JP2811105B2 - Pneumatic booster - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pneumatic booster used for a brake system of an automobile or the like.

(Prior Art) In recent years, many vehicles use a pressure difference between an engine suction negative pressure and atmospheric pressure to increase a brake fluid pressure generated in a master cylinder, and obtain a large braking force with a small pedaling force. A pneumatic booster is provided.

A general example of such a pneumatic booster will be described with reference to FIG. This pneumatic booster has a housing 3 composed of a front shell 1 and a rear shell 2, and the inside of the housing 3 has a front power piston 6 and a rear power piston 7 having a front diaphragm 4 and a rear diaphragm 5, respectively. By front constant pressure chamber 8
And front transformer room 9 and rear constant pressure room 10 and rear transformer room 11
Each is defined. Each power piston 6, 7 is fixed to a valve body 12, to which an output rod 13 is connected and a plunger 15 connected to an input rod 14 is slidably inserted.
Further, an atmosphere valve 16 and a vacuum valve 17 are provided in the valve body 12. When the input rod 14 moves forward, the atmospheric valve 16 allows communication between each of the transformation chambers 9 and 11 and the atmosphere, and the vacuum valve 17
When the input rod 14 is retracted, the variable pressure chambers 9, 11 communicate with the constant pressure chambers 8, 10.

In the pneumatic booster of this configuration, when a brake pedal (not shown) is depressed, the input rod 14 moves forward (moves leftward in FIG. 4) from the initial state in FIG. Atmosphere is introduced into the front transformer chamber 9 and the rear transformer chamber 11 as indicated by the arrow A. As a result, differential pressures are generated in the front variable pressure chamber 9 and the front constant pressure chamber 8 and between the rear variable pressure chamber 11 and the rear constant pressure chamber 10, and the respective power pistons 6 and 7 move forward. And the thrust is transmitted to the output rod 13.

When the depression of the brake pedal is stopped, the atmosphere valve 16 is closed to cut off the communication between each of the variable pressure chambers 9, 11 and the atmosphere, and the vacuum valve 17 is opened to open each of the variable pressure chambers 9, 11 and each of the constant pressure chambers.
8 and 10 are communicated with each other to become a negative pressure and return to the initial state.

(Problems to be Solved by the Invention) By the way, when the vehicle is suddenly braked, it is necessary to generate a large braking force instantaneously with rapid operation of the brake pedal. However, in the conventional pneumatic booster described above, Since there is a limit to the speed of the atmosphere introduced into the transformer chambers 9 and 11 through the atmosphere valve 16 due to inflow resistance and the like, there is a problem that the above-mentioned demand cannot be sufficiently satisfied.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a pneumatic booster with good output response.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a constant pressure chamber communicating with a negative pressure source inside a housing by a power piston and a diaphragm, and a negative pressure source or a variable pressure chamber communicating with the atmosphere. In the pneumatic booster, the input rod is moved to introduce the atmosphere into the transformation chamber through the atmosphere valve through the atmosphere valve, and the thrust boosted to the output rod is transmitted to the output rod by the pressure difference between the constant pressure chamber and the transformation chamber. A valve opening detecting means for detecting a predetermined opening degree of the atmospheric valve, and an air introducing means capable of communicating the variable pressure chamber with the atmosphere, and the valve opening detecting means based on the detection of the valve opening detecting means It is characterized in that the atmosphere introduction means is controlled to introduce the atmosphere into the transformation chamber.

(Operation) Since the present invention is configured as described above, when the brake pedal is strongly depressed to rapidly advance the input rod at the time of sudden braking or the like, the atmospheric valve is opened, and the valve opening detecting means is operated by the atmospheric valve. Is detected, the air introduction means is controlled based on the detection, and the variable pressure chamber and the atmosphere side are communicated with each other, so that the air can be rapidly introduced into the variable pressure chamber.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show a tandem-type pneumatic booster according to a first embodiment of the present invention. The housing 21 of this tandem type pneumatic booster is composed of a front shell 22 and a rear shell 23. The inside of the housing 21 is divided by a center plate 24 into two front and rear chambers. The front chamber is equipped with a front diaphragm 25 and a front power piston 26.
28 and is defined. The rear chamber is the rear diaphragm
The rear constant pressure chamber 31
And a rear transformer chamber 32. The front shell 22 has a negative pressure connection pipe for connecting a negative pressure source such as an intake manifold (not shown) to the front constant pressure chamber 27.
33 are provided.

A solenoid valve 34 is connected to the outside of the rear shell 23. The solenoid valve 34 is normally in a closed state, and is opened when a current is supplied from a control device 35 described later, so that the atmosphere is supplied to the rear transformer chamber 32 through the solenoid valve 34. In this embodiment, the solenoid valve 34 constitutes an atmosphere introducing means.

Front power piston 26 and rear power piston
30 is fixed to a cylindrical valve body 37 made of an insulating material such as phenolic resin having a concave portion 36 formed on the front side. A return spring 38 is interposed between the concave portion 36 of the valve body 37 and the front shell 22, and the front power piston 26 and the rear power piston 30 are constantly moved through the valve body 37 by the spring force of the return spring 38. It is biased backward. Further, a cylindrical convex portion 39 is formed in the concave portion 36, and the output rod 40 is connected to the cylindrical base portion.
41 is fitted to the convex portion 39 and connected to the valve body 37 with a reaction disk 42 interposed between the convex portion 39 and the convex portion 39. An input rod 44 made of a conductive material and connected to a brake pedal (not shown) is inserted into the internal space 43 of the valve body 37 so as to be able to move forward and backward. A spring 45 is interposed between the input rod 44 and the valve body 37, and the input rod 44 is urged rearward (rightward in FIG. 1) by this spring force. A plunger 46 made of a conductive material that is slidably fitted to the valve body 37 is connected to the tip of the input rod 44.

The plunger 46 and the valve body 37 are each provided with a stop key 47 made of a conductive material and a groove 48 into which the stop key 47 is inserted.
The position of the plunger 46 moving forward is restricted by contacting the front wall 49 of the 48. In addition, a part of the inner peripheral side end of the diaphragm retainer 50 made of a conductive material that retains the inner peripheral side of the rear diaphragm 29
It is extended along. This extended portion serves as a contact portion 51 of the switch.

The valve body 37 has a front transformer chamber 28 and a rear transformer chamber.
32, a second passage 53 communicating the front constant pressure chamber 27 and the rear constant pressure chamber 31, and a third passage communicating the rear variable pressure chamber 32 and the internal space 43 of the valve body 37. 54 and a fourth passage communicating the rear constant pressure chamber 31 with the internal space 43
55 are formed. The valve body 37 has a built-in atmosphere valve 56 and a vacuum valve 57. The atmosphere valve 56 includes a valve body 58 attached to the inner periphery of a portion behind the passage 55 in FIG.
A first valve seat 59 formed on the inner periphery of the valve body 37 in front of the fourth passage 55, and the vacuum valve 57 is provided with the valve body 58 serving also as the atmospheric valve 56, and a plunger. 46, a second valve seat 60 formed at the rear end.

The tandem-type pneumatic booster is provided with a control device 35 connected to the solenoid valve 34. The control device 35, the input rod 44, the plunger 4
6, Stop key 47 and diaphragm presser 50
When the contact is closed in the circuit 61, the control unit 35 detects this and supplies a current to the solenoid valve 34 to open the solenoid valve 34. In this embodiment, the diaphragm retainer thus configured is used.
The 50 and the stop key 47 constitute a valve opening detecting means.

In the tandem type pneumatic booster, in the initial state (when the brake pedal is not depressed), the valve body 58 is in the first position.
(Ie, both the atmospheric valve 56 and the vacuum valve 57 are closed), the front constant pressure chamber 27, the rear constant pressure chamber 31, the front variable pressure chamber 28, and the rear variable pressure Each of the chambers 32 is in a negative pressure state.

In this state, when the brake pedal is rapidly depressed, for example, during sudden braking, the input rod 44 advances greatly, and the valve body 58
Is released from the second valve seat 60 and the atmosphere valve 56 is opened. Further, as the input rod 44 advances, when the atmosphere valve 56 is opened to the maximum, the stop key 47 contacts the contact portion 51 of the diaphragm presser 50, and a current flows through the circuit 61, and the control device 35 operates the solenoid valve 34. Supply current to the solenoid valve
34 is opened (see FIG. 2).

As a result, the atmosphere is introduced not only through the atmosphere valve 56 but also through the solenoid valve 34 into the rear transformer chamber 32, and further into the front transformer chamber 28 through the first passage 52. As a result, the front transformer chamber 28 and the rear transformer chamber 32 into which the atmosphere is introduced
A large pressure difference is generated between the front constant pressure chamber 27 and the rear constant pressure chamber 31 which are in negative pressure, the front power piston 26 and the rear power piston 30 advance, the valve body 37 advances with a large force, and the output rod 40 Large thrust is immediately transmitted to the motor. This makes it possible to quickly generate a braking force at the time of sudden braking.

When the depression of the brake pedal is stopped, the valve body is
37 and the input rod 22 are returned to the rear, the second valve seat 60 and the valve body 58 are seated and the atmosphere valve 56 is closed, and the valve body 58 and the first valve seat 59 are further separated. As a result, the vacuum valve 57 is opened. At this time, the input rod 44 and the stop key 47 are moved backward with respect to the valve body 37 by the spring 45, and the stop key 47 is separated from the contact portion 52,
As a result, the control device 35 causes the solenoid valve 34 to close. Thus, the atmosphere valve 56 and the solenoid valve 34
Is closed, the introduction of air into each of the transformer chambers 32 and 28 is shut off. By opening the vacuum valve 57 in this state,
Each of the variable pressure chambers 32 and 28 and the constant pressure chambers 31 and 27 communicate with each other to have a negative pressure, and the apparatus returns to the initial state as shown in FIG.

When the brake pedal is gradually depressed, the stop key 47 advances to the front side, but the atmospheric valve 57 opens and the transformer chambers 32, 28
The pressure rises, the valve body 37 also moves forward, the atmospheric valve 56 does not open to the maximum, and the stop key 47 does not contact the contact portion 51, so the solenoid valve 34 does not open and the atmospheric valve
Normal boost operation by air introduction via 56 will be performed.

In the first embodiment, the components may be connected so that a circuit is formed by the solenoid valve 34, the input rod 44, the plunger 46, the stop key 47, the diaphragm presser 50, and a power supply (not shown). With this configuration, at the time of sudden braking, the input rod 44 moves forward greatly, and the stop key 47 contacts the contact portion 51 of the diaphragm presser 50, and the contact supplies current to the solenoid valve 34. Then, a large amount of air is rapidly introduced into the rear transformer chamber 32 and the front transformer chamber 28 via the solenoid valve 34.

FIG. 3 shows a second embodiment of the present invention. The second embodiment is different from the first embodiment in that a recess 62 is formed in the front wall 49 of the groove 48.
And a switch 63 is provided in the concave portion 62, and the switch 63 is provided in place of the diaphragm presser 50. The other components are the same as those in the first embodiment. The reference numerals are attached and the description is omitted.

In the figure, the switch 63 has a movable contact 64 so as to be closed when the stop key 47 moves by a predetermined amount. In the present embodiment, this switch 63 constitutes a valve opening detecting means. In this case, when the brake pedal is suddenly depressed, for example, during sudden braking, the input rod 44 advances greatly, and the valve element 58 of the atmospheric valve 56 is separated from the second valve seat 60. Further, as the input rod 44 advances, the stop key 47 advances, the movable contact 64 is pressed by the stop key 47, the switch 63 closes, a current flows through the circuit 61, and the control device 35 operates the solenoid valve 34. A current is supplied, which causes the solenoid valve 34 to open.

As a result, as in the first embodiment, the atmosphere is introduced not only through the atmosphere valve 56 but also through the solenoid valve 34 into the rear transformer chamber 32, and further into the front transformer chamber 28 through the first passage 52. . As a result, a pressure difference is generated between the front transformer chamber 28 and the rear transformer chamber 32 into which the atmosphere is introduced, and the front constant pressure chamber 27 and the rear constant pressure chamber 31 that are in negative pressure, and the front power piston 26 and the rear power piston 30 Moving forward, the valve body 37 is advanced with a large force, and a large thrust is immediately transmitted to the output rod 40.

In each of the above embodiments, a so-called tandem type having two sets of a constant pressure chamber and a variable pressure chamber defined by a diaphragm has been described as an example, but the present invention is not limited to this, and the present invention is not limited to this. It may have a set of a constant pressure chamber and a variable pressure chamber to be formed.

Further, the mounting position of the valve opening detection means is not limited to the above embodiment, and may be any position as long as the opening of the atmospheric valve can be detected. In the first embodiment, the valve opening detecting means (the diaphragm press 50 and the stop key
47) detects the maximum opening of the atmospheric valve, but the present invention is not limited to this, and may detect a predetermined opening.

(Effect of the Invention) According to the present invention, when a predetermined opening of the atmosphere valve is detected by the valve opening detection means, the atmosphere is introduced from the atmosphere introduction means by the control means. When the rod is rapidly advanced, the atmosphere is rapidly introduced into the transformation chamber through the atmosphere valve and the atmosphere introduction means, and a differential pressure is generated in the transformation chamber and the constant pressure chamber to immediately advance the valve body via the power piston. Can be. As a result,
A large braking force can be generated quickly at the time of sudden braking, and the braking performance can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a tandem type pneumatic booster according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of a main part showing the operation of the tandem type pneumatic booster shown in FIG. FIG. 3 is a sectional view showing a tandem-type pneumatic booster according to a second embodiment of the present invention. FIG. 4 is a sectional view showing an example of a conventional pneumatic booster. 21 ... Housing 25 ... Front diaphragm 26 ... Front power piston 27 ... Front constant pressure chamber 28 ... Front variable pressure chamber 29 ... Rear diaphragm 30 ... Rear power piston 31 ... Rear constant pressure chamber 32 ... Rear variable pressure chamber 34… Solenoid valve 35… Control device 37 …… Valve body 43 …… Internal space 44 …… Input rod 46 …… Plunger 47 …… Stop key 50 …… Diaphragm holder 56 …… Atmospheric valve 63 …… Switch

Claims (1)

(57) [Claims] 1. The interior of a housing is defined by a power piston and a diaphragm as a constant pressure chamber communicating with a negative pressure source and a variable pressure chamber communicating with a negative pressure source or the atmosphere, and the input rod is moved through an atmosphere valve by movement of an input rod. In a pneumatic booster that introduces air into a variable pressure chamber and transmits a boosted thrust to an output rod by a differential pressure between a constant pressure chamber and a variable pressure chamber, a valve opening detection that detects a predetermined opening of the atmospheric valve Means, and an air introduction means capable of communicating the transformation chamber with the atmosphere, and controlling the atmosphere introduction means based on the detection of the valve opening degree detection means to introduce the atmosphere into the transformation chamber. A pneumatic booster characterized by: