JPH0347017Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a pneumatic booster for assisting the operation of a brake or clutch device of a vehicle, etc.

(Prior Art) Conventionally, as this type of pneumatic booster, for example, as shown in Japanese Utility Model Application Publication No. 100568/1983,
A movable body movably inserted into an internal space formed in the main body, a low pressure chamber and a high pressure chamber formed on both sides of the movable body, and a movable body formed on the high pressure chamber side of the movable body and movably penetrating the main body. A cylindrical part that protrudes to the outside, an inner hole provided through the cylindrical part and the movable body, an input member and an output member fitted separately on both sides of the inner hole, and a structure between the two members. A valve device is arranged to control communication between the low pressure chamber and the high pressure chamber and an external pressure source, and a return spring urges the movable body to a non-operating position, the valve device being interlocked with the input member. a first valve seat provided in the valve plunger and a second valve seat provided in the inner hole;
A valve device is known that includes a poppet valve body having a movable portion that faces two valve seats so as to be able to sit thereon, and a valve spring that urges the valve device to a non-operating position.

When such a booster is in a non-operating state, the movable body generally comes into contact with the inner surface of the main body due to the biasing force of the return spring, while the valve plunger
The retraction limit is defined by a position defining member inserted into a radially extending hole provided in the movable body.

(Problem to be Solved by the Invention) By the way, in order to avoid unnecessary consumption of the capacity of the external pressure source, when in the non-operating state, the poppet valve must be connected to the first valve seat provided on the valve plunger. It is important to seat your body securely. In particular, since the booster is installed in vehicles that experience strong vibrations, it is important to obtain as large a value as possible for the seating force between the first valve seat and the poppet valve body without impairing the pedal feel. good.
In this regard, in the case of the prior art described above, since the position defining member directly receives the return force of the valve spring applied to the valve plunger, the biasing force of the valve spring cannot be effectively utilized as the seating force.

(Means for Solving the Problems) In this invention, the return force of the valve spring applied to the valve plunger is received by the position determining member with the poppet valve body therebetween. That is, an opening extending in the radial direction is provided in the movable body or the cylindrical part near the movable part of the poppet valve body, and the inner end of the opening can be engaged with the movable part, and the outer end can be engaged with the movable part. A position defining member that comes into contact with the main body is movably fitted in response to the return to the operating position, and the poppet valve body is moved from the non-operating position to the neutral position by resisting the biasing force of the valve spring when the valve body is not operating. This makes it possible to move to.

Furthermore, in this invention, a part of the poppet valve body is used for sealing as a sealing measure against the provision of the opening. That is, a seal portion is provided on the outer periphery of the movable portion of the poppet valve body, and this seal portion is slidably and elastically contacted to the inner wall of the inner hole.

Particularly, in this invention, the position defining member and the poppet valve body are separate bodies, and a return position determining means for determining the return position of the movable body is provided separately from the position determining member. There is.

(Function) When in the non-operating state, the outer end of the position defining member abuts against the main body, thereby fixing the position. Therefore, the movable portion of the poppet valve body that engages with this position determining member receives the return force of the valve spring through the valve plunger while being supported by the position determining member. This means that in the return position, the return force of the valve spring is effectively utilized as a seating force of the poppet valve body against the first valve seat.

The seal provided on the poppet valve body effectively prevents communication between the low pressure chamber and the high pressure chamber through the opening. In this case, the seal portion not only has a sealing effect but also prevents the poppet valve body from falling against the movable body, thereby improving the seating property of the poppet valve body.

(Example) Fig. 1 is a side sectional view showing the overall configuration of a negative pressure booster that is an embodiment of this invention, and Fig. 2 is a sectional view of the main parts along the - line in Fig. 1. .

The negative pressure type booster 1 has a main body 6 in which a front shell 4 and a rear shell 5 are combined, sandwiching an outer peripheral bead portion 3 of a diaphragm 2 therebetween. This main body 6 forms a housing of the booster 1. This main body 6
A movable body 10 formed by joining a plate member 8 and a hub member 9 via the inner peripheral bead portion 7 of the diaphragm 2 is movably arranged inside. This movable body 10, together with the diaphragm 2, has a negative pressure chamber 11 as a low pressure chamber on the front side inside the main body 6,
A variable pressure chamber 12 as a high pressure chamber is formed on the rear side. Here, the negative pressure chamber 11 is connected to a negative pressure source (external pressure source) such as the intake manifold of the engine through a joint (not shown) provided in the front shell 4, and is thereby constantly maintained at negative pressure. ing. On the other hand, the pressure in the variable pressure chamber 12 is switched to atmospheric pressure or negative pressure depending on whether the pressure is activated or not. This point will be discussed in detail later in connection with the valve device.

The hub member 9, which is the main body of the movable body 10, is cylindrical as a whole, and especially the rear portion 91 as the cylindrical portion.
has a smaller diameter than the front portion 92, and the smaller diameter rear portion 91 passes through the central hole 13 of the rear shell 5 and projects to the outside. An output shaft 16 as an output member is fitted into the stepped inner hole 14 passing through the center of the hub member 9 via a retainer 15 at its front end. ,
It comes into contact with the bottom of the recess at the rear of the piston in the master cylinder. Behind the output shaft 16 are a rubber disk 17, a valve plunger 18, and further a valve plunger 1.
An operating shaft 19 as an input member is connected to each of the input members 8 in a swingable manner and secured in the axial direction. Although not shown, a pedal is connected to the rear end of this operating shaft 19 via a clevis.

