JPS6237267A - Pressure control device for booster - Google Patents

Abstract

PURPOSE:To raise control pressure quickly by the overlapped control for opening and closing two solenoid valves connected to each other in series and releasing both of said means concurrently at the time of an output rise. CONSTITUTION:A pressure control device 11 is provided with a primary opening and closing means 15 for making continuous and shutting off between a pilot chamber 14 and a supply source 13 and a secondary opening and closing means 16 for making continuous and shutting off between the pilot chamber 14 and the atmosphere as an exhaust part. The opening and closing of said means 15 and 16 are regulated by a control device 17. The pilot chamber 14 is made continuous to the supply source 13 via a passage 54, a conduit 55 and an opening and closing means 15, and branched from the conduit 55 for continuity to the atmosphere via an other opening and closing means 16. And said opening and closing means 15 and 16 comprise two sets of solenoid valves 15a and 15b, and 16a and 16b respectively connected to each other in series and carry out the overlapped opening and closing control for said valve sets 15a and 15b, and 16a and 16b, when the control pressure has reached a level corresponding to an input value.

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. (For example, Japanese Patent Application Laid-Open No. 188748/1983).

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 you input signals from the detector that detects the weight and deceleration of the vehicle to the above control device,
Since the pressure control device can be finely controlled according to the driving condition of the vehicle, it is possible to obtain an ideal braking force according to 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, an electromagnetic on-off valve is provided in a passage that communicates the control pressure chamber of the two-leg booster with a pressure fluid supply source, and the control pressure chamber and this control pressure chamber are An electromagnetic opening/closing valve is provided in the passage communicating with the discharge part that discharges the pressure fluid, and while detecting the pressure, the electromagnetic valve on the supply side is installed so that the control pressure in the control pressure chamber becomes the required control pressure. An on-off valve and an electromagnetic on-off valve on the discharge side that can be opened and closed can be used.

However, in a pressure control device with such a configuration, the electromagnetic on-off valve generally has a fast operating speed, so there is no problem in terms of responsiveness, but since the pressure control is based on the opening/closing control of a pair of electromagnetic on-off valves, the control pressure may pulsate. This makes it difficult to obtain stable control pressure. Particularly when a small braking force is required, the pressure fluctuation due to the pulsation becomes a relatively large pressure fluctuation with respect to the required control pressure, which causes discomfort to the driver.

In order to improve such a drawback, pressure fluctuations can be reduced by reducing the flow path area of the pair of electromagnetic on-off valves, but in that case, responsiveness will deteriorate.

In view of such circumstances, the present invention provides a pressure control device that generates a control pressure corresponding to the pilot pressure introduced into the pilot chamber, and applies the control pressure to the booster mechanism described above. a relay valve that supplies the control pressure chamber to the control pressure chamber, a first opening/closing means for communicating and cutting off the pilot chamber and a pressure fluid supply source, and a second opening/closing means for communicating and cutting off the pilot chamber and the discharge section. and at least one of the first opening/closing means and the second opening/closing means is constituted by at least two TL electromagnetic opening/closing valves connected in series, and the opening/closing operations of each electromagnetic opening/closing valve overlap with each other. It was designed to be controlled.

"Operation" According to such a configuration, for example, when the first opening/closing means is composed of two electromagnetic switching valves connected in series, when the output increases, control is quickly performed by simultaneously opening both electromagnetic switching valves. On the other hand, when a constant output is required, the opening/closing operations of the solenoid valves are overlapped with each other, and pressure fluid is supplied only during the overlapping period. Since it is possible to obtain a control pressure with smaller pressure fluctuations than when opening and closing a valve, it is possible to obtain a control pressure that is excellent in responsiveness and stable.

