JPH07323836A - Vehicle stop retaining device - Google Patents

Abstract

PURPOSE:To operate surely a vehicle stop retaining device even in a, case in which a vehicle is stopped on a slope road or the like, by proposing a vehicle stop retaining device which can assure a stop retaining function for a fixed time without relation to inclination and load. CONSTITUTION:When the wheels fall into a stop state (a vehicle stop state), the inclination angle of the vehicle and the load of the vehicle are detected by means of an inclination sensor S1 and a load sensor S2, and on the basis of these signals, necessary brake pressure P1, at the time of its state is operated. In addition, the leak portion (alpha) of enclosing pressure opposite to the necessary brake pressure P1 is sought by utilizing a map or the like sought beforehand, and a value which is the necessary brake pressure P1 added with the leak portion (G) (P1+alpha) and the present brake liquid pressure sought by means of a brake pressure detecting sensor S3 are compared with each other, and when it is decided that the present brake liquid pressure is higher, a solenoid valve 4 is closed, and a vehicle stop retaining device is operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle stop holding device capable of automatically holding the braking force at that time to maintain the stopped state of a vehicle when the vehicle is stopped by a brake operation. The present invention relates to a vehicle stop and hold device capable of guaranteeing a stop and hold function for a certain period of time when a vehicle is stopped on a slope or the like by a braking force according to a slope angle of the slope and a load applied to the vehicle.

[0002]

2. Description of the Related Art As is well known, when a vehicle is temporarily stopped at an intersection or the like, many vehicle stop and hold devices maintain the brake hydraulic pressure at that time, and the occupant does not operate the parking brake or continue to depress the brake pedal. When the vehicle is automatically held in a stopped state and the vehicle is subsequently started such as depressing the accelerator, the state is detected and the brake can be automatically released. By the way, in the conventional vehicle stop and hold device, when the stop and hold device is used, for example, on a slope, the pedal force of the brake pedal is weak, and for a vehicle etc. that is barely held by hydraulic pressure and stops, the hydraulic pressure is held for a short time. However, the hydraulic pressure gradually escapes from the solenoid valve in the hydraulic circuit,
There is a problem that the braking force becomes weak and the vehicle may run naturally.

Therefore, in order to solve such a problem of the vehicle stop holding device, for example, a technique disclosed in Japanese Utility Model Laid-Open No. 3-8958 has been proposed. As shown in FIG. 3, the device disclosed in the above publication discloses an electromagnetic control valve 50 that holds a braking force once applied by a vehicle braking device.
And a braking force holding device for holding the braking force by the electromagnetic control valve in response to a driving condition of the vehicle meeting a predetermined condition. Detecting means 51 for detecting whether or not the brake pedal has been depressed, and in response to the detecting means, when the brake pedal is depressed during the holding operation period, the electromagnetic control valve controls And a solenoid valve control unit 52 for canceling the power holding state.

[0004]

However, in the above-mentioned prior art device, when the brake pedal is depressed while the braking force is being held by the electromagnetic control valve, the braking force is held by the electromagnetic control valve. Although the vehicle is prevented from running when the brake pressure is reduced by releasing it, there is a risk that the vehicle gradually runs when the driver does not notice the decrease in the brake pressure.

Therefore, according to the present invention, when the vehicle is stopped on a slope, the necessary brake fluid pressure is calculated based on the slope angle of the slope and the load applied to the vehicle, and the leaked amount α of the containment pressure is calculated based on the calculation result. When the current brake pressure exceeds the hydraulic pressure, the solenoid valve for vehicle stop and hold is activated for the first time to ensure the function of holding and holding the vehicle for a certain period of time regardless of inclination and load. It is an object of the present invention to propose a device, and thereby to make it possible to reliably operate the vehicle stop and hold device even when the vehicle is stopped on a slope or the like.

