JPS6239357A - Pressure control device of magnification device - Google Patents

Abstract

PURPOSE:To enable the use of a small pressure control valve, by a method wherein a titled pressure control device is formed with a relay valve, generating a control pressure responding to a pilot pressure to a boosting mechanism, and a pressure control valve generating a pilot pressure based on an input value. CONSTITUTION:An atmospheric pressure chamber 5 in front of a boosting mechanism 2 boosting a pedal force exerted on a brake pedal 1 is communicated with the open air through an opening formed in a shell 3, and a rear control pressure chamber 6 is selectively connectable to a feed source 13 for compressed air or the open air through a relay valve 12. The relay valve 12 is so constituted as to generate a control pressure responding to a pilot pressure introduced to a pilot chamber 14. A pressure control valve 15 is formed with a first opening and closing valve stage 15a, serving to communicate and discommunicate the pilot chamber 14 to and from a feed source 13, and a second opening and closing means 15b, serving to communicate and discommunicate the pilot chamber 14 to and from the open air, and is controlled by a control device 17 so that a pilot pressure responding to a detecting value of an input applied on an input shaft 8 is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure control device for a booster, and more specifically to a pressure control device for controlling the pressure of pressure fluid supplied to a booster mechanism that constitutes a booster. Regarding a control device.

"Prior Art" Conventionally, as a brake booster, the magnitude of the pedal force applied to the brake pedal is detected by an input detection means, the signal is input to a control device, and this control device controls a pressure control device. A brake fluid pressure is generated in the master cylinder by generating a control pressure corresponding to the magnitude of the pedal force, and supplying this control pressure to a control pressure chamber of a booster mechanism linked to the master cylinder. There are some (for example, JP-A-58-188746).

According to this type of brake booster, the output characteristics of the booster can be easily changed by simply changing the control conditions of the pressure control device in the control device, which increases versatility and improves driver comfort. It is possible to change the output characteristics according to your preference, and if the signals from the detector that detects the weight and deceleration of the vehicle are sent to the control device described in 1-1, the above pressure can be adjusted according to the driving condition of the vehicle. Since the control device can be controlled more precisely, it is possible to obtain an ideal braking force depending on the driving condition.

"Problems to be Solved by the Invention" By the way, the above-mentioned pressure control device is required to be able to stably obtain a control pressure of a necessary magnitude, and to be able to obtain the stable control pressure quickly. However, no conventionally known pressure control device satisfactorily satisfies such conditions.

For example, as a pressure control device for a brake booster, a first electromagnetic on-off valve is provided in a passage communicating between the control pressure chamber of the booster mechanism and a pressure fluid supply source, and the control pressure chamber and this control pressure chamber are provided with a first electromagnetic on-off valve. A second electromagnetic opening/closing valve is provided in a passage communicating with a discharge section for discharging the pressure fluid, and while detecting the pressure so that the control pressure of the control pressure chamber becomes a necessary control pressure, the first An electromagnetic on-off valve and a second electromagnetic on-off valve that can be opened and closed can be used.

However, in a pressure control device having such a configuration, the flow path area of each electromagnetic on-off valve must be made considerably large in order to ensure good responsiveness.

Therefore, each electromagnetic on-off valve has to be large in size, and the power consumption has also increased.

"Means for Solving the Problems" In view of such circumstances, the present invention uses a pressure control device to generate a control pressure corresponding to the pilot pressure introduced into the pilot chamber, and to apply the control pressure to the booster mechanism described above. and a pressure control valve that supplies a pilot pressure based on the input value into the pilot chamber.

"Operation" According to this configuration, the pressure control valve only needs to generate a pilot pressure based on the input value in the pilot chamber of the relay valve, and a large flow rate is not required, so the required pressure can be quickly obtained. If the pilot pressure corresponding to the above input value is quickly obtained, the relay valve is actuated by the pilot pressure to cause the control pressure chamber of the booster mechanism to correspond to the pilot pressure, that is, to correspond to the input value. Control pressure can now be generated quickly.