``Embodiment'' The present invention will be described below with reference to the illustrated embodiment. In FIG. 1, 1 is a brake pedal pivotally supported on the vehicle body (not shown), and 2 is a boosting mechanism that boosts the pedal force applied to the brake pedal 1. 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 10 is integrally connected and fixed in front of the power piston 4, and this output shaft 10 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 described in 1 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. There is.

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;
and a second opening/closing means 1G that communicates with and shuts off the pilot chamber 14 and the atmosphere as an exhaust section. These opening/closing means 15 and 16 are controlled to open and close by a control device 17 equipped with a computer, and the control device 17 detects the input applied to the input shaft 8 using input detection means 18 such as a load cell. , while detecting the pilot pressure in the pilot chamber 14 by the pressure detection means 19, controlling each opening/closing means 15 and 16, and applying the Byronto pressure corresponding to the input value to the pilot chamber 14.
It can be generated internally.

However, the relay valve 12 includes a housing 21 consisting of three members in which a through hole 20 is vertically bored, and a first housing 21 formed at a stepped portion by enlarging the diameter below the middle of the through hole 20. a valve seat 22; 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 above-mentioned pressure fluid supply source 1 is provided through a supply passage 37 consisting of a lateral passage 35 and a conduit 36 formed in the housing 21 on the radially outward side of the first seating part 30.
3, and is controlled via a discharge passage 40 consisting of a passage 38 formed in the shaft portion of the valve body 25 on the radially inward side of the second seating portion 31 and a longitudinal passage 39 formed in the housing 21. The pressure decoration body in the pressure chamber 6 is communicated with a discharge section, that is, with the atmosphere.

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 46 formed in the housing 21, and the pressure receiving area of the stepped portion 41 and the first seating portion of the valve body 25 are connected to each other. 30 and the pressure receiving area at the intermediate portion of the second seating portion 31 are made equal, so that 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 above and below the piston 50 is the aforementioned pilot chamber. 14 and a pressure chamber 51 are respectively partitioned. 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 repulsive 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 communicates with the atmosphere through a gap between the valve seat 23 and the valve body 25 and a discharge passage 40.

On the other hand, the pilot chamber 14 includes a passage 54 formed in the housing 21, a conduit 55, and the first opening/closing means 15 described above.
Sources above via! 3, and is branched from the conduit 55 and communicated with the atmosphere via the second opening/closing means 16. In this embodiment, each opening/closing means 15.1B is composed of two electromagnetic opening/closing valves 15a, 15b, IEta, and 18b connected in series.

In the above configuration, in the non-operating state, that is, when no pedal force is applied to the brake pedal l, the control device 1
7 detects its state by the input detection means 18, and the first
The electromagnetic on-off valves 15a and 15b of the on-off means 15 are closed, and the second
The electromagnetic on-off valves 18a and 113b of the on-off means 16 are 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 in this state and the pedal force is transmitted to the input shaft 8, the pedal force is detected by the input detection means 18, and the control device 17 closes the electromagnetic on-off valves 113a, 18b of the second opening/closing means 16. At the same time, the electromagnetic on-off valves 15a and 15b of the first on-off means 15 are opened to supply pressurized fluid into the pilot chamber 14.

When pressure fluid is introduced into the pilot chamber 14, the piston 50 and the plunger 24 integrated therewith are displaced downward, so that the second valve seat 23 and the valve body 25 are seated, and the control pressure chamber 6 After cutting off the communication with the atmosphere, the valve body 25
is moved downward against the spring 26, so the valve body 25 is removed from the first valve seat 22. As a result, pressure fluid is supplied from the supply source 13 into the control pressure chamber 6 of 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, so that the power piston 4 A fluid pressure difference occurs before and after the power piston 4 is moved to the return spring 9.
The object is moved forward against the repulsive force of the object.

