JP2005088612A - Brake system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake system capable of rapidly raising the brake pressure in the initial braking time as necessary, realizing the excellent brake feeling, and enhancing the durability. <P>SOLUTION: The system is constituted so that solenoid control valves 11, 12, 17 and 18 are not changed over when operating a service brake. The equipment pressure of accumulators 15 and 16 is not supplied to wheel cylinders 5, 6, 7 and 8, the brake pressure is not accumulated in the accumulators 15 and 16, and the solenoid control valves 17 and 18 are once opened, and closed when a sudden brake is operated. The equipment pressure of the accumulators is supplied to each wheel cylinder, brake lines 9a and 10a are expanded, the loss stroke of the wheel cylinders disappears, the master cylinder pressure is used for the direct brake pressure, and the brake pressure in the initial braking is rapidly raised. When the sudden brake is released, the solenoid control valves 11 and 12 are once closed, and opened, the solenoid control valves 17 and 18 are once opened, and closed, and the brake pressure is accumulated in the accumulators. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a brake system that operates a brake by supplying a master cylinder pressure generated by a master cylinder to a brake cylinder such as a wheel cylinder, and more particularly, a brake in an emergency or the like operates quickly. The present invention relates to a brake system adapted to improve the responsiveness at the initial stage of braking when this is required.

  2. Description of the Related Art Conventionally, in a brake system for a vehicle such as an automobile, a master cylinder generates a master cylinder pressure when a driver depresses a brake pedal to operate a master cylinder. The master cylinder pressure is supplied as a brake pressure to a brake cylinder such as a wheel cylinder via a brake pipe line, and the brake is operated by operating the brake cylinder.

  By the way, in the brake of a wheel, the wheel cylinder attached to the wheel moves up and down as the wheel moves up and down with respect to the vehicle body by the suspension. In particular, in the brake of the steering wheel, the steering wheel moves left and right during steering. By turning, the wheel cylinder of the steering wheel also turns. For this reason, the connection part with the wheel cylinder of a brake pipe line is formed, for example with flexible pipe | tubes, such as a rubber hose, and the vertical movement and turning of a wheel cylinder are absorbed with the flexible pipe | tube.

  However, when a flexible pipe is provided in the brake pipe line between the master cylinder and the brake cylinder in this way, the master cylinder pressure from the master cylinder is supplied to the brake cylinder when a brake operation such as depression of the brake pedal is performed. At this time, the flexible tube expands due to the master cylinder pressure. Thus, the hydraulic fluid volume and hydraulic pressure from the master cylinder are wasted in the expansion of the flexible pipe, and the brake cylinder actually generates the braking force after the master cylinder generates the master cylinder pressure. A time delay (time lag) occurs until

  Further, when hydraulic fluid from the master cylinder flows in the brake pipe, a hydraulic pressure loss occurs, so that there is a time delay from when the master cylinder sends hydraulic fluid to when the brake cylinder operates. Furthermore, since a loss stroke (invalid stroke) occurs until the position where the master cylinder piston generates the master cylinder pressure, there is a time delay from when the brake operation is performed until the master cylinder generates the master cylinder pressure. Furthermore, since the stroke of the brake cylinder occurs even when a brake force such as a drum brake or a disc brake is filled in a gap of a wheel or the like to generate a braking force, a brake stroke is generated. There is also a time delay before the brake device actually generates the braking force.

  If there is such a time delay, the initial braking force may be delayed and the initial braking response may be impaired. Therefore, conventionally, a hydraulic vehicle brake device has been proposed in which the responsiveness at the initial stage of braking resulting from the delay in the initial braking force is improved (see, for example, Patent Document 1). In the brake device disclosed in Patent Document 1, an accumulator is provided in a hydraulic pipe connecting the master cylinder and the brake cylinder via first and second connecting pipes, and the first connecting pipe is connected to the above-described hydraulic pipe. A one-way valve that allows only the flow of hydraulic fluid toward the accumulator is provided, and a normally closed switching valve is provided in the second communication pipe.

  The switching valve is closed when the brake is not operated, and the accumulator stores the same pressure as the pressure of the hydraulic pipe (that is, the pressure of the brake cylinder) at the time of the previous brake operation. When the brake is operated by depressing the brake pedal, the switching valve opens with a signal from the brake lamp switch. Then, before the hydraulic fluid sent from the master cylinder to the brake cylinder, the hydraulic fluid with a certain pressure stored in the accumulator is sent to the brake cylinder. The hydraulic fluid sent from the accumulator absorbs the loss stroke of the piston of the brake cylinder and the hydraulic pressure loss in the hydraulic piping. At this time, the pressure in the accumulator decreases. Thereafter, the switching valve is closed again, and the pressurized hydraulic fluid sent from the master cylinder is sent to the brake cylinder to operate the brake. At this time, the pressure increase in the master cylinder is quickly performed because the loss stroke and the hydraulic pressure loss are absorbed by the hydraulic fluid sent from the accumulator as described above. Accordingly, the response at the initial stage of braking is improved.

On the other hand, since the pressure of the hydraulic fluid in the hydraulic piping is increased and becomes higher than the pressure in the accumulator, the hydraulic fluid in the hydraulic piping is supplied to the accumulator and the pressure in the accumulator is increased. When braking is released by releasing the brake pedal, no signal is sent from the brake lamp switch to the switching valve, and the switching valve is closed. For this reason, in the accumulator, the same pressure as the pressure in the hydraulic fluid piping (that is, the pressure of the brake cylinder) during braking is stored.
JP-A-7-81543.

  However, since the conventional brake device described above operates based on a signal from the brake switch, the switching valve is switched and opened not only during emergency braking but also during normal service brake operation. That is, every time a brake operation is performed by depressing the brake pedal, the switching valve is opened and the hydraulic fluid of the accumulator is sent to the hydraulic pipe and the brake cylinder. In this way, when the hydraulic fluid from the accumulator is sent to the hydraulic pipe every time the brake is operated, for example, the brake pressure is different between the emergency brake and the normal brake operation. Pressure is stored. For this reason, hydraulic fluids with different pressures in the accumulator are sent to the hydraulic piping during brake operation, and the driver feels uncomfortable with each brake operation, and the brake feeling may be impaired.

