JPH11268619A - Vehicle brake system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow the use of hydraulic energy obtained by recovering kinetic energy during deceleration of the vehicle for braking and accelerating as well as prevent failure in the braking operation owing to the hydraulic pressure loss. SOLUTION: An braking energy recovery unit 3 for recovering the kinetic energy during braking is structured such that a control unit 4 is capable of controlling check pressure of a relief valve 16 for setting a discharge pressure of a hydraulic pressure pump motor 9 and an accumulator control valve 18 for controlling supply of the pressure discharged by the hydraulic pump motor 9 to an accumulator 11. Setting the respective check pressures to appropriate values may avoid the change in the discharge pressure of the hydraulic pump motor 9 in conformity with the accumulator pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering kinetic energy lost when a vehicle is decelerated and for performing subsequent braking operation and starting / starting.
The present invention relates to a vehicular braking device which can improve the energy efficiency of a vehicle by effectively utilizing the acceleration operation, and is also suitable for making the braking function intelligent.

[0002]

2. Description of the Related Art In recent years, brake systems for vehicles have been actively provided with intelligent brake functions such as an anti-lock brake system and a traction control system. In order to cope with such an intelligent system, an electric brake system is being promoted.

[0003] As for the electrification of the brake device, a method of electrifying a friction material driving mechanism itself for pressing a friction material such as a brake pad against a rotating body such as a brake disc, and a method of hydraulically pressing the friction material against the rotating body are used. The method can be roughly classified into a method of electrically driving a pressure generating device as a generation source, and various types have been developed and proposed.

[0004]

However, in the conventional electric brake device, in any case, at the time of braking, electric energy is supplied from a battery mounted on the vehicle to a friction material driving mechanism or a driving portion of a pressure generating device. Need
There has been a problem that the electric energy of the brake device increases the consumption of electric energy in the vehicle, and it is necessary to improve the performance of the vehicle-mounted battery.

[0005] In addition, the conventional brake device generally includes:
When the vehicle decelerates, all kinetic energy is converted into heat and discarded, which has been a factor in reducing the energy efficiency of the vehicle. Therefore, the kinetic energy lost when the vehicle is decelerated is collected as hydraulic energy in the accumulator for hydraulic pressure accumulation, and the collected hydraulic energy is used as drive energy during the start / acceleration operation of the vehicle, thereby improving the energy efficiency of the vehicle. A braking energy regenerating device has also been proposed (see Japanese Patent No. 2503818).

However, in a conventional braking energy regenerating apparatus of the type in which kinetic energy lost during deceleration of a vehicle is recovered as hydraulic energy in a hydraulic pressure accumulator, a braking torque that can be generated generally has an accumulator limit pressure (accumulation level). ), It is necessary to use another brake device in order to obtain a large braking force, and there is a problem that the configuration of the brake system becomes complicated. For example, the braking energy regenerating device disclosed in the above-mentioned Japanese Patent No. 2503818 is configured to be used in combination with an air brake device. Therefore, not only a normal air brake unit is required, but also a pneumatic control system. This requires two control systems, a hydraulic control system for the regenerative device, and there is a problem that the control system is complicated.

Furthermore, even if the accumulator pressure drops,
Depending on the braking conditions, it is not possible to start accumulating pressure in the accumulator immediately, so it is difficult to stably maintain the accumulating pressure of the accumulator, and when using the accumulator pressure as a drive source, malfunction due to a decrease in the accumulator pressure In order to prevent such problems, a large accumulator having a large accumulated pressure must be provided.

In addition, since the braking energy regenerating device is provided between the propeller shaft of the vehicle and the transmission, it is not possible to independently recover energy at the time of braking or to reuse the recovered energy for each wheel. For example, there is also a problem that it cannot be effectively used for an antilock brake system, a traction control system, or the like, which requires individually controlling the braking torque or the driving torque of each wheel.

The present invention has been made in view of the above circumstances, and it is possible to arbitrarily adjust the generated braking force without being affected by the accumulator pressure, and to generate a large braking force without using another braking device. It is also possible to improve the energy efficiency of the vehicle by using the energy collected in the accumulator for braking and starting / acceleration operations at the time of braking, and to stabilize the accumulator pressure and to reduce the accumulator pressure. When used as a drive source, it is possible to prevent malfunctions and the like caused by a decrease in accumulator pressure, and it is possible to easily realize intelligent brake functions such as an antilock brake system and a traction control system, and at the same time, Electrification of electric energy in vehicles by electrification of brake device And an object thereof is to provide a vehicle braking device can be suppressed that but increased.

[0010]

A vehicle braking device according to the present invention for achieving the above object is connected to a wheel rotating shaft, has a first port and a second port, and switches an operation switching valve. The first port acts as a hydraulic pump when the first port is connected to a reservoir and the second port is connected to an accumulator, and the first port functions as an accumulator.
In a vehicle braking device provided with a hydraulic pump motor acting as a hydraulic motor when the second port is connected to a reservoir, a relief valve having a variable check pressure in an oil passage between the second port and the reservoir Is provided.

