JP3458695B2 - Vehicle hydraulic brake system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic brake system for a vehicle, and more particularly to a hydraulic pressure for controlling a hydraulic pressure supplied from a hydraulic pressure source such as a master cylinder to a wheel cylinder for operating a brake of the vehicle. The present invention relates to improving the reliability of a brake system including a control valve device.

[0002]

2. Description of the Related Art In a vehicle hydraulic brake system, as disclosed in, for example, Japanese Patent Laid-Open No. 5-139279, a wheel cylinder for activating a brake of a vehicle and a wheel cylinder for operating a brake operating member are used. A hydraulic pressure source that supplies hydraulic pressure to the wheel cylinder, at least a pressure increasing state that allows the hydraulic fluid to flow into the wheel cylinder from the hydraulic pressure source, and a depressurized state that allows the hydraulic fluid to flow out from the wheel cylinder. , A hydraulic pressure control valve device for controlling the hydraulic pressure supplied to the wheel cylinder. The hydraulic pressure source may be, for example, a power hydraulic pressure source that generates a substantially constant hydraulic pressure with power, or a master cylinder hydraulic pressure of a size that corresponds to the operating state such as the operating force of the brake operating member or the size of the operating stroke. You can use a master cylinder to generate
It is desirable that the hydraulic pressure control valve device can be in a holding state that does not allow the inflow or outflow of the hydraulic fluid to the wheel cylinders, in addition to the pressure increasing state and the pressure reducing state. In addition, a reservoir that stores the hydraulic fluid that is caused to flow out from the wheel cylinder is often provided.

According to this type of vehicle hydraulic brake system, the hydraulic pressure of the wheel cylinder is controlled by the control of the hydraulic control valve device to a magnitude that does not uniquely correspond to the operating state of the brake operating member. be able to. For example, regenerative braking cooperative control can be performed in a vehicle having an electric motor as a vehicle drive source. In vehicles that use an electric motor as a drive source, a regenerative braking system is used that causes the electric motor to function as a generator when braking is needed and stores the generated electrical energy in a storage battery, but only the regenerative braking system. Is often inadequate, and is often coordinated with a hydraulic braking system to produce the braking effect desired by the operator. In this case, the braking force that should be generated by the hydraulic braking system is the braking force desired by the operator minus the braking force of the regenerative braking system, and the hydraulic pressure of the wheel cylinders is unique to the operating state of the brake operating member. Therefore, the regenerative braking cooperative control is required to control the magnitude that does not correspond to each other. Controlling the hydraulic pressure of the wheel cylinder to a magnitude that does not uniquely correspond to the operating state of the brake operating member is not only for the above-mentioned regenerative braking cooperative control, but for example, excessive slip of the wheel during braking can be prevented. Anti-lock control to prevent, acceleration slip control to prevent excessive slip of the wheel during acceleration, running stability control to improve the running stability of the vehicle, and deceleration accurately corresponding to the operating state of the brake operating member. It is also necessary for controlling the braking effect that occurs in the vehicle.

[0004]

According to the vehicle hydraulic brake system including the wheel cylinder, the hydraulic pressure source, and the hydraulic control valve device, as described above, The hydraulic pressure of the wheel cylinder can be controlled to a size that does not uniquely correspond to the operating state of the brake operating member, and various controls such as regenerative braking cooperative control can be performed. It was found that this type of vehicle hydraulic brake system could be further improved in terms of reliability. Therefore,
An object of the present invention is to further improve the reliability of this type of vehicle hydraulic brake system. This problem is solved by adopting a hydraulic brake system for a vehicle as an aspect described in each of the following items. Each aspect, like the claims,
In addition to categorizing into sections, describe in a format that cites other sections as necessary. This is to clarify the possibility of combining the constituent elements of each term. (1) A wheel cylinder that operates a brake of a vehicle, a hydraulic pressure source that supplies hydraulic pressure to the wheel cylinder in response to an operation of a brake operating member, and an inflow of hydraulic fluid from the hydraulic pressure source to the wheel cylinder. A liquid that controls the hydraulic pressure supplied to the wheel cylinder, which can be in a pressure increasing state that allows it, a pressure reducing state that allows outflow of hydraulic fluid from the wheel cylinder, and a holding state that does not allow inflow or outflow of hydraulic fluid. A pressure control valve device; and a reservoir that contains hydraulic fluid that flows out of the wheel cylinder during one braking via the hydraulic pressure control valve device and that returns to the hydraulic pressure source after the braking is finished, and The reservoir capacity, which is the maximum amount of hydraulic fluid that can be stored for the one braking of the reservoir, is the maximum amount of hydraulic fluid that can be stored from the non-braking state to the braking state of the wheel cylinder. Vehicle hydraulic braking system, characterized in that less than the wheel cylinder capacity that (claim 1). In this way, the reservoir should contain the hydraulic fluid that flows out from the wheel cylinder during one braking, and recirculate to the hydraulic pressure source after the braking is completed, and if the reservoir capacity is smaller than the wheel cylinder capacity. ,
Even if the hydraulic pressure control valve device malfunctions or malfunctions during braking and the hydraulic fluid is allowed to flow from the wheel cylinders to the reservoir indefinitely, the vehicle will be braked without any problems. . When a situation occurs where the hydraulic pressure control valve device allows the hydraulic fluid to flow out of the wheel cylinders indefinitely, the hydraulic fluid flows out while the reservoir can store the hydraulic fluid. However, if the total outflow amount is equal to the volume of the reservoir, the hydraulic fluid can no longer flow into the reservoir and therefore cannot flow out of the wheel cylinder. Since the reservoir capacity is smaller than the wheel cylinder capacity, when hydraulic fluid is drained from the wheel cylinder due to malfunction of the hydraulic control valve device, etc. The hydraulic fluid remains and the braking force is secured to some extent. Further, when the hydraulic fluid is replenished from the hydraulic pressure source, it is possible to generate a braking force of a sufficient magnitude for the brake with a relatively small amount of replenishment. When the hydraulic pressure source is a normal master cylinder that generates a master cylinder hydraulic pressure according to the operating force of the brake operating member, the operating stroke of the brake operating member increases by the amount of hydraulic fluid supplied, Although the braking effectiveness is delayed, the increase of the operation stroke and the effectiveness delay can be reduced. Further, when the hydraulic pressure source is a power hydraulic pressure source, the problem of increasing the operation stroke due to the replenishment of the hydraulic fluid does not occur, and the problem of delay of brake effectiveness occurs, but the effect delay is small. Is obtained. As described above, the reliability of the vehicle hydraulic brake system is improved. (2) The total amount of the hydraulic fluid that has flowed out of the wheel cylinder to the reservoir through the hydraulic pressure control valve device during the one braking is the maximum amount of the hydraulic fluid that the reservoir can accommodate for the one braking. The hydraulic brake system for a vehicle according to item (1), characterized in that the hydraulic brake system includes a liquid leak detection unit that determines that hydraulic fluid has leaked when the reservoir capacity is exceeded. In this way, by adding the liquid leak detection means that the liquid leak occurs when the total outflow amount of the hydraulic fluid from the wheel cylinder during one braking exceeds the reservoir capacity, in the event that the liquid leak occurs, , It can be detected early. The smaller the reservoir capacity, the earlier the liquid leak can be detected. In this respect, in the present aspect, the reservoir capacity is smaller than the wheel cylinder capacity, so the liquid leak can be detected particularly early. (3) The hydraulic pressure control valve device is provided with a pressure increasing valve that opens when the hydraulic pressure difference between the hydraulic pressure control device before and after the hydraulic pressure control device exceeds a set hydraulic pressure difference that can be electrically controlled and allows the hydraulic fluid to flow from the hydraulic pressure source into the wheel cylinder. Including, the set hydraulic pressure difference in the state where the electric control is not performed is regulated to be smaller than the maximum hydraulic pressure source hydraulic pressure which is the maximum value of the hydraulic pressure of the hydraulic pressure source (1) or (2) Hydraulic brake system for vehicles. The operation and effect of this configuration will be described later. (4) A wheel cylinder that operates a brake of a vehicle, a hydraulic pressure source that supplies hydraulic pressure to the wheel cylinder in response to an operation of a brake operating member, and an inflow of hydraulic fluid from the hydraulic pressure source to the wheel cylinder. A liquid that controls the hydraulic pressure supplied to the wheel cylinder, which can be in a pressure increasing state that allows it, a pressure reducing state that allows outflow of hydraulic fluid from the wheel cylinder, and a holding state that does not allow inflow or outflow of hydraulic fluid. A pressure control valve device, a reservoir that stores hydraulic fluid that flows out of the wheel cylinder during one braking through the hydraulic pressure control valve device, and returns to the hydraulic pressure source after the braking, and a reservoir during the one braking. The total amount of hydraulic fluid that has flowed from the wheel cylinders to the reservoir via the hydraulic control valve device is the maximum amount of hydraulic fluid that the reservoir can accommodate for the one braking. If it exceeds the reservoir capacity, hydraulic brake system which comprises a liquid leakage detection means for the hydraulic fluid leakage has occurred (Claim
8 ). In this way, the reservoir contains the hydraulic fluid that flows out from the wheel cylinder through the hydraulic pressure control valve device during one braking, and returns to the hydraulic pressure source after the braking is completed. If a liquid leak detection means is provided that determines that a liquid leak has occurred when the total amount of hydraulic fluid flowing out of the cylinder exceeds the reservoir capacity, it is possible to detect it early if a liquid leak occurs. it can. A liquid pressure control entire surface prohibiting means for prohibiting the operation of the entire hydraulic pressure control valve device when the liquid leakage is detected by the liquid leakage detecting means,
By providing a decompression inhibiting means for inhibiting the decompression operation of the hydraulic control valve device, it is possible to suppress the leakage of the hydraulic fluid. When the hydraulic pressure source is a normal master cylinder, the increase in the operation stroke of the brake operating member can be kept small, and when it is a power hydraulic pressure source, it prevents a large amount of hydraulic fluid from leaking. The reliability of the vehicle hydraulic brake system is improved thereby. (5) The hydraulic pressure control valve device is provided with a pressure increasing valve that opens when the hydraulic pressure difference between the hydraulic pressure control device and the hydraulic pressure control device itself exceeds a set hydraulic pressure difference that can be electrically controlled to allow the hydraulic fluid to flow from the hydraulic pressure source into the wheel cylinder. The vehicle hydraulic brake system according to item (4), in which the set hydraulic pressure difference is regulated to be smaller than a maximum hydraulic pressure source hydraulic pressure that is a maximum value of the hydraulic pressure of the hydraulic pressure source. (6) A wheel cylinder that actuates a brake of the vehicle, a hydraulic pressure source that supplies hydraulic pressure to the wheel cylinder in response to an operation of a brake operating member, and at least a hydraulic fluid from the hydraulic pressure source to the wheel cylinder. A pressure increasing state that allows inflow and a pressure reducing state that allows outflow of hydraulic fluid from the wheel cylinder can be included, and a hydraulic control valve device that controls the hydraulic pressure supplied to the wheel cylinder is included, and
The hydraulic pressure control valve device includes a pressure increasing valve that opens when the hydraulic pressure difference between the hydraulic pressure control device and the hydraulic pressure control device exceeds an electrically controllable valve opening pressure to allow the hydraulic fluid to flow from the hydraulic pressure source to the wheel cylinder. The vehicle hydraulic brake system, wherein the valve opening pressure in a state where control is not performed is regulated to be smaller than the maximum hydraulic pressure source hydraulic pressure that is the maximum value of the hydraulic pressure of the hydraulic pressure source (claim 9 ). ). As described above, the hydraulic pressure control valve device includes the pressure increasing valve that opens when the hydraulic pressure difference between the hydraulic pressure control device and the hydraulic pressure control device exceeds the electrically controllable valve opening pressure to allow the hydraulic fluid to flow from the hydraulic pressure source to the wheel cylinder. In addition to that,
If the valve opening pressure in a state where electric control is not performed is regulated to be smaller than the maximum hydraulic pressure source hydraulic pressure, the pressure increasing valve will not be electrically controlled due to failure or malfunction of the hydraulic pressure control valve device (electrical energy The brake can be activated even in the event of a loss of supply. The booster valve opens when the pressure difference between the front and the rear of the booster valve exceeds the valve opening pressure , that is,
It is intended to supply to the wheel cylinders under reduced pressure to a hydraulic pressure source fluid pressure by the valve opening pressure amount, and, since the valve opening pressure in a state in which the electric control is not performed is less than the maximum fluid pressure source pressure, the pressure-increasing valve Even if the hydraulic pressure is not controlled, if the hydraulic pressure source hydraulic pressure is generated in the hydraulic pressure source that exceeds the valve opening pressure in the non-electrically controlled state, the booster valve will open and the hydraulic fluid from the hydraulic pressure source to the wheel cylinder will be released. Is allowed and the brake is activated. (7) The reservoir includes a liquid storage chamber that is urged in a direction in which the volume is reduced by the urging means, and after the end of the braking, the hydraulic fluid in the liquid storage chamber is generated based on the urging force of the urging means. The vehicle hydraulic brake system according to any one of (1) to (5), which discharges (claim 5) . According to this structure of the reservoir, if the hydraulic pressure of the liquid passage to which the reservoir is connected decreases to near atmospheric pressure at the end of braking, the hydraulic fluid in the reservoir is naturally discharged. The liquid storage chamber can be formed, for example, between a housing and a piston that is liquid-tightly and slidably arranged in the housing. In that case, the urging means may be the piston of the liquid storage chamber. An elastic member such as a compression coil spring that urges in a direction to reduce the volume is suitable. The liquid storage chamber can also be formed between the housing and the expansion member disposed inside the housing. The expansion member may be, for example, a rubber bag in which gas is sealed, and in this case, the gas sealed in the rubber bag functions as the biasing means. (8) The hydraulic pressure source includes a main reservoir that stores hydraulic fluid at atmospheric pressure, which is different from the reservoir serving as a sub-reservoir, and the vehicle hydraulic brake system includes the wheel cylinder and the main reservoir. A bypass passage that bypasses the fluid pressure control valve device and is connected via a fluid passage between the fluid pressure source and the fluid pressure control valve device; and a direction from the wheel cylinder toward the main reservoir in the middle of the bypass passage. is of the hydraulic fluid flow allowed to but opposite of the flow and a check valve disposed in the direction of blocking, the secondary reservoir
To the bypass passage, from the secondary reservoir to the bypass passage
Check valve that allows the flow of hydraulic fluid in
(Claim 6) . Thus, by providing the bypass passage having the check valve, when the hydraulic pressure in the hydraulic passage between the hydraulic pressure source and the hydraulic control valve device becomes lower than the hydraulic pressure of the wheel cylinder, the hydraulic control valve device Regardless of the state, the hydraulic fluid is allowed to flow from the wheel cylinder side to the main reservoir side. In particular, if the configuration of this section and the configuration of (7) are adopted together, the hydraulic fluid in the sub-reservoir can be returned to the main reservoir using the bypass passage at the end of braking. (9) A hydraulic pressure control valve device is opened when a hydraulic pressure difference before and after the hydraulic pressure control device exceeds an electrically controllable hydraulic pressure setting hydraulic pressure difference, and allows hydraulic fluid to flow from the hydraulic pressure source to the wheel cylinder. And a pressure reducing valve that opens when the hydraulic pressure difference before and after itself exceeds an electrically controllable depressurizing hydraulic pressure difference to permit the outflow of hydraulic fluid from the wheel cylinder (1) or
The vehicle hydraulic brake system according to any one of (8). The actions and effects of the modes after this section will be clarified in the description of the embodiments of the invention. (10) The check valve is provided in parallel with the pressure increasing valve in such a direction as to allow the flow of the hydraulic fluid in the direction from the wheel cylinder toward the hydraulic pressure source but to prevent the flow in the opposite direction, and in parallel with the pressure reducing valve. The hydraulic brake system for a vehicle according to (9), wherein the check valve is provided with a check valve that allows the flow of the hydraulic fluid in the direction from the reservoir toward the wheel cylinder but blocks the flow in the reverse direction. . (11) The pressure increasing valve includes a seating valve and an electromagnetic urging device, and the seating valve includes a valve seat, a valve seat seated on the valve seat, and an electromagnetically energized member that moves integrally with the valve seat. A body and an elastic member that urges the electromagnetically biased body in a direction in which the valve element is seated on the valve seat, and the electromagnetic biasing device applies a biasing force of the elastic member to the electromagnetically biased body. Includes a coil that applies an electromagnetic biasing force in the opposite direction (3), (5) to (10)
The hydraulic brake system for a vehicle according to any one of items. (12) The pressure increasing valve is configured by an electromagnetic proportional control valve capable of arbitrarily controlling the magnitude of the electromagnetic biasing force by controlling the current supplied to the coil and controlling the opening of the seating valve (11 ) A hydraulic brake system for a vehicle as described in the above item. (13) The vehicle according to any one of (1) to (12), wherein the hydraulic pressure source includes a master cylinder that generates a master cylinder hydraulic pressure having a magnitude corresponding to an operating state of a brake operating member. Hydraulic brake system (claim 10) . (14) A hydraulic pressure supply unit, in which the master cylinder reduces the hydraulic pressure of a power hydraulic pressure source that generates hydraulic pressure by power to a magnitude corresponding to the operating force of the brake operating member and supplies the hydraulic pressure to the wheel cylinder. The vehicle hydraulic brake system according to the item (13). If the master cylinder is of this aspect, the operation stroke of the brake operating member can be reduced by the amount that the hydraulic fluid is supplied from the power hydraulic pressure source to the wheel cylinder when the vehicle hydraulic brake system is normal. Further, when hydraulic fluid flows from the wheel cylinder to the reservoir due to a failure or malfunction of the hydraulic pressure control valve device, if hydraulic fluid is supplied from the power hydraulic pressure source, the operating stroke of the brake operating member is increased or the brake is operated. It is possible to satisfactorily avoid a decrease in the effectiveness of. (15) The hydraulic brake system is provided in a vehicle equipped with a regenerative braking system that causes an electric motor as a vehicle drive source to perform regenerative braking, and the master cylinder hydraulic pressure is used for the regenerative braking force of the regenerative braking system. The vehicle hydraulic brake system according to item (13) or (14), including regenerative braking cooperative control means for controlling the hydraulic pressure control valve device so as to reduce the amount of hydraulic pressure corresponding to the above. (16) Controlling a second hydraulic pressure control valve device provided between the hydraulic pressure control valve device as the first hydraulic pressure control valve device and the wheel cylinder, and the second hydraulic pressure control valve device. Thus, anti-lock control for preventing excessive slip of the wheel during braking, acceleration slip control for preventing excessive slip of the wheel during acceleration, traveling stability control for improving traveling stability of the vehicle, and the brake operation member The second hydraulic pressure control valve device control means for performing at least one braking effect control for causing the vehicle to perform deceleration accurately corresponding to the operation state of (1) to (15). Hydraulic brake system for vehicles. (17) A wheel cylinder that operates a brake of a vehicle, a hydraulic pressure source that supplies hydraulic pressure to the wheel cylinder in response to an operation of a brake operating member, and an inflow of hydraulic fluid from the hydraulic pressure source to the wheel cylinder. A liquid that controls the hydraulic pressure supplied to the wheel cylinder, which can be in a pressure increasing state that allows it, a pressure reducing state that allows outflow of hydraulic fluid from the wheel cylinder, and a holding state that does not allow inflow or outflow of hydraulic fluid. A pressure control valve device; and a reservoir that contains hydraulic fluid that flows out of the wheel cylinder during one braking through the hydraulic pressure control valve device and that returns to the hydraulic pressure source after the braking is completed. When the capacity is such that the amount of hydraulic fluid in the reservoir is the minimum amount and the brake is applied, the hydraulic pressure control valve device is brought into the depressurized state, and the hydraulic pressure is removed from the wheel cylinder. Hydraulic brake system for a vehicle, characterized in that the hydraulic brake system is selected to have a size such that the brake is still effective even if the hydraulic fluid is drained to the server until the reservoir is completely filled. Claim 2). The features described in the above items (2), (3), (7) to (16) can also be adopted in the vehicle hydraulic brake system described in this item and the next item. (18) The hydraulic brake system for a vehicle is the wheel brake.
The hydraulic pressure of the cylinder is based on the operating condition of the brake operating member.
The required braking force according to the driver's intention acquired based on
The hydraulic pressure control valve device so that the target hydraulic pressure is determined by
Any one of (1) to (17), including means for controlling
The vehicle hydraulic brake system according to claim 3). (19) The hydraulic pressure source is the reservoir as an auxiliary reservoir.
It has a main reservoir, which is separate from the
Well, the hydraulic brake system for the vehicle is the wheel
The cylinder and the main reservoir are connected to the hydraulic control valve device.
While bypassing the hydraulic pressure source and the hydraulic pressure control valve device
The bypass passage that connects through the liquid passage between
From the wheel cylinder to the main reservoir in the middle of the passage
Allows flow of hydraulic fluid in the opposite direction, but blocks flow in the opposite direction
And a non-return valve disposed in the direction
From the check valve in the bypass passage.
The hydraulic pressure control valve is connected to the part on the da side via a pressure reducing valve.
A device opens the check valve after the braking is finished.
(7) to (18) including means
A hydraulic brake system for a vehicle (claim 7). (20) The hydraulic pressure control valve device as the first hydraulic pressure control valve device
Second hydraulic pressure provided between the wheel cylinder and the wheel cylinder
Controlling the control valve device and its second hydraulic control valve device
Prevents the wheels from slipping excessively during braking.
Second hydraulic pressure control valve device control means for performing chillock control,
From the wheel cylinder through the second hydraulic control valve device
The sub-reservoir that stores the hydraulic fluid to be discharged.
(1) to (19) including a main reservoir other than the reservoir
The hydraulic brake system for a vehicle according to any one of items
(Claim 4). (21) A wheel cylinder for operating a brake of a vehicle, a hydraulic pressure source for supplying hydraulic pressure to the wheel cylinder in response to an operation of a brake operating member, and an inflow of hydraulic fluid from the hydraulic pressure source to the wheel cylinder. A liquid that controls the hydraulic pressure supplied to the wheel cylinder, which can be in a pressure increasing state that allows it, a pressure reducing state that allows outflow of hydraulic fluid from the wheel cylinder, and a holding state that does not allow inflow or outflow of hydraulic fluid. A pressure control valve device, and a reservoir that contains hydraulic fluid that flows out from the wheel cylinder during one braking via the hydraulic pressure control valve device and that returns to the hydraulic pressure source after the braking is completed. The difference between the two volumes of hydraulic fluid that can each be accommodated in the wheel cylinder in two states in which the capacities are substantially different from each other but the braking effectiveness is different from each other. Vehicle hydraulic braking system, characterized in that it is chosen smaller Ri. The above two states are the state in which the maximum hydraulic pressure planned in the hydraulic brake system is supplied to the wheel cylinder, and the minimum hydraulic pressure in the range in which it can be said that the brake is substantially effective is supplied to the wheel cylinder. In the two states, the difference in the amount of hydraulic fluid in the wheel cylinder between the two states is maximum. If the capacity of the reservoir is selected to be smaller than this maximum difference, the requirements of the invention of this aspect are satisfied, but it is not essential,
The volume of the reservoir can be selected to any size within the range smaller than this maximum difference. The smaller the capacity of the reservoir is selected, the smaller the decrease in braking effectiveness when hydraulic fluid in the wheel cylinder flows out to the reservoir due to malfunction of the hydraulic control valve device, etc. It is necessary that the hydraulic fluid discharged from the storage device has a capacity that can be accommodated. The capacity of the reservoir should be selected from the ranges in which the maximum value of the difference between the above two states and the amount of hydraulic fluid that normally flows out from the wheel cylinder during one braking are the upper limit and the lower limit, respectively. .

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram showing a configuration of a vehicle hydraulic brake system that is an embodiment of the present invention. The hydraulic brake system 10 is used in a hybrid vehicle that includes both an internal combustion engine and an electric motor as drive sources. Braking of the hybrid vehicle of the present embodiment is performed by braking by the hydraulic brake system 10 and regenerative braking by a regenerative braking system (not shown). The regenerative braking system is a system that brakes the vehicle by causing the electric motor to function as a generator and storing the electric energy generated thereby in a storage battery. If the storage battery is charged by the electromotive force (simply referred to as regenerative electromotive force) generated in the electric motor when the rotating shaft of the electric motor is forcibly rotated by an external force, the electric motor is driven by the external force. And becomes a load, and braking force is generated. The battery is charged only when the vehicle needs to be braked. A part of the kinetic energy of the vehicle during braking is converted into electric energy and stored in the storage battery, which not only can brake the vehicle but also reduce the consumption of electric energy in the storage battery. It is possible to extend the traveling distance without charging.

Regenerative braking force (referred to as regenerative braking force)
The size of is not always constant. For example, when the traveling speed of the vehicle is extremely low, the regenerative braking force becomes almost zero. In addition, when the capacity of the storage battery is completely filled, control is often performed to prohibit the regeneration of energy in order to prevent deterioration of the storage battery due to overcharging, and in this case, the period during which regeneration is prohibited. The regenerative braking force becomes 0 in the middle. On the other hand, the magnitude of the braking force of the vehicle needs to be controlled to a magnitude that is not directly related to the magnitude of the regenerative braking force and that corresponds to the intention of the operator. Therefore, the magnitude of the hydraulic braking force to be generated by the hydraulic brake system 10 is the magnitude obtained by subtracting the regenerative braking force from the required braking force according to the operator's intention. Such control of the hydraulic brake system 10 is referred to as regenerative braking cooperative control. The magnitude of the required braking force can be easily known from the braking operation status such as the operating force of the brake operating member, the operating stroke, and the operating time. Further, information regarding the magnitude of the regenerative braking force can be obtained from the regenerative braking system.

FIG. 5 conceptually shows an example of the relationship between the required braking force according to the driver's intention, the regenerative braking force by the regenerative braking system, and the hydraulic braking force by the hydraulic braking system. As is clear from the figure, the hydraulic braking force and the regenerative braking force are increased as the required braking force acquired from the brake operation state increases. In FIG. 5, the regenerative braking force starts increasing slightly later than the hydraulic braking force, but this is not essential. After the regenerative braking force reaches the maximum value determined according to the vehicle speed and the like, the increase in the required braking force is realized by the increase in the hydraulic braking force.
In the present embodiment, the regenerative braking system is configured to utilize the regenerative braking force as effectively as possible. When braking is performed, the vehicle speed gradually decreases, and thus the regenerative braking force also gradually decreases. However, FIG. 5 is drawn as a constant regenerative braking force for simplification. If the required braking force is reduced, first, the hydraulic braking force is reduced. When it becomes impossible to reduce the hydraulic braking force (the reason will be described later), the regenerative braking force is reduced, and after the regenerative braking force becomes zero, the hydraulic braking force becomes the required braking force. It keeps about the same size and decreases. The reason for this will be described later.

The hydraulic brake system 10 includes a master cylinder 12, a pump 14, and an accumulator 16 for accumulating high-pressure hydraulic fluid supplied from the pump 14. In the master cylinder 12 and the pump 14,
The hydraulic fluid is supplied from the master reservoir 18. The master cylinder 12 includes a hydraulic pressure supply unit F and a hydraulic pressure supply unit R described later. Note that the accumulator 16 has a set pressure range (in the present embodiment, 17 MPa to 18 MPa≈174 to 184 kg) depending on the operation of the pump 14.
The working fluid in the f / cm ² range is always stored. A pressure switch (not shown) is attached to the accumulator 16, and the pump 14 is started and stopped according to ON / OFF having hysteresis of the pressure switch. A constant hydraulic pressure source 20 that supplies a substantially constant hydraulic pressure is configured.

The hydraulic pressure supply portion F of the master cylinder 12 extends from the hydraulic pressure supply portion F and bifurcates into a fluid passage 22.
Thus, the wheel cylinder 24 for the left front wheel (abbreviated as FL cylinder 24) and the wheel cylinder 26 for the right front wheel
(FR cylinder 26).
The FL cylinder 24 of the bifurcated portion of the liquid passage 22
A normally open electromagnetic on-off valve 30 is provided in a portion connected to the, and a normally open electromagnetic on-off valve 32 is provided in a portion connected to the FR cylinder 26. In the portion of the liquid passage 22 on the hydraulic pressure supply portion F side (not bifurcated),
The hydraulic pressure sensor 34 is connected. This hydraulic pressure sensor 34
The hydraulic pressure measured by is referred to as a master cylinder hydraulic pressure Pmc. Solenoid on-off valve 30 of liquid passage 22 and FL cylinder 24
The portion between and is connected to the liquid passage 40, and the portion between the electromagnetic on-off valve 32 and the FR cylinder 26 is connected to the liquid passage 40 by the liquid passage 38. Further, normally closed electromagnetic on-off valves 42 and 44 are attached in the middle of the liquid passages 36 and 38, respectively.

On the other hand, the hydraulic pressure supply portion R has a wheel cylinder 50 for the left rear wheel (abbreviated as RL cylinder 50) and a right rear wheel by a liquid passage 48 extending from the hydraulic pressure supply portion R and bifurcating midway. Wheel cylinder 52 (abbreviated as RR cylinder 52). In the middle of the portion of the fluid passage 48 on the hydraulic pressure supply section R side (not bifurcated), the linear valve device 56, in order from the hydraulic pressure supply section R side.
A normally open electromagnetic on-off valve 58 and a proportioning valve 60 (abbreviated as P valve 60) are provided respectively. A fluid pressure sensor 62 is provided in a portion of the fluid passage 48 between the master cylinder 12 and the linear valve device 56, and
A hydraulic pressure sensor 64 is connected to a portion between the linear valve device 56 and the electromagnetic opening / closing valve 58. The hydraulic pressure acquired by the hydraulic pressure sensor 62 is the input hydraulic pressure Pin, and the hydraulic pressure sensor 64
The hydraulic pressure obtained by the above is called the output hydraulic pressure Pout1. The hydraulic pressure on both sides of the linear valve device 56 can be measured. The measurement results of the hydraulic pressure sensors 34, 62 and 64 (master cylinder hydraulic pressure Pmc, input hydraulic pressure Pin and output hydraulic pressure Pout1) are acquired by the controller 66. As will be described later, the controller 66 controls the state of the linear valve device 56 based on the measurement result of the hydraulic pressure sensor 64. A portion of the liquid passage 48 between the electromagnetic opening / closing valve 58 and the P valve 60 and the liquid passage 40 are connected by a liquid passage 70, and a normally closed electromagnetic opening / closing valve 72 is provided in the middle of the liquid passage 70. ing.

A liquid passage 76 is connected to a portion of the liquid passage 48 between the linear valve device 56 and the electromagnetic opening / closing valve 58. The liquid passage 76 extends from the liquid passage 48 and bifurcates in the middle, and a normally closed electromagnetic opening / closing valve 80 is provided in the middle of a portion that does not branch. Also, the liquid passage 76
One of the two branched parts is connected to the FL cylinder 24 through the liquid passages 36 and 22, and a normally open electromagnetic opening / closing valve 84 is provided on the way. Further, the other of the two branched portions of the liquid passage 76 has the liquid passages 38, 22.
Is connected to the FR cylinder 26 via a solenoid valve and a normally open solenoid valve 86 is provided in the middle. Each of the solenoid on-off valves 30, 32, 42, 44, 58, 7 described above
2, 80, 84 and 86 are controlled by the controller 66. A liquid pressure sensor 88 is connected to a portion of the liquid passage 76 between the electromagnetic on-off valve 80, the electromagnetic on-off valve 84 and the electromagnetic on-off valve 86. The measurement result by the hydraulic pressure sensor 88 is referred to as the output hydraulic pressure Pout2. Output hydraulic pressure Pout2
Is acquired by the controller 66, and the hydraulic pressure sensor 6
4 is used to monitor whether the output is normal. The output of the hydraulic pressure sensor 64 may be abnormal when the value of the output hydraulic pressure Pout1 detected by the hydraulic pressure sensor 64 is different from the value of the output hydraulic pressure Pout2 when the electromagnetic opening / closing valve 80 is in the open state. It is determined that there is sex. This is the solenoid valve 8
If 0 is open, hydraulic pressure sensor 64 and hydraulic pressure sensor 88
Are in communication with each other and the hydraulic pressure sensors 64, 88
If both are normal, output hydraulic pressure Pout1 and output hydraulic pressure Pout2
And should be almost the same. In the present embodiment, the operator is informed of the abnormality of the hydraulic pressure sensor based on the determination result. However, in addition to or instead of the notification, the controller 66 is prohibited from controlling the linear valve device. Good.

The liquid passages (the liquid passage 48 and the liquid passage 76) provided with the normally open electromagnetic on-off valves 58, 84 and 86 are respectively provided with bypass liquid passages for bypassing those electromagnetic on-off valves. Check valves 90, 92 and 94 are provided in the middle of the respective bypass liquid passages. These check valves 90, 92 and 9
4 is the corresponding wheel cylinder to master cylinder 1
It is mounted in such a direction that the flow of the hydraulic fluid toward 2 is allowed, but the flow in the opposite direction is blocked. Hydraulic pressure supply unit F
Receives the supply of hydraulic fluid from the master reservoir 18,
In addition to the master reservoir 18, the hydraulic pressure supply unit R can receive the hydraulic fluid from the constant hydraulic pressure source 20.

FIG. 2 is a sectional view schematically showing the internal structure of the master cylinder 12. The master cylinder 12 has a sliding hole 100 provided in its casing and a sliding hole 1 thereof.
00 slidable and liquid-tightly fitted to 00
And a spool 104. A spring 108 is provided between the plunger 102 and the spool 104.
However, a spring 112 is provided between the spool 104 and the bottom surface 110 of the sliding hole 100. The spring 108 and the spring 112 are the same. Plunger 102 and spool 10 of sliding hole 100
The space between 4 and 4 communicates with the master reservoir 18 in the state shown in FIG. 2, and is filled with the hydraulic fluid supplied from the master reservoir 18. This space is the first hydraulic chamber 1
It is called 16. The first hydraulic chamber 116 has the plunger 102.
Regardless of the position within the sliding hole 100, the liquid passage 22 (see FIG. 1) is always communicated.

The ring-shaped space formed by the reduced diameter portion of the spool 104 and the sliding hole 100 also communicates with the master reservoir 18 in the state shown in FIG. 2 and is filled with hydraulic fluid. This space is referred to as the second hydraulic chamber 118. The second hydraulic pressure chamber 118 is provided in the sliding hole 10 of the spool 104.
Regardless of the position within 0, it is always in communication with the liquid passage 48 (see FIG. 1). Also, the sliding hole 100
The space between the bottom surface 110 and the spool 104 is communicated with the liquid passage 48 by the liquid passage 120, and this space is also filled with the hydraulic fluid. This space
It is called the third hydraulic chamber 122. The hydraulic pressures of the hydraulic fluid in the first hydraulic chamber 116, the second hydraulic chamber 118, and the third hydraulic chamber 122 are referred to as the first hydraulic pressure P1, the second hydraulic pressure P2, and the third hydraulic pressure P3, respectively. The second hydraulic pressure P2 and the third hydraulic pressure P3 have the same value due to the existence of the liquid passage 120 described above.
The hydraulic pressure supply unit F is a part of the configuration of the master cylinder 12 that generates the hydraulic pressure P1 in the first hydraulic pressure chamber 116, and the hydraulic pressure supply unit R is in the second hydraulic pressure chamber 118. It is a portion that generates the second hydraulic pressure P2 and the third hydraulic pressure P3 in the third hydraulic pressure chamber 122.

When the brake pedal 126 (see FIG. 1) is depressed by the operator, the pedaling force is boosted by a vacuum booster (not shown) and acts on the plunger 102 in the direction of the arrow shown in FIG. The boosted pedaling force moves the plunger 102 in the direction of the arrow and contracts the spring 108, and the elastic force moves the spool 104 in the direction of the arrow and contracts the spring 112. When the first hydraulic chamber 116 is shut off from the master reservoir 18 by the movement of the plunger 102,
The first hydraulic pressure P1 starts rising from atmospheric pressure. First hydraulic pressure P1
Is an end surface 130 of the spool 104 on the side of the first hydraulic chamber 116.
Urging the spool 104 in the same direction as the boosted pedaling force. The magnitude of this urging force (denoted by F1) is P1 · A1 when the area of the end surface 130 of the spool 104 is represented by A1. Spool 104 is spring 1
It is moved by the elastic force of 08 and the urging force F1,
When the second hydraulic chamber 118 is blocked from the master reservoir 18 by the spool 104 and the spool 104 is further moved, the second hydraulic pressure P2 and the third hydraulic pressure P3 increase. If the spool 104 moves further, the second hydraulic chamber 1
18 is communicated with the constant hydraulic pressure source 20, and the hydraulic fluid having a hydraulic pressure higher than the first hydraulic pressure P1 is supplied from the constant hydraulic pressure source 20 to the second hydraulic pressure chamber 11.
8 and the third hydraulic pressure chamber 122, the second hydraulic pressure P2 and the third hydraulic pressure P3 also increase.

At this time, the force for sliding the spool 104 in the sliding hole 100 is the urging force F1, the elastic force of the springs 108 and 112 (these are the elastic force f1 and the elastic force f3, respectively). Represents)
And the urging force (F3 by the hydraulic pressure P3 of the third hydraulic chamber 122).
Is represented). The second hydraulic pressure P2 has the same magnitude on the end faces of the two expanded diameter portions of the spool 104 on the side of the reduced diameter portion, and acts in opposite directions, so that it can be ignored. Biasing force F3
Is an end surface 132 of the spool 104 on the spring 112 side.
When the area of is A3, it is P3 · A3. Since the area A3 of the end surface 132 is equal to the area A1 of the end surface 130, if these areas are rewritten as A, the spool 104
The balance formula of the force to move the inside of the sliding hole 100 is as follows. P1 · A + f1 = P3 · A + f3 (1) Elastic force f1 (and f of springs 108 and 112)
3) is smaller than the urging force F1 based on the boosted pedaling force at the time of normal braking, and if these elastic forces are ignored to simplify the explanation, formula (1) becomes It becomes the following formula. P1 = P3 (2) That is, the first hydraulic pressure P1 and the third hydraulic pressure P3 (= second hydraulic pressure P
The spool 104 stands still at the position where 2) is equal.

At this time, the plunger 102 is the first hydraulic chamber 1
While approaching spool 104 as the volume of 16 decreases, spool 104 remains in a position to isolate second hydraulic chamber 118 from both master reservoir 18 and constant hydraulic pressure source 20. The FL cylinder 24 and the FR cylinder 26 are supplied with the hydraulic fluid in the first hydraulic chamber 116, while the RL cylinder 50 and the RR cylinder 52 are supplied with the hydraulic fluid from the constant hydraulic pressure source 20, Brake pedal 12
The operation stroke of 6 is small. Also, the pump 14
When the constant hydraulic pressure source 20 falls into a state in which the hydraulic fluid cannot be supplied due to a failure such as the above, the spool 104 is set to the first hydraulic pressure P1.
Then, the second hydraulic pressure P2 and the third hydraulic pressure P3 are moved to have the same pressure. Thereby, the first hydraulic chamber 1
The hydraulic fluid is supplied from 16 to the fluid passage 22, and the third hydraulic chamber 1
The hydraulic fluid is supplied from 22 to the fluid passage 48. That is, the first hydraulic chamber 116 and the third hydraulic chamber 122 play the same role as the two hydraulic chambers of the conventional tandem master cylinder.

FIG. 3 shows the linear valve device 5 shown in FIG.
It is a systematic diagram which shows the structure of No. 6 roughly. The linear valve device 56 includes a pressure increasing linear valve 150, a pressure reducing linear valve 152, a pressure reducing reservoir 154, and check valves 156, 1.
Includes 58. The first port 162 of the booster linear valve 150 is communicated with the portion of the liquid passage 48 on the master cylinder 12 side by the liquid passage 164, and the second port 166 is connected by the liquid passage 168 to the liquid pressure sensor of the liquid passage 48. It is communicated with the part on the 64 side. The liquid passage 164 and the liquid passage 168 are connected by a bypass passage 170, and in the middle of the bypass passage 170,
The above-described check valve 156 is provided with the liquid passages 168 through 164.
The flow direction of the hydraulic fluid is allowed to flow toward, but the opposite direction is blocked. Pressure reducing linear valve 152
The first port 172 of the
8, the second port 176 is connected to the pressure reducing reservoir 154 by a liquid passage 178. Liquid passage 1
74 and the liquid passage 178 are connected by a bypass passage 180, and the check valve 1 is provided in the middle of the bypass passage 180.
58 is provided in a direction that allows the flow of the hydraulic fluid from the liquid passage 178 toward the liquid passage 174, but blocks the reverse flow.

The decompression reservoir 154 has a housing 18
2 and a piston 184 fitted in the housing 182 so as to be liquid-tight and slidable. Between the housing 182 and the piston 184, the piston 184
Of the compression coil spring 18 is formed.
The elastic force of 8 urges the liquid storage chamber 186 in a direction in which the volume of the liquid storage chamber 186 decreases. Therefore, the hydraulic fluid stored in the liquid storage chamber 186 is pressurized by the elastic force of the compression coil spring 188. However, the elastic force of the compression coil spring 188 is relatively small, and the liquid storage based on the above pressure is stored. The hydraulic pressure in the chamber 186 is set to the master cylinder 1 during braking.
The size is negligible with respect to the hydraulic pressure generated in the wheel cylinders 24, 26, 50 and 52.
However, if the sum of the valve opening pressure of the check valve 156 and the valve opening pressure of the check valve 158 is larger and the liquid pressure in the liquid passage 48 decreases to near atmospheric pressure, the hydraulic fluid in the liquid storage chamber 186 will be reduced. Can open the check valves 156 and 158 and return to the master reservoir 18 via the master cylinder 12.

The volume of the liquid storage chamber 186 of the decompression reservoir 154 is such that the piston 184 has a compression coil spring 188.
The minimum value (0 in the illustrated example) is reached in the state where the piston 184 is advanced to the forward end position by the urging force (elastic force) of the piston 184, and the piston 184 retracts to the backward end position against the urging force (elastic force) of the compression coil spring 188. The maximum value is reached. The difference obtained by subtracting the minimum value from the maximum value of this volume is the reservoir capacity, and the maximum amount of hydraulic fluid that the depressurizing reservoir 154 can store during one braking is equal to this reservoir capacity. In the present embodiment, the reservoir capacity is smaller than the sum of the capacities of the wheel cylinders 24, 26, 50, 52. Here, the wheel cylinders 24, 26, 50, 52
Capacity of the wheel cylinder means the maximum amount of hydraulic fluid that the wheel cylinder can contain from the non-operating state to the operating state.

The pressure-increasing linear valve 150 includes a seating valve 190, an electromagnetic urging device 194, and a housing 196 that also functions as a connecting member integrally connecting the seating valve 190 and the electromagnetic urging device 194. I'm out. The seating valve 190 includes the valve 200 and the valve seat 2
02 and the electromagnetically biased body 2 that moves integrally with the valve 200.
04, and a spring 206 as an elastic member that biases the electromagnetically biased body 204 in the direction in which the valve 200 is seated on the valve seat 202. Further, the electromagnetic urging device 194 is
A solenoid 210, a resin holding member 212 for holding the solenoid 210, a first magnetic path forming body 214,
The second magnetic path forming member 216 is included. Solenoid 21
When voltage is applied to both ends of the 0 winding, the solenoid 21
A current flows through the zero winding, forming a magnetic field. Most of the magnetic flux is the first magnetic path forming body 214 and the second magnetic path forming body 21.
6, Passing through the air gap between the electromagnetically biased body 204 and the second magnetic path forming body 216 and the electromagnetically biased body 204. If the voltage applied to the winding of the solenoid 210 is changed,
The magnetic force acting between the electromagnetically biased body 204 and the second magnetic path forming body 216 also changes. The magnitude of this magnetic force increases with the magnitude of the voltage applied to the winding of the solenoid 210, and they can know the relationship between the applied voltage and the magnetic force in advance. Therefore, by continuously changing the applied voltage according to the relation,
The force for urging 4 can be arbitrarily changed. The decompression linear valve 152 is also basically a pressure increase linear valve 15
Although it is the same as 0, as will be described later, the urging force of the spring 220 serving as an elastic member increases the pressure increasing linear valve 15
It is different from the zero spring 206. In the structure of the pressure reducing linear valve 152, the same parts as those of the pressure increasing linear valve 150 are designated by the same reference numerals and the description thereof will be omitted.

The pressure increasing linear valve 150 has a first port 1
The hydraulic pressure of 62 becomes higher than the hydraulic pressure of the second port 166,
The urging force of the valve 200 based on the pressure difference is applied to the spring 20.
It opens when it becomes larger than the biasing force of 6. The magnitude of the differential pressure at this time is called the valve opening pressure. In the present embodiment, the valve opening pressure of the pressure-increasing linear valve 150 is about 3 MPa (about 3 MPa).
0.6 kgf / cm ² ). On the other hand, the opening pressure of the decompression linear valve 152 is 18 MPa (≈184 kg
f / cm ² . It is set higher than the maximum hydraulic pressure of the hydraulic fluid supplied by the constant hydraulic pressure source 20. The biasing force of the spring 220 is larger (about 6 times) than that of the spring 206. In the hydraulic brake system 10 of the present embodiment, the pressure reducing linear valve 15
The maximum hydraulic pressure of the hydraulic fluid supplied to the first port 172 of No. 2 is the maximum hydraulic pressure supplied by the pump 14 and stored in the accumulator 16. The hydraulic pressure due to the pedal force of the operator exceeds this maximum hydraulic pressure, and the pressure reducing linear valve 1
It may be considered that the hydraulic pressure of the hydraulic fluid acting on the first port 172 of 52 does not substantially exceed the opening pressure of the pressure-reducing linear valve 152. The hydraulic fluid stored in the decompression reservoir 154 when the decompression linear valve 152 is opened opens the fluid passages 178 and 180 and the check valve 15 after the braking is completed.
8, liquid passages 174, 170, check valve 156, liquid passage 48
Then, it is returned to the master reservoir 18 via the hydraulic pressure supply source R of the master cylinder 12.

At the time of normal braking in which the regenerative braking cooperative control is performed and the hydraulic brake system 10 is operating normally, the electromagnetic opening / closing valves 30 and 32 are closed, and the electromagnetic opening / closing valve is closed. 80 is opened, and
The other electromagnetic on-off valves are in the state shown in FIG. Supply of hydraulic fluid to the FL cylinder 24 and the FR cylinder 26
It is not performed from the hydraulic pressure supply unit F of the master cylinder 12 through the liquid passage 22 but from the hydraulic pressure supply unit R to the liquid passage 4
8 is performed, and the hydraulic fluid is supplied from the constant hydraulic pressure source 20 like the RL cylinder 50 and the RR cylinder 52. As a result, the hydraulic pressures of all the wheel cylinders are controlled by the pressure increasing linear valve 150 and the pressure reducing linear valve 152 of the linear valve device 56.

The stroke simulator 2 is provided in the liquid passage 22.
30 (see FIG. 1) is connected to the solenoid valves 30 and 3
Brake pedal 1 when both 2 are closed
It is avoided that the stroke of 26 becomes almost zero. The stroke simulator 230 uses the plunger 23
It is a container whose volume changes by the movement of 2. Since the plunger 232 is biased by the spring 234 in the direction in which the internal volume decreases, the stroke simulator 2
The accumulated amount of hydraulic fluid in 30 increases as the hydraulic pressure of the hydraulic fluid supplied by the hydraulic pressure supply unit F (master cylinder hydraulic pressure Pmc) increases. As a result, even when both the electromagnetic opening / closing valves 30 and 32 are closed, the brake pedal 1
The stroke of 26 becomes almost 0, and it is avoided that the driver feels uncomfortable. The space in which the spring 234 of the stroke simulator 230 is arranged is communicated with the liquid passage 40 by the liquid passage 236.
Even when the hydraulic fluid leaks from the gap between the plunger 232 and the container, the leaked hydraulic fluid is returned to the master reservoir 18. This avoids a reduction in the amount of hydraulic fluid in the hydraulic braking system 10.

When both the regenerative braking cooperative control and the anti-skid control are performed while the hydraulic brake system 10 is operating normally, the controller 66 is used.
The solenoid on-off valves 30 and 32 are closed by the on-off valve 8
0 is opened, and then the solenoid on-off valves 42, 44, 5
8, 72, 84 and 86 are independently controlled as needed. For example, RL cylinder 50 and RR
The hydraulic pressure of the cylinder 52 is increased and the FL cylinder 24
When the hydraulic pressure of the FR cylinder 26 is maintained (maintained at a constant pressure), the electromagnetic opening / closing valve 58 may be opened and the other electromagnetic opening / closing valves 42, 44, 72, 84 and 86 may be closed. . When the hydraulic pressure of the RL cylinder 50 and the RR cylinder 52 is reduced and the hydraulic pressure of the FL cylinder 24 and the FR cylinder 26 is maintained, the solenoid opening / closing valve 72 is opened and the other solenoid opening / closing valves 42, 44, 58, 84 and 86 are closed. Further, when the hydraulic pressure of all the wheel cylinders is maintained, all the solenoid on-off valves 42, 4
4, 58, 72, 84 and 86 are closed. FL
When increasing the pressure of the cylinder 24 and holding the FR cylinder 26 and reducing the pressure of the RL cylinder 50 and the RR cylinder 52, the solenoid opening / closing valves 72 and 84 are opened and the solenoid opening / closing valves 42, 44, 58 and 86 are opened. Closed state. Hereinafter, although not described one by one, the solenoid on-off valves 42, 4
By independently controlling the states of 4, 58, 72, 84, and 86, the hydraulic pressure of the wheel cylinders of the left and right rear wheels, the hydraulic pressure of the FL cylinder 24, and the FR cylinder 2
The hydraulic pressures of 6 and 6 can be controlled independently of each other.

If the controller 66 of the hydraulic brake system 10 fails and cannot control the solenoid on-off valve or the linear valve device 56, each solenoid on-off valve becomes the state shown in FIG. 1, and No voltage is applied to the windings of the solenoid 210 of the pressure increasing linear valve 150 and the pressure reducing linear valve 152 of the linear valve device 56.
At this time, the controller 66 may or may not operate the constant hydraulic pressure source 20. As described above, even if the hydraulic fluid is not supplied from the constant hydraulic pressure source 20,
This is because the master cylinder 12 functions like a normal tandem master cylinder and supplies substantially equal hydraulic pressure from the hydraulic pressure supply parts F and R. When each electromagnetic on-off valve is in the state shown in FIG. 1, the hydraulic fluid from the hydraulic pressure supply unit F is applied to the FL cylinder 24 and the FR cylinder 26, and the hydraulic fluid from the hydraulic pressure supply unit R is increased in pressure. It is supplied to the RL cylinder 50 and the RR cylinder 52 via 150. However, while the hydraulic pressure of the hydraulic fluid supplied to the FL cylinder 24 and the FR cylinder 26 is substantially equal to the hydraulic pressure supplied from the hydraulic pressure supply unit F, the RL cylinder 50 and the RR cylinder
The hydraulic pressure of the hydraulic fluid supplied to the cylinder 52 is lower than the hydraulic pressure of the hydraulic fluid supplied from the hydraulic pressure supply unit R by the valve opening pressure of the pressure-increasing linear valve 150 by about 3 MPa. In this way, the hydraulic pressure of the hydraulic fluid supplied to the wheel cylinders differs between the front wheels and the rear wheels, but the hydraulic pressure is supplied to both the front and rear wheel cylinders, and Since the hydraulic pressure of the hydraulic fluid supplied to the cylinder does not decrease, the deterioration of the braking performance when the controller 66 fails is small. Further, since the hydraulic pressure of the supplied hydraulic fluid decreases on the rear wheel side, the posture stability of the vehicle during braking can be kept good.

In the present embodiment, the constant hydraulic pressure source 2
When 0 fails and hydraulic pressure is no longer supplied to the hydraulic pressure supply unit R, the controller 66 is configured to supply no current to all the electromagnetic on-off valves and linear valve devices 56. Therefore, when the constant hydraulic pressure source 20 fails, the hydraulic braking system 10 operates in the same manner as when the constant hydraulic pressure source 20 is not operated, when the controller 66 fails. However, even if the constant hydraulic pressure source 20 fails, if the controller 66 is normal, the controller 66 can be configured to control the electromagnetic opening / closing valve and the linear valve device 56 as usual. The operating stroke of the brake pedal 126 is longer than usual because the hydraulic fluid is not supplied from the constant hydraulic pressure source 20. However, in this case, in order to make the operation stroke of the brake pedal 126 as small as possible, a normally closed electromagnetic opening / closing valve is provided between the liquid passage 22 and the stroke simulator 230. It is desirable that the electromagnetic on-off valve be closed to prevent hydraulic fluid from flowing into the stroke simulator 230.

FIG. 4 is a pressure boosting linear valve 1 shown in FIG.
50 is a front cross-sectional view showing a more specific form of 50,
Components corresponding to those shown in FIG. 3 are designated by the same reference numerals. In FIG. 4, the spring 206 is replaced by the spring 22.
By changing it to 0, the first port 162 is read as the first port 172, and the second port 166 is read as the second port 176 (see FIG. 3), a front view of the pressure reducing linear valve 152 is obtained. Valve 2 of seating valve 190
00 is held integrally with the rod member 250.
After the rod member 250 is fitted into the fitting hole of the electromagnetically biased body 204, the inner diameter of the portion of the fitting hole corresponding to the stepped portion 252 formed in the rod member 250 is reduced by plastic deformation. Then, the electromagnetically biased body 204 is stakingly fixed. The second port 166 has a holding hole 256.
Are formed at two locations on the peripheral wall of the first member 260 that holds the rod member 250 movably in the axial direction. Moreover, the first port 162 is formed as a through hole of the second member 262 in which the valve seat 202 is formed. First member 2
The 60 and the second member 262 are integrally coupled in a non-separable state by the latter being tightly fitted into the fitting hole formed in the former. The second member 262 includes a third member 26 including an oil seal 264 and a filter 266.
And 8 are attached. A fitting projection 272 is formed on an end surface of the electromagnetically biased body 204 on the second magnetic path forming body 216 side, and the electromagnetically biased body 20 of the second magnetic path forming body 216 is formed.
A fitting hole 274 is formed in the end surface on the fourth side so as to be fitted to the fitting protrusion 272 in a state of being relatively movable in the axial direction. In addition, the electromagnetically biased body 204 and the second magnetic path forming body 216
A ring-shaped spacer 276 is fitted between and.

There is a slight gap between the holding hole 256 of the first member 260 and the rod member 250, and the frictional resistance due to the axial movement of the rod member 250 is made extremely small. Further, due to the existence of this gap, the hydraulic pressure of the second port 166 also acts on the surroundings of the electromagnetically biased body 204. The hydraulic fluid also reaches the periphery of the spring 206 by a not-shown notch formed in the electromagnetically biased body 204. Therefore, the valve 20
0, the rod member 250 and the electromagnetically biased body 204 are integrated (simply referred to as a movable member), the magnitude of the biasing force based on the hydraulic pressure of the hydraulic fluid that acts in the axial direction is equal to the first port 162. Is equal to the product of the differential pressure between the hydraulic pressure of the second port 166 and the hydraulic pressure of the second port 166, and the area of the circle surrounded by the ring that is the contact portion between the valve 200 and the valve seat 202. From these facts, in the seating valve 190, the product of the above-mentioned valve opening pressure (about 3 MPa) and the area of the circle is the spring 2
It can be seen that it is equal to the biasing force of 06. To change the valve opening pressure, the biasing force of the spring 206 or the area of the circle may be changed.

The electromagnetic urging device 194 includes a solenoid 210.
The first magnetic path forming body 214 and the second magnetic path forming body 216 are included in order to reduce the magnetic resistance of the magnetic path which is the path of the magnetic flux generated by. The magnetic path is the first magnetic path forming body 21.
4, the electromagnetically biased body 204 and the second magnetic path forming body 216, and these members are made of a material having a small magnetic resistance. The housing 196 is made of paramagnetic material. Since the paramagnetic material of the housing 196 exists between the first magnetic path forming member 214 and other magnetic path forming members, the magnetic resistance of the entire magnetic path increases. , Housing 196
Are formed so thin that this is not a problem. Further, the spacer 276 is also formed of a paramagnetic material like the housing 196.

The electromagnetically biased body 204 and the second magnetic path forming body 21.
The magnetic resistance of the magnetic path formed by 6 and 6 changes depending on the relative axial positions of the electromagnetically biased body 204 and the second magnetic path forming body 216. Specifically, the electromagnetically biased body 2
04 and the second magnetic path forming member 216 in the axial relative position change, a small gap between the fitting protrusion 272 of the electromagnetically biased member 204 and the fitting hole 274 of the second magnetic path forming member 216. The areas of the cylindrical surfaces (the outer peripheral surface of the fitting projection 272 and the inner peripheral surface of the fitting hole 274 that face each other) that face each other with a gap therebetween change. If the electromagnetically biased body 204 and the second magnetic path forming body 216 simply face each other with a small gap between the end faces, the electromagnetically biased body 204 and the second magnetic path forming body 216. As the axial distance between and decreases, that is, the magnetic resistance decreases at an accelerated rate as the distance approaches, the magnetic force acting between the two increases at an accelerated rate. On the other hand, in the pressure-increasing linear valve 150 of the present embodiment, the electromagnetically biased body 20
4, the area of the cylindrical surface of the fitting protrusion 272 and the fitting hole 274 increases as the fourth magnetic path forming body 216 approaches.
While the magnetic flux passing through this cylindrical surface increases, the electromagnetically biased body 2
The magnetic flux passing through the air gap between the end surface of 04 and the end surface of the second magnetic path forming member 216 is reduced. As a result, the solenoid 21
If the voltage applied to 0 is constant, the electromagnetically biased body 20
The magnetic force that urges No. 4 toward the second magnetic path forming member 216 is substantially constant regardless of the relative axial positions of the electromagnetically biased member 204 and the second magnetic path forming member 216. On the other hand, the urging force of the spring 206 for urging the electromagnetically biased body 204 in the direction away from the second magnetic path forming body 216 is accompanied by the approach of the electromagnetically biased body 204 and the second magnetic path forming body 216. Increase. Therefore, when the urging force based on the hydraulic pressure difference is not acting on the valve element 200, the movement of the electromagnetically urged body 204 in the direction of the second magnetic path forming body 216 causes the spring 2 to move.
When the biasing force of 06 and the magnetic force are equalized, the driving force is stopped.

When the pressure-increasing linear valve 150 is attached to the main body 280 (see FIG. 4) of the linear valve device 56, first, the first member 260 and the second member 262 are inserted into the attachment holes 282 formed in the main body 280. And the third member 268 is fitted. However, this fitting is performed by the first magnetic path forming body 21.
4 and the solenoid 210 held by the holding member 212 are performed without being attached to the housing 196. After this fitting is done, the flange portion 284 formed by the first member 260 and the housing 196.
However, it is irremovably attached to the enlarged diameter portion of the mounting hole 282 by the assembling member 286. After that, the first magnetic path forming body 21
4 and the solenoid 210 held by the holding member 212 are assembled to the housing 196, and the attachment of the pressure boosting linear valve 150 to the main body 280 is completed. In addition,
The first magnetic path forming body 214 is separable and connectable into two parts with a plane perpendicular to the axis as a boundary, so that the first magnetic path forming body 214 can be easily assembled.

The controller 66 is mainly composed of a computer having a ROM, a RAM, a PU (processing unit), etc.
Various control programs including the processes represented by the flowcharts shown in FIGS. 11, 18 and 19 are stored. FIG. 6 is a functional block diagram showing an outline of the hydraulic pressure control executed by the controller 66. The linear valve device 56 to be controlled is controlled by the feedforward control unit 300 and the feedback control unit 302. The control target value is the target hydraulic pressure Pref, and the output is the output hydraulic pressure Pout1. In the present embodiment, the target hydraulic pressure Pref is the master cylinder hydraulic pressure Pmc (corresponding to the intention of the operator), which is the output value of the hydraulic pressure sensor 34, minus the hydraulic pressure corresponding to the braking force by regenerative braking. Is obtained as a value.

The feedforward control unit 300 determines the feedforward boosted voltage V based on the target hydraulic pressure Pref.
Fapply and feedforward reduced voltage VFreleas
Calculate e. Further, the feedback control unit 302
The feedback boosted voltage VBapply and the feedback depressurized voltage VBrelease are calculated as voltages for bringing the deviation error, which is a value obtained by subtracting the output hydraulic pressure Pout1 from the target hydraulic pressure Pref, close to zero. As described above, the control of the controller 66 in the present embodiment includes both feedforward control and feedback control.

FIG. 7 is a flow chart showing the main part of the main processing of the control program stored in the ROM of the controller 66. First, step 10 (hereinafter, S10
Is abbreviated. The same for the other steps)
VFapply and VFrelease calculation processing, which is a subroutine for calculating the feedforward boosted voltage VFapply and the feedforward reduced voltage VFrelease, is called. This process is performed by the feedforward control unit 3 described above.
This corresponds to the processing of 00 (the content will be described later). Next, S
12, the feedback boost voltage VBapply and the feedback boost voltage VBrelease are set to the deviation err.
The VBapply and VBrelease calculation processing which is calculated based on or is called. This processing corresponds to the processing of the feedback control unit 302 described above, and for example,
The deviation error is brought close to 0 by general PID control or I control which is a simplified version of PID control. When this process is completed, in S14, the voltage applied to the solenoid 210 of the pressure increasing linear valve 150 (referred to as pressure increasing side applied voltage Vapply) and the pressure reducing linear valve 152.
Applied to the solenoid 210 of the
V) which is a subroutine for calculating
The apply and Vrelease calculation processing is called.

In the subroutine Vapply and Vrelease calculation processing, the value of the pressure-increasing side applied voltage Vapply is set to one of 0 and the sum of the feedforward pressure-increasing voltage VFapply and the feedback pressure-increasing voltage VBapply. . Further, the value of the reduced voltage applied voltage Vrelease is
The sum of the feedforward reduced voltage VFrelease and the feedback reduced voltage VBrelease is set to either 0 or 0. Details will be described later. Following S14,
A hydraulic fluid leak detection process is executed in S16. In this hydraulic fluid leakage detection process, one braking is performed after the depression of the brake pedal 126 is started to when the depression is completely released, and the wheel cylinder 24,
It is monitored whether the total amount of the hydraulic fluid discharged from the pressure reducing reservoirs 154, 26, 50, 52 to the pressure reducing reservoir 154 is larger than the reservoir capacity of the pressure reducing reservoir 154. This is a process of determining that a hydraulic fluid leak has occurred in a portion closer to the pressure reducing reservoir 154 than the pressure reducing valve 56 (including the pressure reducing reservoir 154 itself) and prohibiting hydraulic pressure control or the like using the linear valve device 56. Details will be described later. After performing the above processing, S1
8, the pressure increase side applied voltage Vapply and the pressure decrease side applied voltage V
After release is applied to the solenoid 210 of the pressure increasing linear valve 150 and the pressure reducing linear valve 152, respectively, the processing from S10 is repeated.

FIG. 8 is a flowchart showing the contents of the VFapply and VFrelease calculation processing called in S10 of FIG. 7, and corresponds to the processing of the feedforward control unit 300 as described above. First, S20
In the above, the target hydraulic pressure Pref for each fixed time (which is 6 ms in the present embodiment, as will be described later)
It is determined whether or not the target hydraulic pressure change dPref, which is the amount of change (the calculation of which will be described later), is positive, that is, whether or not the target hydraulic pressure Pref is increasing. If it is increasing, it is determined in S22 whether the value of the variable startFlag is 0 or not. If the value of the variable startFlag is 0, the value of the target hydraulic pressure Pref is assigned to the pressure increasing side initial value variable Pinita in S24, and the value of the variable startFlag is 1
If the value of the variable startFlag is not 0 after substituting, S24 is bypassed and the initial value setting process ends. The variable startFlag is set to 0 in the initial setting (not shown) of the main process. If the determination result in S20 is NO (if the target hydraulic pressure change dPref is not positive), the target hydraulic pressure change dPref is determined in S26.
Is determined to be negative. This judgment result is YES
If so, in S28, it is determined whether or not the variable startFlag is 1. If the determination result in S28 is YES, in S30, the value of the target hydraulic pressure Pref is substituted into the pressure reducing side initial value variable Pinitr, and 0 is set in the variable startFlag.
Is substituted. If the determination result of S22, S26 or S28 is NO, or if the process of S24 or S30 ends, the process of S40 is executed.

At S40, the voltage Vrele applied on the pressure reducing side.
Whether ase is positive, that is, the linear valve device 56
At, it is determined whether or not decompression is being performed. If the pressure is being reduced, in S42, the feedforward boosted voltage constant value VFca is calculated based on the following equation. VFca ← MAPa (Pin−Pout1) (3) Here, the function MAPa is a feedforward boosted voltage constant value VFca with Pin−Pout1 (this is referred to as pressure boost side hydraulic pressure deviation Pdiffa) as an argument. It is a function to return. FIG. 9 shows an example of the function MAPa. As shown in this figure,
The function MAPa1 returns the feedforward boosted voltage constant value VFca as a value that linearly decreases as the boosting side hydraulic pressure deviation Pdiffa increases. Pressure increase side hydraulic pressure deviation Pdiffa is 0
The feedforward boosted voltage constant value VFca at the time of is the feedforward boosted maximum voltage VFmaxa, and the feedforward boosted voltage constant value VFca when the boost side hydraulic pressure deviation Pdiffa is the maximum hydraulic pressure deviation Pdiffmaxa is the feedforward boosted voltage. It is the minimum voltage VFmina. Here, the maximum hydraulic pressure deviation Pdiffmaxa is the valve opening pressure (3
MPa) and the feedforward boosting maximum voltage V
Fmaxa is a force by which the electromagnetically biased body 204 is biased by the magnetic field generated when it is applied to the solenoid 210 of the pressure-increasing linear valve 150.
It is made to be equal to the urging force of the spring 206 in the state of sitting on 2. In this way, S40
In the state where the determination result of is YES, that is, during the pressure reduction, the feedforward boosted voltage constant value VFca used at the time of the next pressure increase (if it is performed) is calculated in advance.

If the determination result in S40 is NO, S
At 44, it is determined whether the pressure-increasing-side applied voltage Vapply is positive, that is, whether the linear valve device 56 is increasing pressure. If the pressure is being increased, S46
In, the feedforward reduced voltage constant value VFcr is calculated based on the following equation. VFcr ← MAPr (Pout1−Pres) (4) where the function MAPr is Pout1−Pres (this is referred to as the pressure reducing side hydraulic pressure deviation Pdiffr. Also, the reservoir hydraulic pressure P
res is the hydraulic pressure of the depressurizing reservoir 154, which is equal to the atmospheric pressure) and is a function that returns the feedforward depressurized voltage constant value VFcr. FIG. 10 shows an example thereof.
As is apparent from the figure, the function MAPr returns the feedforward reduced pressure voltage constant value VFcr as a value that linearly decreases with an increase in the reduced pressure side hydraulic pressure deviation Pdiffr. The feedforward pressure reduction voltage constant value VFcr when the pressure reduction side hydraulic pressure deviation Pdiffr is 0 is the feedforward voltage pressure reduction maximum value VFmaxr, and the feedforward pressure reduction voltage constant value when the pressure reduction side hydraulic pressure deviation Pdiffr is the maximum hydraulic pressure deviation Pdiffmaxr. VFcr is 0. Here, the maximum hydraulic pressure deviation Pdiffmaxr
Is equal to the opening pressure of the pressure-reducing linear valve 152 (greater than 18 MPa), and the feedforward voltage pressure-reducing maximum value VFmaxr is electromagnetically energized by the magnetic field generated when it is applied to the solenoid 210 of the pressure-reducing linear valve 152. The force with which the body 204 is urged causes the valve 200 to move to the valve seat 2
It is made to be equal to the urging force of the spring 220 when seated on 02. In this way, in the state where the determination result of S44 is YES, that is, during the pressure increase, the feedforward pressure-reduced voltage constant value VFcr used during the next pressure reduction is calculated in advance.

If the determination result of S44 is NO, or if the processing of S42 or S46 is completed, S
At 47, it is determined whether or not the initial increase is necessary depending on whether the target hydraulic pressure change dPref is positive and the target hydraulic pressure Pref is less than the threshold value Pth, and the determination result is YES. For example, in S48, the increase voltage VFcainc
Is substituted into the feedforward boosted voltage constant value VFca. The physical meanings of the initial boost amount and boost voltage VFcainc will be described later. After executing S47 and S48, in S50, the feedforward boosted voltage VFapply or the feedforward reduced voltage VFrelease is calculated based on the following equation, and then VFapply is calculated.
, VFrelease calculation processing ends. VFapply <-GAINa * (Pref-Pinita) + VFca ... (5) VFrelease <-GAINr * (Pinitr-Pref) + VFcr ... (6) Here, coefficient GAINa and coefficient GAINr are positive constant values set beforehand Is.

FIG. 11 is a flow chart showing the contents of the timer interrupt process executed to calculate the target hydraulic pressure Pref and the target hydraulic pressure change dPref. First, S80
At, the target hydraulic pressure Pref is obtained as a value obtained by subtracting the hydraulic pressure corresponding to the current regenerative braking from the master cylinder hydraulic pressure Pmc which is the output value of the hydraulic pressure sensor 34. Next, in S82, the target hydraulic pressure change dPref is calculated based on the following equation. dPref ← Pref-prevPref (7) Here, the value of the previous target hydraulic pressure prevPref is the value of the target hydraulic pressure Pref at the time when the previous timer interrupt process was executed. Next, in S84, in order to prepare for the next timer interrupt processing, the value of the target hydraulic pressure Pref in the current timer interrupt processing is substituted for the previous target hydraulic pressure prevPref, and then the timer interrupt processing ends. This timer interrupt process is repeatedly called every 6 ms during the braking period. As described above, the target hydraulic pressure Pref and the target hydraulic pressure change dPref are the latest values every 6 ms during the braking period. Will be updated to.

The feedforward reduced voltage VFrele
The physical meaning of ase is that the value of the depressurizing side hydraulic pressure deviation Pdiffr gradually decreases during depressurization, and the force for separating the valve 200 of the depressurizing linear valve 152 from the valve seat 202 decreases. By the feedforward control, the decompression linear valve 152 is opened so that decompression can be continued. That is, when the pressure-reduction-side hydraulic pressure deviation Pdiffr is relatively large, the value of the feedforward pressure-reduction voltage VFrelease necessary for performing the pressure reduction may be relatively small, but the pressure-reduction-side hydraulic pressure deviation Pdi
When ffr becomes small, pressure reducing linear valve 152
It is necessary to apply a larger voltage to the solenoid 210 of the pressure-reducing linear valve 152 in order to open the valve. In the present embodiment, this is realized by increasing the value of the feedforward reduced voltage VFrelease.

FIG. 12 shows the initial depressurization side hydraulic pressure deviation Pdiff.
Two examples of reduced pressure with different values of r are shown in (a) and (b). These are examples in which the output hydraulic pressure Pout1 decreases from each value at each reduction rate, and finally the output hydraulic pressure Pout1 becomes atmospheric pressure and the pressure reduction is completed. In these two examples, when the values of the pressure-reducing side hydraulic pressure deviation Pdiffr are equal to each other, as indicated by the alternate long and short dash line in the figure, the values of the feedforward pressure-reducing voltage VFrelease are also equal. Then, when the pressure reduction is finally completed, the pressure reduction side hydraulic pressure deviation Pdiff
The value of r becomes 0, and the feedforward reduced voltage VFre
The value of lease is the feedforward decompression maximum voltage VF
It has a value equal to maxr. The physical meaning of the feedforward boosted voltage VFapply is substantially the same as the feedforward reduced voltage VFrelease. However, while the hydraulic pressure at the second port 176 of the pressure reducing linear valve 152 is a constant value (reservoir hydraulic pressure Pres), the hydraulic pressure at the first port 162 and the second port 166 of the pressure increasing linear valve 150 is The input hydraulic pressure Pin and the output hydraulic pressure Pout1 are different from each other in that they both fluctuate during the braking period.

It is assumed that the function MAPa and the function MAPr are linear with respect to the pressure increase side hydraulic pressure deviation Pdiffa and the pressure decrease side hydraulic pressure deviation Pdiffr, respectively.
Both graphs are shown as straight lines. This is because in the pressure-increasing linear valve 150 and the pressure-decreasing linear valve 152, it may be considered that the magnetic force acting on the electromagnetically biased body 204 is substantially proportional to the voltage applied to each solenoid 210. Generally, this magnetic force is proportional to the square of the voltage applied to the solenoid 210. However, in the pressure-increasing linear valve 150 and the pressure-decreasing linear valve 152 of this embodiment, the change in the magnetic force causes the solenoid 210 to change. It is used in a region that can be considered to be almost proportional to the applied voltage. When it cannot be considered that the magnetic force is proportional to the voltage applied to the solenoid 210, the processes of S40 to S46 shown in FIG. 8 are omitted, and the magnetic force is calculated based on the equation (5) or the equation (6) in S50. The feedforward boosted voltage VFapply or the feedforward reduced voltage VFrelease may be changed so as to be calculated based on the following equation (8) or equation (9), respectively. VFapply ← GAINa '· √ (Pdiffmaxa-Pdiffa) + VFmaxa ... (8) VFrelease ← GAINr' · √ (Pdiffmaxa-Pdiffa) ... (9)

Further, in addition, when the feedforward boosted voltage is calculated based on the equation (5), the value of the feedforward boosted voltage constant value VFca changes during braking as is apparent from FIG. This is a possible value. However, in reality, the change in the pressure increase side hydraulic pressure deviation Pdiffa is often relatively small. Therefore, even if the value of the constant feedforward boosted voltage VFca is fixed to a specific value (for example, the maximum feedforward boosted voltage VFmaxa), the control performance is not significantly impaired.

FIG. 13 shows an example of changes in the target hydraulic pressure Pref and FIGS. 7 and 8 based on the changes in the target hydraulic pressure Pref.
12 is a graph qualitatively showing changes in the values of the feedforward boosted voltage VFapply and the feedforward reduced voltage VFrelease calculated by the processing shown in FIG. 11. The target hydraulic pressure Pref starts to increase from 0 at time t1, increases during the period between time t1 and time t2 (referred to as period t1-2. The same applies to the other periods), and at period t2-3. It becomes constant, decreases during the period t3-4, and becomes 0 again at time t4.
In FIG. 13, the feedforward boosted voltage VFap
ply has a non-zero value only during the period t1-2, and the feedforward reduced voltage VFrelease
Is a non-zero value only during the period t3-4.
These values can actually take non-zero values even in the period t2-3 (see FIG. 8), but as will be described later, the value of the target hydraulic pressure Pref is as in the period t2-3. In many cases, the pressure-increasing side applied voltage Vapply and the pressure-decreasing side applied voltage Vrelease are both 0, and in that case, the feedforward pressure-increasing voltage VFapply and the feedforward pressure-decreasing voltage VFrelease are values other than 0. However, that value is never used for actual control. FIG. 13 shows an example of such a case.
Feedforward boosted voltage VFap in period t2-3
The values of ply and the feed-forward decompression voltage VFrelease are shown as 0 because they are not used for actual control.

When the target hydraulic pressure Pref changes as shown in FIG. 13, the pressure-increasing-side initial value variable Pinita contains the time t1.
The value of the target hydraulic pressure Pref at is set. this is,
This is because at the time point t1, the determination results of S20 and S22 of FIG. 8 become YES and S24 is executed. Further, the value of the pressure reduction side initial value variable Pinitr is set to the value of the target hydraulic pressure Pref by the determination result of S20 being NO and the determination result of S26 being YES at the subsequent time point t3. Feedforward boost voltage VFapply of FIG.
In the graph of, the value of the second term on the right side of the equation (5) (the value of the feedforward boosting voltage constant value VFca) is shown by the height of the hatched area, and the value of the first term on the right side is the area without hatching. Indicated by the height of. On the other hand, in the graph of the feedforward reduced voltage VFrelease, the value of the second term on the right side of the expression (6) (the value of the constant feedforward reduced voltage VFcr) is shown by the height of the hatched rectangular area. The value of the term is shown as the height of the unhatched triangular area. The value of the target hydraulic pressure Pref is
If the change shown by the alternate long and short dash line in FIG.
The values of the feedforward boosted voltage VFapply and the feedforward reduced voltage VFrelease change as shown by the chain double-dashed line. This is because the value calculated by the first term on the right side of the equations (5) and (6) changes in such a manner in response to the change in the target hydraulic pressure Pref.

The feedback control and the feedforward control described above make it possible to achieve both stability and responsiveness, but there is a possibility that pressure increase and pressure decrease may be repeated frequently. The frequency of the pressure increase / decrease repeated by the linear valve device 56 increases, and the solenoid 210 of the pressure increase linear valve 150 and the pressure decrease linear valve 152 is increased.
There is a possibility that the amount of electricity stored in the storage battery will be unnecessarily reduced due to the large amount of electric energy supplied to. That is, the travelable distance using the electric motor is shortened, and the performance of the hybrid vehicle is impaired. If a dead zone is provided around the target hydraulic pressure Pref and the output hydraulic pressure Pout1 is a value within the dead zone, the linear valve device 56 is kept in a holding state, thereby reducing the frequency of increasing and decreasing pressure. be able to. However, even in that case, if the gain of the feedback control is increased in order to improve the responsiveness, hunting occurs due to the control delay, as shown in FIG. If the width of the dead zone is increased or the gain of the feedback control is decreased in order to prevent this hunting, the hydraulic pressure control accuracy becomes insufficient. In other words, only by providing a dead zone,
It is difficult to sufficiently reduce the repetition frequency of pressure increase / decrease while maintaining the hydraulic pressure control accuracy.

The hydraulic control device of the present embodiment solves the above problems by adding the processing described below,
This has succeeded in sufficiently reducing the repetition frequency of pressure increase / decrease while maintaining the hydraulic pressure control accuracy. FIG. 15 is a chart showing an example of the contents of the processing, and shows an example of the contents of the Vapply and Vrelease calculation processing shown in S14 of FIG. As shown in this figure, the control state of the linear valve device 56 is determined based on the values of the deviation error and the target hydraulic pressure change dPref. Specifically, the target hydraulic pressure change dPref is a preset positive hydraulic pressure change threshold dP.
When it exceeds th1 (this state is indicated by and is hereinafter referred to as a state), the pressure is increased or held according to the sign of the deviation error. When the target hydraulic pressure change dPref is equal to or less than the hydraulic pressure change threshold dPth1 and is equal to or more than the negative hydraulic pressure change threshold dPth2 (referred to as a state), the deviation error is set to a preset upper limit hydraulic pressure. When the deviation is larger than the deviation err1, the pressure is increased, when the deviation is smaller than the preset lower limit hydraulic pressure deviation err2, the pressure is decreased, and in other cases, the pressure is maintained. When the target hydraulic pressure change dPref is less than the hydraulic pressure change threshold dPth2 (referred to as “state”), the deviation error
Holding or depressurization is performed based on the sign of.

The above state is a state in which the target hydraulic pressure Pref shows an increasing tendency in a broad sense (including a case where it does not change). In order to make the output hydraulic pressure Pout1 follow the target hydraulic pressure Pref, only increase and hold are performed. Controlled by. The state is a case where the target hydraulic pressure Pref shows a decreasing tendency in a narrow sense (not included when it does not change), and in this case, it is controlled by pressure reduction and holding. In this state, even if the output hydraulic pressure Pout1 exceeds the target hydraulic pressure Pref, the target hydraulic pressure change d
Since Pref is 0 or more, if the output hydraulic pressure Pout1 is maintained at a constant hydraulic pressure, the target hydraulic pressure Pref will eventually change to exceed the output hydraulic pressure Pout1, so there is no need to reduce the pressure. . On the contrary, in the state, it is not necessary to increase the pressure. As described above, in the state and in the state, compared with the case where the pressure increase and the pressure decrease are repeated as conventionally performed, the opportunity of the pressure increase and the pressure decrease is reduced, and the solenoid 210 of each linear valve as a whole is operated. The power supply can be saved. The above upper limit hydraulic pressure deviation er
r1 and err2 are values that define the upper limit and the lower limit of the deviation error that is allowed to occur in the holding state, and if the absolute values thereof are made small, the deviation error can be made small, but the pressure increasing linear valve 150 Alternatively, the pressure reducing linear valve 152 operates more frequently, and conversely, if the absolute values thereof are increased, the valve operating frequency decreases, but the deviation error increases. Therefore, an appropriate value should be determined in consideration of both the valve operating frequency and the deviation error.

In the present hydraulic pressure control device, the power supply to the linear valve device 56 is reduced by the measures described above, but further, the following process is performed so that good hydraulic pressure control can be performed. Has been done. The braking delay and drag are reduced.

First, the reduction of effectiveness delay will be described.
FIG. 16 shows a state in which the target hydraulic pressure Pref is 0 (i.e., the state where the braking is not being performed), the braking is started at the time ti, and the target hydraulic pressure Pref increases linearly. Further, the output hydraulic pressure P accompanying the change of the target hydraulic pressure Pref
Changes in out1 and wheel cylinder hydraulic pressure Pwc are also shown. As is clear from the figure, even if the output hydraulic pressure Pout1 obtained by the hydraulic pressure sensor 64 is in good agreement with the target hydraulic pressure Pref, the wheel cylinder hydraulic pressure Pwc is larger than the target hydraulic pressure Pref immediately after the start of braking. Come off. This is because immediately after the start of braking, a large amount of hydraulic fluid is required to increase the hydraulic pressure in the wheel cylinder by a unit amount, and the hydraulic fluid flow rate in the fluid passage connecting the linear valve device 56 and the wheel cylinder 24, etc. This is because the large pressure causes a large difference between the output hydraulic pressure Pout1 and the wheel cylinder hydraulic pressure Pwc. By providing a hydraulic pressure sensor that directly obtains the value of the wheel cylinder hydraulic pressure Pwc, for example, the input of the feedback control unit 302 shown in FIG. 5 is set to Pref−Pwc instead of the deviation error, and It is also possible to make the hydraulic pressure Pwc follow the target hydraulic pressure Pref with good responsiveness. However, the wheel cylinder hydraulic pressure Pwc
It is necessary to individually install a hydraulic pressure sensor for each wheel on each wheel, which increases cost and complicates control. Further, when the flow passage area of the pressure-increasing linear valve 56 immediately after the start of braking with a large hydraulic fluid flow rate is the same as during normal pressure increase with a small hydraulic fluid flow rate, the output hydraulic pressure Pou is increased.
There may occur a case where t1 itself cannot accurately follow the target hydraulic pressure Pref.

Therefore, in this embodiment, the flow rate of the hydraulic fluid supplied to each wheel cylinder is specially increased at the initial stage of braking by the method described below. This is the above-mentioned initial amount increase. The initial increase is
The target hydraulic pressure change dPref is positive, and the target hydraulic pressure Pre
When f is less than a certain threshold Pth, the value of the feedforward boosting voltage constant value VFca is set to the above-mentioned function MAP.
It is realized by making it larger than the voltage given by a. This increased voltage is the aforementioned increased voltage VFcainc. Here, the increasing voltage VFcainc is
It shall be a constant value given in advance. When the above-described condition for performing the initial increase is satisfied, the value of the pressure increase side hydraulic pressure deviation Pdiffa is small, and thus the value of the function MAPa is large. Therefore, the value of the increased voltage VFcainc is made larger than the feedforward boosted maximum voltage VFmaxa (see FIG. 9). When the target hydraulic pressure change dPref becomes 0 or less, or when the target hydraulic pressure Pref becomes the threshold value Pth or more, the initial increase is finished. That is, the value of the feedforward boosted voltage constant value VFca is the function MAPa.
Is returned to the value of. However, if the difference between the value of the function MAPa and the value of the increase voltage VFcainc is large at the time when the initial increase is completed, the value of the feedforward boosted voltage constant value VFca is gradually brought close to the value of the function MAPa. It is desirable that processing be performed. This is because the braking force changes abruptly when the value of the feedforward boosted voltage constant value VFca changes abruptly.

Next, reduction of brake drag will be described. With the above-mentioned control alone, the output hydraulic pressure P is set after the end of braking.
out1 does not become 0 completely. This non-zero output fluid pressure Pout1
Is called residual pressure. If the residual pressure is not 0, the brake pedal 1
Even when the depression of 26 is completely released, each brake is slightly operating (this is the drag of the brake), giving the driver a feeling of discomfort (drag feeling) and eliminating the need for a brake pad. It causes wear and wasteful energy consumption. Therefore, it is desirable to make the residual pressure zero by some method. Setting this residual pressure to 0 is called residual pressure release. In order to release the residual pressure, the braking is actually ended, or the portion of the liquid passage 48 on the RL cylinder 50 and RR cylinder 52 sides of the linear valve device 56 immediately before the braking is set to the master cylinder 12 side. Just connect to the part.
Therefore, in the present embodiment, when the target hydraulic pressure Pref becomes less than a certain small hydraulic pressure threshold value δ while the pressure is reduced or held, the solenoid 210 of the pressure increasing linear valve 150 is applied for a period Δt. The maximum applied voltage Vmax, which is the maximum possible voltage, is applied to release the residual pressure.

FIG. 17 shows the target hydraulic pressure P when the processing shown in FIG. 15 and the above-mentioned initial increase and residual pressure release are carried out.
6 is a graph showing an example of changes in ref, output hydraulic pressure Pout1, target hydraulic pressure change dPref, pressure increase side applied voltage Vapply, and pressure decrease side applied voltage Vrelease. Although the pressure is increased in the state, immediately after the start of braking, that is, while the target hydraulic pressure Pref is less than the threshold value Pth, the boosting side applied voltage Vapply is normally increased by the execution of the initial increase (the target hydraulic pressure Pref Is greater than the threshold value Pth), and the deviation of the output hydraulic pressure Pout1 (and thus the wheel cylinder hydraulic pressure Pwc) from the target hydraulic pressure Pref due to the shortage of the brake fluid flow rate is reduced. In the state, if the output hydraulic pressure Pout1 is a value included in the shaded region (dead zone) in FIG. 17, the holding is performed. However, arrow b
At the location shown by, the output hydraulic pressure Pout1 has an overshoot, and the absolute value of the deviation error has become large, so that the pressure is being reduced. In the state, the target hydraulic pressure Pre
As the f decreases, the output hydraulic pressure Pout1 is decreased by the pressure reduction and the holding. However, the hydraulic fluid discharged from the wheel cylinders eventually fills the pressure reducing reservoir 154, and even if the pressure reducing linear valve 152 is opened, the output hydraulic pressure Pout1 does not decrease.

This state is detected in the hydraulic fluid leak detection process described later, and in accordance with the detection, as shown in FIG.
In the regenerative braking system, the regenerative braking force is reduced as the required braking force (corresponding to the depression force of the brake pedal 126) is reduced. Then, in the state where the regenerative braking force is reduced to 0, the hydraulic pressure (input hydraulic pressure Pin) in the portion of the liquid passage 48 closer to the master cylinder 12 than the linear valve device 56.
Is the hydraulic pressure at the wheel cylinder side (output hydraulic pressure Pout
It becomes equal to 1), and if the former hydraulic pressure further decreases, the latter hydraulic pressure also decreases. Check valve 156 shown in FIG.
This allows the flow of hydraulic fluid from the wheel cylinder side to the master cylinder side. As described above, even if the pressure reducing linear valve 152 is opened, the output hydraulic pressure Pou
Even after it is detected that t1 has stopped decreasing, the above-mentioned FIG.
Although it is possible to apply the pressure reducing side applied voltage Vrelease to the solenoid 210 of the pressure reducing linear valve 152 in S18 of FIG. The application of the side applied voltage Vrelease is prohibited.

Immediately before the end of braking, when the target hydraulic pressure Pref becomes less than the hydraulic pressure threshold value δ, the pressure-increasing side applied voltage Vapply is set to the maximum applied voltage Vmax, and the residual pressure is released. When the target hydraulic pressure Pref is kept substantially constant in a large state, that is, when the target hydraulic pressure change dPref is kept at 0,
While some deviation error may remain between the target hydraulic pressure Pref and the output hydraulic pressure Pout1,
At the end of braking when the target hydraulic pressure Pref becomes 0, the residual hydraulic pressure is released and the output hydraulic pressure Pout1 is set to 0.
There is no r left.

FIG. 18 shows S1 of the main process shown in FIG.
6 is a flowchart showing an example of the contents of the Vapply and Vrelease calculation processing shown in FIG. This process is a process of determining the pressure-increasing side applied voltage Vapply and the pressure-decreasing side applied voltage Vrelease so that both the process shown in FIG. 15 and the initial pressure increase and residual pressure release can be realized. First, S1
The deviation error is calculated at 00, and the target hydraulic pressure change dPref is at the hydraulic pressure change threshold dPth at S102.
It is determined whether it is greater than 1. If the result is YES, in S104, it is determined whether or not the deviation error is 0 or more. If it is 0 or more, the applied voltage v1 for pressure increase is set as the pressure increase side applied voltage Vapply in S106, and the pressure reduction is performed. The side applied voltage Vrelease is set to zero. Here, the value of the applied voltage v1 is S50 shown in FIG.
Feedforward boost voltage VFap calculated in
It is calculated as the sum of ply and the feedback boosted voltage VBapply calculated in S12 of FIG. Next, in S108, after the value indicating the pressure increase is assigned to the variable flag, the Vapply and Vrelease calculation processing ends.
Calculation of the applied voltage for pressure increase through the above path corresponds to pressure increase in the state of FIG. In addition to the above routes, the determination result of S102 is NO.
The pressure increase is performed even when the determination result of the subsequent S110 is NO and the determination result of the subsequent S112 is YES. S110 is the target hydraulic pressure change dP
It is a process of determining whether ref is less than the target hydraulic pressure threshold dPth2, and S112 is a process of determining whether the deviation error is larger than the upper limit hydraulic pressure deviation err1. That is, the processing of S106 and S108 through this route corresponds to the case where the pressure is increased in the state of FIG.

When the determination result of S110 is YES and the determination result of the subsequent S114 is YES,
In step S116, the pressure-increasing side applied voltage Vapply is set to 0, and the pressure-decreasing side applied voltage Vrelease is set to the applied voltage v2 for pressure reduction. The value of the applied voltage v2 is calculated as the sum of the feedforward reduced voltage VFrelease calculated in S50 of FIG. 8 and the feedback reduced voltage VBrelease calculated by the feedback control in S12 of FIG. Next, S
At 118, after the value indicating the pressure reduction is substituted into the variable flag, the Vapply and Vrelease calculation processing ends. The calculation of the applied voltage for depressurization through the above route is shown in FIG.
This corresponds to depressurization in the state of No. 5. In addition to the above route, the pressure reduction is performed also when the determination result of S112 is NO and the determination result of S120 that follows is YES. S120 is the deviation err
This is a process of determining whether or is less than the lower limit hydraulic pressure deviation err2. The processing of S116 and S118 by this route corresponds to the case where the pressure reduction is performed in the state of FIG.

If any of the determination processes of S104, S114 and S120 is performed and the result is NO,
The determination process of S121 and S122 is performed. S1
In 21, it is determined whether or not the variable FlagC is 1, but initially the determination result is NO, and in S122, the value of the variable condition calculated by the following equation is T.
It is determined whether it is RUE or FALSE. condition ← ((flag = "reduction") ∨ (flag = "hold")) ∧ (Pref <δ) (10) If the result is FALSE, the pressure increase side applied voltage Vapply and the pressure decrease side applied voltage are obtained in S124. After Vrelease is set to 0, a value indicating retention is substituted in the variable flag in S126, 0 is set to the variable counter, and the Vapply and Vrelease calculation processing ends. If the determination result of S122 is TRUE, S1
At 27, it is determined whether counter <Cth holds. Here, Cth is a preset count number that is set in advance, and by changing this value, it is possible to change the time during which the above-described depressurization for residual pressure release is performed. Initially, the determination result in S127 is YES, so in S128, the maximum applied voltage Vmax is set to the pressure-increasing side applied voltage Vapply, 0 is set to the pressure-decreasing side applied voltage Vrelease, and in the following S130, the variable flag indicates the pressure increase. After the value is substituted and the value of the variable counter is incremented, the Vapply and Vrelease calculation processing ends. After S128 and S130 are repeated for a certain period of time, the determination result of S127 becomes NO, and in S131, the variables FlagC and counter are both set to 0, and Vap is set.
The ply and Vrelease calculation processing ends.

FIG. 19 shows details of the hydraulic fluid leak detection processing called in S16 of the main processing shown in FIG. First, in S150, it is determined whether or not braking is being performed, that is, whether or not the brake pedal 126 is depressed, based on whether or not the brake lamp switch 306 is ON. If the determination result is NO, in S152, the total working fluid inflow amount ΣΔQ, which is the sum of the inflow amounts of the working fluid into the pressure reducing reservoir 154, is cleared, and 1 is set in the variable FlagA and 0 is set in the variable FlagB. Substitution is performed and one processing ends. On the other hand, if the decision result in S150 is YES, the start of a series of pressure reductions by repeating the holding and pressure reduction in S154 and S156 is waited for.
0 is assigned to FlagA and 1 is assigned to the variable FlagB.
At 160, the value startPout1 at the start of a series of pressure reductions of the output hydraulic pressure Pout1 is stored. The determination of whether or not the pressure is reduced in S156 is performed based on the content of the variable flag set in the Vapply and Vrelease calculation processing.

The following S162 and S164 are steps for detecting the start of pressure increase, which means the end of the series of pressure reductions. Since 0 is substituted in the variable FlagB in S152 and 1 is substituted in S158, the determination result in S162 executed immediately after the start of braking is NO, and the pressure increase determination in S164 is not performed. The pressure increase determination in S164 is performed only after a series of pressure reductions. Therefore, S16
The determination result of 4 being YES means the start of pressure increase after a series of pressure reduction, that is, the end of a series of pressure reduction, and in S166, 1 is assigned to FlagA and 0 is assigned to FlagB. After preparation for detecting the start of the next series of pressure reductions, the value endPout1 of the output hydraulic pressure Pout1 at the end of the series of pressure reductions is stored in S168.

On the other hand, if the decision result in S164 is NO, a decision is made in S170 based on the state of the brake lamp switch 306 as to whether the braking is completed or not, and a decision is made in S172 as to whether or not the pressure reduction is impossible. The determination as to whether or not the pressure cannot be reduced means that the pressure-reducing reservoir 154 can no longer store the working fluid as described above, and therefore the pressure-reducing linear valve 152 is used.
It is to determine whether or not it is not possible to reduce the pressure even when opened, and various means are possible.
In the present embodiment, the target hydraulic pressure change dPref is smaller than the negative setting value, and the output hydraulic pressure P
When out1 does not decrease, it is determined that the pressure cannot be reduced. Then, S170 and S17
If either of the determination results of 2 is YES, S
166 and S168 are executed. The value endPout1 at the end of a series of pressure reductions is stored not only at the start of a series of pressure increases but also at the end of braking and when pressure reduction is impossible.

After the execution of S168, in S174, the amount ΔQ of the hydraulic fluid that has flown into the pressure reducing reservoir 154 due to the series of pressure reductions is acquired from the stored startPout1 and endPout1, and the hydraulic fluids up to that point are acquired. It is added to the total inflow amount ΣΔQ. The amount ΔQ of the hydraulic fluid that has flowed into the depressurization reservoir 154 with the series of depressurizations may be obtained by any method, but in the present embodiment, FIG.
It is acquired by the map represented by the graph of 0. It can be considered that the output hydraulic pressure Pout1 is substantially equal to the wheel cylinder hydraulic pressure, and
There is a relationship shown in FIG. 20 between the quantity Q of the hydraulic fluid contained in 4, 26, 50 and 52. Therefore, while the output hydraulic pressure Pout1 decreases from the value startPout1 to the value endPout1, the wheel cylinders 24, 26, 50 and 5
The amount ΔQ of the hydraulic fluid that has flowed out of No. 2 and has flowed into the decompression reservoir 154 can be obtained from the map shown in the graph of FIG.

The total inflow amount ΣΔQ of the hydraulic fluid acquired in S174 is the maximum value ΣΔ thereof in S176.
Qmax, that is, compared with the reservoir capacity, and if the hydraulic fluid total inflow amount ΣΔQ is larger than the reservoir capacity, it is determined that liquid leakage has occurred in the portion on the pressure reducing reservoir 154 side of the pressure reducing linear valve 152, and regenerative braking is performed in S178. Regenerative braking by system and linear valve device 56
1 is assigned to the flag that prohibits the hydraulic control using the. Accordingly, the solenoids of the solenoid on-off valves 30, 32 and 80 are demagnetized, and the linear valve device 5
Application of voltage to 6 is prohibited, and this hydraulic brake system 1
0 is set to a state where it functions as a normal hydraulic brake system. The content of the flag is also referred to in a regenerative braking system (not shown). If the content is 1, regenerative braking is prohibited.

As described above, if the voltage application to the linear valve device 56 is prohibited in response to the detection of the hydraulic fluid leakage, the pressure increasing linear valve 150 is set to 3 MPa as described above.
The RL cylinder 50
And the hydraulic pressure of the RR cylinder 52 is unnecessarily suppressed to a small value. In order to avoid this as much as possible, at least during braking, the solenoid 210 of the pressure-increasing linear valve 150 may be applied with a voltage that does not cause a problem of overheating even if continuously applied. Further, although regenerative braking is not prohibited and control of the pressure increasing linear valve 150 is normally performed, control of the pressure reducing linear valve 152 may be prohibited. In this case, for example, most of the main routine of FIG. 7 is executed as usual, but in the application process of S18, the voltage-reduced voltage Vrele is applied.
The application of ase should be prohibited. Further, it is desirable that the regenerative braking force be controlled in the regenerative braking system so that the sum of the regenerative braking force and the hydraulic braking force becomes equal to the required braking force. The hydraulic fluid leak detection process of S16 may or may not be performed.

In this embodiment, the controller 16
6 or pressure reducing linear valve 152 due to failure or malfunction,
Even if the decompression linear valve 152 is kept open, the hydraulic braking force is secured. As described above, since the reservoir capacity is smaller than the wheel cylinder capacity, even if the decompression linear valve 152 is kept open during braking, the operation inside the wheel cylinders 24, 26, 50, 52 is prevented. All the liquid does not flow out, and a certain amount of hydraulic braking force is secured. And the controller 16
If the control of the pressure-increasing linear valve 150 by 6 is normal, the hydraulic fluid is replenished from the master cylinder 12 via the pressure-increasing linear valve 150, and the wheel cylinder hydraulic pressure is restored to a normal level. In addition, the controller 16
Even when the control of the pressure increasing linear valve 150 by 6 is not normal, as described above,
Since the hydraulic fluid can be supplied only by using the pressure reducing valve of MPa, the wheel cylinder hydraulic pressure can be restored to a sufficient level if the operator increases the pedaling force of the brake pedal 126. Moreover, in the present embodiment, since the hydraulic fluid is supplied from the constant hydraulic pressure source 20 via the hydraulic pressure supply unit R of the master cylinder 12, the operation stroke of the brake pedal 126 does not increase.

As is apparent from the above description, in this embodiment, the master cylinder 12 and the constant hydraulic pressure source 20 are provided.
Together form a hydraulic pressure source, and the master reservoir 18
Functions as a main reservoir, and the decompression reservoir 154 functions as a sub reservoir. Further, a pressure increasing linear valve 150 as a pressure increasing valve and a pressure reducing linear valve 152 as a pressure reducing valve, each of which is composed of an electromagnetic proportional control valve, constitute a first hydraulic pressure control valve device, and electromagnetic opening / closing valves 42, 44, and 5
8, 72, 84, 86 and the like constitute the second electromagnetic hydraulic pressure control valve device. The portion of the controller 66 that controls the first hydraulic pressure control valve device constitutes a valve device control device, and the first hydraulic pressure control valve device and the valve device control device constitute a hydraulic pressure control device. There is. Further, in the part of the controller 66 that controls the first hydraulic pressure control valve device, the part that executes the process of S12 constitutes the feedback means, and the part that executes the process of S14 constitutes the standby control means. . The part of the controller 66 that executes S10, S12, S14 and S18 constitutes the regenerative braking cooperative control means, and the part that executes S16 constitutes the hydraulic fluid leak detection means.

The above-described embodiment is a case where the present invention is applied to a hydraulic brake system for a vehicle provided with a regenerative braking system, but the present invention is applied to a hydraulic brake system for a vehicle not provided with a regenerative braking system. It is also possible to apply. The present invention can be similarly implemented except that the process of determining the hydraulic braking force by subtracting the regenerative braking force from the required braking force is unnecessary. Further, instead of the linear valve device 56, a hydraulic pressure control valve device including an electromagnetic directional control valve and an electromagnetic opening / closing valve can be used to implement the present invention.
Further, the residual pressure can be released when the brake operating member such as the brake pedal is returned to the non-operating position when it is detected by the detecting means such as the detecting switch. In addition, the present invention can be implemented in various modified and improved modes without departing from the scope of the claims.

[Brief description of drawings]

FIG. 1 is a system diagram showing a configuration of a hydraulic brake system that is an embodiment of the present invention.

FIG. 2 is a front sectional view schematically showing an internal structure of a master cylinder in the hydraulic brake system.

FIG. 3 is a system diagram schematically showing a configuration of a linear valve device in the hydraulic brake system.

FIG. 4 is a front sectional view showing the structure of the pressure boosting linear valve shown in FIG. 3 in more detail.

FIG. 5 is a graph showing an outline of braking force control in the hydraulic brake system.

FIG. 6 is a functional block diagram relating to hydraulic pressure control of the controller shown in FIG.

FIG. 7 is a flowchart showing an example of contents of main processing executed by the controller.

8 is a VFapply called in S10 of FIG.
, VFrelease calculation process.

9 is a function MAPa used in S42 of FIG.
It is a graph which shows.

FIG. 10 is a function MAP used in S46 of FIG.
It is a graph which shows r.

FIG. 11 is a flowchart showing the content of a timer interrupt process executed to calculate a target hydraulic pressure Pref and a target hydraulic pressure change dPref.

FIG. 12 is a graph showing two examples of decompression performed by the respective processes shown in FIGS. 7, 8 and 11.

FIG. 13 shows an example of changes in the target hydraulic pressure Pref and the feedforward boosted voltage VFapply and the feed calculated by the processing shown in FIGS. 7, 8 and 11 based on the changes in the target hydraulic pressure Pref. Forward reduced voltage V
It is a graph which shows the change of the value of Frelease.

FIG. 14 shows an example of a change in target hydraulic pressure Pref and an example of a change in output hydraulic pressure Pout1 output by the processing shown in FIGS. 7, 8 and 11 based on the change in target hydraulic pressure Pref. It is a graph shown.

FIG. 15 is a Vapply called in S14 of FIG.
, Vrelease is a chart for explaining an example of the content of a Vrelease calculation process.

FIG. 16 is a graph for explaining the necessity of the initial amount increase.

FIG. 17 shows an example of changes in the target hydraulic pressure Pref and the accompanying output hydraulic pressure Pout1 and target hydraulic pressure change dPref when the processing whose contents are shown in FIG. 15 and the initial amount increase and residual pressure relief are performed. 6 is a graph conceptually showing changes in pressure-increasing side applied voltage Vapply and pressure-decreasing side applied voltage Vrelease.

18] Vapply and Vrelease shown in S14 of FIG.
It is a flow chart which shows an example of the contents of calculation processing.

FIG. 19 is a flowchart showing an example of the contents of the hydraulic fluid leakage detection process shown in S16 of FIG.

20 is a graph showing the relationship between the wheel cylinder hydraulic pressure used in S174 of FIG. 19 and the amount of hydraulic fluid in the wheel cylinder.

[Explanation of symbols]

10: Hydraulic brake system 12: Master cylinder 14: Pump 16: Accumulator 24: FL cylinder 2
6: FR cylinder 30, 32, 42, 44, 58,
72, 80, 84, 86: electromagnetic on-off valves 34, 62,
64, 88: Hydraulic pressure sensor 50: RL cylinder 5
2: RR cylinder 56: Linear valve device 60: Proportioning valve (P valve) 66: Controller 100: Sliding hole 102: Plunger 104: Spool 108, 112, 2
06, 220: Spring 116: First hydraulic chamber
118: Second hydraulic chamber 122: Third hydraulic chamber 12
6: Brake pedal 150: Boosting linear valve
152: Decompression linear valve 154: Decompression reservoir 162, 172: First port 166, 176:
Second port 182: Housing 184: Piston 186:
Liquid storage chamber 188: compression coil spring 19
0: Poppet valve 194: Electromagnetic biasing device 196: Housing 200: Valve 202: Valve seat 204: Electromagnetically biased body 210: Solenoid
212: Holding member 214: First magnetic path forming body 216: Second magnetic path forming body 230: Stroke simulator 250: Rod member 260: First member
262: Second member 268: Third member 272: Fitting protrusion 274: Fitting hole 276: Spacer 300: Feedforward controller 30
2: Feedback control unit 306: Brake lamp switch

Front Page Continuation (72) Inventor Akira Sakai 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (56) References JP-A-8-113133 (JP, A) JP-A-8-2395 (JP, A) JP-A-6-312656 (JP, A) JP-A-6-127358 (JP, A) JP-A-9-290732 (JP, A) JP-A-10-6953 (JP, A) (58) Survey Areas (Int.Cl. ⁷ , DB name) B60T 8/32-8/96

Claims (10)

(57) [Claims] 1. A wheel cylinder for operating a brake of a vehicle, a hydraulic pressure source for supplying hydraulic pressure to the wheel cylinder in response to an operation of a brake operating member, and a hydraulic fluid from the hydraulic pressure source to the wheel cylinder. Controls the hydraulic pressure supplied to the wheel cylinders by enabling a pressure increase state that allows inflow, a pressure reduction state that allows outflow of hydraulic fluid from the wheel cylinder, and a holding state that does not permit inflow or outflow of hydraulic fluid. A hydraulic pressure control valve device, and a reservoir that stores hydraulic fluid that flows out of the wheel cylinder during one braking through the hydraulic pressure control valve device, and that returns to the hydraulic pressure source after the braking is finished, and The reservoir capacity, which is the maximum amount of hydraulic fluid that can be stored for the one braking of the reservoir, is the maximum amount of hydraulic fluid that can be stored from the non-braking state to the braking state of the wheel cylinder. A hydraulic brake system for vehicles that is smaller than the maximum wheel cylinder capacity. 2. A wheel cylinder for operating a brake of a vehicle, a hydraulic pressure source for supplying hydraulic pressure to the wheel cylinder in response to an operation of a brake operating member, and a hydraulic fluid from the hydraulic pressure source to the wheel cylinder. Controls the hydraulic pressure supplied to the wheel cylinders by enabling a pressure increase state that allows inflow, a pressure reduction state that allows outflow of hydraulic fluid from the wheel cylinder, and a holding state that does not permit inflow or outflow of hydraulic fluid. A hydraulic pressure control valve device, and a reservoir that stores hydraulic fluid flowing from the wheel cylinder during one braking through the hydraulic pressure control valve device and returns to the hydraulic pressure source after completion of the braking, The capacity of the reservoir is such that the hydraulic pressure control valve device is set to the depressurized state from a state where the amount of hydraulic fluid in the reservoir is the minimum amount and the brake is applied, and the wheel cylinder A hydraulic brake system for a vehicle, wherein the hydraulic fluid is selected to have a size such that the brake is still effective even if the hydraulic fluid is drained from the reservoir to the reservoir until the reservoir is completely filled. 3. The vehicle hydraulic brake system comprises:
Wheel cylinder Is the operating pressure of the brake operating member.
Required braking according to the driver's intention acquired based on the situation
The hydraulic pressure control valve so that the target hydraulic pressure is determined according to the force.
Vehicle according to claim 1 or 2, including means for controlling the device.
Dual hydraulic brake system. 4. The hydraulic control as a first hydraulic control valve device.
No. 1 provided between the valve device and the wheel cylinder
Controls the two hydraulic control valve device and its second hydraulic control valve device.
This prevents excessive slip of the wheels during braking.
Second hydraulic control valve device control means for anti-lock control
From the wheel cylinder to the second hydraulic control valve device
In the reservoir containing the hydraulic fluid that is drained through
2. A primary reservoir, separate from one secondary reservoir.
Hydraulic brake system for vehicle according to any one of 3
Tem. 5. The volume of the reservoir is increased by a biasing means.
A liquid storage chamber biased in a decreasing direction is provided, and the braking end
After the completion, the liquid storage chamber is based on the urging force of the urging means.
5. The hydraulic fluid inside is discharged.
The hydraulic brake system for vehicles according to. 6. The hydraulic pressure source serves as the sub-reservoir.
Main reservoir that stores hydraulic fluid at atmospheric pressure, separate from reservoir
And the hydraulic brake system for the vehicle is
The oil cylinder and the main reservoir are connected to the hydraulic pressure control valve.
By-passing the device and installing the hydraulic pressure source and hydraulic control valve
A bypass passage connected via a liquid passage between the
From the wheel cylinder to the main reservoir in the middle of the bypass passage
Allows the flow of hydraulic fluid in the direction of
Includes a check valve arranged in a blocking direction.
Bypass the secondary passage to the bypass passage from the secondary reservoir
Allow hydraulic fluid flow to passage and prevent reverse flow
The vehicle hydraulic pressure according to claim 5, which is connected via a check valve.
Brake system. 7. The hydraulic pressure source serves as the sub-reservoir.
Main reservoir that stores hydraulic fluid at atmospheric pressure, separate from reservoir
And the hydraulic brake system for the vehicle is
The oil cylinder and the main reservoir are connected to the hydraulic pressure control valve.
By-passing the device and installing the hydraulic pressure source and hydraulic control valve
A bypass passage connected via a liquid passage between the
From the wheel cylinder to the main reservoir in the middle of the bypass passage
Allows the flow of hydraulic fluid in the direction of
Is arranged in the opposite direction to prevent Including a stop valve,
The server has a wheel from the check valve in the bypass passage.
The hydraulic pressure is connected to the cylinder side through a pressure reducing valve.
The control valve device opens the check valve after the braking is finished.
The vehicle hydraulic brake according to claim 5, further comprising:
system. 8. A wheel cylinder for operating a brake of a vehicle, a hydraulic pressure source for supplying hydraulic pressure to the wheel cylinder in response to an operation of a brake operating member, and a hydraulic fluid from the hydraulic pressure source to the wheel cylinder. Controls the hydraulic pressure supplied to the wheel cylinders by enabling a pressure increase state that allows inflow, a pressure reduction state that allows outflow of hydraulic fluid from the wheel cylinder, and a holding state that does not permit inflow or outflow of hydraulic fluid. A hydraulic pressure control valve device, a reservoir that stores the hydraulic fluid that flows out of the wheel cylinder during one braking through the hydraulic pressure control valve device, and returns to the hydraulic pressure source after the braking is finished; The total amount of hydraulic fluid that has flowed from the wheel cylinders to the reservoir through the hydraulic control valve device is the maximum amount of hydraulic fluid that the reservoir can accommodate for the one braking. A hydraulic brake system for a vehicle, comprising: a liquid leak detecting unit that determines that a hydraulic fluid has leaked when a large reservoir capacity is exceeded. 9. A wheel cylinder for operating a brake of a vehicle, a hydraulic pressure source for supplying hydraulic pressure to the wheel cylinder in response to an operation of a brake operating member, and at least an operation from the hydraulic pressure source to the wheel cylinder. A pressure-increasing state that allows the inflow of liquid and a depressurizing state that allows the outflow of hydraulic fluid from the wheel cylinder, and includes a hydraulic control valve device that controls the hydraulic pressure supplied to the wheel cylinder, and The hydraulic pressure control valve device includes a pressure increasing valve which opens when a hydraulic pressure difference between the hydraulic pressure control device and the hydraulic pressure control device exceeds an electrically controllable valve opening pressure to allow the hydraulic fluid to flow from the hydraulic pressure source to the wheel cylinder. A hydraulic brake system for a vehicle, wherein a valve opening pressure in a state where electric control is not performed is regulated to be smaller than a maximum hydraulic pressure source hydraulic pressure that is a maximum value of the hydraulic pressure of the hydraulic pressure source. 10. The hydraulic pressure source controls the operation of a brake operating member.
Generate a master cylinder hydraulic pressure of the size
10. A master cylinder according to claim 1, including a master cylinder.
The vehicle hydraulic brake system described.