Is suppressed.

Therefore, according to the present invention, in a sudden braking operation state, an inappropriate operation of the brake device based on a mismatch between the driver's intention and the operation state amount is avoided, and the braking is performed against the driver's intention. Since the decrease in the operating force is suppressed, the effect of improving the safety of the vehicle is obtained.

In this brake device, "brake" includes, for example, a friction type and a regenerative braking type. The friction type includes a type using a fluid pressure as a driving source, a type using a motor as a driving source, and the like, and also includes a disk type, a drum type, and the like. The “operation state amount” includes an operation force and an operation stroke. In addition, for example, an operation in which the operation speed of the brake operation member is higher than a set value,
An operation in which the operation speed of the brake operation member is higher than the set value and the operation force of the brake operation member is higher than the set value is included.

In this brake device, the "sudden brake operation detecting means" has, for example, a sensor for detecting the operating force or the operating stroke (operating position) of the brake operating member, and detects suddenly based on the speed of change of the detected value. A sensor that detects a brake operation or detects a brake operation state amount related to the operation state amount of the brake operation member, for example, a master cylinder hydraulic pressure, a brake cylinder hydraulic pressure, a brake operating force, a vehicle deceleration, and the like. And an abrupt braking operation may be detected based on the speed of change of the detected value.

In this brake device, the "brake operating force reduction suppressing means" can be provided on the brake operating member, provided on the brake driving device, or provided on the brake. When the brake drive device is of a hydraulic type in which the master cylinder and the brake cylinder are connected to each other by a fluid passage, the brake drive device can be provided in the master cylinder, in the brake cylinder, or in the fluid passage. When the driving device has a booster between the brake operating member and the master cylinder, the booster can be provided in the booster.

[0016] "Brake actuation force reduction suppressing means"
Can be a mode in which the amount of increase in the brake operating force from the value corresponding to the operation state amount is a fixed value or a mode in which the amount is a variable value. One mode in which the variable value is used is a mode in which the brake operating force is maintained despite a decrease in the brake operation state amount.

In one embodiment of the brake device, the brake driving device comprises: (a) a master cylinder for generating a hydraulic pressure having a height corresponding to the operation state amount; and (b) a master cylinder and a liquid passage. A brake cylinder for operating the brake based on a master cylinder hydraulic pressure, wherein the brake operating force reduction suppressing means is provided in the middle of the liquid passage, and is operated from the master cylinder to the brake cylinder. A check valve that allows the flow of liquid but prevents the flow in the opposite direction; (b) a bypass passage provided in parallel with the check valve; and (c) an electromagnetic on-off valve provided in the middle of the bypass passage. (D) connected to the electromagnetic on / off valve and the sudden brake operation detecting means, and after detecting the sudden brake operation, closing the electromagnetic on / off valve to thereby evacuate the brake cylinder. Prevents the flow of hydraulic fluid towards the Tashirinda, thereby holding the brake cylinder pressure, it is in a manner that includes thereby a complete controller for avoiding decrease in brake effort

According to another embodiment of the brake device, the brake driving device comprises: (a) a master cylinder for generating a hydraulic pressure having a height corresponding to the operation state amount; and (b) a master cylinder and a hydraulic passage. And a brake cylinder that operates the brake based on a master cylinder hydraulic pressure, wherein the brake operating force reduction suppressing means includes: (a) a throttle (orifice or the like) provided in the middle of the liquid passage;
(b) a bypass passage provided in parallel with the throttle and allowing a flow of hydraulic fluid between the master cylinder and the brake cylinder with a smaller resistance in the throttle, and (c) provided in the middle of the bypass passage. An electromagnetic on-off valve, and (d) a flow of hydraulic fluid connected from the brake cylinder to the master cylinder by closing the electromagnetic on-off valve after detecting the sudden braking operation, connected to the electromagnetic on-off valve and the sudden brake operation detecting means. With a large resistance, thereby reducing the speed at which the brake cylinder fluid pressure is reduced, and thereby partially suppressing the reduction in the brake operating force.

[0019]

[0020]

Further , in this brake device, if the brake operating member is operated to reduce the brake operating force according to the driver's intention after the detection of the sudden braking operation, the brake operating force is changed according to the operation state amount. It is allowed to decrease.

Therefore, according to the present invention, in the case of shifting from a sudden braking operation state to a non-rapid braking operation state in one braking operation, a braking actuation force that accurately corresponds to the driver's intention in the sudden braking operation state Not only is obtained, but also in the subsequent non-emergency braking operation state, a brake actuation force accurately corresponding to the driver's intention is obtained, and an effect is obtained that an easy-to-use brake device is provided.

In one embodiment of the brake device, the matching reduction operation detecting means includes: (a) an operating state amount detecting means for detecting the operating state amount; and (b) a sudden braking operation by the sudden braking operation detecting means. And determining means for determining that the matching reduction operation has been performed when a decrease amount of the operation state amount detected by the operation state amount detection means exceeds a set value after the detection of the operation state amount. In the present embodiment, for example, a value larger than an experimentally obtained value may be used as the “set value” as the total decrease amount of the operation state amount in the holding stage of the sudden braking operation state.

In another embodiment of the brake device, the brake operating member is provided so as to be displaceable between a non-operating position and an operating position, and the alignment lowering operation detecting means includes: (a) operating the brake operating member; The first signal when in position,
A brake switch for outputting a second signal when the brake switch is in the non-operation position; and (b) determining means for determining that the matching reduction operation has been performed when the output signal of the brake switch changes from the first signal to the second signal. It is an aspect including: This embodiment is based on the fact that when the brake operating member is operated from the operating position to the non-operating position, it can be considered that it is clear that the driver has the intention to reduce the brake operating force.

By the way, the present applicant has previously developed the following brake device. That is, the brake driving device is (a) a master cylinder that generates a hydraulic pressure having a height corresponding to the operation state amount, and (b) is connected to the master cylinder by a liquid passage and is supplied from the liquid passage. A brake cylinder that operates the brake based on hydraulic pressure;
(c) operation state amount detection means for detecting the operation state amount,
(d) provided in the middle of the fluid passage so as to be connected to the operation state amount detecting means, and at least at one time during operation of the brake operation member, a fluid pressure higher than the master cylinder fluid pressure is applied to the brake cylinder. As well as
And a hydraulic pressure control device for determining an increase amount of the brake cylinder hydraulic pressure with respect to the master cylinder hydraulic pressure in accordance with the operation state amount detected by the operation state amount detection means.

In the developed brake system, since the hydraulic pressure control device determines the pressure increase amount of the brake cylinder according to the operation state amount, the operation state amount in the holding stage of the sudden braking operation state is changed by the driver. If it decreases contrary to will, the pressure increase amount of the brake cylinder also decreases against the driver's will.

