JPH01164669A - Hydraulic brake device - Google Patents

Abstract

PURPOSE:To allow the delicate hydraulic control by providing the second operating member and controlling the magnitude of the brake hydraulic pressure according to the preset relationship with the electric signal in response to the operation. CONSTITUTION:A front wheel cylinder 18 is connected to a master cylinder 14 generating the first brake hydraulic pressure with the magnitude nearly proportional to the operating force of a braking distance brake pedal 10 via a main liquid passage 20. A spool type proportional solenoid hydraulic control valve 30 is inserted between a rear wheel cylinder 32 and a hydraulic source constituted of a pump 130 and an accumulator 22. This control valve 30 is controlled by a computer 92 to obtain the rear hydraulic pressure suitable to gradually reduce the car speed at the fixed high speed until a slow brake switch 108 is operated again after it is operated during the fixed-speed running. The car speed can be slightly reduced without operating the brake pedal 10 each time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic brake device for a vehicle.
In particular, it relates to technology that simplifies part of the brake operation.

[Conventional technology]

A hydraulic brake device is generally provided with an operating member, a brake cylinder, and between these operating members and the brake cylinder, and uses the hydraulic pressure of the brake cylinder to the operating force of the operating member,
The hydraulic control device is configured to include a hydraulic pressure control device that controls the height according to an operation amount such as an operation stroke.

Additionally, the hydraulic pressure of the brake cylinder is electrically controlled. For example, as described in JP-A-62-55083, braking force is automatically controlled regardless of variations in the friction coefficient of each brake friction material, the size of the loaded weight, variations in the slope angle of the road surface, etc. Anti-skid control that automatically controls the braking force according to the slip situation that occurs on the drive wheels when braking, or anti-skid control that automatically controls the braking force according to the slip situation that occurs on the drive wheels when starting. This is done when performing traction control to generate braking force that appropriately reduces the

[Problem that the invention seeks to solve]

When driving on a substantially straight and flat road such as a highway, the vehicle can maintain a substantially constant speed. Brake operation to slightly reduce the vehicle speed from this constant speed driving state does not require changing the amount of operation each time unlike normal braking when driving in urban areas, and although it is generally relatively simple, Subtle adjustment is required. Therefore, there is a desire to automate this adjustment to reduce the burden on the driver. However, a hydraulic brake device that can satisfy this demand has not yet been known.

[Means for solving problems]

In order to satisfy this demand, the present invention includes the aforementioned operating member,
A second operating member separate from the operating member is used in a hydraulic brake device including a brake cylinder and a hydraulic pressure control device, and an electrical signal is generated in accordance with the operation of the second operating member, and the electrical signal is transmitted to the hydraulic brake device. a signal generating means for supplying the signal to the pressure control device, and the hydraulic pressure control device includes an electrohydraulic pressure control section that controls the height of the hydraulic pressure of the brake cylinder according to a predetermined relationship according to the electric signal. It is something that

[Effect]

In the hydraulic brake device according to the present invention, the height of the hydraulic pressure in the brake cylinder, and thus the magnitude of the braking force, is determined in advance according to the operation of a second operation member different from the main operation member. Controlled according to relationships. The operation of the second operating member is transmitted to the electro-hydraulic control unit of the hydraulic pressure control device by an electric signal, and the hydraulic pressure is automatically controlled, so the operation of the second operating member corresponding to obtaining a predetermined braking force is performed. It is easy to make the amount relatively small and to make the operation itself relatively simple. For example, by using the second operating member as a switch means, it is possible to obtain a predetermined braking force simply by turning on the switch means, or to obtain a braking force that changes over time in a predetermined relationship. It is also possible to use the second operating member as a sliding switch means to obtain a predetermined braking force depending on the amount of displacement of the slider.

〔Effect of the invention〕

As described above, according to the present invention, in order to obtain a predetermined braking mode, it is possible to perform a relatively simple operation of the second operating member, and the effect of reducing the burden on the driver can be obtained. .

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to a hydraulic brake system for a four-wheel vehicle will be described in detail below with reference to the drawings.

Reference numeral 10 in FIG. 1 indicates a brake pedal as an operating member. The brake pedal 10 is connected to a brake mask cylinder 14 (hereinafter simply referred to as a mask cylinder) via a hydraulic booster 12.
The brake fluid pressure is generated at a height corresponding to the operating force of the brake pedal 10. Mask cylinder 14
A front main fluid passage 20 connects the front wheel cylinder 18 of the front wheel to the front main fluid passage 20 . Hydraulic booster 12
is well known and is not essential to understanding the present invention, so a detailed explanation will be omitted. Hydraulic pressure booster 12 is connected to accumulator 22 via first accumulator passage 24 and to reservoir 26 via first reservoir passage 28 .

