JPS6334274A - Brake control device for self-traveling vehicle - Google Patents

Abstract

PURPOSE:To facilitate the operation of a vehicle by carrying out the control of the prevention of slip at the time of starting, the prevention of the locking of wheels at the time of reducing speed and stopping a vehicle, the prevention of slipping down at the time of starting on a slope, etc. collectively and consistently. CONSTITUTION:A brake device feeds the hydraulic pressure in a master cylinder 6 which is generated by stepping in a brake pedal 5, to wheel cylinders 3 via a push-in valve 7 and a gate valve 8, and through a group of feed and discharge valves M consisting of a hold valve 9 and a decay valve 10. The hydraulic pressure is also fed to the wheel cylinders 4 of driven wheels 2 via a proportioning valve 11 and a shut off valve 12. And, the push-in valve 7, hold valve 9, decay valve 10, and shut off valve 12 are controlled by the command of a control means 16, and the port 7b of the push-in valve 7 is faced to the master cylinder 6 when not being electrified, while the hold valve 9 is in an open position when not being electrified.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a brake control device for a self-propelled vehicle, which maintains brake pressure during stopping, eliminates drive wheel slip when starting and when braking. The present invention is intended to perform brake control that is effective in preventing wheel locking of vehicles, and can be applied to automobiles, tractors, etc.

(Prior art) Various methods have been proposed for containment control of wheel cylinder hydraulic pressure to maintain braking force while the vehicle is stopped, anti-slip control at the initial stage of starting, and anti-locking control during braking. ing.

However, there is no suitable brake control that can consistently and comprehensively perform start control and travel control even when the vehicle is stopped.

(Problems to be Solved by the Invention) This invention is devised to suitably perform a series of controls for maintaining braking force while stopped, eliminating slippage when starting, and preventing wheel locking during braking. Its configuration is that the hydraulic pressure of the pump 14 is supplied to the supply/discharge valve group M for supplying and discharging hydraulic pressure to and from the wheel cylinders 3 and 4, and the master/cylinder 6 is The additional hydraulic pressure can be supplied to the supply/discharge valve group M, and the additional hydraulic pressure can be supplied to the supply/discharge valve group M.The additional hydraulic pressure can be supplied to the supply/discharge valve group M.The additional hydraulic pressure is added to the additional hydraulic pressure valve 7, which is equipped with a 4-door a, and the shutoff valve 12, which supplies and cuts off hydraulic pressure to the trailing wheel wheel cylinder, is connected to the driving wheel cylinder. 1. A plurality of rotation sensors S, , S2 detecting the rotation speed of the driven wheel 2, and a plurality of rotation sensors S, , S,
Based on the output of During the stop, the deceleration state setting means 20 that sets the threshold value controls the supply valve 7 to the supplement port 7a and the cutoff valve 12 to the supplement port 7a, and the wheel cylinder 3.4 is controlled by the actual starting operation. The supply/discharge valve group M is controlled to discharge the hydraulic pressure of After the slip is eliminated, the supply/discharge valve group M is controlled to close the supply/discharge valve group M, and after the slip is eliminated, the additional valve 7 is opened at port 7b, the cutoff valve 12 is controlled at supply port 12a, and the deceleration state threshold of the deceleration state setting means 20 is set. This is a brake control device for a self-propelled vehicle, comprising a control means 16 configured to control a supply/discharge valve group M based on a comparison between a value and a wheel speed.

(Function) When the vehicle is stopped, the hydraulic pressure in the wheel cylinders 3 and 4 is maintained by the pressure increase port 7a of the pressure increase valve 7, which prevents the vehicle from sliding down the slope. The hydraulic pressure is discharged to the reservoir 1:3 by the discharge operation of the supply/discharge valve group M, and the brake is loosened, and the oil returned to the reservoir 13 is used as the hydraulic pressure source for the pump f14 in the slip-on prevention control at the time of starting. After the acceleration slip of the drive wheels is detected immediately after starting,
The shutoff valve 12 is closed and the brake is not applied to the driven wheel 2, and the supply/discharge valve group M is connected to the wheel cylinder 3 of the driving wheel 1.
The hydraulic pressure caused by the operation of the switch acts to quickly release the IJ knob.

When the brake pedal 5 is operated while driving, the detected deceleration state is controlled based on the deceleration state threshold and the supply/discharge valve group M is operated, preventing wheel locking and efficiently decelerating. and stop control will be performed, and in the driving wheel slip prevention control and wheel lock prevention control by the operation of the supply/discharge valve group M, the gate valve 8 is shut off, and the gate valve 8 is shut off. -), the shock feeling of the fluid pressure fluctuation accompanying the supply/discharge operation of the supply/discharge valve group M is not transmitted to the brake pedal 5, so that the operation feeling does not deteriorate.

(Example) Next, embodiments of the present invention will be described based on the drawings.

Fig. 2 shows a circuit diagram of a brake control device applied to an automobile as an example of a self-propelled vehicle, and Fig. 1 shows its control block diagram. Respective wheel cylinders 3, 3 and 4, 4 of rear driven wheels 2, 2
The hydraulic pressure of the brake system acts on this. The brake device supplies the hydraulic pressure of the master cylinder 6 generated by pressing the brake pedal 5 to a supply/discharge valve consisting of a hold valve 9 and a decay valve 10 via an increase valve 7 and an opened gate valve 8. It is supplied to the wheel cylinders 3° 3 through the group M, and to the wheel cylinders 4 and 4 of the driven shafts 2 and 2 via the zero positioning valve 11 and the cutoff valve 12, and is discharged from the decay valve 10 to the reservoir 13. The hydraulic pressure is supplied from the pump 14 to the Aquino regulator 15, respectively.

In the gate valve 8, a piston 8a moves upward by the hydraulic pressure of the accumulator 15 and hits a valve seat 8b, thereby cutting off the supply of hydraulic pressure from the replenishment valve 7 to the hold valve 9. The replenishment valve 7, the hold valve 9, the decay valve 10, and the cutoff valve 12 are all electromagnetic valve types that are controlled based on commands from a control means 16, which will be described later. In the refill valve 7, the refill port 7a opens into the master cylinder 6 when the power is not energized, and the open port 7b opens into the master cylinder 6 when the power is energized. The hold valve 9 is in an open position when not energized and is in a closed position when energized. The decay valve 10 closes when not energized and opens when energized. Shutoff valve 12
is controlled by the supply port 12a when the power is not energized, and is cut off and ff-) 12b when the power is energized.

The rotational speeds of the driving wheels 1, 1 and the driven wheels 2, 2 are detected by the rotation sensors Sl, Sz, and the slip of the driving wheel 1 at the time of starting is determined based on, for example, the output of the rotation sensor S2 of the driven wheel 2. Calculated by Surinozo detection means 17.

In order to detect whether or not each wheel 1, 2 is locked during braking, the degree of wheel lock is calculated by the deceleration state detection means 18 based on the rotational speed of each wheel 1, 20.

The slip rate in the vicinity where the adhesion coefficient between the tire and the road surface is maximum is set in advance by the slip setting means 19, and
As a desirable deceleration state of the wheels 1.2 during braking, for example, the deceleration rate of the wheels in a state where wheel lock does not occur during braking is set by the deceleration state setting means 20. For example, the deceleration rate close to the limit at which wheel lock occurs is set as the deceleration warning horn 3 threshold, and the deceleration rate at which there is no problem even if the braking force is further increased is set as the deceleration warning horn 1 threshold.
The deceleration state setting means 20 sets a deceleration rate which is between these threshold values and when it is desirable not to increase or decrease the braking force as the deceleration horn 2 threshold value.

The slip setting means 19, the slip detection means 17, the deceleration state detection means 18, the deceleration state verification means 20, and the control means 16 are constituted by, for example, a microcontroller, and each of these detection means and setting means Based on the output, a control command is output from the control means 16 to the aforementioned joint venture.

Next, an example of control will be explained based on the control characteristic diagram shown in FIG.

When the vehicle is traveling at the current rotational speed, when the brake pedal 5 is depressed to stop the vehicle, wheel lock prevention control (a), as shown in the left part of FIG. 3, is performed.

That is, as the hydraulic pressure of the master cylinder 6 increases, the rotational speed begins to decrease and the deceleration state reaches the deceleration horn 2 threshold value (point A), the hold valve 9 is closed by a command from the control means 16. The hydraulic pressure in wheel cylinders 3 and 4 is held (point A), and when the deceleration warning horn 3 threshold is reached due to brake lock starting to appear (point B).
, the decay valve 10 opens and the hydraulic pressure in the wheel cylinders 3 and 4 is discharged to the reservoir 13, the brake force decreases, and the pump 14 starts operating, so the hydraulic pressure difference between the hold valve 9 side and the pump 14 side causes The gate valve 8 is closed (point b).