Against this background, another object of the present invention is to provide a brake device that has been developed as described above, and in the case of a sudden brake operation state, the inappropriateness of the brake device based on the mismatch between the driver's intention and the amount of operation state. Another object of the present invention is to improve the safety of a vehicle by avoiding an unnecessary operation.

According to the present invention, the object includes (a) the master cylinder, (b) the brake cylinder, (c) the operation state amount detecting means, and (d) the hydraulic pressure control device, The brake operating force reduction suppressing means is provided in the hydraulic pressure control device, after the sudden braking operation is detected by the sudden braking operation detecting means, and at least after the operation state amount is about to be reduced, Increase the pressure
The problem is solved by providing a brake device (Claim 2 ) including pressure increase amount increasing means for increasing the pressure in accordance with the operation state amount. Further, according to the present invention, (1) brake operation
Working member and (2) the amount of operating state of the brake operating member.
Master cylinder that generates hydraulic pressure at the same height
Fluid passage connected to the master cylinder of the
Actuates the brake based on the hydraulic pressure supplied from the
And (4) detecting the operation state quantity
(5) the operation state quantity detecting means in the middle of the liquid passage;
Provided in a state connected to the operation state amount detecting means,
At least one time during operation of the rake operating member, the
If the hydraulic pressure of the brake cylinder is
To the master cylinder hydraulic pressure.
The amount of increase in the brake cylinder fluid pressure is detected by the operation state amount.
Hydraulic pressure determined according to the operating state quantity detected by the means
A control device; and (6) provided in the hydraulic control device,
The brake operation by the driver is performed by the operation state amount detection means.
After the sudden braking operation of the operation member is detected,
At least after the operation state quantity is about to decrease, the increase
Pressure increase to increase the pressure amount from a value corresponding to the operation state amount
Brake actuation force decrease suppression means including an amount increase means
The solution is also provided by providing a brake device (claim 3).
Is decided. Further, (a) the brake operation by the driver
The operation of lowering the operating force of the member depends on the driver's intention.
An operation of lowering the alignment that detects that the operation is a lowering operation of alignment
Operation detection means, and
After the operation for lowering the alignment is detected, the brake operation force is reduced.
By terminating the operation of the lower restraint means, the operating force
Is allowed to decrease in accordance with the operation state amount.
Brake device including a brake operating force reduction permitting means (claim
4) is solved.

In this brake device, the pressure increase amount of the brake cylinder is increased from a value corresponding to the operation state amount after the sudden braking operation is detected and at least after the operation state amount is about to decrease.

Therefore, according to the present invention, in the developed brake device, the brake cylinder fluid pressure is prevented from being reduced against the driver's will in the sudden braking operation state, so that the vehicle safety is improved. The effect of improving is obtained.

In this brake device, for example, when the brake device has a booster between the brake operating member and the master cylinder for assisting the operating force of the brake operating member, the "hydraulic pressure control device" May be operated in a state where it exceeds the assisting limit, or may be operated after detection of a sudden braking operation, regardless of whether or not the booster has reached the assisting limit, regardless of whether or not the booster has reached the assisting limit. it can. That is, for the "at least one time during the brake operation", for example, a time when the booster exceeds the assisting limit or a time after the detection of the sudden brake operation can be selected.

In this brake device, the "pressure increase amount increasing means" may be, for example, a mode in which the pressure increase amount is increased immediately after the detection of the sudden braking operation, or the operation state amount or the state after the detection of the sudden braking operation. A mode in which the pressure increase amount is increased immediately after the brake cylinder fluid pressure is about to decrease.

In one embodiment of the brake device, the boosting amount increasing means performs the increasing of the boosting amount after the operation state amount is about to decrease, and determines the increasing amount.
It is embodiments including increase amount determining means for determining as the brake cylinder pressure quantity operation state is maintained at a height when trying to reduce (claim 5).

In another embodiment of the brake device, the hydraulic pressure control device includes: (a) provided in the middle of the liquid passage, for controlling a bidirectional flow of hydraulic fluid between the master cylinder and the brake cylinder. A control valve that switches to a plurality of states including an allowable state and a state in which the flow of hydraulic fluid from the brake cylinder to the master cylinder is blocked; and (b) the control valve and the brake cylinder of the liquid passage. discharge side is connected between, and a pump for discharging the discharge side pumping hydraulic fluid from the suction side and in a manner that the joint between them control valve and the pump performs a pressure increase of the brake cylinder (claim 6) . According to the present embodiment, there is provided a brake device of a type in which a hydraulic pressure higher than the master cylinder hydraulic pressure is generated in the brake cylinder by a pump connected downstream of the master cylinder in a brake operation state.

Here, the "control valve" may be a mechanical type that switches to a plurality of hydraulic fluid flow states based on a differential pressure between the master cylinder and the brake cylinder, or may be a type that is controlled based on a magnetic force of a solenoid controlled by control means. It can be of an electromagnetic type that switches to a plurality of hydraulic fluid flow states. In the case of a mechanical type, a type in which the height of the differential pressure between the master cylinder and the brake cylinder is mechanically controlled, or a type in which the level is electromagnetically controlled based on the magnetic force of a solenoid controlled by the control means. be able to.

[0036] The one form of embodiment, the fluid pressure control device, the suction side of the pump is connected to a portion between the control valve and the master cylinder of the fluid passage form (claim 7) It is. According to this embodiment, since the pump need only pump and pressurize the hydraulic fluid pressurized by the master cylinder instead of the hydraulic fluid at atmospheric pressure, the operation responsiveness of the pump is improved and the load on the pump is reduced. You.

All of the above-described brake devices (including the embodiments and modes) may further include an anti-lock control device for preventing the tendency of the wheels to lock when the vehicle is braked. According to this embodiment,
In a sudden braking operation state, despite the operation of the brake operation force reduction suppressing means, the brake operation force does not become excessive in relation to the friction coefficient between the wheel and the road surface or the ground contact load of the wheel, so that the safety of the vehicle is improved. Is further improved.

[0038]

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 according to an embodiment of the present invention. In brief, the brake device is mounted on a four-wheeled vehicle, and includes a booster that assists a brake operation force.

The brake device further includes an anti-lock control device and an effectiveness characteristic control device. The antilock control device is a device that prevents the locking tendency of each wheel from becoming excessive during braking of the vehicle. This anti-lock control device has a pump, and the pump returns the hydraulic fluid in the brake circuit. On the other hand, the effectiveness characteristic control device considers that the booster has an assist limit, and when the vehicle is braking, the vehicle body deceleration has an ideal gradient with respect to the brake operation force (for example, before and after the booster assist limit). This is a device for controlling the braking effectiveness characteristic, which is the relationship between the brake operation force and the vehicle body deceleration, so as to increase at almost the same gradient (regardless of the gradient). This effectiveness characteristic control device
It operates using the above pump. That is, the pump is shared by the antilock control device and the effectiveness characteristic control device.

In the drawing, reference numeral 10 denotes a brake pedal as a brake operation member. The brake pedal 10 is linked to a master cylinder 14 via a vacuum booster 12 as a booster.

As is well known, a vacuum booster (hereinafter simply referred to as a “booster”) 12 assists the depression force of the brake pedal 10 based on the operating force of the power piston based on the difference between the negative pressure and the atmospheric pressure. To do. In the booster 12, a power piston is air-tightly and movably disposed in a housing having a space inside, so that the internal space of the housing becomes a negative pressure chamber 12a on the master cylinder 14 side and a variable pressure chamber 12b on the brake pedal 10 side.
And is divided into.

As is well known, the master cylinder 14 is of a tandem type in which two pistons are slidably fitted in series with each other in a housing. When the pistons operate, the same pressure is generated in each pressurizing chamber formed in front of each piston. A brake cylinder for operating the brake of the left front wheel FL and a brake cylinder for operating the brake of the right rear wheel RR are connected to one pressurizing chamber, and a brake cylinder for operating the brake of the right front wheel FR is connected to the other pressurizing chamber. And a brake cylinder for operating the brake of the left rear wheel RL. 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.

That is, this brake device is a diagonal two-system type in which two independent brake systems are formed diagonally with each other. Since these two brake systems have a common configuration, only one brake system will be described with text and drawings as a representative, and the description of the other brake system will be omitted.

The master cylinder 14 is connected to the brake cylinder 20 of the left front wheel FL and the brake cylinder 20 of the right rear wheel RR by a main passage 18. Main passage 1
Reference numeral 8 denotes a bifurcated branch after extending from the master cylinder 14, and one main passage 24 and two branch passages 26 are connected to each other. The brake cylinder 20 is connected to the tip of each branch passage 26.

A pressure control valve 30 as a control valve is provided in the middle of the main passage 24. The pressure control valve 30 controls the hydraulic pressure on the brake cylinder 20 side in the main passage 18 relatively to the hydraulic pressure on the master cylinder 14 side. Specifically, the hydraulic fluid is discharged from the pump 40. In this state, if the brake cylinder hydraulic pressure is higher than the master cylinder hydraulic pressure but the differential pressure is equal to or lower than the target differential pressure, the flow of the hydraulic fluid from the pump 40 toward the master cylinder 14 is blocked, and the brake cylinder hydraulic pressure is reduced. If the master cylinder hydraulic pressure is higher than the master cylinder hydraulic pressure and the differential pressure is going to be higher than the target differential pressure, the flow of the hydraulic fluid from the pump 40 to the master cylinder 14 is allowed, so that the brake cylinder hydraulic pressure becomes higher than the master cylinder hydraulic pressure. Further, control is performed so that the differential pressure becomes the target differential pressure.

In this embodiment, the pressure control valve 30 is of a type that electromagnetically controls the height of the differential pressure between the brake cylinder 20 and the master cylinder 14. Specifically, as shown in FIG. 2, the pressure control valve 30 includes a housing (not shown) and a valve 70 for controlling a flow state of hydraulic fluid between the master cylinder side and the brake cylinder side in the main passage 18. A valve seat 72 on which it should sit,
And a solenoid 74 for generating a magnetic force for controlling the relative movement of the valve 70 and the valve seat 72.

In the pressure control valve 30, in a non-operating state (OFF state) where the solenoid 74 is not excited,
The resilient force of the spring 76 separates the valve 70 from the valve seat 72, thereby permitting bidirectional flow of the hydraulic fluid between the master cylinder side and the brake cylinder side in the main passage 18. When the brake operation is performed, the brake cylinder hydraulic pressure is changed at the same pressure as the master cylinder hydraulic pressure. During this braking operation, the valve 7
At 0, a force acts in a direction away from the valve seat 72. Therefore, as long as the solenoid 74 is not excited, even if the master cylinder hydraulic pressure, that is, the brake cylinder hydraulic pressure increases,
The valve 70 does not sit on the valve seat 72. That is, the pressure control valve 30 is a normally open valve.

On the other hand, in the operation state (ON state) where the solenoid 74 is excited, the armature 78 is attracted by the magnetic force of the solenoid 74, and the armature 7
A valve element 70 as a movable member that moves integrally with 8 is seated on a valve seat 72 as a fixed member. At this time, the attraction force F based on the magnetic force of the solenoid 74 is applied to the valve 70.
_1, it acts on the sum and the mutually opposite between the elastic force F ₃ of the force F ₂ and the spring 76 based on the difference between the brake cylinder pressure and the master cylinder pressure. Magnitude of the force F ₂ is the difference between the brake cylinder pressure and the master cylinder pressure, the valve member 70 is expressed by the product of the effective pressure receiving area which receives the brake cylinder pressure.

The operating state in which the solenoid 74 is excited (O
N state), the discharge pressure of the pump 40,
The cylinder pressure does not increase so much, F_Two ≤F₁ -F_Three In the region where the relationship represented by the following formula is established, the valve 70
The hydraulic fluid from the pump 40 is seated on the valve seat 72,
Escape to the Linda 14 is prevented, and the discharge of the pump 40
The pressure increases and the master cylinder fluid
A hydraulic pressure higher than the pressure is generated. In contrast, the pump
The discharge pressure of 40, that is, the brake cylinder fluid pressure is further increased.
In addition, F_Two > F₁ -F_Three In the region where the relationship expressed by
The valve 70 is separated from the valve seat 72 and the hydraulic fluid from the pump 40
Is released to the master cylinder 14, and as a result, the pump 4
The discharge pressure of 0, that is, the brake cylinder fluid pressure increases further.
Addition is prevented. In this way, the brake
The elastic force F of the spring 76 is applied to the _Three Ignore
For example, the solenoid suction force F₁ 
, A hydraulic pressure that is higher by the differential pressure is generated.

The pressure control valve 30 is arranged such that the magnitude of the solenoid attraction force F ₁ changes linearly in accordance with the magnitude of the exciting current I of the solenoid 74 as shown in the graph of FIG. Designed to.

As shown in FIG. 1, the pressure control valve 30 is provided with a bypass passage 82,
A check valve 84 is provided in the middle of Step 2. By any chance,
Even if the pressure control valve 30 is closed by the fluid force generated in the movable member in the pressure control valve 30 when the brake pedal 10 is depressed, the flow of the hydraulic fluid from the master cylinder 14 to the brake cylinder 20 is ensured. To do that. The pressure control valve 30 is further provided with a relief valve 86 in parallel with it. This is to prevent the discharge pressure of the pump 40 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 26. The pressure-increasing valve 90 allows the flow of hydraulic fluid from the master cylinder 14 to the brake cylinder 20 in the open state. 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 26 between the pressure intensifying valve 90 and the brake cylinder 20, and 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 reservoir passage 96, and realizes a reduced pressure state in which the flow of the hydraulic fluid from the brake cylinder 20 to the reservoir 98 is allowed in an open state. The reservoir 98 is formed by fitting a reservoir piston 104 to the 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. It is housed under pressure.

