JPH01178061A - Brake hydraulic pressure controller for vehicle - Google Patents

Abstract

PURPOSE:To improve the turning faculty by lowering the brake hydraulic pressure of the wheel on the turning center inner side when the detection value of a means for detecting the turning brake operation for a car body exceeds a prescribed value and also lowering the brake hydraulic pressure of the wheel on the outer side when the detection value exceeds the prescribed value succeedingly. CONSTITUTION:The pressure reducing solenoid valves 21-24 are interposed in the pipes 17-20 branched form the brake pipes 5-8 for introducing each brake hydraulic pressure supplied from a master cylinder 2 into the wheel cylinder 9a-12a for the wheels, and these solenoid valves are controlled by a controller 40, and a lateral accelerating speed sensor 30 for detecting the accelerating speed in the lateral direction which is applied onto a car body during value, the brake hydraulic pressure of the wheel on the turning center inside is lowered, and when the above-described detection value exceeds the prescribed value again after decompression, the pressure decreasing solenoid valves 21-24 are controlled so that the brake hydraulic pressure for the wheel on the tuning center outer side is lowered.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention maintains good turning performance by increasing or decreasing the pressure of brake fluid supplied to left and right wheels when braking a vehicle while it is turning. The present invention relates to a vehicle brake fluid pressure control device.

2. Description of the Related Art Generally, when a vehicle is braking while turning, the braking force tends to cause the vehicle to oversteer and spin. Therefore, a so-called anti-skid control device is used to apply the optimum braking force without locking the wheels. As is known, this type of control device increases the frictional force between the tires and the road surface by reducing the braking force of the wheels on the inside of the turning center during normal braking, and prevents the vehicle from oversteering. There are common ways to prevent this from happening.

As an example of the above means, for example, Japanese Patent Application Laid-Open No. 57-1441
In Publication No. 58, in the middle part of the brake pipe disposed between the mask cylinder and the rear wheels, the rate of increase in braking fluid pressure for the rear wheels on the inside side of the turning center is determined by the braking fluid pressure increase rate for the rear wheels on the outside of the turning center. A left and right hydraulic pressure control device is provided so that the rate of increase in hydraulic pressure is lower than the rate of increase in hydraulic pressure, and the left and right hydraulic pressure control device is operated based on the action of a detection mechanism that detects lateral acceleration applied to the vehicle body. An example of a configuration is disclosed in which a difference is created between the brake fluid pressures of the left and right wheels of the vehicle.

Furthermore, a separate anti-skid solenoid valve is provided, and by opening and closing the solenoid valve using the movement of the suspension arm during turning, etc., the brake fluid pressure applied to the wheels is appropriately controlled, and the brake fluid pressure applied to the wheels is controlled appropriately. Examples of devices designed to prevent spin are also known.

Problems to be Solved by the Invention However, in such conventional brake fluid pressure control bag devices, particularly in the example of the device described in Japanese Patent Application Laid-Open No. 57-144158, the mechanism for detecting lateral acceleration applied to the vehicle is insufficient. Because it is necessary to create a difference in the brake fluid pressure supplied to the left and right rear wheels based on the action, a left and right fluid pressure control device with a complicated valve device is required, which is difficult to manufacture. This has the disadvantage that it leads to an increase in costs. Furthermore, when the valve body is seated, the brake fluid passage on the inner side of the turning center is completely closed, resulting in a one-sided braking condition and deterioration of turning performance.

In addition, in the case where a separate solenoid valve for anti-skibutting is provided to control the hydraulic pressure applied to the wheels, the solenoid valve must be constantly operated by duty control, so the frequency of on/off operation of the solenoid valve becomes extremely high. It has the disadvantage of reduced durability.

Furthermore, in the case of the above-mentioned brake fluid pressure control device, when the steering wheel is returned to its original position while the vehicle is turning or after a turn with the brake pedal depressed, the braking force on the vehicle body increases, while the brake fluid in the wheels on the outside of the center of the turn increases. Since the pressure remains higher than the brake fluid pressure on the inner side of the turning center, the braking force on the wheels on the outer side of the turning center is greater than the braking force on the wheels on the inner side of the turning center. However, there is a problem in that a so-called drift-out phenomenon in which the vehicle body is swept away laterally may occur.

Therefore, the present invention solves the problems of the conventional vehicle brake fluid pressure control device, simplifies the overall configuration, and reliably controls the supply of brake fluid to the left and right wheels. It is an object of the present invention to provide a brake fluid pressure control device that can maintain good turning performance, eliminate drift-out phenomenon during braking, and increase the durability of the device itself.