By loosening the brake mentioned above, the wheel lock begins to be released,
When the rotational speed tends to rise slightly (point 6), the decay valve 10 closes and the hydraulic pressure in the wheel cylinder 3.4 is held (point 6).

When the wheels are no longer locked (point D), hold valve 9 opens and the hydraulic pressure in the accumulator increases to valve 8c.
is transmitted to the wheel/linders 3 and 4 via the hold valve 9.
repeats opening and closing several times, and the rotational speed begins to decrease again, and when the deceleration warning horn 2 threshold is reached (point E), the hold valve 9 closes, and the control from points A to D described above is repeated. The vehicle comes to a stop while preventing the occurrence of wheel lock (point F).

At this time, the control means 16 outputs a command so that the additional port 7a enters the master/linda 6, the pump 14 is stopped, the gate valve 8 is opened, and the decay valve 10 is closed (+ point). Therefore, the hydraulic pressure of wheels/cylinders 3 and 4 is
The brake is held in a state where it can be increased by operating the brake lever 5, and containment control (b) is performed.

In this stopped state, the accelerator pedal is depressed or
Clutch connection operation is detected by a start operation detection means S3 such as a microswitch, and after this detection operation (0 point), slip prevention control (c) is performed, and the decay valve 10 is opened. The opening operation continues for a time T1 sufficient for all the hydraulic pressure in the wheel cylinders 3 and 4 to be discharged (point i), the -F fertilizer solution is stored in the reservoir 13, and the replenishment valve 7 is opened. When the rotational speed of the driving middle wheel ■D rises and the slip of the driving wheel 1 reaches the first threshold value (for example, determined based on the rotational speed of the driven wheel 20■T) (point H), the cutoff occurs. The valve 12 is closed, the replenishment valve 7 is switched to port 7a, the pump 14 starts operating, and the port tP8 is closed, so the hydraulic pressure in the wheel/cylinder 3 of the drive wheel 1 increases. ,
The wheel/cylinder 4 of the driven wheel 2 is not supplied with hydraulic pressure.

Rotation speed■. continues to rise for a while, but when it reaches the peak value (second threshold when considered as acceleration O) (point 1), hold valve 9 closes and the hydraulic pressure is maintained (point X), and the slip is eliminated. It gradually decreases and the rotational speed vD also decreases.

When the rotational speed vD decreases with slip and reaches the first threshold value again (5 points), the decay valve 9 repeats the opening and closing operation and the hydraulic pressure gradually decreases.

When the rotation speed vD reaches the lowest value (third threshold value) (point K), the decay valve 9 remains closed and the hydraulic pressure is maintained (point k), and the rotation speed VD starts to rise again, and the When the threshold value of 1 is reached, the same control as in the case between points H and above is repeated.

When the slip luff 0 rate becomes sufficiently small and the hold valve 9 becomes closed for more than the predetermined time T2, the wheel slip prevention control (c) at the time of starting is completed, and both the refill valve 7 and the hold valve 9 are closed. Open, Decay valve 10 closes, Inf1
4 is rotated for a certain period of time, the hydraulic pressure is returned to the master cylinder 6 from the booster valve 7 by opening the valve portion 8c of the gate valve 8, and at the same time, the shutoff valve 12 is opened.

”-A flowchart of reporter control is shown in FIG.

In another example, half of the brake control system is shown in FIG.
3 is equipped with a switching valve 17 that can directly discharge the air, and when wheel lock due to braking occurs on the rear wheel, which is the driven wheel 2, before the front wheel, which is the driving wheel 1 (6th
Since the exhaust port 17a of the switching valve 17 communicates between the rear wheel/cylinder 4 and the reservoir 13, the hydraulic pressure P2 of the wheel/cylinder 4 rapidly decreases between points n and p. ), when the lock of the rear wheels is released immediately (point P), the switching valve 17 is controlled by the communication port ( ) 17b to maintain the hydraulic pressure, and in this way, the rear wheels are When the wheels lock, the hydraulic pressure of the rear wheel/sudder 4 is quickly discharged directly from the switching valve 17 to the reservoir I3, quickly resolving the rear wheel lock.

The control in the embodiment shown in FIG. 5 is obtained by adding the flowchart shown in FIG. 7 to the nol coachyard shown in FIG.

In addition to the above-mentioned types and numbers of threshold values in the wheel lock prevention control and the wheel slip prevention control at the time of starting, various threshold values may be used.

(Effects of the Invention) The brake control device for a self-propelled vehicle according to the present invention is configured as described above, and when the vehicle is stopped, the hydraulic pressure of the wheels/cylinders 3 and 4 is increased and the hydraulic pressure of the valve 7 is increased. Port 7a
This prevents the vehicle from sliding down the slope, and when starting the vehicle, the wheel/cylinder 3
, 4 is discharged from the reservoir 1 by the discharge operation of the supply/discharge valve group M.
3, the brake loosens, and the reservoir 1
The oil returned to No. 3 can be used as a hydraulic pressure source for the pump 14 in the next slip prevention control, and after a slip is detected immediately after starting, the shutoff valve 12 is closed and the brake is applied to the driven wheel 2. Without a doubt, the hydraulic pressure due to the operation of the supply/discharge valve group M acts on the wheel cylinder 3 of the driving wheel 1, and the slip is quickly eliminated.

When the brake pedal 5 is operated while driving, the detected deceleration state is controlled based on the deceleration state threshold and the supply/discharge valve group M is operated, thereby preventing wheel locking and efficiently. Deceleration and stop control will be performed, and in the slip prevention control and wheel lock prevention control by the operation of the supply/discharge valve group M, since the dirt valve 8 is controlled to the cutoff port, the supply of the supply/discharge valve group M is The shock feeling caused by the fluid pressure fluctuation accompanying the evacuation operation is no longer transmitted to the brake pedal 5, and the operability is improved. As mentioned above,
Slip prevention control when the vehicle starts, wheel lock prevention control when the vehicle decelerates and stops, and slip-off prevention control during stopping and starting operations are now performed as a series of operations.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which Fig. 1 is a control block diagram, Fig. 2 is a schematic diagram of the control device, Fig. 3 is a control characteristic diagram, Fig. 4 is a control flowchart, and Fig. 5 is a control block diagram of another embodiment. FIG. 6 is a schematic diagram of the main parts of the control device, FIG. 6 is a main part control characteristic diagram in another embodiment, and FIG. 7 is a main part control flowchart. ■...driving wheel, 2...driven wheel, 3, 4 middle boil cylinder, 6...master cylinder, 7...additional valve,
7a...Additional port, 7b...Open port, 8
...Kate valve, 12...Shutoff valve, 16...Control means, 17.Slip lag detection means, 18.Deceleration state detection means, 19.Slip setting means, 2o.Deceleration Condition setting means, M... supply/discharge valve group, S,, S2... rotation sensor. Patent applicant: Akebono Brake Industry Co., Ltd. Representative
Masanobu Ichiki 1,) Open Uffi63
-34274 (9) Figure 6

Claims (1)

[Claims] A supply/discharge valve group that supplies and discharges hydraulic pressure to and from the wheel cylinders, and an increaser that supplies hydraulic pressure from the pump to the supply/discharge valve group, and can increase the master cylinder's hydraulic pressure to the supply/discharge valve group. A replenishment valve with a refill port, a cutoff valve that supplies and shuts off hydraulic pressure to the trailing wheel cylinder, a driving wheel,
A plurality of rotation sensors that detect rotational speeds of driven wheels, a slip detection means that detects drive wheel slip based on the outputs of these plurality of rotation sensors, a deceleration state detection means that detects a deceleration state of the wheels, and a slip threshold. a slip setting means for setting a deceleration state threshold during braking, a deceleration state setting means for setting a deceleration state threshold during braking, and a control valve for controlling the replenishment valve to the replenishment port and the cutoff valve to the supply port when the brake is stopped, so as to effectively start the vehicle. In addition to controlling the supply/discharge valve group to discharge the hydraulic pressure of the wheel cylinder to the reservoir by operation, after detecting a slip immediately after starting, the shutoff valve is controlled to the shutoff port, and the slip threshold value of the slip setting means is controlled. The supply/discharge valve group is controlled to bring the speed closer, and after the slip is eliminated, the additional valve is opened to the port, the cutoff valve is controlled to the supply port, and the deceleration state threshold of the deceleration state setting means is compared with the wheel speed. A brake control device for a self-propelled vehicle, comprising a control means configured to control a supply/discharge valve group.