According to the above configuration, when the vehicle is braked, the operation of the pump is performed such that the first port of the hydraulic pump motor is connected to the accumulator and the second port of the hydraulic pump motor is connected to the reservoir. By controlling the switching valve, the hydraulic pump motor is operated as a hydraulic pump. In this case, the driving torque for rotating the hydraulic pump acts as a load on the wheels, and becomes a braking force for reducing the rotation of the wheels.

[0012] Then, in operating a hydraulic pump motor as a hydraulic pump, based on the target relief pressure P ₀ which is set according to the braking force required, the check pressure of the relief valve and the accumulator control valve Control. That is, when the target relief pressure P ₀ is lower than the hydraulic pressure stored in the accumulator (hereinafter, referred to as the accumulator pressure), the check pressure of the relief valve is set to the target relief pressure P ₀ .

If the target relief pressure P ₀ is higher than the current accumulator pressure P _{X and} lower than the accumulator limit pressure (accumulation level) P _max , the check pressure of the accumulator control valve and the accumulator Control so that the sum of the pressure and the target pressure becomes the target relief pressure P ₀ , and the check pressure of the relief valve is set to an appropriate value higher than the target relief pressure P _0. Function as

As described above, if the check pressure of the relief valve or the pressure accumulating control valve is properly controlled, the pump discharge pressure (ie, relief pressure) can be adjusted to an arbitrary value, and is determined by the pump discharge force. The driving torque of the hydraulic pump (that is, the generated braking force) can be adjusted to an arbitrary value.

Further, in the above configuration, an inconvenience in which the pump discharge pressure is determined by the accumulation of the accumulator by the relief valve can be avoided, and the discharge pressure of the pump is controlled by controlling the check pressure of the accumulator control valve. By setting the above high pressure, a large braking force can be generated.

At the time of start / acceleration, the accumulator pressure is supplied to the hydraulic pump motor, and the pump operation switching valve and the pressure accumulating control valve are controlled so that the hydraulic pump motor operates as a hydraulic motor and transmits driving force to wheels. Control.

By setting the maximum check pressure of the relief valve to be equal to or less than the maximum allowable pressure of the components of the apparatus or the oil passage, it is possible to prevent the hydraulic equipment and the oil passage from being damaged due to an overload.

Further, in the vehicle braking device of the present invention, a braking energy regenerating unit is provided for each wheel, and the control device controls the pressure accumulating control valve according to the rotation of the wheel or the state of the vehicle.
With a configuration in which the pump operation switching valve, the relief valve, and the like are controlled, energy recovery and reuse of the recovered energy can be performed independently for each wheel.

It is preferable that a manual operation mechanism for switching an operation state is provided for each valve whose operation is controlled by the control device. With this configuration, even when the control device is turned off and the vehicle is parked or the electric system fails, the pump operation switching valve and the pressure accumulation control valve are manually operated to bring the braking energy regeneration unit into the braking state. , The braking force can be generated.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a vehicle brake system according to an embodiment of the present invention.
FIG. 1 shows a first embodiment of a vehicular braking device according to the present invention. Vehicle braking device 1 of the first embodiment
0, as shown in the figure, comprises a braking energy regeneration unit 3 provided for each wheel of the vehicle, and a control device 4 for controlling the braking energy regeneration unit 3. The control device 4 is installed at an appropriate position away from wheels on a vehicle body on which a power device such as an engine is mounted.

As shown, the braking energy regenerating unit 3 includes a hydraulic brake unit 7 for braking wheels by hydraulic pressure, a hydraulic pump motor 9 having a pump shaft 9c connected to a wheel shaft 21, and a wheel A hydraulic clutch device 24 engaged with and disengaged from the shaft 21, an accumulator 11 for accumulating hydraulic pressure, a reservoir 13 for storing hydraulic oil, a clutch operation switching valve 25 for switching the operation of the hydraulic clutch device 24, and a hydraulic pump motor 9. 1st port (discharge port)
A pressure control valve 18 for controlling the hydraulic pressure supply from 9 a to the accumulator 11, a pump operation switching valve 15 for switching the operation of the hydraulic pump motor 9, a relief valve 16 for adjusting the discharge pressure of the hydraulic pump motor 9, an accumulator 1
An accumulator output control valve 17 capable of opening and closing an oil passage 5a for communicating the hydraulic fluid with the hydraulic brake unit 7 and a check valve 19 for accumulator protection in which a check pressure is set so that the accumulator pressure does not rise more than necessary. ing. The check valve 19 sets the check pressure to, for example, the accumulator limit pressure of the accumulator 11, and when the accumulator pressure exceeds the check pressure, releases the accumulator pressure to the reservoir 13 to maintain the accumulator pressure within the accumulator limit pressure. .

The hydraulic pump motor 9 operates as a hydraulic pump for discharging the hydraulic oil of the reservoir 13 supplied to the first port 9a from the second port 9b when a rotational force is input to the pump shaft 9c (for the pump). When the operation switching valve 15 is in the position B), and when the hydraulic pressure of the accumulator 11 is supplied to the second port 9b, it operates as a hydraulic motor in which the pump shaft 9c rotates by the supplied oil pressure (pump operation). (When the switching valve 15 is in the position A).