Means for Solving the Problems In order to achieve the above object, the present invention provides a vehicle brake fluid pressure control device that independently controls the brake fluid pressure applied to the wheels. swing braking detection means for detecting swing braking, and deceleration detection means for detecting deceleration during braking; The control valve is equipped with a control valve that opens and closes based on the brake fluid supplied to each wheel cylinder of the front and rear wheels, and when the output of the turning braking detection means exceeds a predetermined value The brake fluid pressure of the wheels on the inner side of the center is reduced, and if the output of the deceleration detection means exceeds a predetermined value after the pressure reduction, the brake fluid pressure of the front wheels or rear wheels on the outer side of the turning center is reduced. The structure is equipped with a controller that reduces the pressure.

According to this configuration, when the vehicle starts turning in either the left or right direction, the turning braking detection means provided at an arbitrary position on the vehicle body detects, for example, lateral acceleration or wheel load applied to the vehicle body. Transmit the lever output to the controller. When the output of the swing braking detection means exceeds a predetermined value, the controller receives the output of the swing braking detection means and issues a signal to shut off the solenoid valve for increasing the pressure of the wheel on the inner side of the turning center. A signal is issued to cause the solenoid valve for pressure reduction in the wheels to flow for a certain period of time, causing a certain amount of brake fluid in the brake pipe to flow out into the reservoir tank. As a result, the brake fluid pressure of the wheels on the inner side of the turning center decreases, so the braking force applied to the vehicle body decreases, and the lateral force of the vehicle body, particularly the rear wheels, increases by a predetermined amount. At this time, the brake fluid pressure of the wheels on the outer side of the turning center is maintained. Therefore, a moment is generated around the center of gravity O of the vehicle body in the opposite direction to the moment that causes the vehicle body to spin, thereby reducing the moment that causes spin due to braking. Next, when the vehicle body finishes turning and moves straight ahead with the brake pedal depressed, the braking force applied to the vehicle body increases, but the deceleration detection means senses that this braking force has changed, When the output of the deceleration detection means becomes larger than a predetermined value set in advance, the controller receives the output of the deceleration detection means, and
A signal is issued to shut off the pressure increase solenoid valve of the front wheel or rear wheel on the outside of the turning center, and a signal is issued that causes the pressure decrease solenoid valve of the same wheel to flow for a certain period of time, thereby reducing the amount of brake fluid in the brake pipe. leaks into the reservoir tank. As a result, the brake fluid pressure of the wheels on the outside of the turning center is reduced to the same fluid pressure as the brake fluid pressure on the inside of the turning center, making the brake fluid pressure of both left and right wheels the same, which improves the straight-line performance of the vehicle. The drift-out phenomenon of the vehicle body is prevented.

Embodiment Hereinafter, one embodiment of the vehicle brake fluid pressure control device according to the present invention will be described in detail with reference to the drawings.゛ Fig. 1 is a schematic diagram showing the present invention as a whole, and in the same figure, 1 is a brake pedal, 2 is a mask cylinder linked to the brake pedal l, and the brake fluid 4 in the reservoir tank 3 is
from the rear wheel liquid chamber 2a and the front wheel liquid chamber 2b in the mask cylinder 2 via brake pipes 5, 6, 7.8, respectively, to the right rear wheel 9. Left rear wheel 10. Right front wheel 11. It is designed to be supplied to each wheel cylinder 9a, lOa, 11a, 12a of the left front wheel 12. Each brake pipe above 5, 6,
7. In the middle of 8, there are solenoid valves 13, 14, 15 for pressure increase.
．． 16, and each brake pipe 5, 6
, pipes 17.18, 19.20 branched from 7.8
Solenoid valves 21, 22, 23, 24 for pressure reduction are installed in the middle part, and the solenoid valves 21, 22, 23.24 for pressure reduction are equipped.
The other end of 4 is connected to the reservoir tank 3. The solenoid valves 13, 14, 15, and 16 for pressure increase are normally located at positions that allow the brake fluid 4 from the mask cylinder 2 to flow to all of the wheels as shown in the figure.
, 15.16 solenoids 13a, 14a, 15a, 1
When the solenoid valve 6a is energized, the solenoid valves 13, 14, 15, and 16 are switched to the left side, thereby blocking the flow of the brake fluid 4. On the other hand, the pressure reducing solenoid valves 21, 22, 23, and 24 are normally in positions that block the brake fluid 4 from the mask cylinder 2 as shown in the figure, and the solenoid valves 2! , 22.23.24, when the solenoids 21a, 22a, 23a, 24a of the solenoid valves 21, 22.23.
24 is switched to the left side to allow the brake fluid 4 to flow toward the reservoir tank 3 side.

