JPH01178059A - Brake hydraulic pressure controller for vehicle - Google Patents

Abstract

PURPOSE:To prevent the drift-out phenomenon of a car body by installing a means for detecting the turning brake application for a car body and lowering the brake hydraulic pressure for a wheel on the turning center inner side and maintaining the brake hydraulic pressure for the wheel on the outer side when the output of the above-described means exceeds the first prescribed value. CONSTITUTION:The pressure increasing solenoid valves 13-16 are interposed in the pipes 5-8 for introducing each brake hydraulic pressure into the wheel cylinders 9a-12a, and the pressure reducing solenoid valves 21-24 are interposed in the pipes 17-20 branched from the pipes 5-8, 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 turning is installed. When the detection value exceeds the first prescribed value, the brake hydraulic pressure (inside hydraulic pressure) of the wheel on the turning center inside is lowered, and the brake hydraulic pressure of the wheel on the outer side (outside hydraulic pressure) is maintained. Further, when the detection value is less than the second prescribed value (<first prescribed value), the outside hydraulic pressure is lowered to the equal hydraulic pressure to the inside hydraulic pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides -1 (improving turning performance by increasing or decreasing the hydraulic pressure of the brake fluid supplied to the left and right wheels when braking while both wheels are turning; The present invention relates to a brake fluid pressure control device for a vehicle.

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 also prevents the vehicle from oversteering. Generally, there are measures to prevent this from happening.

- As an example of the means described in
Publication No. 158 discloses that 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, such conventional brake fluid pressure control devices,
In particular, in the example of the device described in JP-A-57-144158, it is necessary to create a difference in the brake fluid pressure supplied to the left and right rear wheels based on the action of the lateral acceleration detection mechanism applied to the vehicle. Therefore, a left and right hydraulic pressure control device having a complicated valve device is required, which is difficult to manufacture and increases 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 anti-skid solenoid valve is provided to control the hydraulic pressure applied to the i1 wheel, the solenoid valve must be constantly operated under duty control, so the frequency of on/off operation of the solenoid valve is extremely high. However, the disadvantage is that the durability decreases.

Furthermore, in the case of the above-mentioned brake fluid pressure control device, if the steering wheel is returned to its original position while the brake pedal is depressed after the vehicle has turned, the brake fluid pressure of the wheels on the outside of the center of the turn will remain at the center of the turn, although the lateral force will decrease. Since the brake fluid pressure on the inside side remains high, the braking force on the wheels on the outside of the turning center is greater than the braking force on the wheels on the inside of the turning center, causing the vehicle to move sideways. There is a problem in that a so-called drift-out phenomenon, in which the object is swept away in one direction, 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 the drift-out phenomenon, 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. A turning braking detection means for detecting turning braking is provided, and when the output of the turning braking detecting means exceeds a first predetermined value set in advance, the brake fluid pressure of the wheel on the inner side of the turning center is reduced. At the same time, the brake fluid pressure of the wheels on the outside of the turning center is maintained, and when the output of the turning braking detection means falls below a second predetermined value that is smaller than the first predetermined value, the brake fluid pressure on the wheels on the outside of the turning center is maintained. This configuration includes a controller that increases the brake fluid pressure of the wheels on the side until it reaches the same fluid pressure as the brake fluid pressure of the wheels on the inner side of the turning center.

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 turning braking detection means exceeds a first predetermined value, the controller issues a signal to shut off the pressure increasing solenoid valve for the wheel on the inner side of the turning center, and also shuts off the pressure reducing solenoid valve for the wheel on the inner side of the turning center. A signal is issued to cause the brake fluid to flow for a certain period of time, causing a certain amount of brake fluid in the brake pipe to flow 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, around the center of gravity 0 of the vehicle body, a moment is generated 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 completes turning and shifts to straight-ahead running, when the output of the turning braking detection means falls below a second predetermined value that is set in advance and is smaller than the first predetermined value, the controller A signal is issued to shut off the pressure increase solenoid valve of the 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, and a certain amount of brake fluid in the brake pipe is transferred to the reservoir tank. Let it flow out.