The reservoir 98 is connected by a suction passage 110 to the suction side of the pump 40, and the discharge side of the pump 40 is connected by a discharge passage 114 to a portion of the main passage 18 between the pressure control valve 30 and the pressure increasing valve 90. Have been. 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 40 is reduced.

By the way, during execution of the effectiveness characteristic control, the pump 40 pumps up the hydraulic fluid from the reservoir 98 and discharges the hydraulic fluid to each brake cylinder 20, whereby each brake cylinder 20 is increased in pressure. When the lock control is not being executed, it is normal that there is no hydraulic fluid to be pumped into the reservoir 98. To ensure the execution of the effectiveness characteristic control, regardless of whether the antilock control is executed, It is necessary to replenish the reservoir 98 with hydraulic fluid. Therefore, in this embodiment,
The master cylinder 14 and the pressure control valve 3 in the main passage 24
A supply passage 130 is provided extending from the portion between 0 and the reservoir 98 to reach the reservoir 98. However, this supply passage 130
, The master cylinder 14 and the reservoir 98 are always in communication with each other, so that even if the brake pedal 10 is depressed, the reservoir piston 1
Only after the bottoming of the cylinder 04, the master cylinder 14 cannot increase its pressure, causing a delay in braking.
Further, during the anti-lock control, the pump 40 pumps the hydraulic fluid from the master cylinder 14 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 14.
When it is necessary to replenish the hydraulic fluid to the reservoir 8, it is opened to allow the flow of the hydraulic fluid from the master cylinder 14 to the reservoir 98, while it is not necessary to replenish the hydraulic fluid from the master cylinder 14 to the reservoir 98. Sometimes, it is closed, and the flow of the hydraulic fluid from the master cylinder 14 to the reservoir 98 is blocked, so that the pressure rise by the master cylinder 14 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 14 during the antilock control, and there is no hydraulic fluid to be pumped by the pump 40 in the reservoir 98 during the antilock control. Or not, and
The determination of the presence or absence of the hydraulic fluid is performed by calculating the integrated value of the time during which the pressure increasing valve 90 is in the pressure increasing state and the integrated value of the time during which the pressure reducing valve 100 is in the pressure reducing state. This is performed by estimating the remaining amount of the working fluid in the reservoir 98 based on the above.

During the braking operation, when the pump 40 pressurizes the hydraulic fluid by using the hydraulic fluid in the portion of the main passage 18 upstream of the pressure control valve 30, the high pressure operation in the upstream portion is performed. Pump 4
Pumping without reducing pressure to the reservoir 98 improves pump operability and pump 4 by reducing the load on the pump 40, rather than pumping by the reservoir 98.
0 can be easily reduced.

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. A check valve 142 is provided to block the flow and allow the flow in the opposite direction.

FIG. 4 shows an electrical configuration of the brake device. The brake device consists of a CPU, ROM and R
An electronic control unit (ECU) 150 mainly including a computer including an AM is provided. ROM effect characteristic control routine (shown in a flowchart in FIG. 5), inflow control valve control routine (shown in a flowchart in FIG. 6), sudden braking determination routine (shown in a flowchart in FIG. 7) And various routines such as an anti-lock control routine (not shown) are stored. When these routines are executed by the CPU while using the RAM, the effect characteristic control and the anti-lock control are respectively executed. .

The brake switch 162, the booster negative pressure switch 164, the master cylinder hydraulic pressure sensor 166, and the wheel speed sensor 168 are connected to the input side of the ECU 150.

The brake switch 162 outputs an OFF-state brake operation signal (first signal) when the brake pedal 10 is not depressed, and outputs O when the brake pedal 10 is depressed.
The ECU 150 outputs a brake operation signal (second signal) in the N state, and thereby outputs information indicating the presence or absence of the brake operation to the ECU 150.
To supply.

The booster negative pressure switch 164 is turned on when the pressure in the transformation chamber 12b of the booster 12 is lower than the atmospheric pressure.
The booster negative pressure signal (first signal) in the FF state is output, and the booster negative pressure signal (second signal) in the ON state is output when the pressure is equal to or higher than the atmospheric pressure.

The master cylinder fluid pressure sensor 166 detects the master cylinder fluid pressure, and is a master cylinder fluid pressure signal for defining the height of the master cylinder fluid pressure. And output the one that changes continuously.

The wheel speed sensor 168 is provided for each wheel, and outputs a wheel speed signal defining the wheel speed of each wheel.

On the other hand, a pump motor 170 for driving the pump 40 is connected to the output side of the ECU 150, and a motor drive signal is output to the pump motor 170.
The output side of the ECU 150 further includes the pressure control valve 30.
The solenoids 174 of the solenoid 74, the inflow control valve 140, the pressure increasing valve 90, and the pressure reducing valve 100 are also connected. A current control signal for linearly controlling the magnetic force of the solenoid 74 is output to the solenoid 74 of the pressure control valve 30, while each of the solenoids 174 of the inflow control valve 140, the pressure increasing valve 90, and the pressure reducing valve 100 respectively. ON / OF for driving the solenoid 174 ON / OFF
An F drive signal is output.

Here, the effect characteristic control by the ECU 150 will be described in detail.

When the depressing force F of the brake pedal 10 increases to a certain value, the pressure in the variable pressure chamber 12b of the booster 12 rises to the atmospheric pressure and reaches the assisting limit. After the assisting limit, the booster 12 cannot boost the pedaling force F. Therefore, if no countermeasures are taken, as shown in a graph of FIG. the height of the brake cylinder pressure P _B is lower than the height of the brake cylinder pressure P _B when it is assumed that there is no boosting limit. Focusing on this fact, the effect characteristic control is performed. Specifically, as shown in the graph of FIG. 9, after the booster 12 reaches the assisting limit, the pump 40 is operated and the master is controlled. the (master cylinder fluid increasing relative pressure P _M increase amount of the brake cylinder pressure P _B) only high hydraulic pressure cylinder fluid pressure difference ΔP from pressure P _M is generated in the brake cylinder 20, whereby the booster 1
Stabilize the braking effect before and after the assistance limit of 2. Here, the relationship between the differential pressure ΔP and the master cylinder pressure P _M is, for example, are those represented by the graph in FIG. 10.

By the way, as described above, the present applicant has conducted a study on the operating characteristics of the brake operating member by the driver, and as a result, in a sudden braking operation state, as shown in FIG. , Brake pedal 10
In order to increase the depressing force F of the brake pedal 10, an operation of moving the depressed position of the brake pedal 10 from the non-operation position to the operation position is performed (in an increasing stage). An operation of holding the depressed position constant is performed (holding stage). In this holding stage, the driver actually operates the brake pedal 10 with the intention of maintaining the pedaling force F constant, but actually, the pedaling force F
At the beginning of the holding phase, it decreases with time t, contrary to the driver's will, and eventually has an operating characteristic of being kept constant.