[0006]

Therefore, the technical solution adopted by the present invention is a vehicle stop holding device capable of automatically holding the braking force by detecting the stopped state of the vehicle. A tilt sensor S1 for determining the tilt angle of the vehicle, a load sensor S2 for determining the load of the vehicle when the vehicle is stopped, a brake pressure detection sensor S3, and a required brake pressure is calculated based on signals from the tilt sensor S1 and the load sensor S2. At the same time, a containment pressure corresponding to the calculation result is obtained, and the control circuit 6 is provided with a determination means for determining whether the brake fluid pressure from the brake pressure detection sensor S3 is higher or lower than the result of adding them. Solenoid valve 4 configured to operate by a signal from the control circuit
It is characterized by having and.

[0007]

When it is determined that the wheels are stopped (the vehicle is stopped), the inclination angle of the vehicle and the load of the vehicle are detected by the inclination sensor S.
1. Detected by the load sensor S2, the required brake pressure P1 in that state based on the tilt angle and the load signal
Is calculated to obtain. Further, the required brake pressure P1
The leak amount α of the containment pressure corresponding to the above (in other words, the leak amount of the containment pressure in a fixed time) is obtained by using a previously obtained map or the like not shown. Then, the required brake pressure and the leakage amount α are added (P1 + α). Then, the current brake fluid pressure obtained by the brake pressure detection sensor S3 is compared with the brake fluid pressure (P1 + α), and if it is determined that the current brake fluid pressure is higher,
The electromagnetic valve 7 is closed, and the vehicle shifts to the vehicle stop holding state. At the same time, the solenoid valve actuating lamp illuminates to notify the driver that the vehicle is in the stopped and held state. By the above-mentioned operation, the stopping and holding function for a certain time is guaranteed by the braking force according to the slope angle of the slope and the state of the load applied to the vehicle.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of a vehicle stop holding device as an embodiment according to the present invention. In FIG. 1, a vehicle brake includes a master cylinder 2 that generates a brake pressure by operating a brake pedal 1 as well known, and a brake cylinder 3 that brakes wheels by a brake pressure supplied from the master cylinder 2. When the brake pedal is operated, the brake pressure acts on the brake cylinder and the vehicle can be stopped.

Further, an electromagnetic valve 4 for shutting off the oil passage is provided in the pipe connecting the master cylinder 2 and the brake cylinder 3 described above. Further, an electromagnetic valve operating lamp 7 is provided at a proper place in the vehicle to inform the driver that the vehicle stop and hold device is operating. The solenoid valve 4 has a function of shutting off a hydraulic circuit by a signal from a control circuit 6 described later to maintain a vehicle stop state, and the solenoid valve operating lamp 7 is turned on while the vehicle stop holding device is operating. , Has a function of informing the driver that the vehicle stop holding device is operating.

A control circuit 6 for controlling the operation of the solenoid valve 4.
Will be described below. The control circuit 6 uses the tilt sensor S
1, load sensor S2, brake pressure detection switch S3,
The solenoid valve 4 and the operation lamp are operated or released by input signals from the clutch switch S4 and the parking switch S5. The inclination sensor S1 is a sensor that detects an inclination angle of a road on which the vehicle is stopped, the load sensor S2 is a sensor that detects a load state of the vehicle, the brake pressure detection sensor S3 is a sensor that detects a hydraulic pressure of a brake, and a clutch. The sensor S4 is a sensor that detects the operating state of the clutch, and the parking switch is a sensor that detects the on / off state of the parking brake. The clutch switch S4 and the parking switch S5 are not always essential in this control.

When a signal from each of the above sensors is input to the control circuit 6, the control circuit turns on / off the solenoid valve 4 as follows according to the flowchart shown in FIG.
Note that this flowchart shows a control mode in which signals from the clutch switch S4 and the parking switch S5 are not fetched. In FIG. 2, when the execution of this program is started, first, at step 10, it is judged whether or not the wheels have stopped based on signals from a speed sensor, a clutch sensor S4 and the like (not shown). When it is determined that the wheels are stopped (vehicle stop state), the routine proceeds to step 11, where the inclination angle of the vehicle is detected by the inclination sensor S1, and subsequently at step 12 and the load state of the vehicle is detected by the load sensor S2. To be done. Next, in step 13, the required brake pressure P1 in that state is calculated in the control circuit 6 based on the inclination angle and the load signal. Next, at step 14, the leakage amount α of the containment pressure corresponding to the required brake pressure P1.
(In other words, leakage of containment pressure in a certain time)
Is calculated using a previously obtained map (not shown) or the like, and the leak amount α is added to the required brake pressure (P1
+ Α)

