JPH01175557A - Pneumatic pressure type booster device - Google Patents

Abstract

PURPOSE:To obtain the hysteresis of an input/output characteristic without lowering durability by making the inner peripheral side of the seal face of a poppet seal on which the breather valve of a plunger is seated/separated displaceable in the axial direction. CONSTITUTION:When an input shaft 9 is advanced by stepping in a brake pedal, a breather valve 10a is separated from a poppet seal 16 and the air is introduced into a transformer chamber 6 advancing a diaphragm 4 due to the pressure difference toward a negative pressure chamber 5, to transmit the thrust of a booster to an output shaft 11. Then, as the stepping of the pedal is stopped, since a valve body 7 is advanced with a plunger 10 being moved back, the breather valve 10a is seated on the inner periphery side of a seal face 16a which was minutely displaced forward. The breather valve 10a presses the inner periphery side of the seal face 16a to displace same rearward and, further, a vacuum valve 7a is separated from the seal face 16a in the rear end position of the plunger 10. As the transformer chamber 6 is connected to the negative pressure chamber 5, the pressure difference is lowered moving the diaphragm 4 backward, returning to an initial nonoperating condition.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pneumatic booster used in the brake system of automobiles, etc. The present invention relates to a pneumatic booster used in the brake system of automobiles, etc. Regarding a type booster.

(Prior Art) In recent years, as automobiles become faster and more powerful, air pressure boosters have been installed in brake systems. This pneumatic booster uses the pressure difference between the negative pressure generated in the intake manifold and the atmospheric pressure of outside air to move the diaphragm, and operates the mask cylinder in conjunction with the brake pedal depression force, even with a small pedal pressure. Sufficient braking force can be obtained. A typical pressure booster is shown in FIG. 6.

To explain this, a main body 3 is formed from a front shell 1 and a rear shell 2, and a diaphragm 4 defines the main body 3 into a negative pressure chamber 5 on the front shell I side and a variable pressure chamber 6 on the rear shell 2 side.

One end of the valve body 7 is attached to the diaphragm 4, and the other end projects outward from the main body 3 on the rear end side. Further, a cylinder portion 8 is formed in the axial direction of the front end of the valve body 7, and a plunger IO that is interlocked with the input shaft 9 is slidably fitted into the cylinder portion 8.

Further, an output shaft 11 is connected to the valve body 7 and extends forward so as to face the plunger IO.

Further, a vacuum valve 7a is formed in the valve body 7, and a poppet seal 12 is seated and disposed on the vacuum valve 7a, thereby communicating and cutting off the negative pressure chamber 5 and the variable pressure chamber 6.
Further, an atmospheric valve 10a is formed at the rear end of the plunger lO, and a poppet seal 12 is provided in this atmospheric valve 10a.
The variable pressure chamber 6 and the atmosphere are communicated and cut off by being seated and separated from each other.

Note that 13 is a return spring for retracting the diaphragm 4, 14 is a return spring for retracting the input shaft 9, and 15 is a poppet spring that urges the sealing surface 12a side of the poppet seal I2 forward.

The pneumatic booster configured in this manner operates as follows.

First, in the non-operating state, the atmospheric valve 10a and the vacuum valve 7a
is seated on the poppet seal 12, and when the brake pedal (not shown) is depressed from this state, the input shaft 9 advances, the plunger 10 is pushed forward, and the atmospheric valve 10a is pushed forward.
The air is separated from the poppet seal 12, and the atmosphere is introduced into the variable pressure chamber 6. When the atmosphere is introduced into the variable pressure chamber 6.

The pressure inside the variable pressure chamber 6 increases, the diaphragm 4 moves, and the boosted thrust is transmitted to the output shaft 11.

Then, when the brake pedal is stopped, the plunger IO stops and the valve body 7 moves forward, so that the poppet seal 12 and the atmospheric valve 10a.

The poppet seal 12 and the vacuum valve 7a formed in the valve body 7 are further separated from each other. As a result, the variable pressure chamber 6 and the negative pressure chamber 5 are communicated with each other, and the diaphragm 4 is retracted by the return spring 1, returning to the initial non-operating state.