As shown in FIG. 2, the hydraulic clutch device 24 engages with a spline 9d at the tip of the pump shaft 9c so as to be able to advance and retreat on the pump shaft 9c toward a brake disk 22 integrated with the wheel shaft 21. A plywood 27, a clutch housing 28 fitted to the pump shaft 9c so as to be sandwiched between the engagement plate 27 and the pump swash plate 9e of the hydraulic pump motor 9, and a spring 2 housed in the clutch housing 28
The piston 30 presses the engagement plate 27 against the brake disk 22 by the urging force of the piston 9 and the clutch housing 28 so that the supplied hydraulic pressure urges the piston 30 away from the brake disk 22 against the spring 29. The engagement plate 27 is provided between the liquid chamber 31 formed and the abutment plate 32 fixed to the clutch housing 28 and the engagement plate 27 so that the engagement plate 27 keeps a state in which the engagement plate 27 is in contact with the tip of the piston 30. A return spring 33 biasing the piston 30 side.

The return spring 33 is set to have a smaller urging force than the spring 29, and when no hydraulic pressure equal to or more than the reference value is supplied to the liquid chamber 31, the urging force of the spring 29 pushes the engagement plate 27 against the brake disk 22. It is kept in the state. The engaging plate 27 is provided with a connecting pin 34 for engaging with a connecting concave portion 35 formed on the surface of the brake disk 22. The engaging plate 27 pressed against the brake disk 22 is connected to the connecting pin 34 by the connecting pin 34. By the engagement with the concave portion 35, a connection state in which the brake disk 22 and the brake disk 22 rotate together is established.

That is, the hydraulic clutch device 24 is
When the hydraulic pressure supplied to the hydraulic pump motor 9 is equal to or less than the urging force of the spring 29, the engaging plate 27 is engaged with the brake disc 22 by the urging force of the spring 29, and the pump shaft 9c of the hydraulic pump motor 9 is moved to the wheel shaft 21. When the hydraulic pressure supplied exceeds the urging force of the spring 29, the engagement plate 27 is moved from the brake disk 22 by the displacement of the piston 30 against the spring 29 due to the hydraulic pressure. Then, the pump shaft 9c of the hydraulic pump motor 9 is separated from the wheel shaft 21.

The clutch operation switching valve 25 has a three-port two
When the vehicle is running, for example, when the braking operation or the start / acceleration operation is not detected by the position switching valve, the valve position is set to the position A, and the hydraulic pressure of the accumulator 11 is set to the hydraulic clutch device 24.
Of the oil path to be supplied to the liquid chamber 31 is made. Thus, if the oil pressure supplied to the liquid chamber 31 is higher than the reference value, the piston 30 is displaced in the direction of compressing the spring 29, the engagement plate 27 is separated from the brake disk 22, and the wheel shaft 21 is A clutch-off state where torque is not transmitted to the pump shaft 9c is established. In addition, the clutch operation switching valve 25 sets the valve position to the position B at the time of braking or start / acceleration, and creates an oil path connection state in which the liquid chamber 31 communicates with the reservoir 13. As a result, the oil pressure in the liquid chamber 31 is released to the reservoir 13, and the urging force of the spring 29
7 is connected to the brake disc 22, and a clutch-on state in which the wheel axle 21 and the pump shaft 9c rotate integrally is provided.

In the case of the present embodiment, the pressure accumulating control valve 18 is
A check valve whose check pressure can be changed by a control signal from the control device 4. The check valve is provided in a pressure accumulating oil passage 5 b for guiding the oil pressure discharged from the hydraulic pump motor 9 to the accumulator 11. If the discharge pressure of the hydraulic pump motor 9 is equal to or lower than the check pressure, the supply of the hydraulic pressure to the accumulator 11 is stopped while keeping the pressure accumulating oil passage 5b closed. Check pressure change
This is performed by adjusting the amount of deflection of the valve spring 18a by a linear motion device 18b utilizing a stepping motor 18c.

The pump operation switching valve 15 is a 5-port 2-position switching valve. When the valve position is set to the position A, the accumulator 11 and the first port 9a of the hydraulic pump motor 9 are switched.
And the reservoir 13 is connected to the hydraulic pump motor 9.
When the first oil passage connection state connected to the second port 9b is formed and the valve position is set to the position B, the pressure accumulation oil passage 5
b is connected to the second port 9b and the reservoir 13 is connected to the first port 9a to form a second oil passage connection state.

The relief valve 16 has a configuration in which the check pressure can be changed by a control signal from the control device 4, and is provided in the pressure accumulation oil passage 5b between the oil pressure control valve 18 and the pump operation switching valve 15. The discharge pressure of the hydraulic pump motor 9 is adjusted by adjusting the hydraulic pressure flowing through the accumulating oil passage 5b by the check pressure. The check pressure is changed by adjusting the amount of deflection of the valve spring 16a by a linear motion device 16b using a stepping motor 16c.