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, in which l is a brake pedal, and 2 is the brake pedal l.
The brake fluid 4 in the reservoir tank 3 is transferred to the rear wheel fluid chamber 2a in the mask cylinder 2.
and brake pipes 5, 6, 7 from the front wheel fluid chamber 2b, respectively.
．． 8 to the right rear wheel 9. Rear left wheel IO1, front right wheel It, front left wheel 12, each wheel cylinder 9a, 10a, lla,
12a. In the middle of each brake pipe 5, 6, 7.8 above, there is a solenoid valve 1 for pressure increase.
3, 14, 15.16, and a pipe 17.1 branched from each brake pipe 5, 6, 7.8.
8, 19. In the middle of 20, there is a solenoid valve 21.22 for pressure reduction,
23 and 24 are equipped, and the solenoid valve 21 for pressure reduction,
The other ends of 22, 23 and 24 are connected to the reservoir tank 3. Solenoid valves 13, 14, 15, 16 for the above pressure increase
Normally, as shown in the figure, the brake fluid 4 from the mask cylinder 2 is in a position to flow to all of the wheels, and the solenoids 13a, 14 of the solenoid valves 13, 14, 15, 16 are
When power is applied to a, 15a, and 16a, the solenoid is activated.
Depending on the use, each electromagnetic valve 13, 14, 15, 16 is switched to the left side, and the flow of brake fluid 4 is cut off. On the other hand, the solenoid valves 21.22.23.24 for depressurization are normally in the position of blocking the brake fluid 4 from the mask cylinder 2 as shown in the figure, and the solenoid valves 21.22.2
3.24 solenoids 21a, 22a, 23a, 24a
When energized, each solenoid valve 2 is activated by the action of the solenoid.
1,22. - 23 and 24 are switched to the left side to allow the brake fluid 4 to flow to the reservoir tank 3 side.

A lateral acceleration sensor 30 is provided at a desired position on the vehicle body, and this lateral acceleration sensor 30 detects lateral acceleration applied to the vehicle body when the vehicle turns.

40 receives a detection signal from the lateral acceleration sensor 30 and outputs a signal output line 51.52 to indicate the open/closed states of the pressure increase solenoid valves 13, 14, 15.16 and the pressure decrease solenoid valves 21, 22, 23.24. .53.54.55,56,57.58
This is the controller that outputs the output.

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 l 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
．． te to each of the four wheel cylinders 9a and IOa.
.

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

Next, when lowering the hydraulic pressure of the brake fluid 4 applied to a certain specific wheel, a signal output line from the controller 40 is used to control the pressure increasing solenoid valves 13, 14, 15 attached to the wheel whose hydraulic pressure is to be lowered. 16 is shut off, and at the same time, the pressure increasing solenoid valves 13, 14, 15.
The pressure reducing solenoid valve 21.22.23.2 corresponding to 16
4 is switched to the circulation side to cause the brake fluid 4 in the brake pipe 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 the braking force X applied to a car and the lateral force Y. Generally, as shown in the figure, when the braking force X is reduced by 8Fx, the lateral force Y increases by Δpy. It is known. Next, when the brake pedal is depressed while the car is turning, the braking force of the automatic car causes it to tend to oversteer and may even spin. This situation will be explained with reference to FIG. That is, when the brake pedal is depressed while the vehicle body 45 is turning to the left as indicated by the arrow, a moment M is generated around the center of gravity 0 as indicated by a broken line. In this case, the braking force applied to the left rear wheel 10 is Px, and the lateral force is py. 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 ΔPi, the lateral force Py will be reduced by Δp.
Increase by y. Therefore, around the Iri center 0 of the vehicle body 45, a moment is generated that cancels the moment M3 shown by the solid line, that is, the moment M shown by the broken line, and reduces the moment that causes spin due to braking. This brings about the effect of

FIG. 4 is a time chart showing an actual example of the present invention based on the above-mentioned operation, in which the operations of each member corresponding to the symbols attached to the constituent members shown in FIG. 1 are plotted on the horizontal axis. Time t. , j+, Lx, ts.

It is shown in correspondence with L4. In this example, it is assumed that a braking force is applied while the vehicle body 45 is turning left.

Graph ■ in the figure is the wheel cylinder 10 of the left rear wheel IO.
Graph (■) 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 and flow state of the pressure reducing solenoid valve 22. and distribution status. Furthermore, graph ■ shows the brake fluid 4 supplied to the wheel cylinder 9a of the right rear wheel 9.
Graph ■ shows the shutoff and flow states of the pressure increasing solenoid valve 13 attached to the right rear wheel 9, and graph ■ shows the shutoff and flow states of the pressure reducing solenoid valve 21, respectively. There is. Graph (2) is a graph showing the detected value G of the lateral acceleration sensor 30. The detected value G of the lateral acceleration sensor 30 includes a first predetermined value G0 and a second predetermined value G smaller than the first predetermined value G0.

is set in advance, and the output is the above predetermined value G. ,G
The controller 40 is configured to issue a control signal when the + value is reached.

The operation of the above time chart will be explained. That is, time t0
Then, the wheel cylinder lOa of the left rear wheel 10 and the right rear wheel 9
The hydraulic pressure P is equivalent to that of the wheel cylinder 9a. Brake fluid 4 is applied. Next, as the left turn of the vehicle body progresses, the detected value G of the lateral acceleration sensor 30 shown in the graph (3) gradually increases, and at time t, the detected value G reaches G. When the controller 40 detects that the pressure has been reached, the controller 40 issues a detection signal to the signal output line 52, and this detection signal energizes the solenoid 14a of the pressure increase solenoid valve 14 attached to the left rear wheel IO. be exposed. Then, the electromagnetic valve I4 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 signal output line 5 of the controller 40
A solenoid valve 22 for pressure reduction attached to the left rear wheel lO by 4
The solenoid 22a is also energized, and the electromagnetic valve 22 is similarly switched to the left side to return the brake fluid 4 in the brake vibro to the reservoir tank 3 side for a predetermined time τ as shown in graph (3). Furthermore, as shown in graph ■, right rear wheel 1
Switch the pressure increase solenoid valve 13 of No. 3 to the cutoff side. Therefore, the brake fluid pressure applied to the wheel cylinder 9a of the right rear wheel 9 is maintained at a constant value P0.

With the above control, as shown in the graph (■), the left rear wheel I
Brake fluid 4 supplied to wheel cylinder IOa 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. Force FY can be increased by ΔFF. Therefore, around the center of gravity 0 of the vehicle body 45, a moment M 1 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. Note that the broken line Q shown in FIG. It is clear that by controlling the flow time τ of the valve 22, the brake fluid pressure of the left rear wheel IO can be adjusted.

Next, the operation when the vehicle body finishes turning and shifts to straight running will be explained. That is, when the vehicle body moves straight ahead, the output of the lateral acceleration sensor 30 shown in graph (2) gradually decreases, and when the output reaches the second predetermined value Gl at time t,
A signal is output from the controller 40 via the signal output line 53 to the solenoid 21a of the pressure reducing electromagnetic valve 21 of the right rear wheel 9, and the electromagnetic valve 21 is activated within the brake pipe 5 for a predetermined time τ as shown in graph (2). Return the brake fluid 4 to the reservoir tank 3 side. Therefore, as shown in graph (2), the hydraulic pressure of the brake fluid 4 supplied to the wheel cylinder 9a of the right rear wheel 9 is reduced by ΔP, and becomes the same as the brake fluid pressure supplied to the wheel cylinder 10a of the left rear wheel 1O. . Therefore, the hydraulic pressures of the left and right wheels are equalized, 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.

