JPH07117661A - Vacuum circuit for brake device - Google Patents

Abstract

PURPOSE:To prevent the generation of alarm if the time does not reach an upper limit value even after the lapse of a prescribed time, when vacuum pressure is frequently used during the time when a vehicle travels on a slope. CONSTITUTION:A timer 50 which starts counting after the closure of a lower limit switch 46 is reset by closing a brake switch 52 each time when a brake pedal is stepped ON.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum circuit for a brake device, which is used in a brake device of a vehicle, for example, and supplies a vacuum pressure to a brake booster of the brake device.

[0002]

2. Description of the Related Art For example, Japanese Patent Laid-Open No. 4-24
Japanese Patent No. 4471 discloses a braking device for a vehicle, and a vacuum pump is used for this, and a braking force is obtained by this negative pressure. However, the vacuum generation capability of this vacuum pump is natural. While decreasing with use time. It is not possible to determine the maintenance timing due to this deterioration in capacity. If you drive this vehicle without being aware of this deterioration, you may encounter an unexpected accident.

In view of the above-mentioned problems, the present applicant has previously provided a vacuum pump which is driven by an external power source to generate a vacuum pressure for the purpose of providing a vacuum pump circuit capable of reliably determining the maintenance timing of the vacuum pump. A tank for storing a vacuum pressure generated by the vacuum pump, a lower limit switch for driving the vacuum pump when the vacuum pressure in the tank reaches a first predetermined pressure, and a vacuum pressure in the tank for the vacuum pressure in the tank. In a vacuum pump circuit having an upper limit switch for stopping the vacuum pump when a second predetermined pressure higher than a predetermined pressure of 1 is reached, the upper limit switch is activated after the lower limit switch is activated. Japanese Patent Application No. 5-76336 has proposed a vacuum pump circuit provided with an alarm device for issuing an alarm when a predetermined time elapses.

However, when a vehicle equipped with the above-mentioned vacuum circuit and equipped with a brake booster as a device requiring a vacuum pressure, for example, travels on a downhill, the number of brake operations increases, and In this case, the amount of vacuum pressure consumed increases, and the operating time of the pump increases. For this reason, a certain period of time may elapse before the lower limit switch operates and the upper limit switch operates.At this time, the vacuum circuit issues an alarm, so an alarm is issued even when the pump is normal. Will be lost.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. For example, when traveling on a downhill, the number of brake operations increases and the vacuum pressure consumption is high. The object of the present invention is to provide a vacuum circuit for a brake device that can suppress the alarm.

[0006]

[Means for Solving the Problems] The above objects are: a pump that is driven by external power to generate a vacuum pressure; and a brake booster that is supplied with vacuum pressure from the pump and consumes the vacuum pressure by the driver's braking operation. A device, a brake switch that outputs a brake signal in response to a brake operation, a lower limit switch that drives the vacuum pump when the vacuum pressure generated by the vacuum pump reaches a first predetermined pressure, and a vacuum pump generated by the vacuum pump. When the vacuum pressure to be reached reaches a second predetermined pressure that is higher than the first predetermined pressure, an upper limit switch that stops the vacuum pump, and until the lower limit switch operates until the upper limit switch operates A timer for measuring the time of, and when the timer measures a predetermined time or more,
In a brake device vacuum circuit including an alarm device for issuing an alarm, a brake device vacuum circuit in which the timer is set to an initial state in response to the brake signal.

[0007]

For example, when traveling downhill, the number of times of brake operation increases, but a brake signal is generated from the brake switch each time the brake pedal is stepped, and a timer for measuring the time after the lower limit switch is activated by this is provided. The time is reset and the time is measured again from time 0.
Therefore, since the predetermined time set in the timer is not reached, the alarm device does not issue an alarm. Of course, even if some equipment malfunctions and the vacuum pressure is not consumed so much by the brake operation, if the predetermined time set in the timer or more has elapsed since the lower limit switch was activated, the alarm will be issued as before. The device raises an alarm.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vacuum circuit for a brake device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a piping system of a vehicle having a vacuum circuit according to the present invention and equipped with a controller 17. A tandem master cylinder 1 with a brake booster is shown in FIG.
Is configured in a known manner, and the brake booster unit 2 supplies vacuum pressure by the vacuum tank 12 via the check valve 14 and the conduit 19. A drive signal for driving the electric motor 10 is generated from the controller 17, whereby the vacuum pump 11 is driven to supply a vacuum pressure to the vacuum tank 12 via the pipe line 18 and the check valve 13.