The pressure introduced into the pilot chamber 14 is detected by a pressure detection means 19, and when the pressure reaches a pressure corresponding to the input, the control device 17 controls the first opening/closing operation as described in detail below. Close means 15. On the other hand, the pressure in the control 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 valve body 25 moves to the first valve seat 2.
2, the second valve seat 23 and the valve body 25 are also seated, but at this time, it takes a little time to close the first opening/closing means 15, so the pressure in the pilot chamber 14 is slightly lower than the target pressure. becomes higher. Then, the second opening/closing means 16 is activated to lower the pressure in the pilot chamber 14. Furthermore, if the pressure in the pilot chamber 14 drops too much, the control device l? The first opening/closing means 5 is opened again, and the second opening/closing means 16 is closed to supply pressure fluid to the pilot chamber 14.

However, in the embodiment, each pair of electromagnetic on-off valves 15a, 1
5b, IEia, and leb are controlled to open and close in an overlapping manner, thereby reducing pressure fluctuations in the pilot chamber 14 and, therefore, pressure fluctuations in the control pressure chamber 6. That is,
As shown in FIG. 2, when each of the opening/closing means 15 and 16 is constituted by one electromagnetic opening/closing valve, and the opening/closing of the electromagnetic opening/closing valves is controlled alternately, the pressure fluctuation range P in the pilot chamber 14 becomes large. Become.

On the other hand, as shown in FIG. 3, the opening/closing means 15.1B
Two electromagnetic on-off valves 15a, 15b and 1 constitute the
By controlling the opening and closing of valves 8a and 18b in an overlapping manner, pressure fluid can flow only during the time period T when both electromagnetic valves are opened at the same time.

In this state, compared to the case shown in Fig. 2, the pilot room 1
4, the pressure fluctuation width p becomes smaller.

Therefore, in the control pressure chamber 6, there are electromagnetic on-off valves 15a, 15b and le that correspond to the input applied to the input shaft 8 and that are controlled to open and close in a mutually overlapping manner.
With the operation of a and IBb, a small pulsating control pressure is introduced.

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.

In this way, when pressure 1:, both electromagnetic on-off valves 15a,
15b can be opened to immediately cause the booster mechanism 2 to generate an output, and when the control pressure reaches the required pressure corresponding to the input value, each electromagnetic on-off valve +5a, 15b and t(la , 16b, pressure fluctuations can be reduced by mutually overlapping opening/closing control.
Responsiveness is good and discomfort to the operator can be prevented.

In addition, in the two-legged embodiment, each opening/closing means I5.16 is a pair of electromagnetic opening/closing valves 15a, 15b and lea, 16.
(b), but is not limited to this; for example, one of the opening/closing means may be a pair of electromagnetic opening/closing valves connected in parallel with different flow path areas, and the Alternatively, one or both of the parallel electromagnetic on-off valves may be selectively used.

Furthermore, it goes without saying that the control pressure may be comprehensively determined by inputting various conditions such as the loading state of the vehicle and deceleration into the control device 17.

"Effects of the Invention" As described above, according to the present invention, it is possible to obtain an output of a boosting mechanism that is excellent in responsiveness and stable.

[Brief explanation of drawings]

Fig. 1 shows an embodiment of the present invention, and is a system diagram with a sectional view of the main parts, and Fig. 2 shows an example in which each opening/closing means is composed of one electromagnetic opening/closing valve, and both are controlled to open and close alternately. FIG. 3 is a diagram illustrating the pressure fluctuation width P in the present invention. 1...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 room 15...First opening/closing means 16...
-Second opening/closing means 15a, 15b, 1f3a, 16b-
・-Solenoid on-off valve 17...Control device 18...
Input detection means patent applicant Jidosha Kiki Co., Ltd. Figure 2

Claims (1)

[Claims] 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, the pressure control device comprising: 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 communicates and shuts off the pilot chamber and the pressure fluid supply source. at least one of the first opening and closing means and the second opening and closing means are connected in series. A pressure control device for a booster, comprising two electromagnetic on-off valves, and controlling the opening and closing operations of each electromagnetic on-off valve in an overlapping manner.