In addition, when the driver performs a brake operation that applies a light brake for the purpose of performing a slight deceleration rather than the purpose of stopping while the vehicle is running, the braking force rises rapidly, contrary to the intention of the driver. Excessive braking force will be generated. For this reason, even during such a light brake operation, the driver may feel uncomfortable with each brake operation, and the brake feeling may be impaired.
Further, since the switching valve is switched every time the brake is operated, the switching valve is frequently operated, and the durability of the switching valve may be impaired.

  The present invention has been made in view of such circumstances, and an object thereof is to improve the brake feeling and improve the durability while quickly raising the brake pressure at the initial stage of braking when necessary. It is to provide a braking system that can.

  In order to solve the above-described problems, a brake system according to a first aspect of the present invention includes a brake operation member, a master cylinder that generates a master cylinder pressure by operating the brake operation member, and the master cylinder pressure is A brake cylinder that generates a braking force by being supplied as a brake pressure; a brake pipe that connects the master cylinder and the brake cylinder to supply hydraulic fluid from the master cylinder to the brake cylinder; and the brake pipe A first electromagnetic on-off valve that is provided on the road and is set to an open position when not activated and set to a closed position when activated; an accumulator connected to the brake line via a branch line; and the branch pipe A second electromagnetic on-off valve provided on the road, which is set to a closed position when not operated and set to an open position when operated; At least an electronic control device for controlling the operation of each second electromagnetic on-off valve, and an operation amount detection means for detecting an operation amount of the brake operation member and outputting an operation amount detection signal to the electronic control device, The electronic control unit determines whether or not it is necessary to quickly increase the brake pressure at the initial stage of braking based on a detection signal of the operation amount of the brake operation member from the operation amount detection means during the brake operation. When it is determined that it is necessary to quickly increase the brake pressure at the initial stage of braking, the second electromagnetic on-off valve is once set to the open position and then set to the closed position. The first electromagnetic on-off valve is once set to the closed position, the second electromagnetic on-off valve is once set to the open position, and then the first electromagnetic on-off valve is set to the open position again. Both are characterized by setting again the closed position the second solenoid valve.

  The invention according to claim 2 is a brake operation member, a master cylinder that generates a master cylinder pressure by operating the brake operation member, and a braking force that is supplied as the master cylinder pressure as a brake pressure. A brake cylinder that generates a brake, a brake pipe that connects the master cylinder and the brake cylinder and supplies hydraulic fluid from the master cylinder to the brake cylinder, and is provided in the brake pipe and is open when not in operation. And an accumulator connected to the brake line via a branch line, and provided in the branch line, the non-operating state when the non-operating state is set. Set to a check valve position that allows only the flow of hydraulic fluid from the brake line to the accumulator and is open when activated A second electromagnetic opening / closing valve to be set, an electronic control device for controlling the operation of the first and second electromagnetic opening / closing valves, and an operation amount detection signal of the operation amount of the brake operation member. An operation amount detection means for outputting to the control device, and the electronic control device detects the brake pressure at the initial stage of braking based on a detection signal of the operation amount of the brake operation member from the operation amount detection means during a brake operation. When it is determined whether it is necessary to make the rise of the brake quick, and when it is judged that it is necessary to make the rise of the brake pressure early in the initial stage of braking, the second electromagnetic opening / closing valve is temporarily set to the open position. After that, when the brake is released, the first electromagnetic on / off valve is temporarily set to the closed position and the second electromagnetic on / off valve is temporarily set to the open position. Is characterized in that setting thereafter the first re-check valve said second solenoid valve sets the electromagnetic valve to again open position location.

  Further, the invention according to claim 3 is a brake operation member, a master cylinder that generates a master cylinder pressure by operating the brake operation member, and a braking force that is supplied as the master cylinder pressure as a brake pressure. A brake cylinder that generates a hydraulic pressure, a brake pipe that connects the master cylinder and the brake cylinder to supply hydraulic fluid from the master cylinder to the brake cylinder, and is connected to the brake pipe via a branch pipe. An accumulator that is provided in the branch pipe and is set to a check valve position that allows only a flow of hydraulic fluid from the brake pipe toward the accumulator when not in operation and is set to an open position when in operation A valve, an electronic control device for controlling the operation of each of the electromagnetic on-off valves, and operation of the brake operation member And an operation amount detecting means for outputting an operation amount detection signal to the electronic control device, and the electronic control device detects an operation amount of the brake operation member from the operation amount detection means during a brake operation. Based on the detection signal, it is determined whether or not the rise of the brake pressure at the initial stage of braking needs to be accelerated, and when it is determined that the rise of the brake pressure at the initial stage of braking needs to be accelerated, the The electromagnetic open / close valve is once set to the open position and then set to the check valve position.

Further, the invention of claim 4 is characterized in that when it is judged that the rise of the brake pressure at the initial stage of braking needs to be made quickly, it is during a sudden braking operation.
Further, the invention according to claim 5 is the hydraulic pressure control in which the brake pipe line between the master cylinder and the branch point of the branch pipe line is set to a closed position when not operating and to an open position when operating. A hydraulic pressure control device having an electromagnetic on / off valve is provided, and the first electromagnetic on / off valve is composed of this hydraulic pressure control electromagnetic on / off valve.
Further, the invention of claim 6 is characterized in that the hydraulic control device is an anti-lock control modulator and the hydraulic control electromagnetic on-off valve is an anti-lock control holding valve.