However, the relief valve 16 is provided with a check pressure increasing mechanism 20. The check pressure increasing mechanism 20 includes a linear motion device 16b and a valve spring 16a.
, A displacement transmitting member 20a for transmitting the displacement of the linear motion device 16b to the valve spring 16a, a piston member 20b slidably supported in a valve housing 16d of the relief valve 16, and a valve housing 16d. Check pressure boosting spring 20c, which is press-fitted between the piston member 20b and biases the displacement transmitting member 20a in the compression direction of the valve spring 16a via the piston member 20b, and an accumulator pressure detecting chamber 20d into which the accumulator pressure is guided. And

The accumulator pressure detecting chamber 20d is
The accumulator pressure is provided so as to apply a biasing force to the piston member 20b in a direction to compress the check pressure boosting spring 20c. That is, the check pressure increasing mechanism 2
0, the hydraulic pressure accumulated in the accumulator 11 is received by the accumulator pressure detection chamber 20d, and when the hydraulic pressure falls below the reference pressure, the piston member 20b causes the displacement transmitting member 20a to move the displacement transmitting member 20a to the valve spring 16a by the urging force of the check pressure boosting spring 20c. Displaced in the compression direction, the relief valve 1
6 is a configuration for increasing the check pressure.

If the accumulator pressure drops after the vehicle has been left for a long time, the hydraulic clutch device 24 cannot be disconnected. In this case, the check pressure boosting mechanism 20 is controlled to
The check pressure is maximized. When the vehicle is driven in this state, the hydraulic pump operates to increase the accumulator pressure, and the hydraulic clutch device 24 is disconnected.

The accumulator output control valve 17 is a three-port three-position switching valve. When the valve position is at the position A, the accumulator output control valve 17 supplies the hydraulic pressure accumulated in the accumulator 11 to the hydraulic brake unit 7. Holds the hydraulic pressure supplied to the hydraulic brake unit 7 and the hydraulic pressure of the accumulator 11, and when the valve position is at the position C, the hydraulic brake unit 7
Is returned to the reservoir 13. That is, the accumulator output control valve 17 controls the supply of hydraulic pressure to the hydraulic brake unit 7.

The hydraulic brake unit 7 includes a pair of friction members 71 and 72 arranged so as to sandwich the brake disk 22 which rotates integrally with the wheels.
4 is a hydraulic disc brake that generates a braking force by being pressed against the brake disc 22 by a hydraulic piston 75 housed and held in the brake disc 4. The hydraulic pressure accumulated in the accumulator 11 is supplied to the cylinder 74 of the caliper 73 via the accumulator output control valve 17.

The control unit 4 receives various signals such as a steering angle, a brake pedal depression force, a wheel speed and a yaw rate from various sensors and switches (not shown) mounted on the vehicle to detect the rotation state of each wheel and the running state of the vehicle. Then, based on the various signals obtained, by independently controlling the braking energy regeneration units 3 provided for each wheel, in order to optimize the braking torque and the driving torque given to each wheel,
The clutch operation switching valve 25, the pump operation switching valve 15, the direct acting device 16b of the relief valve 16, the direct acting device 18b of the accumulator control valve 18, and the accumulator output control valve 17 of each braking energy regenerating unit 3 are controlled.

More specifically, the control device 4 sets the valve position of the clutch operation switching valve 25 to the position B during braking or starting / acceleration of the vehicle, and sets the hydraulic clutch device 24 to the position B.
The pump shaft 9c of the hydraulic pump motor 9 via the wheel shaft 2
Make it connected to 1. In the case of braking, the first port 9a of the hydraulic pump motor 9 is connected to the reservoir 13 and the second port 9b of the hydraulic pump motor 9 is connected.
Is connected to the accumulator 11 by the oil passage 5b via the pressure control valve 18 so that the pump operation switching valve 15
Is set to the position B, and the hydraulic pump motor 9 is operated as a hydraulic pump. In this case, the driving torque for rotating the hydraulic pump acts as a load on the wheels, and becomes a braking force for reducing the rotation of the wheels.

[0037] Incidentally, on the basis of the target relief pressure P ₀ which is set according to the braking force required, linear motion device 16b of the relief valve 16 and the accumulator control valve 18 controls the 18b, each of these Set an appropriate check pressure to valves 16 and 18. In other words, by controlling the check pressure of the relief valve 16 and the pressure accumulating control valve 18 so that the discharge pressure of the hydraulic pump motor 9 is proportional to the required braking force, the braking force generated by the pressure accumulating operation to the accumulator 11 is reduced. It can be a value proportional to the brake pedal depression force.

Specifically, when the target relief pressure P ₀ is lower than the accumulator pressure, the check pressure of the relief valve 16 is set to the target relief pressure P ₀ . This allows
Normally, since the relief pressure at the relief valve 16 is lower than the sum of the check pressure of the pressure accumulating control valve 18 and the accumulator pressure, the discharge pressure from the hydraulic pump is controlled to the relief pressure and the hydraulic pump is discharged. The operating oil thus returned is returned to the reservoir 13 via the relief valve 16, and the accumulator 11 is disconnected from the discharge port of the hydraulic pump motor 9. Therefore, a desired small braking force can be accurately generated without being affected by the pressure of the accumulator 11, and fine adjustment of the braking force can be easily and reliably performed.