Reference numeral 30 denotes a lateral acceleration sensor as turning braking detection means provided at an arbitrary position on the vehicle body, and this lateral acceleration sensor 30 detects the magnitude of lateral acceleration applied to the vehicle body when the vehicle turns.

Reference numeral 31 denotes a deceleration sensor as a deceleration detection means that is similarly provided at an arbitrary position on the vehicle body, and this deceleration sensor 31 measures the magnitude of the braking force applied in the longitudinal direction of the vehicle body when braking the vehicle. It is something to detect.

40 receives the detection signals from the lateral force sensor 30 and deceleration sensor 31, and operates the pressure increasing solenoid valves 13, 14, 1.
5.16 and the open/close status of the solenoid valves 21, 22, 23, and 24 for pressure reduction are signal output lines 51, 52, 53, 54, 5.
This is a controller that outputs signals 5, 56, 57, and 58.

The basic operation of the device of the present invention with such a configuration is as follows. That is, when the driver depresses the brake pedal i in the illustrated state, the pressure of the brake fluid 4 inside the front wheel fluid chamber 2a and the rear wheel fluid chamber 2b of the mask cylinder 2 increases, and the brake fluid from the reservoir tank 3 increases. 4 are brake pipes 5, 6, 7° 8 and pressure increasing solenoid valves 13, 14, 15
．． 16 to each of the four wheel cylinders 9a, lOa.
.

11a and 12λ, and a braking force is generated at each wheel. At this time, the pressure reducing solenoid valves 21, 22, 23 and 24 are closed.

Next, when lowering the hydraulic pressure of the brake fluid 4 applied to a particular wheel, the pressure increasing solenoid valves 13, 14, 15 attached to the wheel whose hydraulic pressure is to be lowered are determined by a signal output line from the controller 40. 16 is shut off, and at the same time, the pressure increasing solenoid valves 13, 14, 15.
The pressure reducing solenoid valves 21.22, 23.2 corresponding to 16
4 is switched to the circulation side, and the brake fluid 4 in the brake pipe is made to flow out to the reservoir tank 3 side for a certain period of time. By performing such an operation, it is possible to reduce only the brake fluid pressure of a specific wheel whose pressure is desired to be reduced.

Further regarding the operation of the present invention based on the above operating principle,
This will be explained using FIGS. 3, 3, and 4.

Figure 2 shows the relationship between braking force X and lateral force Y applied to a car. Generally speaking, when braking force X is reduced by ΔFx as shown in the figure, lateral force Y increases by ΔFy. It has been known. Next, when the brake pedal is depressed while the automobile is turning, the braking force causes the automobile to tend to oversteer and may even spin. This state will be explained with reference to FIG. 3. That is, the vehicle body 45 is indicated by arrow A.
When the brake pedal is depressed during a left turn as shown in , a moment M is generated around the center of gravity 0 as shown by a broken line. In this case, the braking force applied to the left rear wheel 10 is Fx, and the lateral force is FV. If the hydraulic pressure of the brake fluid 4 supplied to the wheel cylinder 10a (Fig. 1) of the left rear wheel lO is lowered to reduce the braking force Px by 8 FK, the lateral force py will be ΔF
Increases by F. Therefore, around the center of gravity 0 of the vehicle body 45,
A moment Ml shown by the solid line, ie, a moment in a direction that cancels the moment M shown by the broken line, is generated, resulting in an effect of reducing the moment that causes spin due to braking.

FIG. 4 is a time chart showing an actual example of the present invention based on the above-mentioned operation, in which the operation of each member corresponding to the reference numeral assigned to the component shown in FIG. 1 is plotted at each time on the horizontal axis. to, t+, tt, ts.

It is shown in correspondence with t4. In this example, it is assumed that a braking force is applied while the vehicle body 45 is turning left.

The graph ■ in the figure indicates the wheel cylinder 10 of the left rear wheel lO.
Graph 1 shows the hydraulic pressure P of the brake fluid 4 supplied to the left rear wheel 10, Graph 2 shows the shutoff and flow state of the pressure increasing solenoid valve 14 attached to the left rear wheel 10, and Graph 2 shows the shutoff of the pressure reducing solenoid valve 22. and distribution status. Furthermore, graph ■ indicates the front or rear wheel on the outside of the turning center, in this case the right front wheel 11.
The graph ■ shows the hydraulic pressure P of the brake fluid 4 supplied to the wheel cylinder lla of the wheel cylinder lla. Graph (2) shows the shutoff and flow states of the pressure reducing solenoid valve 23, respectively. Graph (2) shows the detected value G of the lateral acceleration sensor 30, and graph (2) shows the detected value G' of the deceleration sensor 31.