At time t, the controller 40 detects that the running state of the vehicle has returned to normal running based on the output of the lateral acceleration sensor 30, and adjusts the hydraulic pressure of the brake fluid 4 applied to the left rear wheel 10 and the right rear wheel 9. P respectively. , and normal braking operation is performed.

In addition, in the embodiment of "Y", the left rear wheel 10 and the right rear wheel 9
Although only the control of the brake fluid pressure has been described, it goes without saying that similar control can be performed not only for the left and right rear wheels but also for the right front wheel 11 and the left front wheel 12, if necessary.

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 detection means for detecting turning braking of the vehicle, and when the output of the turning braking detecting means exceeds a first predetermined value set in advance, the brake fluid pressure of the wheel on the inner side of the turning center is At the same time, the brake fluid pressure of the wheels on the outer side of the turning center is maintained, and when the output of the turning braking detection means falls below a second predetermined value that is smaller than the first predetermined value, Since the configuration includes a controller that reduces the brake fluid pressure of the wheels on the outside of the center until it becomes equal to the brake fluid pressure of the wheels on the inside of the turning center, the following effects are brought about. That is, when the automobile starts turning in either the left or right direction, the turning braking detection means detects turning braking of the vehicle, transmits this detected value to the controller, and uses the output signal of the controller to turn the center of gravity of the vehicle toward the inside. The solenoid valve for increasing the pressure of the wheel is shut off, and the solenoid valve for reducing the pressure of the same wheel is allowed to flow for a certain period of time, allowing a certain amount of brake fluid in the brake pipe to flow out to the reservoir tank. By lowering the brake fluid pressure on the wheels of the vehicle, the braking force applied to the vehicle can be reduced. Therefore, a moment in the opposite direction to the direction that causes the vehicle body to spin is generated around the R-center O of the vehicle body, which has 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, a second output signal whose output is smaller than the first predetermined value is set.
When the pressure drops below a predetermined value, 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 is the same. As a result, the drift-out phenomenon of the vehicle body can be prevented. Since the main parts of the above structure are not based on mechanical means, the operation is stable and there is no need for a hydraulic control device with a complicated valve device, simplifying the overall structure and making it easier to manufacture. This has the advantage of reducing costs.

Furthermore, the various solenoid valves mentioned above are not controlled by duty, but simply by one control.
Since the solenoid valve can be operated by on/off control once or several times, the number of times the solenoid valve is operated can be significantly reduced, and the durability of the parts can be improved. Further, unlike the conventional device, the brake fluid 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 applied to one side, so that turning performance can always be maintained at a good level. -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 the wheel cylinder on the wheel side is
Even if pulsation occurs due to fluid pressure reduction, it has no effect on the fluid pressure inside the mask cylinder, so there is no unpleasant vibration transmitted to the foot that is pressing the brake pedal before driving. It also has an effect.

[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. ! ...Brake pedal, 2...Mask cylinder, 3
...Reservoir tank, 5,6.7.8...Brake pipe, 9...Right rear wheel, lO...Left rear wheel, II...
・Front right wheel, 12...Front left wheel, 13.14, 15.16
...Solenoid valve (for pressure increase), 21.22.23.24.
... Solenoid valve (for pressure reduction), 30... Lateral acceleration sensor,
40...Controller, Figure 1 12 and front fi 116 error 1
Rito? ＆輌 Soseki f support - Fig. 2 Sho Shouto Fig. 3

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 is provided at an arbitrary position on the vehicle body, and the turning braking detection means is provided at an arbitrary position on the vehicle body. When the output of the means exceeds a first predetermined value set in advance, the brake fluid pressure of the wheels on the inner side of the turning center is reduced, and the brake fluid pressure of the wheels on the outer side of the turning center is maintained; When the output of the turning braking detection means falls below a second predetermined value that is smaller than the first predetermined value, the brake fluid pressure of the wheels on the outer side of the turning center is changed to the brake fluid pressure of the wheels on the inner side of the turning center. A brake fluid pressure control device for a vehicle, comprising a controller that reduces the pressure until the fluid pressure becomes equal to the fluid pressure.