``Embodiment'' The present invention will be described below with reference to the illustrated embodiment. In FIG. This booster mechanism 2 includes a shell 3 as a sealed container, a power piston 4 provided inside the shell 3 so as to be able to move forward and backward, and a power piston 4 that moves inside the shell 3 between an atmospheric pressure chamber 5 at the front and an atmospheric pressure chamber 5 at the rear. A control pressure chamber 6 and a diaphragm 7 are provided.

The cylindrical shaft portion 4a of the power piston 4 protrudes through the shell 3 to the rear while maintaining airtightness, and is linked to the brake pedal 1 via an input shaft 8 whose tip is pivotally supported on the power piston 4. The power piston 4 is normally held in a retracted, non-operating position as shown in the figure by a return spring 9.

An output shaft 1o is integrally connected and fixed in front of the power piston 4, and this output shaft 1o is interlocked with a master cylinder (not shown) attached to the front part of the shell 3.

The atmospheric pressure chamber 5 in front of the booster mechanism 2 is always in communication with the atmosphere through an opening provided in the shell 3, and the control pressure chamber 6 in the rear is connected to a relay valve constituting the pressure control device 11 of the present invention. Communication can be switched via 12 to a supply source 13 of compressed air or to the atmosphere. The relay valve 12 generates a control pressure corresponding to the pilot pressure introduced into the pilot chamber 14 as described later, and supplies the control pressure to the control pressure chamber 6 of the booster mechanism 2. .

Further, the pressure control device 11 includes the pilot chamber 14
first opening/closing means 15 for communicating and cutting off the supply source 13 and the supply source 13;
a, and a second opening/closing means 15b for communicating and blocking the pilot chamber 14 and the atmosphere as a discharge section. Each of the above opening/closing means 15a, 15
b are designed to be opened and closed respectively by a control device 17 equipped with a computer, and the control device 17
detects the input applied to the input shaft 8 with the input detection means 18 such as a load cell, and controls the opening/closing means 15a and 15b while detecting the pilot pressure in the pilot chamber 14 with the pressure detection means 19. A pilot pressure corresponding to the value can be generated in the pilot chamber 14.

The relay valve 12 includes a housing 21 consisting of three members in which a through hole 20 is vertically bored, and a first valve formed at a stepped portion by enlarging the diameter of the lower middle of the through hole 20. a plunger 2 that is slidably fitted into the through hole 20 and has a second valve seat 23 formed at its lower end;
4. A cylindrical valve body 25 is slidably fitted into the lower part of the through hole 20, and a spring 26 elastically loaded between the valve body 25 and the housing 21 causes the valve body 25 to
The upper end surfaces of the valve seats 22 and 23 are urged upward so that they are seated on the respective valve seats 22 and 23.

Therefore, the valve body 25 includes a first seat portion 30 that seats on the first valve seat 22 and a second seat portion 3 that seats on the second valve seat 23.
1, and the booster mechanism 2 is controlled through a control passage 34 consisting of a lateral passage 32 and a conduit 33 formed in the housing 21 at an intermediate portion between the first seating part 30 and the second seating part 31. It communicates with the control pressure chamber 6.

Further, the radially outward side of the first seating portion 30 is communicated with the above-mentioned pressure fluid supply source 13 via a supply passage 37 formed in the housing 21 and consisting of a lateral passage 35 and a conduit 36, and The radially inward side of the second seating portion a1 is communicated with the atmosphere through a discharge passage 40 consisting of a passage 38 formed in the shaft of the bipedal valve body 25 and a longitudinal passage 39 formed in the housing 21. There is.

Further, the valve body 25 has a stepped portion 41 at the intermediate portion by making the diameter smaller from the intermediate portion downward, and a space including this stepped portion 41 is created between the valve body 25 and the housing 21. The supply passage 3 is sealed by the stretched diaphragm-shaped seal member 42 and the ring-shaped seal member 43 provided in the housing 21 and slidably in contact with the lower part of the outer peripheral surface of the valve body 25.
It is formed as a pressure chamber 44 divided from 7 and a discharge passage 40.

