JPS59124455A - Brake toggle joint - Google Patents

Abstract

PURPOSE:To reduce an overall length and prevent the occurrence of an unusual sound by engaging a link member with a key member for stopping the coming out of a valve plunger and bringing said link member in contact with a shell through a diaphragm. CONSTITUTION:A key member 7 for preventing a valve plunger 20 from coming out of a valve body 3, is freely swingable with a fulcrum 7b as its center, which is formed at the central part of the key 7. One end of the plunger 20, which is installed in a valve body 3 and can be axially reciprocated, is opposed to the end part of the key member 7, and the other end of the plunger 20 is opposed to one end of an operating lever 21 provided on the constant-pressure chamber 5 side. The operating lever 21 is supported by a return spring 18 on the front end surface of the valve body 3 while its end is positioned in the opening 23 formed in a power piston 2 and opposed to a diaphragm 4 from the constant-pressure chamber 5 side. And, when not operating, the end of the operating lever 21 is brought in contact with a shell through the diaphragm 4.

Description

[Detailed description of the invention]

The present invention relates to a brake booster, and more particularly to a brake booster that reduces stroke loss of an input shaft at the start of operation. This type of brake booster secures a large flow passage area of the valve mechanism when the power piston is retracting, so that the retraction operation can be performed quickly, and when the brake couple device is not operating, the flow passage area is increased. It is made small or zero so that the flow path of the valve mechanism can be immediately switched when the input shaft advances due to the next depression of the brake pedal,
This reduces the stroke loss of the input shaft required to move the input shaft forward and block the flow path, compared to a general brake booster in which the flow path area remains large even in non-production conditions. This is what I did. Conventionally, the configuration for obtaining such an island function is to provide a stopper member on the rear shell that restricts the retreating position of the input shaft, and only when the stopper member is not in operation, prevents the input shaft from freely retreating relative to the valve mechanism. There are known devices in which stroke loss is reduced. Alternatively, as another configuration, a key member that prevents the valve plunger constituting the valve mechanism from being removed from the valve body is provided to be slidable with respect to the valve body, and the key is attached to the inner surface of the rear shell when not in operation. A device is known in which the key is brought into contact with the valve body to prevent the key from freely retracting from the valve body, thereby preventing the free retracting of the input shaft that is interlocked with the key via the valve plunger, thereby reducing the above-mentioned loss stroke. . However, in the former configuration, it is necessary to provide a stopper member that contacts the input shaft outside the shell, which tends to increase the overall length, and in the latter configuration, the key member contacts the inner surface of the rear shell, causing abnormal noise. It was getting easier. In view of these circumstances, the present invention utilizes a diaphragm that divides the inside of the shell into a constant pressure chamber and a variable pressure chamber, and makes a link member corresponding to the key member contact the shell through the diaphragm. To provide a brake booster which can have a short overall length and is less likely to generate abnormal noise. The present invention will be described below with reference to the illustrated embodiment. In FIG. The installed power piston, 13, is a valve body installed at the bottom of this power piston (2), and a diaphragm (4) is installed on the back of the power piston (2).
) to divide the interior of the shell f1) into a constant pressure chamber (5) at the front and a variable pressure chamber (6) at the rear. The outer periphery of this diaphragm (4) is sandwiched between the inner periphery of the front shell lla) and the inner surface of the annular groove 11c) of the palm shell 11b), and the inner periphery has an annular structure formed in the valve body (3).

[
3a) and the inner circumferential portion of the power piston (2) to maintain airtightness. The above cyclic rA[3
In the embodiment shown in Fig. 1, a) is partially cut out to form an insertion hole (8) for a key member (7), which will be described in detail later, and a part of the key member (7) is passed between the cutouts. A member 19) is provided to form a continuous annular groove [3a] in the circumferential direction. The terminal cylindrical part (3b) of the valve body [3] protrudes from the detail of the palm shell (1b) to the outside while keeping airtight with a sealing member (io), and a valve mechanism (11) is installed in the cylindrical part 13b). has been established. This valve mechanism-l) has a valve plunger (12) and an input shaft (
13), and a negative pressure introduction pipe (14) when not in operation.
The negative pressure that is constantly introduced into the constant pressure chamber (5) through the
Axial passage formed in the valve body (3) +15),
The variable pressure chamber (6) is connected to the variable pressure chamber (6) through the gap between the valve body (16) and the valve seat (3c) of the valve body (3) and the radial passage 117).
A return spring (18) holds the valve body (3) in a non-operating position. The aforementioned key member (7) that prevents the valve plunger (12) from being pulled out from the valve body (3) has an engaging portion (7) at the tip that engages with the intermediate small diameter portion of the valve plunger (12).
a and a fulcrum 17b) formed in the center,
It can swing freely around this fulcrum (7b). The valve body (3) is attached to the end of the key member (7).
), one end of a plunger (20) provided so as to be able to reciprocate in the axial direction is opposed to the plunger (20), and the other end of this plunger (20) is opposed to one end of an actuation lever (21) disposed on the constant pressure chamber (5) side. ing. At this time, a seal member 122) is provided on the plunger C20), and this seal member (22) prevents the constant pressure chamber (5) and variable pressure chamber (6) from communicating with each other. As shown in FIGS. 1 and 2, the actuating lever (21) is constructed by bending a part of a long and thin plate and using the projecting side as a fulcrum [
21a), and the fourth part side is the above return spring f18.
), the return spring (
18) on the front end surface of the valve body (21). One tip of this operating lever (21) is opposed to the plunger (2o) as described above,
The other end is located within an opening (23) formed in the power piston (2) and faces the diaphragm (4) from the constant pressure chamber (5) side. This operating lever 12]
) is the valve plunger (12) in the natural state where the input shaft (13) and the valve plunger (12) are held at the backward end by the spring (24) constituting the valve gear a (11).
becomes the retreating end, and the key member (7) becomes the fulcrum (7).
It rotates in the time phase direction in Figure 1 with a) as the center, and this causes the plunger (2o) to move to the left, so that the plunger (2o) rotates counterclockwise around the fulcrum [21a]. , the above power piston (2)
The tip of the operating lever (21) located in the opening (23) causes the diaphragm (4) to protrude toward the variable pressure chamber (6) (see FIG. 3). And this diaphragm f4)ic
i. The valve body (3) and the power piston (2) are held in the non-operating position by the return spring (18), and the valve body (3) and the power piston (2) are held in the non-operating position by the return spring (18). When the force is applied, the actuating lever +21L resists the splash (24).
The plunger (20) and key member (7) are actuated in the opposite direction to that described above, thereby advancing the valve plunger (112) and input shaft (13) to reduce stroke loss. Furthermore, a reaction disk C25) and an exit shaft (26) are arranged in front of the valve plunger (12),
The tips of the output shafts (2) protrude outside from the shaft of the front shell (la) via the sealing member (27). As mentioned above, in the non-operating state shown in FIG. 1, the valve plunger ( 12) and the input shaft (13) are in a forward state, and the gap between the valve body (16) and the valve seat f3C) is very small, resulting in a small loss stroke. From this state, the valve plunger [12] is connected via the input shaft (13).
As soon as the upper valve body (16) is moved forward, the upper valve body (16) is moved forward.
c) to cut off the communication between the constant pressure chamber (5) and the variable pressure chamber (6), and - when the valve plunger (12) is continued to move forward, the end of the valve plunger (12) touches the valve body (16). The air is introduced into the variable pressure chamber (6). This moves the power piston (2) forward and performs a braking action. When the forward force of input IFII+ (13) is released, the third
As shown in the figure, the input shaft (13) and the valve plunger (12) are retracted to the retraction end position by the return spring (24) of the input shaft (13), and thereby the valve plunger (12) is retracted to the retracted end position.
) is seated on the valve body (16) and connected to the atmosphere and the variable pressure chamber (6).
At the same time as blocking the communication between the valve body (16) and the valve seat (3
The constant pressure chamber (5) and the variable pressure chamber (6) are communicated through the gap between the constant pressure chamber (5) and the variable pressure chamber (6). In this state, the valve body (16) is attached to the valve seat (3C
), the constant pressure chamber (5) and variable pressure chamber (6)
The space is communicated with a sufficient flow path area. Further, at this time, as described above, the tip of the operating lever (21) curves and projects the diaphragm (4) toward the variable pressure chamber (6). When the valve body (3) is moved back to near the non-operating position by the return spring (18) while maintaining the state shown in FIG. 3, the diaphragm (4) protruded by the tip of the operating lever (21) Rear shell opening b)
the actuating lever (2) against the spring (24).
1) will now rotate counterclockwise. Therefore, when the power piston (2) and the valve body (3) stop retracting, the valve plunger (12) and the input shaft (
13) is in an advanced position relative to the valve body (3), and the gap between the valve body (16) and the valve seat (3C) is very small or zero. In addition, in the above embodiment, the key member (7) and the plunger l
20) The link mechanism is configured by the three members of the operating lever (21), but the link mechanism is not limited to this. For example, the link mechanism and the opening C23) are provided symmetrically with respect to the axis, and each of the three members is configured. The same effect can also be obtained by integrally connecting them in a relatively inoperable manner. As described above, in the present invention, since the link mechanism interlocking with the valve plunger is brought into contact with the shell via the diaphragm, it is possible to simultaneously prevent an increase in the overall length and the generation of noise. You can get the effect of

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
FIG. 3 is an enlarged perspective view of the operating lever shown in the figure, and FIG. 3 is a cross-sectional view of the main part showing a state different from that in FIG. 11) Shell (2) Power piston (
3) Valve body (4) Diaphragm (5)
... Constant pressure chamber (6) ... Variable pressure chamber (7) ... Key part (11) ... Valve mechanism (12) ... Valve plunger (13) ... Input shaft 120) ... Plunger (2
1)...Operating lever f23)...Opening Fig. 3 3a

Claims (1)

[Claims] A power piston slidably disposed within the shell, a diaphragm disposed on the back of the power piston that divides the interior of the shell into a constant pressure chamber and a variable pressure chamber, and a valve plunger constituting a valve mechanism are advanced. an input shaft that creates a pressure difference between the constant pressure chamber and the variable pressure chamber, and a link that, when interlocked with the valve plunger, faces the diaphragm from the constant pressure chamber side and causes the diaphragm to curve and protrude toward the variable pressure chamber in its natural state. What is claimed is: 1. A brake booster comprising a mechanism, wherein when the brake booster is not in operation, the valve plunger is moved forward via a link mechanism by contact between the curved and protruding diaphragm and the shell.