  According to the brake system of the first to sixth aspects of the present invention configured as described above, when the electronic control unit determines that it is necessary to rapidly increase the brake pressure at the initial stage of braking, Since the electromagnetic on-off valve or the electromagnetic on-off valve is once set to the open position and then set to the closed position or the check valve position, the hydraulic pressure in the accumulator can be supplied to the brake cylinder only when necessary.

  Then, after the expansion of the brake line and the loss of the brake cylinder loss stroke (or before and after), the master cylinder pressure is supplied to the brake cylinder, so that the master cylinder pressure is effectively used to increase the brake pressure. Can be used. As a result, the brake pressure of the brake cylinder can be quickly raised and increased. Therefore, it is possible to quickly and reliably apply the brake when there is a need to quickly increase the brake pressure at the initial stage of braking, with almost no time delay. In this way, at the time of brake operation that requires rapid rise of brake pressure at the beginning of braking, it is possible to prevent the driver from feeling uncomfortable while quickly raising the brake pressure at the beginning of braking. Can be improved.

  Further, since accumulator pressure accumulation is performed only when the accumulator fluid pressure is required, the accumulator can store a relatively large substantially constant fluid pressure when the accumulator fluid pressure is necessary. Therefore, when using the accumulator hydraulic pressure, a substantially constant hydraulic pressure can be used, so that when using the accumulator hydraulic pressure, the driver can be further prevented from feeling uncomfortable and brake feeling can be further increased. Can be good.

  Furthermore, since the driver does not use the hydraulic pressure of the accumulator even when the driver performs a brake operation to apply a light brake for the purpose of slightly decelerating, not for the purpose of stopping the vehicle, It is possible to prevent the braking force from rising rapidly. Thereby, it is possible to prevent an excessive braking force against the driver's will from being generated. Accordingly, the brake feeling can be improved without causing the driver to feel uncomfortable even during such a light brake operation.

  Since each electromagnetic on-off valve is switched only when it is necessary to quickly increase the brake pressure at the initial stage of braking, the operation frequency of each electromagnetic on-off valve can be reduced. Therefore, durability of each electromagnetic on-off valve can be improved. In particular, normal service brake operations and light brake operations are extremely frequent, so it is more effective to make each solenoid on / off valve more durable by not switching each solenoid on / off valve during these brake operations. Can be improved.

In particular, according to the invention of claim 4, since the hydraulic pressure of the accumulator is used at the time of sudden braking operation, the braking force can be quickly raised and the sudden braking can be effectively and reliably applied.
Further, according to the inventions of claims 5 and 6, a conventional existing hydraulic control device arranged as a first electromagnetic on-off valve in a brake line between a master cylinder and a branch point of the branch line Therefore, a dedicated electromagnetic on-off valve as the first electromagnetic on-off valve can be dispensed with. Thereby, the number of parts can be reduced and the cost can be reduced. In particular, according to the sixth aspect of the present invention, it is possible to quickly raise the brake pressure at the initial stage of braking when necessary, while enabling anti-lock control.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a diagram schematically showing the best mode of the brake system of the present invention.
As shown in FIG. 1, the brake system 1 includes a brake pedal (corresponding to a brake operation member of the present invention) 2 that is depressed by a driver when a brake is operated, and a pedal depression force that is controlled by the depression of the brake pedal 2. A negative pressure booster 3 that boosts and outputs at a predetermined servo ratio; a tandem-type master cylinder 4 that is operated by the output of the negative pressure booster 3 to generate a master cylinder pressure; and first and second The wheel cylinders 5, 6, 7, 8 of the first and second systems are provided corresponding to the wheels of the system and generate the braking force of the corresponding wheels by supplying the master cylinder pressure as the brake pressure. And the master cylinder 4 and the wheel cylinders 5, 6, 7, 8 of the first and second systems are respectively connected to supply the master cylinder pressure to the wheel cylinders 5, 6, 7, 8. The first and second electromagnetic lines are disposed in the first and second brake lines 9, 10 and the first and second brake lines 9, 10 of the first and second systems, respectively, and are normally open. On-off valves (corresponding to the first electromagnetic on-off valve of the present invention) 11 and 12, and the first and second electromagnetic on-off valves 11 and 12 of the first and second brake pipe lines 9 and 10, each wheel cylinder 5. , 6, 7 and 8 side to the first and second branch pipelines 13 and 14 branched from the first and second brake pipelines 9a and 10a, respectively, and the first and second branch pipelines 13 and 14, respectively. The first and second accumulators 15 and 16 connected to the first and second branch pipes 13 and 14 are connected to the third and fourth electromagnetic on-off valves 17 and 18 that are normally closed (the present invention). No. 2 electromagnetic on-off valve or the electromagnetic on-off valve of the present invention) and negative pressure multiplication A stroke sensor 19 for detecting the stroke amount or the stroke speed of the input shaft 3a of the force device 3 (that is, the pedal stroke amount or the pedal depression speed of the brake pedal 2), the first and second electromagnetic on-off valves 11, 12, and the third And the fourth electromagnetic on-off valves 17 and 18 and the electronic control device (hereinafter also referred to as ECU) 20 to which the stroke sensor 19 is electrically connected.

Negative pressure booster 3, tandem master cylinder 4, wheel cylinders 5, 6, 7, 8, first to fourth electromagnetic on-off valves 11, 12, 17, 18, first and second accumulators 15, 16 The stroke sensor 19 may be a conventionally known one. Therefore, detailed description thereof will be omitted.
Both the first and second electromagnetic on-off valves 11 and 12 have the same configuration, and are opened when the first and second brake pipes 9 and 10 are in communication with each other, which is set during normal non-operation. And a closed position which is set at the time of operation and puts the first and second brake pipelines 9 and 10 into a shut-off state, respectively.

  Further, the third and fourth electromagnetic on-off valves 17 and 18 have the same configuration, and are set at the time of normal non-operation, respectively, so that the first and second branch pipes 13 and 14 are cut off. A closed position and an open position that is set during operation to bring the first and second branch pipes 13 and 14 into communication.