The operation of the above time chart will be explained below.

That is, at time t0, the wheel cylinder 10a of the left rear wheel 10
The brake fluid 4 having the same hydraulic pressure P0 is applied to the wheel cylinder lla of the right front wheel 11. Next, as the left turn of the vehicle progresses, the detected value G of the lateral acceleration sensor 30 shown in the graph (3) gradually increases, and at time 1. The controller 4 indicates that the detected value G b < G O has been reached.
0 is detected, the controller 40 issues a detection signal to the signal output line 52, and this detection signal causes the left rear wheel I
Solenoid 14a of solenoid valve 14 for pressure increase attached to O
energization is performed. Then, the solenoid valve 14 is switched to the left side from the state shown in FIG. 1, and the flow of the brake fluid 4 is cut off as shown in graph (2). At the same time, the solenoid 22a of the pressure reducing electromagnetic valve 22 attached to the left rear wheel 10 is also energized by the signal output line 54 of the controller 40, and the electromagnetic valve 22 is similarly switched to the left side as shown in graph (3). The brake fluid 4 in the brake vibro is returned to the reservoir tank 3 side for a predetermined time τ.

With the above control, as shown in the graph ■, the left rear wheel l
Brake fluid 4 supplied to the wheel cylinder 10a of O
The hydraulic pressure P decreases from Po by ΔP, and this state is maintained. Therefore, as explained in the operating principle of FIG. The force py can be increased by Δpy. Therefore, around the center of gravity O of the vehicle body 45, a moment Ml shown by the solid line, that is, a moment in a direction that cancels the moment M shown by the broken line is generated, thereby reducing the moment that causes spin due to braking. becomes possible. The broken line Q shown in FIG. 4 indicates the decrease in the brake fluid pressure applied to the left rear wheel 10 when the pressure reducing solenoid valve 22 is left in the flow state, and this causes the pressure reducing solenoid valve 22 to remain in the flow state. It is clear that by controlling the flow time τ of the valve 22, the brake fluid pressure of the left rear wheel 10 can be adjusted.

Next, an explanation will be given of the effect when the vehicle body completes a turn and shifts to straight-ahead travel while keeping the brake pedal depressed. That is, when the vehicle shifts to straight-ahead running, the detected value G of the lateral acceleration sensor 30 shown in graph (2) changes to time 1. Thereafter, the detection value G' of the other deceleration sensor 3I gradually decreases and increases, but when the detection value G' reaches Gl' at time t3, the signal output line 58.
56, a signal is output to the solenoid 15a of the pressure increasing solenoid valve 15 of the right front wheel 11 and the same pressure reducing solenoid valve 23,
As shown in graphs ■ and ■, the pressure increasing solenoid valve 15 is shut off, and the brake fluid 4 in the brake pipe 5 is drained into the reservoir tank 3 for a predetermined time τ' of the pressure reducing solenoid valve 15.
Return it to the side. Therefore, as shown in graph (2), the hydraulic pressure of the brake fluid 4 supplied to the wheel cylinder lla of the front right wheel 11 is reduced by ΔP' and becomes the same as the brake fluid pressure supplied to the wheel cylinder 10a of the rear left wheel 10. Become.

Therefore, the hydraulic pressures of the brake fluid in the left rear wheel IO and the right front wheel 11 become equal, so that the straight-line performance of the vehicle is improved and the occurrence of a drift-out phenomenon of the vehicle body is prevented.

After time t4, as the vehicle moves straight, the detected value G of the lateral acceleration sensor 30 decreases, and the detected value G' of the deceleration sensor 31 also returns to 0, returning the vehicle to normal running. The controller 40 senses this state, returns the hydraulic pressure of the brake fluid 4 applied to the left and right wheels to P0, and performs a normal braking operation.

In the above embodiment, only the control of the brake fluid pressure of the left rear wheel IO and the right front wheel 2 was described, but the same control can be performed for the left rear wheel IO and the right rear wheel 9 as necessary. be able to. Furthermore, it goes without saying that when the vehicle turns to the right, the above-mentioned operation acts between the right rear wheel 9 and the left front wheel I2.