The pressure chamber 44 is communicated with the control passage 34 through a horizontal passage 45 and a vertical passage 4B formed in the housing 21, and the pressure receiving area of the stepped portion 4 and the first seating area of the valve body 25 are By making the pressure-receiving area equal in the intermediate portion between the portion 30 and the second seating portion 31, the valve body 2
The control pressure applied to 5 is balanced.

Next, a piston 50 is integrally formed at the upper end of the plunger 24 and is slidably fitted in the through hole 20 in an airtight manner. and a pressure chamber 51, respectively. The lower pressure chamber 51 is communicated with the control passage 34 through a passage 52 formed in the housing 21.

A spring 53 housed in the pressure chamber 51 is elastically mounted between the piston 50 and the housing 21, and this spring 53 holds the piston 50 at the upper end position when the relay valve 12 is inactive. There is. In this state, the piston 50
The plunger 24 integrated with the second valve seat 2 is also located at the rising end.
3 and the valve body 25 are separated from each other, and the valve body 25 is seated on the first valve seat 22 due to the elastic force of the spring 26. Therefore, the control pressure chamber 6 of the booster mechanism 2 is connected to the control passage 34 and the first valve seat 22. 2 Valve seat 23 and valve body 2
5 and a discharge passageway 40, which communicates with the atmosphere.

On the other hand, the pilot chamber 14 is communicated with the supply source 13 via the passage 54 formed in the housing 21, the conduit 55, and the above-mentioned @1 opening/closing means 15a, and also from the foot temperature cf'F55. It is branched and communicated with the atmosphere via the second on-off valve means 15b. In this embodiment, each of the opening/closing means 15a, 15b is composed of one electromagnetic opening/closing valve. Also, pressure control: Jf15 is controlled to control the control pressure based on the input value to the control pressure chamber 6 of the booster mechanism 2.
When generating the pressure, the pressure detection means 19 does not directly detect the pressure in the control pressure chamber 6, but can detect the pilot pressure in the pilot chamber 14, thereby obtaining a stable control pressure. That's what I do.

In the above configuration, in a non-operating state, that is, a state in which no pedal force is applied to the brake pedal 1, the control device 1
7 detects its state by the input detection means 18, and the first
The opening/closing means 15a is closed and the second opening/closing valve means 15b is opened to communicate the pilot chamber 14 with the atmosphere. In this state, as described above, the control pressure chamber 6 of the booster mechanism 2 is in communication with the atmosphere via the control passage 34, the gap between the second valve seat 23 and the valve body 25, and the discharge passage 40, and therefore Since no pressure difference is generated before and after the power piston 4, the power piston 4 is also held in the non-operating position by the return spring 9.

When the brake pedal 1 is depressed from this state and the pedal force is transmitted to the input shaft 8 (see polygonal line A in FIG. 2), the pedal force F is detected by the input detection means 18, and the control device 1
7 closes the second opening/closing valve means 15b and opens the first opening/closing means 15a to supply pressure fluid into the pilot chamber 14.

Then, the piston 50 and the plunger 2 integrated therewith
4 is displaced downward, the second valve seat 23 and the valve body 25 are seated to cut off communication between the control pressure chamber 6 and the atmosphere, and the valve body 25 continues to move downward against the spring 2B. Since the valve body 25 is moved, the valve body 25 is removed from the first valve seat 22. As a result, pressure fluid is supplied from the supply source 13 to the booster mechanism 2 through the supply passage 37, the gap between the valve body 25 and the first valve seat 22, and the control passage 34.
Since the fluid is supplied into the control pressure chamber 6, a fluid pressure difference is generated before and after the power piston 4, and the power piston 4 is moved forward against the elastic force of the return spring 9.

The pressure introduced into the pilot chamber 14 is detected by a pressure detection means 19, and when the pressure reaches a required pressure corresponding to the input, the control device 17 closes the first opening/closing means 15a. On the other hand, the pressure in the control pressure chamber 6 is guided to the pressure chamber 51 through the passage 52 and urges the piston 50 upward. As a result, the plunger 24 moves upward, so that the first valve body 25 is seated on the first valve seat 22. As a result, a control pressure corresponding to the input applied to the input shaft 8 is introduced into the control pressure chamber 6 (see curve B in FIG. 2). As a result, the power piston 4 and the output shaft 10 integrated therewith are moved forward with an output corresponding to the input, and brake fluid pressure is generated in a master cylinder (not shown) linked to the output shaft 10 to perform a braking action. It becomes like this.

At this time, the pressure in the control pressure chamber 6 is detected by the pressure detection means 18, and the signal from the detection means is transmitted to each opening/closing means 15a,
15b is used as a feedback signal for controlling the pilot chamber 14, as shown by curve C in FIG.
Since there is a time lag between the pressure fluctuations in the pilot chamber 14 and the pressure fluctuations in the control pressure chamber 6, the control pressure introduced into the control pressure chamber 6 will pulsate greatly. If the pressure is detected, the pulsation can be made small.

In the above embodiment, each of the opening/closing means 15a, 15b constituting the pressure control valve 15 is composed of one electromagnetic opening/closing valve, but the invention is not limited to this, for example,
One or both of the opening/closing means is composed of a plurality of electromagnetic opening/closing valves connected in parallel to each other, and in the parallel electromagnetic opening/closing valves, depending on the magnitude of the input value, only one solenoid opening/closing valve is controlled to open or close, or all of the solenoid opening/closing valves are controlled. It is also possible to control the opening and closing of an electromagnetic on-off valve.

Moreover, the pressure control valve 15 is connected to the pilot chamber 1 of the relay valve 12.
Since it is only necessary to generate a pilot pressure in the valve 4 and a large flow rate is not required, it is possible to use an appropriate pressure control valve other than those mentioned above. Furthermore, the control device 17
Of course, the control pressure may be determined comprehensively by inputting various conditions such as the loading state of the vehicle and the deceleration.

"Effects of the Invention" As described above, according to the present invention, the pressure control valve only needs to generate pilot pressure in the pilot chamber of the relay valve, so a small pressure control valve can be used. You can get the effect of becoming.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and is a system diagram showing a cross-sectional view of the main parts, and FIG. 2 is a characteristic curve diagram. l...Brake pedal 2...Boosting mechanism 3...Shell 4...Power piston 6...Control pressure chamber 8...Input shaft 11...Pressure control device 12
... Relay valve 13 ... Supply source 14 ...
Pilot chamber 15...pressure control valve 15a, 15
b... Opening/closing means 17... Control device 18...
・Input detection means 19...Pressure detection means Patent applicant Jidosha Kiki Co., Ltd. Figure 2

Claims (3)

[Claims] (1) A pressure control device for a booster that detects an input applied to an input shaft and supplies a control pressure based on the input value to a control pressure chamber of a booster mechanism to generate an output, which controls the pressure as described above. The device includes a relay valve that generates a control pressure corresponding to the pilot pressure introduced into the pilot chamber and supplies the control pressure to the control pressure chamber of the booster mechanism, and a pilot pressure that is generated in the pilot chamber based on the input value. A pressure control device for a booster, comprising a pressure control valve that supplies a pressure control valve. (2) The pressure control valve includes a first opening/closing means for communicating and blocking the pilot chamber with a supply source that supplies pressure fluid, and a second opening/closing means for communicating and blocking the pilot chamber and the discharge section. A pressure control device for a booster according to claim 1. (3) The pressure control device includes a pressure detection means for detecting the pressure in the pilot chamber, and receives a feedback signal from the pressure detection means to supply pilot pressure into the pilot chamber based on the input value. A pressure control device for a booster according to claim 1 or 2.