Reference numeral 30 indicates a spool type proportional electromagnetic hydraulic control valve (hereinafter simply referred to as a control valve). This is accumulator 22
．． Reservoir 26 and rear wheel cylinder 3
2 and a second accumulator passage 34. It is connected by a second reservoir passage 36 and a rear main liquid passage 38. The control valve 30 is similar to the one described in Utility Model Application No. 170587/1987, and excites the hydraulic pressure of the rear wheel cylinder 32 (hereinafter referred to as rear hydraulic pressure) by controlling the excitation current of the solenoid. The height is controlled to correspond to the magnitude of the current.

Reference numeral 92 indicates the CPU, ROM, RAM, and human power section.

1 shows a computer including an output section and a bus. The input section of the computer 92 includes a brake pedal 1 sensor 94 for detecting depression of the brake pedal 10.
a pedal force sensor 96 that detects a pedal force of 0; and an accelerator pedal sensor 100 that detects the pedal force of an accelerator pedal 98, which is a speed increasing operation member operated to increase the vehicle speed.
A front hydraulic pressure sensor 102 detects the hydraulic pressure of the front wheel cylinder 18 (hereinafter referred to as front hydraulic pressure).A rear hydraulic pressure sensor 104 detects the rear hydraulic pressure. A rear wheel load sensor 106 that detects the load applied to the rear wheels and a slow braking switch 108 are connected, while a solenoid control circuit 110 and a warning light 112 are connected to the output section. The computer 92 is configured to control the rear hydraulic pressure to an appropriate level based on various input signals by executing a control program (the program shown in the flowchart in FIG. 2) stored in the ROM. There is.

The above control and the function of the slow braking switch 108 will be described in detail later.

The liquid in the reservoir 26 is pumped up into the accumulator 22 by a pump 130 and stored at a certain range of liquid pressure. A motor 132 that drives the pump 130 is connected to the output section of the computer 92 via a motor control circuit 134, and the pump 1
30 drive states are controlled. A level switch 140 is attached to the reservoir 26 so that the liquid level in the reservoir 26 can be monitored by the computer 92.

Next, the operation will be explained.

At the same time as the power is turned on, the computer 92 is activated and the hydraulic pressure control program shown in the flowchart of FIG. 2 is executed. First, step Sl (hereinafter simply referred to as 81. The same applies to the following steps.

), the initial flag of the CPU is reset, and in S2, a pressure reduction command is issued to the control valve 30 so that the rear hydraulic pressure becomes the value O. In other words, the excitation current of the solenoid is controlled to such a level that the rear wheel cylinder 32 is disconnected from the accumulator 22 and communicated with the reservoir 26. Then, in S3, it is determined whether the slow braking switch 108 has been operated.

First, the operation when the slow braking switch 108 is not operated will be explained.

In this case, the determination result in S3 is No, the slow braking flag of the CPU is reset in S4, and in S5 it is determined by the brake depression sensor 94 whether or not the brake pedal 10 has been operated. If the brake pedal 10 is operated and the determination result is YES, the steps from S6 onwards are executed, and at the same time, brake fluid pressure of a height corresponding to the depression force of the brake pedal 10 is generated in the mask cylinder 14, and as a result, , the front hydraulic pressure increases. On the other hand, the brake pedal 10 is not operated and the determination result in S5 is N.
If o, return to execution of Sl.

In S6, it is determined whether the first time flag is set. If the determination result is NOl, that is, if 86 is executed for the first time during one consecutive brake operation,
In S7, a signal representing the rear wheel load is taken in from the rear wheel load sensor 106, but if YES, that is,
If S6 is executed for the second time or later, S7 is bypassed. In this embodiment, brake fluid pressure control corresponding to one consecutive brake operation is performed based on the actual rear wheel load immediately after the start of the brake operation. After the initial flag is set in S8, a signal representing the pedal force is fetched from the pedal force sensor 96 in S9, and a signal indicating front hydraulic pressure is fetched from the front hydraulic pressure sensor 102 in SIO.