By the way, in such a boost operation, if the input/output characteristics have hysteresis, a preferable operating feeling can be obtained. In particular, it has been found that when operating the brakes while driving at high speeds, it is possible to maintain a sense of residual braking effect, resulting in an extremely stable braking feeling.

Conventionally, the sealing surface 12a of the poppet seal 12
By lowering the hardness of the sides or increasing the wall thickness, the atmospheric valve 10a and the vacuum valve 7a remain seated on the poppet seal 12 for a long time when the brake pedal is stopped, thereby reducing hysteresis. I was trying to get it.

(Problems to be Solved by the Invention) However, conventional means for obtaining hysteresis by lowering the hardness of the sealing surface 12a side of the poppet seal 12 or increasing the wall thickness.

There is a problem in that the sealing surface 12a tends to cave in due to changes over time due to long-term use, resulting in reduced durability.

As a result, a problem arises in that the sealing performance is degraded and the pneumatic booster may malfunction.

The present invention has been made in view of the above problems, and its purpose is to provide a pneumatic booster that can provide hysteresis in input/output characteristics without reducing durability. .

(Means for Solving the Problems) As a means for solving the above problems, the vacuum valve formed in the valve body is seated and separated to communicate and cut off the negative pressure chamber and the variable pressure chamber, and furthermore, after the plunger In a pneumatic booster that has a poppet seal that connects and disconnects the variable pressure chamber and the atmosphere by sitting on and off an atmospheric valve formed at the end.

The atmospheric valve of the plunger leaves and seats. The inner peripheral side of the seal surface of the poppet seal is freely displaceable in the axial direction.

(Function) With this configuration, when the brake pedal is stopped being depressed, the valve body moves forward and the atmospheric valve of the plunger, which had been separated, seats on the poppet seal, and then seats on the poppet seal. By displacing the inner peripheral side of the seal surface where the atmospheric valve of the poppet seal seats and leaves in the axial direction, both valves remain seated on the poppet seal for a long time until the vacuum valve of the valve body separates. This means that hysteresis can be obtained without reducing the durability of the poppet seal.

(Example) Next, an example of the present invention will be described based on the drawings. The present invention differs from the conventional pneumatic booster only in the configuration of the poppet seal, so the same reference numerals are given to the same or equivalent members as in the conventional pneumatic booster. A detailed explanation will be omitted.

FIGS. 1(a) and 1(b) show a poppet seal 16 according to an embodiment of the present invention, in which a flexible seal body 17 is shown.
and a support plate 18.

As shown in FIG. 1(a), the support plate 18 consists of a ring-shaped inner part 18a, an outer part 18b, and four thin connection parts 18c that connect the inner part 18a and the outer part 18b. Inner part 1
8a and the outer portion 18b are configured to be relatively movable in the axial direction. Note that a projection 1ad for fixing the poppet spring 15 is provided on the inner periphery of the inner portion 18a.
is formed.

The operation of the pneumatic booster equipped with the poppet seal 16 configured as described above will be explained.

When the brake is not in operation, both the vacuum valve 7a of the valve body 7 and the atmospheric valve 10a of the plunger 10 are seated on the sealing surface 16a of the poppet seal 16 (see FIG. 3).

When the brake pedal is depressed to advance the input shaft 9, the atmospheric valve 10a of the plunger 10 closes the poppet seal 16.
The air is introduced into the variable pressure chamber 6, and the differential pressure between the variable pressure chamber 6 and the negative pressure chamber 5 causes the diaphragm 4 to move forward, and the boosted thrust is transmitted to the output shaft 11 (see Figure 4). ).

At this time, the inner peripheral side of the sealing surface 16a of the poppet seal 16 is slightly displaced forward by the poppet spring 15.

Here, when the depression of the brake pedal is stopped, the valve body 7 moves forward and the plunger 10 moves backward, so that the plunger lO is placed on the inner peripheral side of the sealing surface 16a of the poppet seal 16, which is slightly displaced forward. The atmospheric valve 10a is seated. Then, the atmospheric valve 10a presses the inner peripheral side of the sealing surface 16a of the poppet seal 16 to displace it rearward, and furthermore, at the rear end position of the plunger IO, the vacuum valve 7a of the valve body 7
(See FIG. 5).