The first and second brake pipelines 9a, 10a are branched into first to fourth branch brake pipelines 9b, 9c; 10b, 10c for each wheel cylinder 5, 6, 7, 8 respectively. The connecting portions 9b ₁ , 9c ₁ ; 10b ₁ , 10c ₁ of the first to fourth branch brake pipes 9b, 9c; 10b, 10c with the wheel cylinders 5, 6, 7, 8 can be rubber hoses or the like. It consists of a flexible tube. In the brake system 1, during normal service brake operation, the loss stroke of the negative pressure booster 3, the loss stroke of the master cylinder 4, the loss strokes of the wheel cylinders 5, 6, 7, and 8, 2) Hydraulic pressure loss of the brake lines 9, 10; expansion of the connecting portions 9b ₁ , 9c ₁ ; 10b ₁ , 10c _{1 made} of flexible pipes of the first to fourth branch brake lines 9b, 9c; 10b, 10c A time delay due to a hydraulic pressure loss due to the pressure is hardly caused.

  When the driver depresses the brake pedal 2 and performs a brake operation while the vehicle is traveling, the ECU 20 calculates the stroke speed based on the stroke amount detection signal supplied from the stroke sensor 19, and the obtained stroke speed is calculated in advance. When it is below the set stroke speed set larger than the stroke speed at the time of normal service brake operation, it is determined that it is not necessary to quickly raise the brake pressure at the initial stage of braking, and the first to fourth electromagnetic on-off valves 11, No switching signal is output to 12, 17 and 18. Further, when the obtained stroke speed is larger than the set stroke speed, the ECU 20 determines that the brake pressure must be quickly raised at the initial stage of braking, and the first to fourth electromagnetic on-off valves 11, 12, 17,. A control signal is output to 18. Note that the ECU 20 may directly detect the stroke speed of the input shaft 3a by the stroke sensor 19 and compare the stroke speed supplied from the stroke sensor 19 with the above-described set stroke speed in advance.

  In that case, in the initial stage of braking when it is determined that the stroke speed is greater than the set stroke speed, the ECU 20 outputs a switching signal to the third and fourth electromagnetic on-off valves 17 and 18, and the third and fourth electromagnetic on-off valves The valves 17 and 18 are set to the open position for a preset first set time, and then set to the closed position again. In addition, when releasing the brake when it is determined that the stroke speed is greater than the set stroke speed, the ECU 20 sets the first and second electromagnetic on-off valves 11 and 12 to the closed position for a preset second set time. Similarly, the third and fourth electromagnetic on-off valves 17 and 18 are set to the open position for the second set time, and then the first and second electromagnetic on-off valves 11 and 12 are set to the open position again and the third and fourth The electromagnetic on-off valves 17 and 18 are set to the closed position.

  In the first and second accumulators 15 and 16, first, for example, the brake pressure generated by stepping on the brake pedal 2 when starting the engine, or the range setting of the transmission after the engine is started and before the vehicle starts running. The hydraulic fluid pressure such as the brake pressure generated by depressing the brake pedal 2 when the shift lever is operated is stored. As this pressure accumulating method, for example, when the engine is started in a state where the brake pedal 2 is depressed, the ECU 20 outputs a switching signal to the third and fourth electromagnetic opening / closing valves 17, 18, and the third and fourth The electromagnetic on-off valves 17 and 18 are set to the open position for the second set time described above, and then set to the closed position again. As a result, the brake pressure generated in each wheel cylinder 5, 6, 7, 8 is stored in the first and second accumulators 15, 16. As a condition for setting the first and second electromagnetic on-off valves 11 and 12 in the closed position and setting the third and fourth electromagnetic on-off valves 17 and 18 in the open position for pressure accumulation, the second set time described above is used. Instead, for example, a pressure detection sensor for detecting the pressure in the first and second accumulators 15 and 16 is installed, and the ECU 20 causes the first and second accumulators 15 to be based on the pressure detection signal from the pressure detection sensor. The third and fourth electromagnetic on-off valves 17 and 18 can be set to the open position until it is determined that the pressure in the first and second pressures has reached a preset pressure.

  In the brake system 1 configured as described above, when the brake is not operated when the brake pedal is not depressed, the first and second electromagnetic on-off valves 11 and 12 are set to the open position, and the third and fourth electromagnetic valves are set. The on-off valves 17 and 18 are set to the closed position. In order to drive the vehicle, the engine is started and the shift lever of the transmission is operated. At this time, since the driver depresses the brake pedal 2 as described above, a brake pressure is generated in each of the wheel cylinders 5, 6, 7 and 8, and this hydraulic fluid pressure is the first and second as described above. It is stored in the accumulators 15 and 16.

  When the driver releases the side brake, releases the brake pedal 2 and depresses an accelerator pedal (not shown) for starting the vehicle, the vehicle starts. When the brake pedal 2 is released, the brake pressure in each of the wheel cylinders 5, 6, 7, 8 and the first and second brake pipes 9, 10 disappears, but the third and fourth electromagnetic on-off valves 17, 18 Since it is set to the closed position, the hydraulic pressure stored in the first and second accumulators 15 and 16 does not leak to the first and second brake pipe lines 9a and 10a, and does not decrease.

  When the driver performs a service brake operation by depressing the normal brake pedal 2 to stop the vehicle, the negative pressure booster 3 boosts and outputs the pedal depression force as in the conventional brake system, and the master The cylinder 4 generates a master cylinder pressure corresponding to the output of the negative pressure booster 3. The generated master cylinder pressure is supplied as brake pressure to the wheel cylinders 5, 6, 7, 8 via the first and second brake pipes 9, 10, and each wheel cylinder 5, 6, 7, 8 is a master cylinder. The service brake is applied to the corresponding wheel with the braking force corresponding to the pressure.

  During this service brake operation, the ECU 20 determines whether the stroke speed calculated based on the stroke amount detection signal supplied from the stroke sensor 19 or the measured stroke speed based on the stroke speed detection signal supplied from the stroke sensor 19 is the service brake operation. Since it is smaller than the set stroke speed, it is determined that it is not necessary to quickly increase the brake pressure at the initial stage of braking, and no switching signal is output to the third and fourth electromagnetic on-off valves 17 and 18. Accordingly, during service braking, the third and fourth electromagnetic on-off valves 17 and 18 are held in the closed position, and the hydraulic pressure in the first and second accumulators 15 and 16 is supplied to the first and second brake conduits 9a and 10a. Not. Thereby, at the time of service brake operation, the brake pressure of each wheel cylinder 5,6,7,8 is not influenced by the hydraulic pressure of the 1st and 2nd accumulator 15,16. In addition, as described above, time delay is not a significant problem during service braking. Therefore, when the service brake is operated, the driver does not feel uncomfortable and the brake feeling is good.

  When the brake pedal 2 is released and a service brake release operation is performed, the stroke of the input shaft 3a is reversed from the operating direction. The stroke in the reverse direction of the input shaft 3 a is detected by the stroke sensor 19 and input to the ECU 20. However, since the ECU 20 determines that it is not necessary to quickly increase the brake pressure at the initial stage of braking as described above, the ECU 20 does not output a switching signal to the third and fourth electromagnetic on-off valves 17 and 18. Therefore, the third and fourth electromagnetic on-off valves 17 and 18 do not change, and the brake pressure of each wheel cylinder 5, 6, 7, 8 is not stored in the first and second accumulators 15, 16, but each wheel cylinder The hydraulic fluids 5, 6, 7, and 8 are returned to the master cylinder 4. As a result, the service brake is released.

If the driver depresses the brake pedal 2 quickly to apply a sudden brake while the vehicle is running, the stroke speed will be much faster when the service brake is operated. Therefore, the ECU 20 determines that the stroke speed calculated in the same manner as described above or the measured stroke speed is larger than the set stroke speed, and outputs a switching signal to the third and fourth electromagnetic on-off valves 17 and 18. Then, the third and fourth electromagnetic on-off valves 17 and 18 are switched and set to the open position, and the hydraulic pressure in the first and second accumulators 15 and 16 is supplied to the first and second brake conduits 9a and 10a. Is done. As a result, the connecting portions 9b ₁ , 9c ₁ ; 10b ₁ , 10c ₁ made of the flexible pipes of the first to fourth branch brake pipes 9b, 9c; 10b, 10c rapidly expand, and each wheel cylinder 5 , 6,7,8 loss strokes disappear quickly. At this time, since the first and second electromagnetic on-off valves 11 and 12 are set to the open position, the first and second accumulators 15 and 16 supplied to the first and second brake conduits 9a and 10a Although the hydraulic pressure tends to leak to the master cylinder 4 side, the master cylinder pressure of the master cylinder 4 is supplied to the first and second brake pipes 9a and 10a, so that it does not leak much to the master cylinder 4 side. It is used effectively for expansion of the connecting portions 9b ₁ , 9c ₁ ; 10b ₁ , 10c ₁ and disappearance of the loss strokes of the wheel cylinders 5, 6, 7, 8.

The ECU 20 sets the third and fourth electromagnetic on-off valves 17 and 18 to the closed positions again when the above-described first set time has elapsed. The connecting portion _{9b 1, 9c 1; 10b 1} , the expansion of 10c ₁ ends and after the disappearance of the loss stroke of each wheel cylinder 5, 6, 7, 8 (or one behind the other), the master cylinder pressure is the It is supplied to the wheel cylinders 5, 6, 7 and 8. Therefore, the master cylinder pressure is not supplied to the first and second accumulators 15 and 16, and is used directly and effectively for increasing the brake pressure of the wheel cylinders 5, 6, 7, and 8. The braking force of each wheel cylinder 5, 6, 7, 8 increases rapidly. Moreover, when the master cylinder pressure is supplied to the wheel cylinders 5, 6, 7, and 8, the brake fluid is already transmitting pressure to the hydraulic fluid almost more than the flow rate, so there is almost no flow of hydraulic fluid. There is almost no hydraulic pressure loss due to resistance to the flow of the brake line.

Thereby, the rise of the brake pressure of each wheel cylinder 5, 6, 7, 8 approaches the rise of the master cylinder pressure, and the sudden brake is applied quickly and reliably with almost no time delay.
In this way, during a sudden braking operation, the brake pressure at the beginning of braking rises quickly, and the driver does not feel uncomfortable and the brake feeling is good.

  When the brake pedal 2 is released to release the brake suddenly, the input shaft 3a moves in the return direction, and the ECU 20 releases the brake suddenly by the stroke amount detection signal or the stroke speed detection signal from the stroke sensor 19 described above. And a switching signal is output to the first to fourth electromagnetic on / off valves 11, 12, 17, and 18, and the first and second electromagnetic on / off valves 11 and 12 are set to the closed position for the second set time. At the same time, the third and fourth electromagnetic on-off valves 17 and 18 are set to the open position for the second set time. As a result, the brake pressure generated in the wheel cylinders 5, 6, 7, 8 during sudden braking is stored in the first and second accumulators 15, 16. The ECU 20 sets the first and second electromagnetic on-off valves 11 and 12 to the open position again when the second set time has elapsed after outputting the switching signal to each of the electromagnetic on-off valves 11, 12, 17 and 18. The 3rd and 4th electromagnetic on-off valves 17 and 18 are again set to the closed position. The first and second accumulators are used as conditions for setting the first and second electromagnetic on-off valves 11 and 12 in the closed position and the third and fourth electromagnetic on-off valves 17 and 18 in the open position for pressure accumulation. As described above, the pressure within 15 and 16 can be used.