In Sll, the front system, more precisely, the mask cylinder 14. It is determined whether the front wheel cylinder 18 and the front main liquid passage 20 are out of order. In other words, the actual brake pedal force lowers the front hydraulic pressure by 0.5k.
It is determined whether the front hydraulic pressure is below a certain value close to 0 even though it exceeds the value that should be increased to g/cnl. If the determination result is No, that is, the front system is normal, S12 and subsequent steps are executed, but if the determination result is YES, that is, the front system is out of order, S15 and subsequent steps are executed.

First, a case where the front system is normal will be explained. S
After a command to turn off the warning light 112 is issued at step 12, S
At step 13, it is determined whether the slow braking flag is set. At this point, the slow braking flag is not set, so the determination result is No, and in S14, R
A target value of the rear hydraulic pressure is calculated by executing a normal hydraulic pressure calculation program (not shown) of the OM. As shown in the graph in Figure 3, the target value for the rear hydraulic pressure is set to be slightly smaller than the ideal value for the rear hydraulic pressure, which corresponds to the front hydraulic pressure and the rear wheel load, in the unlikely event that the vehicle locks up. In some cases, the rear wheels fall slightly later than the front wheels. In this embodiment, a calculation formula using the rear wheel load and front hydraulic pressure as variables is stored in the ROM, and the target value of the rear hydraulic pressure is calculated using this calculation formula.

Note that FIG. 3 representatively shows the cases of rear wheel loads corresponding to when the vehicle is loaded and when the vehicle is empty.

On the other hand, if the front system is out of order, the determination result in Sit becomes YES, and the warning light 112 is turned on in S15.
After the light is turned on, the slow braking switch 108 is turned on in S16.
It is determined whether or not the is being operated. In this case as well, the determination result is No, and in step 317, the failure hydraulic pressure calculation program (not shown) stored in the ROM is executed.
By executing the above, the target value of the rear hydraulic pressure is calculated. ROM
contains a formula for calculating the rear hydraulic pressure, which is the height that compensates for the decrease in the braking ability of the entire vehicle due to a front failure, using the brake pedal force and rear wheel load as variables. The target value of the hydraulic pressure is calculated.

In both cases, the rear hydraulic pressure sensor 104 is
A signal representing the current rear hydraulic pressure is taken in from , and in S19, the control amount of the rear hydraulic pressure to be controlled this time is calculated by subtracting the current value from the target value. In S20, the control valve 30 is controlled based on the calculated control amount, and the process returns to S3 again.

The above control is repeated until the brake pedal 10 is released and the determination result in S5 becomes No. Thereafter, the control valve 30 is returned to the reduced pressure state in S2, and both the front brake and the rear brake are released.

Next, the operation when the slow braking switch 108 is operated will be explained. It should be noted that the computer 92 is configured to determine that when the slow braking switch 108 is operated once, it is in the ON state, and when it is operated again, it is determined to be in the OFF state.

In this case, the determination result in S3 is YES, and S2
In step S1, it is determined whether the brake pedal 10 is being operated, and in step S22, it is determined whether the accelerator pedal 98 is being operated.

Assuming that neither the brake pedal 10 nor the accelerator pedal 98 is operated at this time, the determination results in S21 and S22 are both NO, and after the slow braking flag is set in S23, the process returns to S6.

From then on, the rear hydraulic pressure is controlled in the same way as when the brake pedal 10 is operated, but the determination results in S13 and S16 are YES in this case, regardless of whether or not the front system is malfunctioning. , S24, a target value of rear hydraulic pressure suitable for reducing the vehicle speed at a constant deceleration is calculated. Then, in steps 318 to 320, the rear hydraulic pressure is controlled as in the case described above, and as a result, the vehicle is decelerated at a constant deceleration. Note that the value of this constant deceleration is preferably in the range of 0.1G to 0.15G. This control continues until the slow braking switch 108 is operated again and the determination result in S3 becomes NO.

If the brake pedal 10 is operated while the slow braking switch 108 is in the ON state, the determination result in S21 is YE.
S, and the routine returns to the execution after S4, that is, the normal control of the rear hydraulic pressure based on the operation of the brake pedal IO. Furthermore, if the accelerator pedal 98 is operated instead of the brake pedal 10, the determination result in S22 becomes YES, the process returns to execution of Sl, and the slow braking is released.

Note that while the brake pedal 10 is being operated, the slow braking switch 1
If 08 is operated, the determination result in S3 is Y.
However, the determination result in S21 becomes YES, the process returns to step 84, and the gentle braking command is ignored.