Furthermore, based on the discovery, such operating characteristics are positively considered on the brake device side to avoid improper operation of the brake device based on a decrease in the pedaling force F contrary to the driver's will. He has noticed that the brakes can always be actuated according to the driver's intention, and as a result, the safety of the vehicle is improved.

Based on such knowledge, in the present embodiment, as shown in FIG. 12, the effectiveness characteristic control device includes (a) a brake operation state amount detection means 180 for detecting the operation state amount of the brake operation member, b) an assist limit detecting means 181 for detecting that the booster 12 has reached the assist limit;
(c) A provisional target differential pressure determining means 1 for determining a temporary target differential pressure ΔP between the brake cylinder 20 and the master cylinder 14 according to the detected operation state amount after the detection of the assisting limit.
82. Further, (d) a sudden brake operation detecting means 184 for detecting a sudden brake operation of the brake operating member by the driver, and (e) a detected amount of operation state that has been detected after the detection of the sudden brake operation is about to decrease. later, the increase INC temporary target differential pressure [Delta] P, based on the amount of decrease in the detected operation state quantity, as represented graphically in FIG. 13, when the brake cylinder pressure P _B is the amount of operation state has attempted to reduce And an increase amount determining means 186 that determines to be held at the height P _B2 . Furthermore, (f) an increase unnecessary detecting means 188 for detecting the unnecessary increase of the differential pressure which is no longer required to increase the provisional target differential pressure ΔP, and (g) a final target differential pressure determination for determining the final target differential pressure ΔP Means 192, before the detection of the need to increase the differential pressure, determines the provisional target differential pressure ΔP and the increment INC, respectively.
The final target differential pressure determining means 192 determines the final target differential pressure ΔP as the final target differential pressure ΔP after detecting that the differential pressure increase is unnecessary.
And (h) control means 194 for controlling the pressure control valve 30 so that the determined final target differential pressure ΔP is realized.

In the present embodiment, the brake operation state amount detecting means 180 mainly includes the master cylinder hydraulic pressure sensor 166.

The boosting limit detecting means 181 detects that the booster 12 has reached the boosting limit when the pressure in the transformer chamber 12b of the booster 12 rises to the atmospheric pressure and the booster negative pressure switch 164 changes from the OFF state to the ON state. It is determined to have arrived.

[0073] Also, the provisional target differential pressure determining means 182, the detected master cylinder pressure P _M, the increment IP _M from the boosting limit value P _M0 is the height at which the booster 12 has reached the boosting limit The provisional target pressure difference ΔP is determined accordingly.

Further, the sudden braking operation detecting means 184
It is intended to detect the sudden braking when the temporal change rate of the detected master cylinder pressure P _M by the master cylinder pressure sensor 166 (dP _M / dt) becomes a positive set value X or more . Master cylinder pressure sensor 16
6 is shared by the brake operation state amount detection means 180 and the sudden brake operation detection means 184.

Further, the increase amount determining means 186 detects
Master cylinder pressure P_MAs it tried to drop
The peak value, which is the height of the
As shown conceptually in rough (however, P_M2,
P_B2Is the master cylinder pressure P_MShows the peak value
Period t₀Master cylinder P at_MAnd brake cylinder
Hydraulic pressure P_BRespectively, and P_M1, P_B1Is the time t₀of
Master cylinder P at any later time t_MAnd bray
Cylinder pressure P_BAnd master respectively), master
Cylinder pressure P_MCurrent value P_M1Of its peak value P_M2Or
Reduction amount ΔP _MAnd increase the provisional target differential pressure ΔP
The situation, the obtained reduction amount ΔP_MBy
Brake fluid pressure P to be generated_BLow
Lower amount ΔP _B(= P_B2-P_B1) And get that fetched
Reduction amount ΔP_BIs determined as the increase amount INC of the provisional target differential pressure ΔP
It is supposed to. Therefore, the provisional target differential pressure ΔP
If you do not increase the
D hydraulic pressure P_MAnd brake cylinder pressure P_BIs the point corresponding to
In the situation of moving from point A to point B, provisional target differential pressure ΔP
To the increment INC (= ΔP_B) Just increase the
The corresponding point moves horizontally from point A to point C (ΔP₁
Is the sum of the provisional target differential pressure ΔP and the increment INC.
Represents the target differential pressure ΔP), and eventually the brake cylinder fluid pressure P
_BIs kept constant.

Also, the differential pressure increase unnecessary detecting means 188 is
After detecting the brake operation, the decrease amount ΔP _MIs a positive set value Y or less
When it becomes higher, it is not necessary to increase the provisional target differential pressure ΔP.
Is determined. The set value Y is
All of the pedaling force F in the holding stage of the brake operation state
It is assumed that the amount of decrease is larger than the value obtained experimentally.
ing. The increase unnecessary detecting means 188 is, for example, a sudden
After detecting the rake operation, the brake switch 162
Key when the operation signal changes from ON to OFF.
It shall be determined that the increase of the target pressure ΔP is unnecessary.
You can also.

The details of the effect characteristic control that has been schematically described above will be specifically described with reference to the routines shown in FIGS.

The effectiveness characteristic control routine of FIG. 5 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), a master cylinder pressure signal is taken in from the master cylinder pressure sensor 166, and then S2 In the booster negative pressure switch 164
Fetches a booster negative pressure signal. Then, in S3, the flag F ₁ provided in the RAM is determined whether it is 1. The flag F ₁ is initialized to 0 with the power-on of ECU150 computer. Assuming that the flag F ₁ this time is 0, the determination moves to NO next, S4.

At S4, it is determined whether or not the booster negative pressure switch 164 is ON, thereby determining whether or not the booster 12 has reached the assisting limit. Assuming that it is not in the ON state this time, the judgment is N
O, and in S5, a signal to turn it off is output to the solenoid 74 of the pressure control valve 30.
The pressure control valve 30 is opened. Then, in S6, the solenoid valve 174 of the inflow control valve 140 is turned off.
F signal is output, whereby the inflow control valve 140
Is closed. Thereafter, in S7, a signal for turning it off is output to the pump motor 170. Subsequently, in S8, the signal for the flag F ₁ to 0 is output. Thus, one execution of this routine ends.

On the other hand, if it is assumed that the booster 12 has reached the assisting limit, the determination in S4 becomes YES, and
In step 9, it is determined whether or not it is determined that the vehicle is in a sudden braking operation state by a sudden braking determination routine of FIG. Assuming that it is determined that the vehicle is not in the sudden braking operation state this time, the determination is NO, and the process proceeds to S10. In this S10, the master cylinder hydraulic pressure P _M
Of the current value, the booster 12 is temporary target differential pressure ΔP in response to increment IP _M from value P _M0 when it reaches the boosting limit is calculated. Incremental IP _M and the relationship between the target differential pressure ΔP is ROM
Is stored in, is the temporary target differential pressure ΔP corresponding to the current master cylinder pressure P _M is determined according to the relationship. The relationship for example, as represented graphically in Figure 15, are related to provisional target differential pressure ΔP as increment IP _M increases increases from 0 linearly.