  After the hydraulic fluid supplied to the wheel cylinders 5, 6, 7, 8 is fed to the first and second accumulators 15, 16, the first and second electromagnetic on-off valves 11, 12 are opened again and the first When the third and fourth electromagnetic on-off valves 17 and 18 are closed again, the control returns to the master cylinder 4 and further returns to the reservoir 4a of the master cylinder 4. As a result, the hydraulic pressure in each wheel cylinder 5, 6, 7, 8 decreases to atmospheric pressure, and the sudden braking is released. Even if the hydraulic pressures of the wheel cylinders 5, 6, 7, and 8 become atmospheric pressure, the hydraulic pressure stored in the first and second accumulators 15 and 16 is the third and fourth electromagnetic on-off valves 17 and 18. Is closed, it does not leak to the first and second brake conduits 9a, 10a. The hydraulic pressure stored in the first and second accumulators 15 and 16 is used in the same manner as described above at the next sudden braking, so that the brake pressure rises quickly and the time delay hardly occurs. The

  When the brake is suddenly released, the first and second electromagnetic on-off valves 11 and 12 are temporarily closed for a second set time, but the second set time is very short, and the first and second electromagnetic on-off valves 11 and 12 are also closed. Since the hydraulic fluid from the wheel cylinders 5, 6, 7, and 8 is supplied to the first and second accumulators 15 and 16 while the cylinder is closed, the brake release is quickly started and the brake is started. -There will be no problems caused by rubbing due to delay in releasing the key.

  In addition, since the hydraulic pressure stored in the first and second accumulators 15 and 16 is used at the time of sudden braking operation, the hydraulic pressure of the first and second accumulators 15 and 16 is not used at the time of service brake operation. The first and second accumulators 15 and 16 are configured to store a substantially constant hydraulic pressure that is greater during the sudden braking operation than during the service braking operation. Therefore, when the hydraulic pressures of the first and second accumulators 15 and 16 are used, a substantially constant hydraulic pressure is used. Therefore, when the hydraulic pressures of the first and second accumulators 15 and 16 are used, the driver No further discomfort and better brake feeling.

  Further, when the driver performs a brake operation to apply a light brake for the purpose of slightly decelerating while the vehicle is traveling (not for the purpose of stopping the vehicle), the ECU 20 performs the first to fourth electromagnetic on-off valves 11, 12, 17 and 18 do not output a switching signal. Therefore, the braking force does not rise rapidly at this time, and an excessive braking force against the driver's will does not occur. Therefore, the driver does not feel uncomfortable even during such a light brake operation, and the brake feeling is good.

  In this brake system 1, the ECU 20 does not switch the first to fourth electromagnetic on-off valves 11, 12, 17, 18 during a normal service brake operation and a light brake operation for the purpose of deceleration, such as a sudden brake. Since the first to fourth electromagnetic on-off valves 11, 12, 17, 18 are switched only when necessary, the operating frequency of the first to fourth electromagnetic on-off valves 11, 12, 17, 18 is low. Therefore, the durability of the first to fourth electromagnetic on-off valves 11, 12, 17, 18 is improved. In particular, the normal service brake operation and the light brake operation are very frequently operated. Therefore, the first to fourth electromagnetic on-off valves 11, 12, 17, and 18 cannot be switched during these brake operations. The durability of the electromagnetic on-off valves 11, 12, 17, 18 is improved more effectively.

FIG. 2 is a view similar to FIG. 1 schematically showing another example of the embodiment of the invention. The same components as those in the above-described example are denoted by the same reference numerals, and detailed description thereof is omitted.
As shown in FIG. 2, in the brake system 1 of this example, one of the hydraulic control devices (hereinafter also referred to as HU) is provided in the first and second branch pipes 13 and 14 extending from the master cylinder 4. An anti-lock control modulator (hereinafter also referred to as an ABS control modulator) 21 is provided. As the ABS control modulator 21, for example, an ABS control modulator disclosed in JP-A-9-315280 can be used. The specific configuration of the ABS control modulator 21 can be understood by referring to Japanese Patent Application Laid-Open No. 9-315280, and the present invention does not feature the ABS control itself, so that the description thereof is omitted.

  In the ABS control modulator 21, the first and second brake lines 9, 10 are respectively connected to the first to fourth branch brake lines 9b, 9c; 10b for the wheel cylinders 5, 6, 7, 8 of each wheel. (The third and fourth branch brake lines 10b and 10c in the ABS control modulator 21 are not shown in FIG. 2, but the first and second branch brake lines 9b and 9c are not shown. Are formed in the same manner). The first and second branch pipelines 13 and 14 in the example shown in FIG. 1 are branched from the first to fourth branch brake pipelines 9b and 9c; 10b and 10c, respectively. In that case, of the first and second branch pipelines 13 and 14, the first to fourth branch brake pipelines 9b and 9c; 10b and 10c side from the third and fourth electromagnetic on-off valves 17 and 18 are The first through fourth branch brake lines 9b, 9c; 10b, 10c are formed as branch lines 13a, 13b; 14a, 14b, respectively.

  In the brake system 1 of this example, the first and second electromagnetic on-off valves 11 and 12 in the example shown in FIG. 1 are used for the ABS control modulator disclosed in Japanese Patent Laid-Open No. 9-315280. The ABS control holding valve is used. Therefore, as shown in FIG. 2, the first electromagnetic on-off valve 11 of the above-described example is a first electromagnetic on-off valve 11a composed of ABS control holding valves provided in the first and second branch brake pipes 9b and 9c, respectively. .11b. The second electromagnetic on-off valve 12 in the above example is not shown in FIG. 2, but in the following description, for convenience of explanation, the second electromagnetic on-off valve 12a.11b is associated with the first electromagnetic on-off valve 11a.11b. This will be described as 12b. These first and second electromagnetic on-off valves 11a.11b; 12a.12b are respectively connected to the ECU 20, and are controlled by the ECU 20 to be the same as the first and second electromagnetic on-off valves 11, 12 in the above-described example. Acts as follows.