In the hydraulic brake system configured as described above, while driving at a constant speed on a highway or the like, the slow braking switch 1 is activated when neither the brake pedal 10 nor the accelerator pedal 98 is operated.
If 08 is operated, the vehicle speed will gradually decrease at a constant deceleration until it is operated again. Therefore, the vehicle speed can be reduced to a desired value by adjusting the period during which the slow braking switch 108 is kept in the ON state by the occupants including the driver. In this way, it is no longer necessary for the driver to operate the brake pedal 10 each time to slightly reduce the vehicle speed, resulting in the effect of reducing the burden on the driver. Additionally, a mechanism is added in which when the driver operates the slow braking switch 108 after setting the desired vehicle speed, the computer 92 automatically adjusts the holding time of the slow braking switch 108 based on the current vehicle speed and the desired vehicle speed. You can also do that.

As is clear from the above explanation, in this example,
Accumulator 22. Control valve 30. Front hydraulic pressure sensor 102. Rear hydraulic pressure sensor 104° Rear wheel load sensor 10
6. A part of the computer 92 that stores each step of the flowchart in FIG. 2 and a part that executes the steps constitute a hydraulic pressure control device, and the rear wheel cylinder 32 is a brake cylinder controlled by the hydraulic pressure control device. . Further, the slow braking switch 108 constitutes a second operating member, and a portion that generates electric signals of ON and OFF signals in accordance with the operation of the slow braking switch 108 of the computer 92 constitutes a signal generating means. Among the pressure control devices, the control valve 30 and S3. of the computer 92 in FIG.
S4. S13°S16. S18. S19. S20. S2
A portion that stores and executes each step of Steps 3 and S24 functions as an electro-hydraulic control portion.

In the above embodiment, it is determined that the vehicle is decelerated when the second operating member is operated.
If the operating member is operated, the hydraulic pressure control device may perform control to maintain the stopped state.

In this case, even if the stopped state is released at the same time as the second operating member is operated again, the accelerator pedal 98
It may also be configured to be automatically released at the same time as the button is pressed. The latter method is particularly effective when starting a manual transmission vehicle from a steep slope. In other words, after the vehicle is stopped on a slope by operating the second operating member, the driver can start the vehicle by simply depressing the accelerator pedal 98 at any time. In conventional hydraulic brake devices, when the vehicle is stopped by operating the parking lever, the vehicle is stopped by simultaneously releasing the parking lever and simultaneously depressing the accelerator pedal 98, or by depressing the brake pedal 10. In such cases, it is necessary to start on a steep slope by simultaneously releasing the brake pedal 10 and depressing the accelerator pedal 98, which requires a complex and quick operation. The parking lever and brake pedal 10 generally need to be operated with a relatively large force and with a relatively large stroke, so they often take time to operate, and in this case, the vehicle may move backwards due to its own weight, resulting in a situation such as an engine stall. There is a problem that this may occur. However, in the above-mentioned aspect, since the stopped state is automatically canceled at the same time as the accelerator pedal 98 is operated, starting on a steep slope can be easily and reliably performed.

In addition, although not illustrated individually, the present invention can be implemented with various modifications, improvements, etc. based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a hydraulic brake system according to an embodiment of the present invention, and FIG. 2 is a flowchart showing a program for hydraulic pressure control in the above embodiment. FIG. 3 is a graph showing the relationship between the rear wheel load, the front wheel cylinder hydraulic pressure, and the front wheel cylinder hydraulic pressure in the above embodiment. 10: Fushiki Betal 12:? &pressure stabilizer 14
Brake mask cylinder 18: Front wheel cylinder 22: Accumulator 30 Nispl type proportional electromagnetic hydraulic control valve 32: Rear wheel cylinder 92: Computer iOS: 11 Brake switch Applicant Toyota Motor Corporation Edition 3 Figure Floft; I! pressure

Claims (1)

[Claims] An operating member, a brake cylinder, and a hydraulic pressure control provided between these operating members and the brake cylinder to control the hydraulic pressure of the brake cylinder to a height corresponding to the operating force of the operating member, the operating amount such as the operating stroke, etc. a second operating member different from the operating member; an electrical signal corresponding to the operation of the second operating member; and the electrical signal is used to control the hydraulic pressure. A signal generating means for supplying the signal to the device is provided, and the hydraulic pressure control device is provided with an electrohydraulic pressure control section that controls the height of the hydraulic pressure of the brake cylinder according to a predetermined relationship according to the electric signal. A hydraulic brake device characterized by: