JPS634672Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a vacuum device for a brake booster, and more particularly to a vacuum device for a brake booster suitable for automobiles having a turbocharger and without a clutch.

[Conventional technology and its problems]

The brake booster increases the force on the brake pedal,
Although it has the effect of amplifying the negative pressure in the intake pipe, when the intake air is pressurized by the turbocharger, the negative pressure in the intake pipe tends to decrease. Such a drop in negative pressure is immediately resolved once the throttle valve is closed, but in automobiles without a clutch, the frequency of opening and closing of the throttle valve is low, and the negative pressure in the intake pipe is not easily restored. The relationship between the pedal force of the brake pedal [Kg] and the deceleration of the car [g] (Note: g is the gravitational acceleration) is as shown in Figure 1, and the negative pressure in the brake booster is P ₀ →P When the deceleration decreases as ₁ → P ₂ → P ₃ → P ₄ , the deceleration for the same pedal depression force, in other words, the amplification factor of the brake booster decreases, and there is a possibility that the deceleration expected by the driver will not be obtained.

This invention was devised to solve these conventional problems, and its purpose is to provide a vacuum device that can ensure sufficient negative pressure for the brake booster in an automobile having a turbocharger.

[Means for solving the problem] In order to achieve the above object, the brake booster vacuum device of the present invention is installed in the exhaust gas flow path for driving the turbine of the supercharger so as to bypass the turbine. a bypass flow path, a valve that opens and closes this bypass flow path, a detector that detects the negative pressure supplied from the intake pipe to the brake booster, and a sensor that detects the negative pressure until the negative pressure reaches a predetermined value or less based on the detection of the detector. It consists of an actuator that opens the valve when the negative pressure decreases, and a delay means that is inserted into the negative pressure supply system of the brake booster and gradually delays the actuator's closing operation of the valve when the negative pressure is restored.

[Effect]

When the negative pressure inside the brake booster drops to a predetermined value or less, the valve is opened, the exhaust gas flows into the bypass flow path, and the drive of the turbine is stopped. Conversely, when the negative pressure is restored, the closing operation of the valve is gradually delayed by the delay means, suppressing the steep rise of the exhaust gas flowing into the turbine, and preventing the supercharger from suddenly restarting operation.

〔Example〕

Next, a first embodiment of the brake booster vacuum device according to this invention will be described based on the drawings.

In FIGS. 2 and 3, the brake booster 1 is connected to the intake pipe 3 by a conduit 2 having a check valve 32, whereby negative pressure is supplied to the brake booster 1 and the check valve 32 is connected to the intake pipe 3. 32 maintains this negative pressure. An actuator 5 is connected to the middle of the pipe line 2 via a branch pipe line 4, and this actuator 5
is activated when the negative pressure in the pipe line 2 drops below a predetermined value. The actuator 5 has negative pressure chambers 6 and 7.
and atmospheric pressure chambers 8 and 9, and is connected to the branch pipe 4 at the negative pressure chamber 6. An atmospheric pressure chamber 8 is adjacent to the negative pressure chamber 6, and the negative pressure chamber 6 and the atmospheric pressure chamber 8 are separated by a diaphragm 10. A negative pressure chamber 7 is adjacent to the atmospheric pressure chamber 8 , and the atmospheric pressure chamber 8 and the negative pressure chamber 7 are separated by a partition wall 11 . An atmospheric pressure chamber 9 is adjacent to the negative pressure chamber 7 , and the negative pressure chamber 7 and the atmospheric pressure chamber 9 are separated by a diaphragm 12 . The diaphragm 10 is biased toward the atmospheric pressure chamber 8 by a coil spring 13. When the negative pressure in the negative pressure chamber 6 decreases, the diaphragm 10 moves in a direction to narrow the negative pressure chamber 6 against the elastic force of the coil spring 13. A piston 14 is fixed to the diaphragm 10 and extends through the atmospheric pressure chamber 8 and the partition wall 11 to reach the vicinity of the diaphragm 12, and the elastic force of the coil spring 13 is transmitted to the diaphragm 12 via the piston 14. The diaphragm 12 is biased toward the negative pressure chamber 7 by a coil spring 15 . When the negative pressure in the negative pressure chamber 7 decreases, the diaphragm 12 moves in a direction to narrow the atmospheric pressure chamber 9 while resisting the elastic force of the coil spring 15. That is, when the negative pressure in the intake pipe 3 decreases, the actuator 5 moves the diaphragm 12 against the elastic force of the coil spring 13 due to the pressure difference between the two surfaces of the diaphragms 10 and 12 and the elastic force of the coil spring 13. is moved in a direction to narrow the atmospheric pressure chamber 9.
A connecting rod 16 is fixed to the diaphragm 12 and extends through the atmospheric pressure chamber 9 to the outside of the actuator 5. When the diaphragm 12 moves, the connecting rod 16 is pushed outward.

In this way, the actuator 5 also functions as a detector for detecting the negative pressure within the intake pipe 3, so there is no need to provide a separate detector.

A bypass flow path 20 that bypasses the turbine 18 is provided in the exhaust gas flow path 19 for driving the turbine 18 in the supercharger 17, and this bypass flow path 20 is opened and closed as appropriate by a valve 21. It's getting old. The valve 21 is a swing lever 2
A valve plate 23 is fixed to the connecting rod 1.
6 is pivotally attached to the tip of the swing lever 22 at its tip. When the cooking rod 16 is pushed outward, the swing lever 22 swings to open the valve 21 (FIG. 3). As a result, the exhaust gas supply to the turbine 18 is stopped, and the turbocharger 1
7 is suppressed, and the negative pressure inside the intake pipe 3 is restored. After this negative pressure is restored, the valve 21 is closed again and the operation of the supercharger 17 is resumed. However, when this operation is suddenly resumed, the engine output increases rapidly, causing a problem for the driver. It gives a strange feeling and makes engine braking unstable during deceleration.

Therefore, the branch pipe 4 is provided with a throttle valve 24 as a delay means that performs a throttle action only in the direction from the negative pressure chamber 6 to the pipe line 2. As shown in FIG. 4, the throttle valve 24 has a check valve 25 that opens only in the direction A from the conduit 2 to the negative pressure chamber 6, and a throttle 26, which opens only in the direction A from the conduit 2 to the negative pressure chamber 6. The airflow passes smoothly through the check valve 25, but the airflow in the opposite direction B passes through the restriction 26 while being blocked by the check valve 25. Therefore, the actuator 5 operates slowly when the negative pressure is restored, the restart of the supercharger 17 is delayed, and a sudden increase in engine output is prevented.

In the second embodiment shown in FIG. 5, the actuator 5 includes the negative pressure chamber 6 and the atmospheric pressure chamber 8 of the first embodiment.
and solenoid 27 instead of diaphragm 10
This solenoid 27 is energized by a negative pressure switch 28 attached to the brake booster 1. The negative pressure switch 28 closes when the negative pressure in the brake booster 1 drops below a predetermined value, and connects the solenoid 27 to the battery 29. By energizing the solenoid 27, the piston 1
4 is brought into contact with the diaphragm 12, and together with the diaphragm 12, the connecting rod 16 is pushed outward. Further, a warning lamp 30 is provided in the circuit from the negative pressure switch 28 to the solenoid 27 to warn that the negative pressure in the brake booster 1 is decreasing.

In the second embodiment, a delay circuit 31 is employed as the delay means, and this delay circuit 31 gradually reduces the operating current of the solenoid 27 when the solenoid 27 is demagnetized.

[Effect of idea]

As described above, according to the present invention, when the negative pressure inside the brake booster drops below a predetermined value, the bypass flow path is opened and the turbine drive is stopped, so that the brake booster can maintain sufficient negative pressure. In addition, the negative pressure supply system of the brake booster is equipped with a delay means that gradually delays the operation of the actuator when the negative pressure in the brake booster is restored, so that the exhaust gas is not suddenly forced into the turbine as the negative pressure in the brake booster is restored. This prevents the restart of the supercharger from being delayed, preventing a sudden increase in engine output, and causing no discomfort to the driver.

It should be noted that this invention is not limited to the above embodiment, and it goes without saying that the negative pressure detector, actuator, valve, and delay means can be modified as appropriate.

[Brief explanation of drawings]

Fig. 1 is a graph showing changes in deceleration relative to brake booster pedal force for each negative pressure in the brake booster, and Figs. 2 to 4 show a first embodiment of the brake booster vacuum device according to this invention. Piping diagram, FIG. 5 is a piping diagram showing the second embodiment. In the drawings, the same or corresponding parts are denoted by the same reference numerals. 1...Brake booster, 2...Pipe line, 3...
Intake pipe, 4... Branch pipe line, 5... Actuator, 6, 7... Negative pressure chamber, 8, 9... Atmospheric pressure chamber, 1
0,12...diaphragm, 11...bulkhead, 1
3, 15...Coil spring, 14...Piston, 1
6... Conn rod, 17... Supercharger, 18... Turbine, 19... Exhaust gas flow path, 20... Bypass flow path, 21... Valve, 22... Rocking lever, 2
3... Valve plate, 24... Throttle valve, 25... Check valve,
26... Throttle, 27... Solenoid, 28... Negative pressure switch, 29... Battery, 30... Warning lamp, 31... Delay circuit, 32... Check valve.

Claims (1)

[Claims for Utility Model Registration] (1) A bypass flow path provided in the exhaust gas flow path for driving the turbine of the supercharger so as to bypass the turbine, a valve for opening and closing this bypass flow path, and an intake air flow path. a detector that detects the negative pressure being supplied from the pipe to the brake booster; an actuator that opens the valve when the negative pressure drops to a predetermined value or less based on detection by the detector; and a negative pressure of the brake booster. A vacuum device for a brake booster, comprising: a delay means inserted into a pressure supply system to gradually delay closing operation of the valve of an actuator when the negative pressure is restored. (2) The vacuum device for a brake booster according to claim 1, wherein the actuator has one or more diaphragms. (3) The brake booster according to claim 2, wherein the delay means is constituted by a throttle valve that performs a throttling action from the diaphragm to the negative pressure source when the negative pressure is restored. Vacuum device for use. (4) The vacuum device for a brake booster according to claim 1, wherein the actuator includes an electromagnetic operating section. (5) The brake according to claim 4, wherein the delay means is constituted by a delay circuit that gradually changes the current supplied to the electromagnetic operation section when negative pressure is restored. Vacuum device for booster.