A pedal force is applied to the master cylinder portion 4 of the tandem master cylinder 1 by the brake pedal assisting action of the vacuum pressure supplied from the vacuum tank 12 when the brake pedal 3 is depressed via the brake booster unit 2. By assisting and activating the piston in the master cylinder part 4,
Rear wheels 8a, 8b from the second hydraulic pressure generation chamber via the pipes 6, 7
Also, hydraulic pressure is supplied to the wheel cylinders of the front wheels 9a and 9b.

A brake switch 20 is provided which, when the brake pedal 3 is stepped on in the vicinity of the brake pedal 3, presses the actuator to generate a brake signal.
The brake signal from now on is supplied to the controller 17.

Next, the vacuum circuit provided in the controller 17 will be described with reference to FIG.

The vacuum circuit is generally designated by 30, and an alarm device 36 is connected between the positive electrode 31 and the negative electrode 33 of the battery via a fuse f and electric lines 35 and 37.
Further, an alarm switch 38 and a timer contact 53 are connected in parallel with the negative electrode 33 side. Further, the ignition switch 34 is connected with a relay contact 44, an electric line 43, a relay 45, and a lower limit switch 46 between the fuse f and the electric line 37 via the electric line 39. Furthermore,
In parallel with this, the electric line 42, the relay 40, the upper limit switch 4
1 is connected. The alarm switch 38 is a switch that closes when the pressure in the vacuum tank 12 drops to a predetermined pressure lower than the lower limit pressure.

A relay contact 48 and a pump 49 are connected between the positive electrode 32 and the negative electrode 33 of the battery via an electric line 47.

Between the contact point 44 of the electric line 43 and the relay 45 and the electric line 37, a timer 50 and a relay contact 51 are provided in parallel with the relay 45 and the lower limit switch 46.
Are connected, and the brake switch 52 is connected in parallel with the above.

In FIG. 1, pressure gauges 15 and 16 for detecting the vacuum pressure in the vacuum tank 12 are connected, which are the upper limit switch 41 and the lower limit switch 46 in FIG.
Shall be included. Further, the fixed contact and the movable contact built in the brake switch 20 in FIG. 1 are denoted by 52 in FIG. Further, although the vacuum pump 11 in FIG. 1 is constructed in a known manner,
The drive of this pump is assumed to be designated 49 in FIG. Further, in this embodiment, the lower limit value of the pressure gauge 15 for measuring the lower limit value is 500 mHg, and the upper limit value of the pressure gauge 16 for detecting the upper limit value is 400 mHg.

The embodiment of the present invention is constructed as described above. Next, this operation will be described.

When the driver depresses the brake pedal 3, hydraulic pressure is generated in the master cylinder portion 4 by the assisting action of the brake booster portion 2, and this causes the front wheel 9 through the pipe lines 6 and 7.
The hydraulic fluid is supplied to the wheel cylinders of a, 9b and the rear wheels 8a, 8b to apply the brakes. When the brake pedal 3 is stepped on, the brake switch 20 is actuated to supply a brake signal to the controller 17. That is, when the brake switch 20 is stepped on in the vacuum circuit of FIG. 2, the contact 52 is closed. Every time the brake pedal 3 is stepped on, the brake booster unit 2 is supplied with vacuum pressure from the vacuum tank 12, that is, exhausted to perform a pedaling force assisting action, but the vacuum pressure in the vacuum tank 12 is the lower limit due to this consumption. When the pressure drops, the vacuum pump 11 is driven. Next, the operation of the vacuum pump circuit causes
This will be described with reference to FIG.

Although FIG. 2 shows the case where the vacuum pressure in the vacuum tank 12 is equal to or lower than a predetermined pressure lower than the lower limit pressure, the alarm switch 38 is closed for this purpose. Therefore, when the engine key is turned on, the alarm device 36 is driven to issue an alarm, but since both the upper limit switch 41 and the lower limit switch 46 are closed, the relay 40 is excited and the relay contact 44 is closed. This excites the relay 45 and closes the contact 48. Therefore, the pump 49
Are driven to supply vacuum pressure to the vacuum tank 12. Therefore, the vacuum pressure in the vacuum tank 12 immediately exceeds a predetermined pressure to be alarmed, and the contact 38 opens. Therefore, the alarm of the alarm device 36 stops immediately. By driving the vacuum pump 11, the vacuum pressure in the vacuum tank 12 eventually exceeds the lower limit pressure. This opens the lower limit switch 46. Although the lower limit switch 46 is opened, the contact 44 is closed, and the contact 51 is closed when the relay 45 is excited.
Even if a current is flowing through the electric line of the relay 45-contact 51 and the lower limit switch 46 is opened, the self-holding action of the relay 45 keeps exciting the relay 45, so that the contact 48 is closed. Keep driving. As a result, the vacuum pressure in the vacuum tank 12 rises between the lower limit pressure and the upper limit pressure, but the contact point 51 closes and the timer 50 starts counting time. If the various devices are normal, the vacuum pressure in the vacuum tank 12 reaches the upper limit value within the set time of the timer 50, and the upper limit switch 41 is opened. Therefore, the relay 40 is de-energized, and the contact 44 is opened, so that the timer 50 stops counting time. That is, the alarm device 36 is not driven.

Next, even if the vacuum tank 12 or its related equipment fails and the vacuum pump 11 (even if it itself fails) continues to operate, the upper limit pressure is not reached within the predetermined time set in the timer 50. In this case, the upper limit switch 41 remains closed, so the relay 40 continues to be energized and thus the contact 44
Is also closed, the timer 50 detects that a predetermined time has elapsed, and accordingly, the timer contact 53 is closed, and the alarm device 3 is closed.
6 is activated and an alarm is issued.

However, when the vacuum tank 12 and the related equipment are normal and the vehicle is traveling on a slope and the brake is applied frequently, the brake switch 52 is closed by depressing the brake pedal 3. . Therefore, even if the lower limit switch 46 is closed and the timer 50 starts counting time, the timer 50 is reset by the voltage applied between the ignition switch 34 and the negative electrode 33 by closing the brake switch 52. Therefore, when the pedal effort is released from the brake pedal 3, time counting starts again from time 0. Each time the brake pedal 3 is stepped on, the time count starts from 0. Therefore, even if a predetermined time or more has elapsed since the lower limit switch 46 was closed and the pump 49 started driving, the timer 50 does not time out. Therefore, the timer contact 53 does not close. Therefore, the alarm device 36 is not driven. That is, no alarm is issued.

The embodiment of the present invention is configured as described above,
Although it operates, the vacuum tank and its related equipment can be accurately maintained, and the alarm device 36
Will not give false alarms.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, although the alarm device 36 is a buzzer, it may be a red lamp provided inside the driver's seat.
The upper limit switch 41 and the lower limit switch 46 have an upper limit value and a lower limit value of 400 mmHg and 500 mmH, respectively.
Although set as g, this numerical value may be changeable in the controller 17 according to the vehicle.

[0025]

As described above, according to the brake circuit vacuum circuit of the present invention, it is possible to accurately know the deterioration of the vacuum pump capacity and the related equipment without erroneous alarming, and to maintain the maintenance. Can be ensured. Even when the capacity of the vacuum pump is low or related equipment is normal and the vacuum pressure is frequently used before the lower limit value is exceeded and the upper limit value is reached, maintenance is performed without giving a false alarm. Is definitely played.

[Brief description of drawings]

FIG. 1 is a piping system diagram of a brake device vacuum circuit according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a vacuum circuit in the controller.

[Explanation of symbols]

 36 Alarm device 50 Timer 52 Brake switch 53 Timer contact

Claims (1)

[Claims] 1. A pump that is driven by an external power source to generate a vacuum pressure, a brake booster that is supplied with the vacuum pressure and consumes the vacuum pressure by a driver's brake operation, and a brake signal according to the brake operation. And the vacuum pressure generated by the vacuum pump is the first
Lower limit switch for driving the vacuum pump when reaching a predetermined pressure, and the vacuum when the vacuum pressure generated by the vacuum pump reaches a second predetermined pressure higher than the first predetermined pressure. An upper limit switch that stops the pump, a timer that measures the time from the activation of the lower limit switch to the activation of the upper limit switch, and an alarm device that issues an alarm when the timer measures a predetermined time or more In a vacuum circuit for a brake device, the vacuum circuit for a brake device, wherein the timer is set to an initial state in response to the brake signal.