Effects of the Invention As explained in detail above, the vehicle brake fluid pressure control device according to the present invention independently controls the brake fluid pressure applied to the wheels. is provided with a turning braking detecting means for detecting turning braking of the vehicle and a deceleration detecting means for detecting deceleration during braking, and the turning braking detecting means and the deceleration detecting means are provided in the middle part of the brake pipe. The control valve is equipped with a control valve that opens and closes based on a detection signal to control brake fluid supplied to each wheel cylinder of the front wheel and rear wheel, and when the output of the swing braking detection means exceeds a predetermined value. The brake fluid pressure of the wheels on the inner side of the turning center is increased, and if the output of the deceleration detection means exceeds a predetermined value after the pressure reduction, the brake fluid pressure of the front wheels or rear wheels on the outer side of the turning center is increased. Since the configuration includes a controller that reduces the hydraulic pressure, the following effects are brought about.

In other words, when the car starts turning in either the left or right direction,
The turning braking detection means detects turning braking of the vehicle body and transmits this detected value to the controller, and in response to the output signal of this controller, the solenoid valve for increasing the pressure of the wheel on the inner side of the turning center of the vehicle body is shut off, and the pressure of the same wheel is reduced. The solenoid valve for the vehicle is allowed to flow for a certain period of time, causing a certain amount of brake fluid in the brake pipe to flow out to the reservoir, thereby reducing the brake fluid pressure of the wheels on the inside of the turning center and reducing the braking force applied to the vehicle body. It can be lowered. Therefore, a moment is generated around the center of gravity O of the vehicle body in the opposite direction to the moment that causes the vehicle body to spin, thereby producing the effect of reducing the moment that causes spin due to braking.

Further, when the vehicle body finishes turning and shifts to straight-ahead running, the deceleration detection means detects a change in the braking force applied to the vehicle body, and this output becomes larger than a predetermined value. At this time, the brake fluid pressure of the wheels on the outside of the turning center is reduced to the same fluid pressure as the brake fluid pressure on the inside of the turning center, so the brake fluid pressure of both left and right wheels becomes the same, and the vehicle body The drift-out phenomenon can be prevented. Since the main part of the above structure is not based on mechanical means,
It has the advantage of stable operation, no need for a hydraulic control device with a complicated valve device, simplified overall configuration, and reduced manufacturing costs. Furthermore, since it is possible to operate the various solenoid valves described above not by duty control but simply by ON/OFF control once or several times, the number of times the solenoid valves are operated can be significantly reduced, and parts can be reduced. can improve the durability of Further, unlike the conventional device, the brake passage on the inner side of the turning center is not completely closed due to the seating of the valve body, and the brake is not in a one-sided state, so that good turning performance can be maintained at all times. -According to the Rikiki invention, when the pressure of the brake fluid in the wheels is reduced, the solenoid valve for pressure increase is maintained in a closed state, so that pulsation caused by the reduction in fluid pressure occurs in the wheel cylinder on the wheel side. Even if this occurs, the hydraulic pressure within the mask cylinder is not affected in any way, so it also has the additional effect that unpleasant vibrations are not transmitted to the foot of the driver who is stepping on the brake pedal.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an embodiment of a vehicle driving force control device according to the present invention, Fig. 2 is a graph showing the relationship between braking force and lateral force applied to a car, and Fig. 3 is a graph showing the relationship between braking force and lateral force applied to a car. FIG. 4 is a time chart showing an example of the operation of the present invention. l...brake pedal, 2...mask cylinder, 3
... Reservoir tank, 5, 6, 7.8... Brake pipe, 9... Right rear wheel, 10... Left rear wheel, II...
・Right front wheel, I2...Left front wheel, 13.14, 15.16
...Solenoid valve (for pressure increase), 21.22.23.24.
... Solenoid valve (for pressure reduction), 30... Lateral acceleration sensor,
31... Deceleration sensor, 40... Controller, 2 other people Figure 1

Claims (1)

[Claims] (1) In a vehicle brake fluid pressure control device that independently controls the brake fluid pressure applied to the wheels, a turning braking detection means for detecting turning braking of the vehicle and a deceleration during braking are provided at any position on the vehicle body. and a deceleration detecting means for detecting the deceleration, and a deceleration detecting means is provided in the middle part of the brake pipe, and a deceleration detecting means is provided in the middle part of the brake pipe to open and close it based on the detection signals of the swing braking detecting means and the deceleration detecting means, and to connect each wheel cylinder of the front wheel and the rear wheel. It is equipped with a control valve that controls the supplied brake fluid, and when the output of the turning braking detection means exceeds a predetermined value, the brake fluid pressure of the wheels on the inner side of the turning center is reduced, and the pressure is reduced. Brake fluid pressure control for a vehicle, characterized by comprising a controller that reduces the brake fluid pressure of a front wheel or a rear wheel on the outside of a turning center if the output of the deceleration detection means exceeds a predetermined value later. Device.