JPH0423087Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a brake oil pressure holding device that automatically confines the brake oil pressure when the vehicle is stopped.

[Background of the idea]

Conventionally known vehicle brake oil pressure holding devices include a return prevention means, such as a normally open solenoid valve, interposed in the brake oil return piping, and this is controlled by an operation control device to close the circuit when the vehicle is stopped. It is common to have a configuration in which the activation is released at the time of the next vehicle start operation.

As a method for detecting the time of the next vehicle starting operation described above, for example, there is a method in which a limit switch detects a constant depression position of the clutch pedal and detects the connection timing when the clutch is released. There is a problem in that the clutch pedal depression position and the actual clutch connection cannot maintain a stable correspondence over time due to wear and tear on the clutch pedal and other mechanical parts.

A system has also been proposed in which the engine rotational speed (rotational speed) is detected and the timing of clutch engagement is detected based on the degree of deceleration of the rotational speed that appears when the clutch is engaged. However, the deceleration rate is not constant depending on the speed of the engine when the clutch is engaged, and the engine may not start smoothly, especially from an idling state. Ta.

[Purpose of invention]

The present invention was developed based on the above-mentioned viewpoints, and its purpose is to release the brake hydraulic pressure automatically maintained in a stopped vehicle smoothly and without causing slippage on an uphill road. An object of the present invention is to provide a brake hydraulic pressure holding device that can perform the same operation.

Another object of the present invention is to provide a brake hydraulic pressure holding device particularly suitable for application to so-called manual transmission vehicles.

[Summary of the idea]

The brake hydraulic pressure holding device of the present invention, which was developed to achieve this purpose, is characterized by the provision of a normally open solenoid valve in the middle of the pipe connecting the master cylinder and the brake device, which maintains the zero state of the wheel speed. The brake hydraulic pressure holding device closes the solenoid valve in response to a detected signal and opens the solenoid valve in response to a signal detected when the accelerator pedal is depressed, and includes a tilt sensor that detects that the vehicle is stopped on an uphill road, and a tilt sensor that detects that the vehicle is stopped on an uphill road. A local maximum value detector is provided to detect the local maximum value of the engine speed caused by clutch engagement during operation, and when an uphill road detection signal is output from the inclination sensor, the local maximum value detection signal of the local maximum value detector causes the electromagnetic valve to be activated. This is because it is configured to open up the .

One of the reasons why such a configuration was adopted in the present invention is that even if the brake hydraulic pressure is released when the driving torque of the wheels is almost zero when the vehicle starts, there is no particular problem; On the other hand, on an uphill road, an inertial force is applied to the vehicle in the direction of the vehicle sliding down, so if the wheels do not have a certain level of driving torque, the vehicle will slide down when the brakes are released, or the engine will stall due to the load. For ease of use, etc., the two cases are distinguished and a desirable timing for releasing the brake hydraulic pressure during the start operation is provided.

[Example of idea]

The present invention will be described below based on embodiments shown in the drawings.

In FIG. 1, 1 is a speed sensor that detects the rotation of the wheel, 2 is a speed zero detector that detects the zero state of the wheel speed based on the signal from the speed sensor 1, and this output is input to the AND gate 9. , This outputs a containment signal which is an activation signal for the solenoid valve 11 (the other two input signals of the AND gate 9 are inverted inputs of the signal for releasing the containment of the brake hydraulic pressure). ).

Note that 10 is an amplifier, and the solenoid valve 11 is
This is a normally open solenoid valve installed in the piping connecting the master cylinder (not shown) and the brake device.
The circuit is closed by the brake oil pressure containment signal.

Reference numeral 4 denotes an accelerator switch, which detects depression of an accelerator pedal (not shown) and outputs a signal to the AND gate 7. Further, 5 is an engine rotation speed detector, and 6 is a maximum value detector for engine rotation speed, which detects the maximum value when the engine rotation speed changes from an increase to a decrease that appears when the clutch is engaged (see point b in Figure 2). It is something to detect. In addition, and gate 7,
The circle marked 9 is a NOT circuit. In other words, the signal from the accelerator switch is an inverted signal from the tilt sensor 3 (i.e., the vehicle is not tilted).
is invertedly input to the AND gate 9 through the AND gate 7 which has the other input, and therefore, when the accelerator pedal is depressed, the AND gate 9
is not established, the output of the brake oil pressure containment signal is stopped, and the solenoid valve 11 is deactivated.

Further, the signal from the engine speed maximum value detector 6 is passed through the AND gate 8 whose other input is the signal from the tilt switch 3 (that is, the vehicle is on an uphill road and is tilted). When the reverse input is made to the AND gate 9 and therefore the local maximum value of the engine speed appears, the AND gate 9 is not established, the output of the brake oil pressure containment signal is stopped, and the solenoid valve 11 is deactivated.

Note that time a shown in FIG. 2 represents the time when the accelerator pedal starts to be depressed, and time c in the figure indicates that the so-called half-clutch state has ended and the engine speed tends to increase as the accelerator pedal is depressed. indicates the point in time.

According to such a configuration, the deactivation of the solenoid valve 11 is performed by the establishment of either AND gate 7 or 8, and the establishment of either of these is switched depending on the presence or absence of the output of the tilt sensor 3. Therefore, there is an advantage that whether the vehicle is stopped on an uphill road or on another road surface can be reliably selected and switched using an inclination sensor such as a mercury switch or the like.

In addition, in this example, the start operation timing of a vehicle stopped on an uphill road is detected by detecting the maximum value of the engine rotation speed, because generally, in a vehicle stopped on an uphill road, the wheels are not yet turned at the time of depressing the accelerator. This is based on the following two findings: the driving torque is insufficient, which tends to cause engine stalling, and the fact that when the clutch is engaged with the accelerator depressed, a maximum value appears in the engine speed increase curve depending on the load. It has been experimentally confirmed that this type of timing detection is effective for determining the timing of brake hydraulic pressure release.

[Effect of idea]

According to the present invention, when the brake hydraulic pressure held in a stopped vehicle is released at the time of the next vehicle starting operation, it can be done without problems such as the vehicle sliding down or stalling on a slope, and can be done on a flat road etc. This has the effect of allowing a smooth start, and particularly in so-called manual transmission vehicles, there is an advantage in that a preferable starting operation is provided.

[Brief explanation of the drawing]

Fig. 1 shows a block circuit diagram of the brake oil pressure holding device according to the present invention, particularly a device for controlling the operation of the brake oil pressure containment means, and Fig. 2 explains the state of change in engine speed when the vehicle starts. It is a diagram. 1...Speed sensor, 2...Zero speed detector, 3...Inclination sensor, 4...Accelerator switch, 5...Engine speed detector, 6...Local maximum value detector, 7, 8, 9, 13 ...And Gate, 1
0...Amplifier, 11...Solenoid valve.

Claims (1)

[Claim for Utility Model Registration] A normally open solenoid valve is provided in the pipe connecting the master cylinder and the brake device, and the solenoid valve is closed in response to a signal that detects the zero state of wheel speed, and the depression of the accelerator pedal is detected. The brake hydraulic pressure holding device opens the electromagnetic valve in response to a signal generated by the vehicle, and includes an inclination sensor that detects when the vehicle is stopped on an uphill road, and a maximum value of the engine rotation speed that occurs when the clutch is engaged when starting the vehicle. A brake hydraulic pressure holding device comprising: a maximum value detector; and when an uphill road detection signal is output from the inclination sensor, the electromagnetic valve is opened by the maximum value detection signal of the maximum value detector.