And, by communicating the variable pressure chamber 6 and the negative pressure chamber 5,
As the differential pressure decreases, the diaphragm 4 will retract and return to its initial non-operating state.

In this way, while the atmospheric valve 10a of the plunger 10 is seated on the sealing surface 16a of the poppet seal 16 that is displaced forward and is displaced backward, the vacuum valve 7 of the valve body 7
Since valve a is also seated on the sealing surface 16a of the poppet seal 16, and both valves 7a and 10a are maintained seated on the sealing surface 16a, hysteresis is obtained.

Here, the input/output characteristics of this pneumatic booster will be explained based on FIG. 2.

When the brake pedal is depressed from a non-operating state, the input and output increase in a proportional relationship due to the boost operation, as shown by line A.

Subsequently, when the brake pedal is stopped being depressed, the atmospheric valve 10a and the vacuum valve 7a are seated on the poppet seal 16, so that the variable pressure chamber 6 and the negative pressure chamber 5 are each blocked from the atmosphere, and as shown in line C from the point where the brake pedal stops being depressed. , the output drops smoothly.

Then, as the vacuum valve 7a separates from the poppet seal 16, the output drops rapidly from the separation start point as shown by line E.

In this way, hysteresis will be obtained.

(Effects of the Invention) As explained above in detail, in the pneumatic booster of the present invention, the inner peripheral side of the sealing surface of the poppet seal, on which the atmospheric valve of the plunger is seated and removed, is freely displaceable in the axial direction. When the brake pedal is depressed and stopped, the atmospheric valve and vacuum valve can remain seated on the poppet seal at the same time for a long time, resulting in good braking without reducing the durability of the poppet seal as in conventional methods. This means that the hysteresis of the characteristics can be ensured.

Therefore, with this pneumatic booster, a good braking feeling can be obtained during braking operations, especially during braking operations at high speeds.

[Brief explanation of the drawing]

FIG. 1(a) is a front view of a support plate of a poppet seal that is an embodiment of the present invention, and FIG.
FIG. 2 is a longitudinal cross-sectional view of a poppet seal incorporating the support plate shown in FIG. Figures 3, 4, and 5 are longitudinal sectional views showing the operating state of the pneumatic booster equipped with the poppet seal shown in Figure 1. Figure 6 is a general pneumatic booster. FIG. 2 is a longitudinal cross-sectional view showing the device. l...Front shell 2...Rear shell 4...
Diaphragm 5... Negative pressure chamber 6... Variable pressure chamber
7...Valve body 7a...Vacuum valve 8
・Fist・Cylinder part 9...Input shaft 10...
Plunger 10a...Atmospheric valve 11...Output shaft 16...Poppet seal 16a...Seal surface Patent applicant Tokiko Co., Ltd. Figure 1 Figure 2 Input

Claims (1)

[Claims] (1) a main body formed from a front shell and a rear shell; a diaphragm that defines the main body into a negative pressure chamber on the front shell side and a variable pressure chamber on the rear shell side; one end attached to the diaphragm and the other end attached to the A valve body protruding outward from the rear end side of the main body, a plunger slidably fitted into a cylinder portion formed in the axial direction at the front end of the valve body and interlocked with an input shaft, and a plunger facing the plunger. an output shaft that is connected to the valve body and extends forward; and an output shaft that is seated on and off from a vacuum valve formed in the valve body to communicate and cut off the negative pressure chamber and the variable pressure chamber, and a rear end of the plunger. In the pneumatic booster, the poppet seal is configured to sit on and off from an atmospheric valve formed in the plunger to connect and cut off communication between the variable pressure chamber and the atmosphere, the poppet seal on which the atmospheric valve of the plunger sits on and off from the atmosphere valve. A pneumatic booster characterized in that the in-plane peripheral side is freely displaceable in the axial direction.