Subsequently, at S11, the pressure control valve 30
The solenoid current value I corresponding to the provisional target differential pressure ΔP is calculated for the solenoid 74. The relationship between the provisional target differential pressure ΔP and the solenoid current value I is stored in the ROM,
The solenoid current value I corresponding to the provisional target differential pressure ΔP is calculated according to the relationship. Subsequently, in S12, the exciting current is supplied to the solenoid 74 at the solenoid current value I, whereby the pressure control valve 30 is controlled. Then, 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. Assuming that it is not being executed, the determination is NO, and in S62, a signal for turning on the solenoid 174 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
4 and can be introduced into the pump 40 via the supply passage 130. Thus, one execution of this routine ends.

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 for estimating the amount of the operating fluid existing as the operating fluid to be pumped by the pump 40 in the reservoir 98, that is, an operation for estimating the remaining amount of the reservoir is performed.
Subsequently, in S64, the estimated reservoir remaining amount becomes zero.
That is, it is determined whether there is no hydraulic fluid to be pumped by the pump 40 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 174 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, assuming 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 flow shifts to S14 in FIG.

In S14, the pump motor 17
A signal for turning it on is output to 0, whereby the hydraulic fluid is pumped from the reservoir 98 by the pump 40,
The hydraulic fluid is discharged to each brake cylinder 20. As a result, each brake cylinder 20 receives the master cylinder hydraulic pressure P
_A fluid pressure higher than _M by a provisional target differential pressure ΔP is generated. In other words, as in this case, if the vehicle is not currently in the sudden braking operation state, the provisional target differential pressure ΔP is directly used as the final target differential pressure ΔP, and the pressure control valve 30 is controlled so that the final target differential pressure ΔP is realized. Is controlled. Thus, one execution of this routine ends.

On the other hand, assuming that it is determined by the rapid brake determination routine of FIG. 7 that the vehicle is currently in a rapid brake operation state, the determination in S9 becomes YES, and in S15, the master cylinder of the master cylinder hydraulic pressure sensor 166 whether the master cylinder pressure P _M is attempting to drop is determined based on the temporal change of the hydraulic signal. That is, it is determined whether or not the vehicle is going to shift from the increasing stage to the holding stage in the sudden braking operation state.
When the master cylinder pressure P _M in the sudden braking state is not trying to decrease, a negative decision (NO) is obtained,
The process proceeds to S10 and below, but if it is going to decrease,
The determination becomes YES, and the process proceeds to S16 and thereafter.

In S16, the master cylinder hydraulic pressure P
_MThe peak value, which is the value at which it was about to fall
Is stored in the RAM, and then, in S17, the flash
F ₁Is set to 1. Then, in S18,
The provisional target differential pressure ΔP is calculated in the same manner as in S10.
Then, in S19, the master cylinder hydraulic pressure P _M
ΔP from the current peak value to its peak value_MIs calculated
Then, in S20, the calculated decrease amount ΔP_M
Reduction amount ΔP corresponding to_BIs the master cylinder pressure P_MWhen
Brake cylinder fluid pressure P_BThe slope of the straight line that represents the relationship with
The increase IN of the provisional target differential pressure ΔP
It is calculated as C. Subsequently, in S21, S18
And the provisional target pressure difference ΔP calculated in
The sum of the calculated increment INC and the final target differential pressure ΔP is
Is calculated. Thereafter, in S22, the sharp
The current non-emergency brake operation state is set by the rake
It is determined whether or not it is determined that there is. This time, still
Assume that it is determined that the vehicle is in a sudden braking operation
If the determination is NO, S23 is skipped and S11
Move to the following.

Therefore, if this routine is thereafter executed, the determination in S3 becomes YES, and S4, S9, S1
5 to S17 are skipped, and in S18 to S21,
A provisional target pressure difference ΔP corresponding to the current value of the master cylinder pressure P _M from the assist limit value P _{M0 according} to IP _M , and a decrease ΔP of the current value of the master cylinder pressure P _M from its peak value
The sum with the increment INC according to _M is set as the final target differential pressure ΔP.

When the depression force F of the brake pedal 10 is reduced as desired by the driver, it is determined by the rapid brake determination routine of FIG. 7 that the vehicle has shifted from the rapid brake operation state to the non-rapid brake operation state. , S in FIG.
The determination at 22 is YES, and the flag F _{1 is set at} S23.
Is set to 0. Therefore, if this routine is thereafter executed, the determination in S3 becomes NO, and the process proceeds to S4 and subsequent steps.

The sudden braking determination routine of FIG. 7 is also repeatedly executed. First, in S101, a master cylinder pressure signal is taken in from the master cylinder pressure sensor 166. Next, in S102, based on the master cylinder fluid pressure signal, the amount of change from the previous value of the current value of the master cylinder pressure P _M is calculated, it, by being divided by the execution cycle of this routine, the master Cylinder pressure P
The change speed of _M is calculated. Further, it is determined whether or not the change speed is equal to or greater than the set value X. It is determined whether a sudden braking operation has been performed. If it is assumed that the change speed is not equal to or greater than the set value X this time, the determination is NO, and in S103, the flag F provided in the RAM is set.
It is determined whether ₂ is 1 or not. The flag F ₂ is also a flag that is reset to zero by the computer is powered on, assuming this time is zero, a negative decision (NO) is obtained in S104, it is determined not to be currently sudden braking state You. Subsequently, in S105, the output signal to reset the flag F ₂ to 0, one cycle of execution of the present routine is terminated.

[0091] On the contrary, assuming that the change rate of the master cylinder pressure P _M is equal to or greater than the set value X, S10
The determination of 2 is YES, and in S106, it is determined that the vehicle is currently in a sudden brake operation state. Subsequently, S107
In the flag F ₂ is set to 1. Thus, one execution of this routine ends.

Thereafter, if this routine is executed, S1
The decision at 02 becomes NO, and since the flag F ₂ is 1, the determination is YES in S103, as long as the determination of S108 without becoming a reduction amount [Delta] P _M is the set value Y or is NO, S104 and S105 is skipped. Also the rate of change of the master cylinder pressure P _M is no longer a set value or more X, as long as the decrease amount [Delta] P _M is not equal to or larger than a set value Y, it is the determination of a sudden braking state is maintained.

Thereafter, assuming that the amount of decrease ΔP _M has become equal to or greater than the set value Y, the determination in S108 becomes YES, and
Steps 104 and S105 are executed, and it is determined that the state has shifted from the sudden braking operation state to the non-rapid braking operation state.

In the antilock control routine, the wheel speed sensor 168 monitors the wheel speed of each wheel and the running speed of the vehicle body, while the pressure increasing valve 90 is in the open state and the pressure reducing valve 100 is in the closed state. 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 170 is operated during the antilock control, and the pump 40 pumps up the hydraulic fluid from the reservoir 98 and returns the hydraulic fluid to the main passage 18.

This antilock control routine is executed regardless of whether or not the effectiveness characteristic control routine is executed. Therefore, during execution of the effectiveness characteristic control, the target differential pressure ΔP
If the locking tendency of each wheel becomes excessive due to the increase in the number, the antilock control routine is executed, and as a result, the operating force of the brake of each wheel does not need to be excessive.

As is clear from the above description, in the present embodiment, the master cylinder hydraulic pressure sensor 166 and the EC
The part that performs S1 in FIG. 5 of U150 cooperates with each other to form a brake operation state amount detection unit 180,
The booster negative pressure switch 164 and the part of the ECU 150 that executes S2 and S4 in the drawing cooperate with each other to form the assisting limit detecting means 181. The master cylinder hydraulic pressure sensor 166 and the S1 and S10 in the ECU 150 shown in FIG. The part that executes S18 cooperates with each other to form provisional target differential pressure determination means 182. Further, the master cylinder hydraulic pressure sensor 166 and the part of the ECU 150 that execute S101, S102 and S106 of FIG.
5, the portions that execute S1, S9, S15, S16, S19 and S20 of FIG. 5 cooperate with each other to constitute the increase amount determining means 186. The master cylinder hydraulic pressure sensor 166 and the ECU
22 and the part that executes S101, S108, and S104 in FIG. 7 cooperate with each other to constitute a differential pressure increase unnecessary detecting unit 188, and the part of the ECU 150 that executes S21 in the figure executes the final target differential pressure determining unit 192. Configure and EC
The part of U150 that executes S5 to S7 and S11 to S14 in the figure constitutes the control means 194.

Further, in the present embodiment, the increase amount determining means 186 constitutes an example of the “increase amount determining means”, and constitutes an example of the “brake operating force reduction suppressing means”. unnecessary detection unit 188 constitute an example of "matching drop operation detecting unit", among the final target differential pressure determining means 192, after the differential pressure increase of the unnecessary detected by the differential pressure increases unnecessary detection unit 188, the provisional target differential pressure determined portion as determined final target differential pressure of the temporary target differential pressure determined by means 182, with each other to constitute an example of "brake operating force decreases allowing means".

It should be noted that the flow control valve control routine of 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 close to it.

FIG. 16 shows a brake device according to another embodiment. In this brake device, a master cylinder 300 and a brake cylinder 302 are connected to each other by a liquid passage 304. In the middle of the liquid passage 304, the master cylinder 300
A check valve 310 is provided to allow the flow of the hydraulic fluid toward 04 and prevent the flow in the opposite direction, and a bypass passage 312 is provided in parallel with the check valve 310. In the middle of the bypass passage 312, the solenoid on-off valve 314
Is provided.

The electromagnetic on-off valve 314 is controlled by the control means 316. The control means 316 is connected to the sudden brake operation detecting means 317, and after detecting the sudden brake operation, closes the electromagnetic on-off valve 314 to prevent the flow of the hydraulic fluid from the brake cylinder 302 to the master cylinder 300, As a result, the brake cylinder hydraulic pressure is maintained, thereby completely suppressing a decrease in the brake operating force. When the amount of decrease in the brake operation state amount is equal to or greater than the set value, the control unit 316 determines that the electromagnetic on-off valve 3
14 to open, thereby allowing the brake cylinder fluid pressure to decrease in accordance with the amount of brake operation.

That is, in this embodiment, the check valve 310, the bypass passage 312, and the electromagnetic on-off valve 3
14 and the portion of the control means 316 that closes the electromagnetic on-off valve 314 cooperate with each other to form a brake cylinder hydraulic pressure holding device 318, which brake cylinder hydraulic pressure holding device 318 according to the present invention is "brake operating force reduction suppression". It constitutes an example of "means". Control means 3
16 out of parts, constitutes the brake cylinder fluid pressure lowering acceptable device, allowed the brake cylinder fluid pressure lowering acceptable device "reduced braking force to open the solenoid on-off valve 314 on the basis of the decrease of the brake operation state quantity It constitutes an example of "means".

FIG. 17 shows a brake device according to still another embodiment. In this brake device as well, similarly to the embodiment of FIG.
And the brake cylinder 302 are connected to each other by a liquid passage 304. However, instead of the check valve 310, a throttle (orifice or the like) 320 that allows the flow of the hydraulic fluid between the master cylinder 300 and the brake cylinder 302 with a large resistance is provided, and in parallel with the throttle 320, the master cylinder 300 A bypass passage 322 is provided to allow the flow of hydraulic fluid between the throttle cylinder 304 and the throttle cylinder 304 with a smaller resistance at the throttle 320. An electromagnetic on-off valve 324 is provided in the middle of the bypass passage 322.

The solenoid on-off valve 324 is connected to the control means 31.
6 is controlled by the same control means 326. The control means 326 is connected to the sudden braking operation detecting means 317, and after detecting the sudden braking operation, the electromagnetic switching valve 324
To allow the hydraulic fluid flow from the brake cylinder 302 to the master cylinder 300 with a large resistance, thereby reducing the speed at which the brake cylinder fluid pressure drops, thereby partially reducing the brake operating force. Suppress. When the amount of decrease in the amount of brake operation is equal to or greater than the set value, the control means 326 opens the electromagnetic on-off valve 324, thereby allowing the brake cylinder fluid pressure to decrease in accordance with the amount of brake operation. .

That is, in the present embodiment, the throttle 320, the bypass passage 322, the solenoid on-off valve 324, and the part of the control means 326 that closes the solenoid on-off valve 324 cooperate with each other to reduce the brake cylinder fluid pressure drop speed. The device 328 is configured, and the brake cylinder fluid pressure reduction speed reducing device 328 is an example of the “brake operating force reduction suppressing unit” in the present invention. Also,
Of the control unit 326, parts, constitutes the brake cylinder fluid pressure lowering acceptable device, the brake cylinder fluid pressure lowering acceptable device "brake operating force to open the solenoid on-off valve 324 on the basis of the decrease of the brake operation state quantity This constitutes an example of the “lowering means”.

As described above, some embodiments of the present invention have been described in detail with reference to the drawings. In addition, 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.

FIG. 2 is a front sectional view for explaining the structure and operation of a pressure control valve 30 in FIG.

It is a graph showing the relationship between the solenoid excitation current I and the solenoid attractive force F ₁ at the pressure control valve of FIG. 3 FIG.