As described above, the first and second electromagnetic on / off valves 11 and 12 can be used as the first and second electromagnetic on / off valves 11 and 12 by using the first electromagnetic on / off valves 11a and 11b including the ABS control holding valves. This eliminates the need for a dedicated solenoid valve. Thereby, the number of parts can be reduced and the cost can be reduced. Moreover, in the brake system 1 of this example, the anti-lock control can be performed, and the brake pressure at the initial stage of braking can be quickly raised when necessary.
In FIG. 2, 22a and 22b are ABS control pressure reducing valves, 23 is a sump device (low pressure accumulator), 24 is an ABS control pump, and 25 is a pump drive motor.
Other configurations and other functions and effects of the brake system 1 of this example are the same as those of the example shown in FIG.
In the example shown in FIG. 2 described above, the ABS control modulator is used as the HU. However, the hydraulic control electromagnetic on / off valve that can perform the same operation as the first and second electromagnetic on / off valves 11 and 12 is provided. Any HU can be used as long as it has HU.

FIG. 3 is a view similar to a part of FIG. 1 schematically and partially showing still another example of the embodiment of the invention. The same components as those in the above-described example are denoted by the same reference numerals, and detailed description thereof is omitted.
In the example shown in FIG. 1 described above, the third electromagnetic opening / closing valve 17 provided in the first branch pipe 13 is configured as an opening / closing valve that closes during normal operation (non-operation) and opens during operation. As shown, in the brake system 1 of this example, the flow of hydraulic fluid from the first branch line 13 to the first accumulator 15 is caused by the check valve 26 at the normal time (non-operation time) as the third electromagnetic on-off valve 17. It is configured as an on-off valve that allows only the flow of the hydraulic fluid between the first branch pipe 13 and the first accumulator 15 and allows it to open freely during operation. Although not shown, the fourth electromagnetic opening / closing valve 18 provided in the second branch pipe 14 is also configured as the same opening / closing valve as the opening / closing valve having the check valve 26 of the third electromagnetic opening / closing valve 17.
Other configurations of the brake system 1 of this example are the same as those in FIG.

In the brake system 1 of this example configured as described above, the third and fourth electromagnetic on-off valves 17 and 18 are set at the check valve 26 position during normal non-operation. As in the example shown in FIG. 1, the first to fourth electromagnetic on-off valves 17 and 18 are not switched during service braking. On the other hand, during the sudden braking operation, the third and fourth electromagnetic on-off valves 17 and 18 are switched to the open position as in the example shown in FIG. 1, and the hydraulic pressure in the first and second accumulators 15 and 16 is changed. The first and second brake pipes 9a and 10a are supplied. As a result, the connecting portions 9b ₁ , 9c ₁ ; 10b ₁ , 10c ₁ made of the flexible pipes of the first to fourth branch brake pipes 9b, 9c; 10b, 10c rapidly expand, and each wheel cylinder 5 , 6,7,8 loss strokes disappear quickly. Then, when the first set time described above has elapsed, the third and fourth electromagnetic on-off valves 17 and 18 are set again to the check valve 26 position. Thereby, since the brake pressure at the time of the sudden brake operation generated in each wheel cylinder 5, 6, 7, 8 is not higher than the accumulated pressure in the first and second accumulators 15, 16 at this time, each wheel cylinder 5 , 6, 7 and 8 are stored in the first and second accumulators 15 and 16 by opening the check valve 26.

At the time of the sudden brake release operation, the first and second electromagnetic on-off valves 11 and 12 are set to the closed position for the above-mentioned second set time as in the example shown in FIG. 18 is also set to the open position for the second set time. As a result, the brake pressure in each of the wheel cylinders 5, 6, 7, 8 is stored in the first and second accumulators 15, 16 without passing through the check valve 26. At this time, the brake pressures in the wheel cylinders 5, 6, 7, and 8 are accumulated in the first and second accumulators 15 and 16 via the check valves 26, respectively. Is stored without passing through the check valve 26, a slightly higher pressure is stored in the wheel cylinders 5, 6, 7, 8 by the valve opening pressure of the check valve 26. When the aforementioned second set time has elapsed, the first and second electromagnetic on-off valves 11 and 12 are set to the open position again, and the third and fourth electromagnetic on-off valves 17 and 18 are set to the check valve 26 position again. The
Other functions and effects of the brake system 1 of this example are the same as those of FIG.

  In the example shown in FIG. 3, the first and second electromagnetic on-off valves 11 and 12 are not necessarily required and can be omitted. In this case, at the time of the sudden brake release operation, the third and fourth electromagnetic on-off valves 17 and 18 are kept at the check valve 26 position by omitting the opening position setting for the second set time. In this case, the brake pressures in the wheel cylinders 5, 6, 7, and 8 are accumulated in the first and second accumulators 15 and 16 via the check valves 26, respectively. The accumulated pressure is slightly lower than the case where there is no. Of course, even if the pressure accumulation in the first and second accumulators 15 and 16 is slightly reduced, the rise of the brake pressure of each wheel cylinder 5, 6, 7, 8 is almost the same as the master cylinder pressure, as in the example shown in FIG. The sudden braking can be applied quickly and reliably with almost no time delay. Further, the first and second electromagnetic on / off valves 11 and 12 may be configured as first and second electromagnetic on / off valves 11a.11b and 12a.12b, which are ABS control holding valves, as in the example shown in FIG. it can.

In each of the above-described examples, a stroke stroke sensor that detects the stroke amount or the stroke speed of the input shaft 3a is used as the operation amount detection means of the brake operation member for determining the sudden brake operation. As the operation amount detection means, any other operation amount detection means such as a pedal force sensor for detecting the pedal depression force can be used as long as it detects the operation amount of the brake operation member.
Further, in each of the above examples, the negative pressure booster 3 is used. However, other boosters such as a hydraulic booster can be used, and these boosters can be omitted. .

  The brake system of the present invention can be suitably used for a brake system of a vehicle such as an automobile.

It is a figure showing typically the best form of the brake system of the present invention. It is a figure similar to FIG. 1 which shows the other example of embodiment of this invention typically. It is a figure similar to a part of FIG. 1 which shows the further another example of embodiment of invention typically and partially.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Brake system, 2 ... Brake pedal, 3 ... Negative pressure booster, 4 ... Master cylinder, 5, 6, 7, 8 ... Wheel cylinder, 9 ... 1st brake pipeline, 9a ... 1st brake pipeline, 9b ... 1st branch brake line, 9c ... 2nd branch brake line, 10 ... 2nd brake line, 10a ... 2nd brake line, 10b ... 3rd branch brake line, 10c ... 4th branch brake line 11, 11a, 11b ... 1st electromagnetic on-off valve, 12, 12a, 12b ... 2nd electromagnetic on-off valve, 13 ... 1st branch pipe, 14 ... 2nd branch pipe, 13a, 13b, 14a, 14b ... Branch pipe, 15 ... 1st accumulator, 16 ... 2nd accumulator, 17 ... 3rd electromagnetic on-off valve, 18 ... 4th electromagnetic on-off valve, 19 ... Stroke sensor, 20 ... Electronic control unit (ECU), 21 ... Anti-lock Modulator (ABS control Modulator)

Claims (6)

A brake operating member, a master cylinder that generates a master cylinder pressure by operating the brake operating member, a brake cylinder that generates a braking force by supplying the master cylinder pressure as a brake pressure, and the master A brake line that connects the cylinder and the brake cylinder to supply hydraulic fluid from the master cylinder to the brake cylinder, and is provided in the brake line and is set to an open position when not activated and to a closed position when activated. A first electromagnetic on-off valve to be set; an accumulator connected to the brake line via a branch line; and a set in the branch line that is set to a closed position when not activated and to an open position when activated A second electromagnetic on-off valve to be set, an electronic control device for controlling the operation of each of the first and second electromagnetic on-off valves, and the blur Detecting an operation amount of the key operating member at least an operation amount detecting means for outputting the operation amount detection signal to the electronic control device,
The electronic control unit determines whether or not it is necessary to quickly start up the brake pressure at the initial stage of braking based on a detection signal of an operation amount of the brake operation member from the operation amount detection means during a brake operation. When it is determined that it is necessary to quickly increase the brake pressure at the initial stage of braking, the second electromagnetic opening / closing valve is once set to the open position and then set to the closed position. Sometimes, the first electromagnetic on-off valve is set to the closed position and the second electromagnetic on-off valve is set to the open position, then the first electromagnetic on-off valve is set to the open position again and the first electromagnetic on-off valve is set to the open position. 2. A brake system characterized in that the electromagnetic on-off valve 2 is set to the closed position again. A brake operating member, a master cylinder that generates a master cylinder pressure by operating the brake operating member, a brake cylinder that generates a braking force by supplying the master cylinder pressure as a brake pressure, and the master A brake line that connects the cylinder and the brake cylinder to supply hydraulic fluid from the master cylinder to the brake cylinder, and is provided in the brake line and is set to an open position when not activated and to a closed position when activated. A first electromagnetic on-off valve to be set, an accumulator connected to the brake line via a branch line, and an action provided to the branch line from the brake line toward the accumulator when not operating A second electromagnetic opening that is set to a check valve position that allows only liquid flow and is set to an open position during operation. A valve, an electronic control device that controls the operation of the first and second electromagnetic on-off valves, and an operation amount detection that detects an operation amount of the brake operation member and outputs an operation amount detection signal to the electronic control device Means at least,
The electronic control unit determines whether or not it is necessary to quickly start up the brake pressure at the initial stage of braking based on a detection signal of an operation amount of the brake operation member from the operation amount detection means during a brake operation. When it is determined that it is necessary to quickly increase the brake pressure at the initial stage of braking, the second electromagnetic opening / closing valve is temporarily set to the open position, then set to the check valve position, and the brake is released. During operation, the first electromagnetic on-off valve is temporarily set to the closed position, the second electromagnetic on-off valve is set to the open position, and then the first electromagnetic on-off valve is set to the open position again. A brake system, wherein the second electromagnetic on-off valve is set to the check valve position again. A brake operating member, a master cylinder that generates a master cylinder pressure by operating the brake operating member, a brake cylinder that generates a braking force by supplying the master cylinder pressure as a brake pressure, and the master A brake line for connecting the cylinder and the brake cylinder to supply hydraulic fluid from the master cylinder to the brake cylinder; an accumulator connected to the brake line via a branch line; and the branch line An electromagnetic on-off valve that is set at a check valve position that allows only a flow of hydraulic fluid from the brake pipe line to the accumulator during non-operation and is set at an open position during operation; and An electronic control device for controlling the operation and an operation amount of the brake operation member are detected and the operation amount is detected. At least an operation amount detecting means for outputting a signal to the electronic control unit,
The electronic control unit determines whether or not it is necessary to quickly start up the brake pressure at the initial stage of braking based on a detection signal of an operation amount of the brake operation member from the operation amount detection means during a brake operation. Then, when it is determined that it is necessary to quickly increase the brake pressure at the initial stage of braking, the electromagnetic on-off valve is set to the open position and then set to the check valve position. The brake system according to any one of claims 1 to 3, wherein when it is determined that the rise of the brake pressure in the initial stage of braking needs to be performed quickly, it is during a sudden braking operation. Fluid pressure control having an electromagnetic on-off valve for fluid pressure control that is set in the closed position when not activated and set to the open position when activated in the brake pipeline between the master cylinder and the branch point of the branch pipeline 5. The brake system according to claim 1, wherein the first electromagnetic on-off valve comprises a hydraulic pressure control electromagnetic on-off valve. 6. The brake system according to claim 5, wherein the hydraulic control device is an anti-lock control modulator, and the hydraulic control electromagnetic on-off valve is an anti-lock control holding valve.

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