Thereafter, in step 15, the judgment means in the control circuit compares and judges the present brake fluid pressure from the brake pressure detection sensor S3 and the brake fluid pressure (P1 + α) obtained in step 14. When it is determined that the current brake fluid pressure is higher, the routine proceeds to step 16, where the solenoid valve 7 is closed and the vehicle stop holding state is entered.
From this time, the vehicle stop holding state is started, and at the same time, the solenoid valve operating lamp is turned on to notify the driver that the vehicle stop holding state is in effect. When it is determined in step 15 that the current brake fluid pressure from the brake pressure detection sensor S3 is lower than the brake fluid pressure obtained in step 14, the routine of step 15 is repeated, and the current brake fluid pressure is determined in step 14. The vehicle stop and hold device does not operate until the brake pressure becomes higher than the required brake fluid pressure.

The vehicle stop-holding device described above is similar to the known vehicle stop-holding device in that the accelerator pedal is depressed,
It goes without saying that the vehicle is automatically released when the vehicle is started. Further, if the signal from the clutch switch S1 is taken in during the work for determining the vehicle stop state and the vehicle start state, the vehicle stop and start states can be more clearly determined. The device will not operate as it is no longer needed.

As described above, in this embodiment, the required brake pressure in that state is calculated based on the inclination angle and the load signal, and the leakage amount α of the containment pressure corresponding to the required brake pressure is calculated, Since the vehicle stop and hold device is prevented from operating until the current brake fluid pressure becomes higher than the fluid pressure to which these are added, it is possible to guarantee the stop and hold state of the vehicle for a certain period of time without being affected by the inclination and the load.

[0015]

As described in detail above, according to the present invention,
Determine the required brake pressure in that state based on the inclination angle when the vehicle stops and the load signal of the vehicle, and then add the leakage amount α of the containment pressure to the required brake pressure to obtain the final hydraulic pressure. Since the vehicle stop and hold device is prevented from operating until the current brake fluid pressure becomes higher than the fluid pressure, the vehicle can be kept stopped and held for a certain period of time without being affected by the inclination and the load. As a result, it is possible to prevent the vehicle from running unexpectedly. That is, it has an excellent effect.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a vehicle stop and hold device as an embodiment according to the present invention.

FIG. 2 is a flowchart for operating a solenoid valve in the vehicle stop and hold device.

FIG. 3 is a schematic configuration diagram of a conventional vehicle stop holding device.

[Explanation of symbols]

 1 Brake Pedal 2 Master Cylinder 3 Brake Cylinder 4 Solenoid Valve 5 Check Valve 6 Control Circuit 7 Operating Lamp S1 Inclination Sensor S2 Load Sensor S3 Brake Pressure Detection Sensor S4 Clutch Sensor S5 Parking Switch

Claims (1)

[Claims] 1. A vehicle stop holding device capable of automatically holding a braking force by detecting a stopped state of a vehicle, wherein an inclination sensor S1 for obtaining an inclination angle of the vehicle when the vehicle is stopped.
And a load sensor S2 for obtaining the load of the vehicle when the vehicle is stopped
A brake pressure detection sensor S3 and the inclination sensor S
1 and the required brake pressure are calculated based on the signals from the load sensor S2, the containment pressure corresponding to the calculation result is obtained, and whether the brake fluid pressure from the brake pressure detection sensor S3 is higher than the sum of these values. A vehicle stop holding device comprising: a control circuit 6 having a determination means for determining whether it is low, and a solenoid valve 4 configured to be activated by a signal from the control circuit.