When the accumulator pressure decreases and the liquid pressure in the liquid chamber 31 becomes smaller than the urging force of the spring 29, the check pressure in the relief valve 16 is increased by the check pressure increasing mechanism 20 provided in the relief valve 16. As a result, the check pressure of the relief valve 16 becomes higher than the check pressure of the accumulator control valve 18. Therefore, the pressure-accumulation control valve 18 substantially functions as a relief valve, and the discharge pressure of the hydraulic pump is supplied to the accumulator 11 via the pressure-accumulation control valve 18, and the pressure accumulation in the accumulator 11 starts. The drop of the accumulator pressure is supplemented. Then, when the accumulator pressure returns to the original appropriate pressure,
The operation of increasing the check pressure by the check pressure increasing mechanism 20 of the relief valve 16 is released. That is, even if the accumulator pressure drops, the accumulator pressure is automatically and promptly started by the check pressure increasing mechanism 20 provided in the relief valve 16 to compensate for the accumulator pressure.

When the target relief pressure P ₀ is higher than the current accumulator 11 pressure P _X , the check pressure of the accumulator control valve 18 is controlled to the target relief pressure P ₀ , and the check of the relief valve 16 is performed. The pressure is the target relief pressure P ₀
Is set to an appropriate value higher than that of the pressure accumulating control valve 1.
8 functions as a relief valve 16. With this control, while the desired braking force is generated, the accumulator 11 functions as the reservoir 13, so that the hydraulic pressure output from the hydraulic pump motor 9 is accumulated in the accumulator 11, and a part of the kinetic energy during deceleration ( The amount not consumed as heat) is collected by the accumulator 11 as oil pressure.

Further, if the braking force is insufficient due to the required braking force due to the pump load alone, the control device 4 activates the hydraulic brake unit 7 with the hydraulic pressure accumulated in the accumulator 11. The valve position of the accumulator output control valve 17 is switched to the position A to compensate for the braking force. Further, the control device 4
When the braking force of the hydraulic brake unit 7 is to be maintained, the valve position of the accumulator output control valve 17 is set to the position B. When the brake of the vehicle is released, the control device 4 sets the valve positions of the clutch operation switching valve 25, the pump operation switching valve 15, and the accumulator output control valve 17 to the positions shown in FIG. That is, the valve position of the clutch operation switching valve 25 is set to the position A, the pump shaft 9c of the hydraulic pump motor 9 is disconnected from the wheel shaft 21, and the pump operation switching valve 15
Is set to the position A, the hydraulic pressure of the accumulator 11 is maintained, the check pressure of the relief valve 16 is set to the minimum value (substantially zero), and the valve position of the accumulator output control valve 17 is set to the position A. C is set, and the hydraulic pressure of the hydraulic brake unit 7 is returned to the reservoir 13.

At the time of start / acceleration, the controller 4
Sets the valve position of the pump operation switching valve 15 to the position A, and supplies the hydraulic pressure accumulated in the accumulator 11 to the first port 9 a of the hydraulic pump motor 9. As a result, the hydraulic pump motor 9 operates as a hydraulic motor and transmits driving force to the wheels.

Further, the maximum check pressure of the relief valve 16 is set to be equal to or less than the maximum allowable pressure of the components of the device or the oil passage, thereby preventing damage to the hydraulic equipment and the oil passage due to overload.
When the braking operation or the start / acceleration operation is unnecessary, the control device 4 separates the pump shaft 9c of the hydraulic pump motor 9 from the wheel shaft 21 by the hydraulic clutch device 24, and an extra load acts on the wheel shaft 21. To prevent that.

According to the above-described vehicle braking device 10, when the vehicle is braked or when the vehicle starts / accelerates, the hydraulic clutch device 24 is used.
The pump shaft 9c of the hydraulic pump motor 9 is
1 is maintained. During braking, a signal from a brake pedal depression force sensor (not shown) and a pressure sensor 4 for detecting the discharge pressure of the hydraulic pump motor 9 are provided.
If the check pressure of the relief valve 16 and the accumulator control valve 18 is appropriately controlled so as to obtain a braking force proportional to the brake pedal depressing force by comparing with the signal from the control signal 9, the pump discharge pressure (ie, relief pressure) Can be adjusted to a desired value,
The drive torque of the hydraulic pump (that is, the generated braking force) determined by the pump discharge force can be adjusted to an arbitrary value.

Accordingly, the pump discharge pressure can be arbitrarily set regardless of the accumulated pressure of the accumulator 11, and
Even when gentle braking is required, the accumulator 1
1 makes it possible to perform good braking without causing a Gack'n effect or the like caused by the high pressure acting as a pump load, and to accumulate the pump discharge pressure in the accumulator 11 without using another brake device. The above high pressure can be set, and a large braking force can be generated. Further, even if the accumulator pressure drops, the accumulator 11 starts accumulating the pressure in the accumulator 11 automatically and promptly by the check pressure increasing mechanism 20 provided in the relief valve 16 to compensate for the accumulator pressure. The accumulated pressure amount can be stably maintained. Therefore, when using the accumulator pressure as a drive source,
It is possible to prevent an operation failure or the like due to a decrease in the accumulator pressure, and to stably maintain the accumulated pressure. Therefore, a stable operation as a driving source can be expected even with a small accumulator 11.

Further, when the accumulator pressure becomes insufficient, the hydraulic pump motor 9 is automatically operated by the operation of the hydraulic clutch device 24, and the accumulator pressure can be recovered.

When the required braking force is not sufficient with the braking force by accumulating pressure in the accumulator 11, the hydraulic braking unit 7 is actuated by the hydraulic pressure accumulated in the accumulator 11 to provide the braking force. Therefore, it is possible to obtain a necessary and sufficient braking force.

At the time of starting / acceleration, the accumulator pressure is supplied to the hydraulic pump motor 9, and the pump operation switching valve 15 is controlled so that the hydraulic pump motor 9 operates as a hydraulic motor and transmits a driving force to wheels. . By performing the operation control in this manner, the energy recovered at the time of deceleration of the vehicle can be effectively used for the braking operation and the start / acceleration operation, so that the energy efficiency of the vehicle can be improved.

Further, when the accumulator 11 is operated to accumulate pressure, the check pressure of the relief valve 16 is set to be equal to or less than the maximum allowable pressure of the components of the device and the oil passage, thereby preventing damage to the hydraulic equipment and the oil passage due to overload. Can be prevented.

When the braking operation or the start / acceleration operation is unnecessary, the hydraulic pump motor 9 is operated by the hydraulic clutch device 24.
Pump shaft 9c is separated from the wheel shaft 21 and the wheel shaft 2
1 can be reliably prevented from acting on an extra load. Further, the hydraulic clutch device 24 provided in the vehicle braking device 10 of the present invention is of a type that disconnects the hydraulic pump from the wheel shaft 21 when a hydraulic pressure equal to or higher than the reference value is supplied. A failure that the hydraulic pressure accumulated in the accumulator 11 drops due to non-use or the like, or a hydraulic pressure that exceeds a reference value cannot be supplied to the hydraulic pump due to a leak of hydraulic pressure from an oil passage from the accumulator 11 to the hydraulic clutch device 24. Even if the occurrence of the above-mentioned situation, although the pump shaft 9c of the hydraulic pump motor 9 cannot be separated from the wheel shaft 21, the load on the wheels slightly increases, but there is a small inconvenience, but the braking operation and the acceleration operation for reusing the recovered energy are performed. For example, it can maintain the same performance as before the occurrence of the fault, and has excellent braking performance reliability and safety .

Also, in the vehicle braking device 10 of the present invention,
Each wheel is equipped with a braking energy regeneration unit 3,
Since the control device 4 can control each braking energy regenerating unit 3 independently of each other, energy can be recovered and the recovered energy can be reused for each wheel independently, and an anti-lock brake system and a traction control system can be used. It is easy to realize intelligent brake functions. That is, when the skid of the wheel at the time of braking by the accumulation of pressure is detected, the linear force device 16b is controlled to reduce the check pressure of the relief valve 16 so that the braking force is reduced. By setting the valve position of the accumulator output control valve 17 to the position A, the braking force is reduced and the wheel skid can be eliminated. Further, when the slip of the driving wheel is detected at the time of start / acceleration, each of the valves 15, 16,
By controlling 17, 18, 25 to apply a braking force to the drive wheels,
The slip can be suppressed.

Further, in the case of the vehicular braking system 10 of the present invention, the hydraulic brake unit 7 of the braking means is operated by the hydraulic pressure accumulated in the accumulator 11 when the vehicle is decelerated. Are not used, and electric energy is supplied to each valve 15, 16, 1
Since only the amount used for the operation control of 7, 18, and 25 is sufficient, it is also possible to suppress an increase in consumption of electric energy in the vehicle due to the electric control of the brake device.

The hydraulic pressure accumulated in the accumulator 11 during the braking operation is used not only as a drive source for the hydraulic brake unit 7 described above or as a drive source for operating the hydraulic pump motor 9 as a hydraulic motor, but also as a hydraulic source. The pump shaft 9c of the pump motor 9 is also used as a drive source of a hydraulic clutch device 24 that is engaged with and disengaged from the wheel shaft 21, and a dedicated drive source for operating the clutch is not required, thereby increasing the number of components. In addition, the size and cost of the device can be reduced.

The above description of the operation of the pump operation switching valve 15 at each of the valve positions A and B is for when the vehicle is moving forward, and when the vehicle is moving backward, the position B is the braking of the accumulated pressure, and the position A is for braking. It becomes driving force assistance.

FIG. 3 shows a second embodiment of the vehicular braking system according to the present invention. The vehicle braking device 40 according to the second embodiment includes the vehicle braking device 1 according to the first embodiment.
0, the hydraulic brake unit 7 and the accumulator output control valve 17 are omitted.
It is the same as the vehicle braking device 10 of the embodiment. This second
The vehicle braking device 40 according to the embodiment includes a hydraulic pump motor 9.
The hydraulic brake unit 7 and the accumulator output control valve 17 are omitted because the necessary and sufficient braking force can be ensured only by the pump load by the pump, and the simplification and downsizing of the braking device is achieved by omitting these components. In addition, cost can be reduced.

FIG. 4 shows a third embodiment of the vehicle brake system according to the present invention. The vehicle braking device 41 of the third embodiment is different from the vehicle braking device 1 of the first embodiment.
At 0, the relief valve 16 and the clutch operation switching valve 25 are each replaced with a relief valve 43 and a clutch operation switching valve 44 by adding manual operation mechanisms 45 and 46 for manually switching operation states.

The relief valve 43 is obtained by adding a manual operation mechanism 45 to the relief valve 16 used in the first embodiment. The relief valve 43 is in a state where the power switch of the vehicle is turned off while the vehicle is parked, or a failure of the electric system. Therefore, even when the control device 4 does not operate, the check pressure can be set to an arbitrary value by manually operating the manual operation mechanism 45. Further, the clutch operation switching valve 44 is obtained by adding a manual operation mechanism 46 to the clutch operation switching valve 25 used in the first embodiment, and is in a state where the vehicle is parked and the power switch of the vehicle is turned off, or Even when the control device 4 does not operate due to the failure of the electric system, the manual operation mechanism 46 can be operated.
Can be manually operated to switch the operating state of the hydraulic clutch device 24.

As described above, the relief valve 43 and the clutch operation switching valve 44 whose operations are controlled by the controller 4
With a configuration in which the manual operation mechanisms 45 and 46 for switching the operation state are provided, even when the control device 4 is turned off and the vehicle is parked or the electric system fails, these valves are manually operated to regenerate the braking energy. The unit 3 can be set to the braking state, and the braking energy regeneration unit 3 can be used for a parking brake or the like.

FIG. 5 shows a fourth embodiment of the vehicle brake system according to the present invention. The vehicle braking device 47 of the fourth embodiment is different from the vehicle braking device 4 of the second embodiment.
At 0, the relief valve 16 and the clutch operation switching valve 25 are replaced with a relief valve 43 and a clutch operation switching valve 44 to which manual operation mechanisms 45 and 46 for manually switching operation states are added, respectively. As in the case of the third embodiment, the braking energy regeneration unit 3
Can be utilized for parking brakes and the like.

In the present invention, the specific configuration of each component is not limited to the above embodiment, and it goes without saying that the shape and the like can be changed in design without departing from the spirit of the present invention.

[0061]

According to the vehicular braking apparatus of the present invention, when braking the vehicle, the first port of the hydraulic pump motor is connected to the accumulator and the second port of the hydraulic pump motor is connected.
The pump operation switching valve is controlled so that the port is connected to the reservoir, and the hydraulic pump motor is operated as a hydraulic pump. In this case, the driving torque for rotating the hydraulic pump acts as a load on the wheels, and becomes a braking force for reducing the rotation of the wheels.

[0062] Then, in operating a hydraulic pump motor as a hydraulic pump, based on the target relief pressure P ₀ which is set according to the braking force required, the check pressure of the relief valve and the accumulator control valve Control. That is, when the target relief pressure P ₀ is lower than the hydraulic pressure stored in the accumulator (hereinafter, referred to as the accumulator pressure), the check pressure of the relief valve is set to the target relief pressure P ₀ . With this control, the hydraulic pressure exceeding the target relief pressure escapes from the relief valve to the reservoir, so that the desired small braking force can be accurately generated without being affected by the accumulator pressure, and the braking force can be finely adjusted. Adjustment and the like can be performed easily and reliably.

If the target relief pressure P ₀ is higher than the current accumulator pressure P _X , the check pressure of the accumulator control valve is controlled to the target relief pressure P ₀ , and the check pressure of the relief valve is set to the target pressure. set to a higher appropriate value than the relief pressure P _0, in effect to function accumulator control valve as a relief valve. With this control, while the desired braking force is generated, the accumulator functions as a reservoir. Therefore, the hydraulic pressure output from the hydraulic pump motor is accumulated in the accumulator, and a part of the kinetic energy during deceleration (consumed as heat). Is collected by the accumulator as hydraulic pressure.

As described above, if the check pressure of the relief valve or the pressure accumulating control valve is properly controlled, the pump discharge pressure (ie, relief pressure) can be adjusted to an arbitrary value, and is determined by the pump discharge force. The driving torque of the hydraulic pump (that is, the generated braking force) can be adjusted to an arbitrary value. Therefore, the pump discharge pressure can be arbitrarily set regardless of the accumulated pressure of the accumulator, and it is possible to perform good braking without causing gakkun effect, and without using another brake device together. In both cases, the pump discharge pressure can be set to a high pressure equal to or higher than the accumulated pressure of the accumulator, and a large braking force can be generated.

At the time of start / acceleration, the accumulator pressure is supplied to the hydraulic pump motor, and the pump operation switching valve is controlled so that the hydraulic pump motor operates as a hydraulic motor and transmits driving force to wheels. By performing the operation control in this manner, the energy recovered at the time of deceleration of the vehicle can be effectively used for the braking operation and the start / acceleration operation, so that the energy efficiency of the vehicle can be improved.

Further, by setting the check pressure of the relief valve to be equal to or less than the maximum allowable pressure of the components of the apparatus or the oil passage, it is possible to prevent the hydraulic equipment and the oil passage from being damaged due to an overload.

The vehicle braking device of the present invention is provided with a braking energy regenerating unit for each wheel, and can be provided for each wheel. Therefore, if a braking energy regeneration unit is provided for each wheel, and the control device is configured to control the pressure accumulating control valve, the pump operation switching valve, the relief valve, and the like according to the rotation of the wheels or the state of the vehicle, Since the energy can be recovered and the recovered energy can be reused independently for each wheel, it is easy to realize intelligent brake functions such as an anti-lock brake system and a traction control system.

If the relief valve is provided with a check pressure increasing mechanism for receiving the hydraulic pressure accumulated in the accumulator and increasing the check pressure of the relief valve when the hydraulic pressure falls below the reference pressure, for example, If the target relief pressure P ₀ in order to obtain a braking force lower than the accumulator pressure, the target relief pressure P check pressure of the relief valve
₀ at the same time controlling the sets the check pressure in the accumulator control valve to a slightly larger value than the target relief pressure P _0. As a result, normally, the relief pressure at the relief valve is lower than the check pressure of the pressure accumulating control valve, so that the discharge pressure from the hydraulic pump is controlled to the relief pressure, and the hydraulic oil discharged from the hydraulic pump is relieved. Returned to reservoir via valve. However, when the accumulator pressure decreases during operation and the accumulator pressure becomes smaller than the target relief pressure P ₀ , the check pressure in the relief valve is increased by the check pressure increasing mechanism provided in the relief valve, and as a result, The check pressure of the relief valve becomes higher than the check pressure of the accumulator control valve.

For this reason, the discharge pressure of the hydraulic pump is supplied to the accumulator via the accumulator control valve, and the accumulator starts accumulating pressure, and the accumulator pressure is reduced. Since the accumulator pressure and returns to the original proper pressure, the boost operation of the check pressure by checking pressure boosting mechanism of the relief valve is released, the check pressure of the relief valve is returned to the original target relief pressure P _0, The working fluid discharged from the hydraulic pump returns to the operation state in which the working fluid flows to the reservoir via the relief valve again. That is, even if the accumulator pressure drops, the accumulator pressure is automatically and quickly started by the check pressure boosting mechanism provided in the relief valve, and the accumulator pressure is compensated.
The accumulated pressure of the accumulator can be stably maintained.
Therefore, when the accumulator pressure is used as a drive source, it is possible to prevent an operation failure or the like due to a decrease in the accumulator pressure, and to stably maintain the accumulated pressure, so that even a small accumulator is stable as a drive source. Operation can be expected.

Further, if each valve controlled by the control device is provided with a manual operation mechanism for switching the operation state, even when the control device is turned off, the vehicle is parked or the electric system is lost. The braking energy regeneration unit can be set to the braking state by manually operating the pump operation switching valve and the pressure accumulation control valve, and the braking energy regeneration unit can be used for a parking brake or the like.

Further, in the case of the vehicle brake system of the present invention, an electric motor or the like which consumes a large amount of electric energy is not used as a drive source, and the electric energy is stored in the pressure control valve, the pump operation switching valve, and the relief valve. Since it is only necessary to use it for the operation control of the valve and the like, it is also possible to suppress an increase in consumption of electric energy in the vehicle by the electric control of the brake device.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of a vehicular braking device according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a hydraulic clutch and a hydraulic pump motor used in the vehicle braking device of FIG.

FIG. 3 is a block diagram showing a configuration of a second embodiment of the vehicular braking device according to the present invention.

FIG. 4 is a block diagram showing a configuration of a third embodiment of the vehicle braking device according to the present invention.

FIG. 5 is a block diagram showing a configuration of a fourth embodiment of the vehicle braking device according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 3 braking energy regeneration unit 4 control device 7 hydraulic brake unit 9 hydraulic pump motor 10 vehicle braking device 11 accumulator 13 reservoir 15 pump operation switching valve 16 relief valve 17 accumulator output control valve 18 pressure accumulation control valve 21 wheel shaft 22 brake disk Reference Signs List 24 Hydraulic clutch 25 Clutch operation switching valve 40, 41, 47 Vehicle braking device 43 Relief valve 44 Clutch operation switching valve

Claims (3)

[Claims] When the first port is connected to a reservoir and the second port is connected to an accumulator by switching of an operation switching valve, the first port is connected to a wheel rotating shaft, and the first port is connected to an accumulator. A vehicular braking system comprising: a hydraulic pump motor that functions as a hydraulic pump, the first port functions as a hydraulic motor when the first port is connected to an accumulator, and the second port is connected to a reservoir, wherein the second port and the reservoir A relief valve having a variable check pressure is provided in an oil passage between the vehicle and the vehicle. 2. The vehicular braking device according to claim 1, wherein the wheel rotation shaft and the hydraulic pump motor are connected via a clutch device, and the clutch device is controlled by an accumulator pressure. 3. Each of the valves whose operation is controlled by the control device,
3. The vehicle braking device according to claim 1, further comprising a manual operation mechanism for switching an operation state.