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

FIG. 5 is a flowchart showing a brake effectiveness characteristic control routine stored in a ROM 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 flowchart showing a sudden braking determination routine stored in the ROM.

8 is a graph showing a relationship between brake operating force F and brake cylinder pressure P _B in the general brake system provided with a vacuum booster.

FIG. 9 is a graph for explaining brake effect characteristic control in the brake device according to the embodiment.

10 is a graph showing the relationship between the differential pressure ΔP between the master cylinder pressure P _M and the master cylinder and the brake cylinder in the brake effectiveness characteristics control.

FIG. 11 shows a brake pedal in a sudden braking operation state.
Force F and master cylinder pressure P _MAnd brake cylinder
Hydraulic pressure P_BAre graphs showing how each changes over time.
It is.

FIG. 12 is a functional block diagram showing the brake device according to the embodiment.

FIG. 13 is a graph for explaining characteristics of the brake effect characteristic control.

FIG. 14 is a graph for explaining the operation principle of the increase amount determining means 186 in FIG.

15 is a graph showing the relationship between the target value of the increment IP _M and the differential pressure ΔP from the boosting limit value P _M0 of the current value of the master cylinder pressure P _M at S10 and S18 in FIG. 5.

FIG. 16 is a system diagram showing a brake device according to another embodiment of the present invention.

FIG. 17 is a system diagram showing a brake device according to still another embodiment of the present invention.

[Explanation of symbols]

10 brake pedal 12 Booster 14,300 master cylinder 20,302 Brake cylinder 30 Pressure control valve 40 pump 150 ECU 162 brake switch 164 Booster negative pressure switch 166 Master cylinder pressure sensor 184,317 Rapid brake operation detecting means 182 provisional target differential pressure determination means 186 Increase determination means 188 Means for detecting increase in differential pressure unnecessary 192 Final target differential pressure determination means 318 Brake cylinder hydraulic pressure holding device 328 Brake cylinder fluid pressure drop speed reduction device

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60T 8/00

Claims (7)

(57) [Claims] 1. A brake device comprising: a brake operating member, a brake for suppressing rotation of wheels, and a brake driving device for operating the brake with a force having a magnitude corresponding to an operation state amount of the brake operating member, A sudden brake operation detecting means for detecting a sudden brake operation of the brake operating member by a driver; and after the sudden brake operation is detected by the sudden brake operation detecting means, the actuation force of the brake is changed according to the operation state amount. (A) (i) an operation state amount detection means for detecting the operation state amount
And (ii) sudden braking by the sudden braking operation detecting means.
Brake operation force is detected,
Where the decrease in the brake operating force is suppressed by
The operation state detected by the operation state amount detection means.
When the amount of state decrease exceeds the set value,
The operation of decreasing the operating force of the brake operating member is
Judge that an operation to lower the alignment that matches the intention of the transferor was performed
(B) matching lowering operation detecting means including
The operation of detecting a decrease in alignment is detected by the operation of detecting a decrease in alignment.
After that, the operation of the brake operating force reduction suppressing means is ended.
By doing so, the operating force depends on the operation state amount.
And a brake operating force reduction permitting means for permitting reduction. 2. The brake driving device according to claim 1, wherein: (a) a master cylinder for generating a hydraulic pressure having a height corresponding to the operation state amount; and (b) a master cylinder connected to the master cylinder by a liquid passage.
A brake cylinder that operates the brake based on the hydraulic pressure supplied from the liquid passage, (c) an operation state amount detection unit that detects the operation state amount, and (d) the operation state in the middle of the liquid passage. The brake cylinder is provided in a state of being connected to an amount detecting means, and at least at one time during operation of the brake operation member, a hydraulic pressure higher than the master cylinder hydraulic pressure is generated in the brake cylinder, and a brake cylinder for the master cylinder hydraulic pressure is generated. A hydraulic pressure control device that determines a pressure increase amount of the hydraulic pressure according to the operation state amount detected by the operation state amount detection unit, wherein the brake operating force reduction suppression unit is provided in the hydraulic pressure control unit. After the sudden braking operation is detected by the sudden braking operation detecting means, and at least after the operation state amount is about to decrease, the pressure increase The braking system of claim 1 including a pressure increase amount increasing means for increasing from a value corresponding to the operation state quantity. 3. A brake operating member, Hydraulic pressure of a height corresponding to the operation state amount of the brake operation member
A master cylinder that generates The master cylinder is connected to the master cylinder by a liquid passage.
The brake is activated based on the hydraulic pressure supplied from the road.
Brake cylinder Operation state amount detection means for detecting the operation state amount, In the middle of the liquid passage, the operation state quantity detecting means is connected.
The brake operation member is provided in the
At least at one time, a fluid higher than the master cylinder fluid pressure
Pressure is generated in the brake cylinder,
Increasing brake cylinder pressure relative to master cylinder pressure
The operation state in which the pressure amount is detected by the operation state amount detection means.
A hydraulic pressure control device determined according to the state quantity, The operation state quantity detection means provided in the hydraulic pressure control device;
Sudden braking of the brake operating member by the driver
Key operation is detected, and at least the operation
After the state is about to decrease, the pressure increase
Includes pressure increase amount increase means for increasing the value from the value corresponding to the state quantity
And a brake operating force reduction suppressing means.
Braking device. 4. An alignment-reducing operation detecting means for detecting that the driver's operation of reducing the operating force of the brake operating member is a matching-reducing operation consistent with the driver's intention; (b) ending the operation of the brake operating force reduction suppressing means after the alignment lowering operation detecting means detects the alignment lowering operation, thereby allowing the operating force to decrease in accordance with the operation state amount. The brake device according to claim 3 , further comprising: a brake operating force reduction permitting unit that performs the braking operation. 5. The pressure-increasing amount increasing means increases the pressure-increasing amount after the operation state amount is about to decrease, and determines the increase amount when the operation state amount is determined by the brake cylinder hydraulic pressure. The brake device according to any one of claims 2 to 4 , further comprising an increase amount determination unit that determines to maintain the height at the time of the decrease. 6. The hydraulic pressure control device according to claim 1, further comprising: (a) a state in which the hydraulic pressure control device is provided in the middle of the liquid passage and allows a bidirectional flow of hydraulic fluid between the master cylinder and the brake cylinder. A control valve that switches to a plurality of states including a state in which the flow of hydraulic fluid toward the master cylinder is blocked, and (b) a discharge side is connected between the control valve and the brake cylinder in the liquid passage, and suction is performed. The pump according to any one of claims 2 to 5 , further comprising a pump for pumping hydraulic fluid from a side and discharging the hydraulic fluid to a discharge side, wherein the pressure of the brake cylinder is increased by a joint use of the control valve and the pump. Brake device. 7. The brake device according to claim 6 , wherein the hydraulic pressure control device is such that a suction side of the pump is connected to a portion of the liquid passage between the master cylinder and the control valve.