A poppet valve body 20 is provided around the operating shaft 19. The poppet valve body 20 is a series made of an elastic material such as rubber, and has a fixed part 21 on the rear side and a movable part 22 on the front side. The fixing part 21 engages with the step part on the rear side of the stepped inner hole 14, and has a cylindrical member 2 that also serves as a spring receiver.
3 supports the inner periphery of the fixed part 21. On the other hand, a ring-shaped reinforcing member 24 is integrally molded at the front end of the movable portion 22 . The reinforcing member 24 partially reinforces the movable portion 22 and also functions as a spring receiver. A spring receiver for each member 23, 24 serving as a spring receiver on the poppet valve body 20 side is a spring receiver 25 that engages with a step in the middle of the operating shaft 19. Each of these spring receivers 25; 23,
A valve spring 26 is provided between the poppet valve body 20 and the operating shaft 19 while being supported by the valve spring 24 . The valve spring 26 consists of a conical spring-shaped first portion 261 that urges the operating shaft 19 rearward, and a second portion 262 that urges the movable portion 22 of the poppet valve body 20 forward. Both parts 261 and 262 are made integrally, but the biasing force of the first part 261 is, for example, 6 to 6.
7 kgf, whereas that of the second portion 262 is, for example, 4 to 5 kgf, and the first portion 261 has a larger biasing force than the second portion 262.

Such a poppet valve body 20 is connected to the valve plunger 1.
Valve seat 2 as a first valve seat provided on the outer periphery of the rear end of 8
7 and a valve seat 28 serving as a second valve seat formed in the stepped portion of the stepped inner hole 14 on the radially outer side thereof, respectively. Therefore, the poppet valve body 20 and both the first and second valve seats 27, 28 constitute a valve device. This valve device has the following three control modes. One is a state in which the poppet valve body 20 is seated on the first valve seat 27 on the inner circumferential side and is separated from the second valve seat 28 on the outer circumferential side, in other words, the negative pressure chamber 11 and the variable pressure chamber 12 This is a non-operating position in which the variable pressure chamber 12 and the negative pressure chamber 11 are in communication with each other through passages 29 and 30, while communication between the variable pressure chamber 12 and the atmosphere is cut off, and the differential pressure between the variable pressure chamber 12 and the negative pressure chamber 11 is eliminated. The other is a state in which the poppet valve body 20 is seated on both the inner and outer valve seats 27 and 28, in other words, the communication between the variable pressure chamber 12 and the negative pressure chamber 11, and the communication between the variable pressure chamber 12 and the atmosphere. This is a state in which communication between both is cut off, and the pressure difference between the variable pressure chamber 12 and the negative pressure chamber 11 is kept constant. Furthermore, the poppet valve body 20 is separated from the first valve seat 27 on the inner circumferential side and is seated on the second valve seat 28 on the outer circumferential side, in other words, the negative pressure chamber 11 and the variable pressure chamber 12 is cut off from communication with the atmosphere, and the variable pressure chamber 12 and the atmosphere are in communication through the filter 31, which is an operating position where a differential pressure is generated.

By the way, in order to properly control such a valve device, each of the first and second valve seats 27, 2
9 and the poppet valve body 20 must be placed in an appropriate positional relationship with respect to each other. In this point,
Generally, the positional relationship of each component is defined in the non-actuated return state. When the booster 1 is in a non-operating state, the movable body 10 is returned to the rear by a strong biasing force of 18 kgf, for example, from the return spring 32, and the rib 2a of the diaphragm 2 or other parts are pressed against the inner surface of the rear shell 5. That's right. At this time, the valve plunger 18 and the operating shaft 19 are urged rearward by the valve spring 26. Therefore, in the past, the positional relationship among the three components was mutually defined by directly defining the position of the valve plunger 18.

In this invention, the position of the movable portion 22 of the poppet valve body 20 is determined by the position determining member 33, thereby indirectly determining the position of the first valve seat 27 on the valve plunger 18 side.

The position defining member 33 has a circular comb-like shape as a whole, and has a half-moon-shaped back portion 34 and teeth portions 35 and 36 integrated therewith. The position defining member 33 having such a shape is the movable portion 2 of the poppet valve body 20.
It is installed so as to straddle the 2. Therefore, the opening 3 extending in the radial direction in the cylindrical part 91 near the movable part 22
7 and 38 are provided. Each opening 37, 38 is large enough to fit a corresponding tooth 35, 36 therein. In particular, the axis d along the axial direction of the cylindrical portion 91 is related to the lift amount of the poppet valve body 20 with respect to the second valve seat 28 (width d - position defining member 33
(thickness = amount of lift), so it is set a little larger.

Therefore, these openings 37 and 38 and the passage 2
It is necessary to prevent the variable pressure chamber 12 and the negative pressure chamber 11 from communicating through the tube 9. As a countermeasure, it is possible to directly seal each part of the openings 37 and 38, but since the position defining member 33 has a complicated shape, the structure of the seal is also complicated, and it is difficult to achieve a stable seal. It is quite difficult. In this regard, in this invention, a seal portion 39 is provided on the outer periphery of the movable portion 22 of the poppet valve body 20, and this seal portion 39 is brought into elastic contact with the inner periphery of the cylindrical portion 91. The seal portion 39 is a lip piece that surrounds the outer periphery of the movable portion 22, and the lip piece faces rearward so that the differential pressure between the pressure change chamber 12 and the negative pressure change 11 can also be used as a sealing force. Since the seal portion 39 is molded integrally with the movable portion 22, it does not complicate the structure in the vicinity. The flange 18a provided on the valve plunger 18 determines the amount of lift of the poppet valve body 20 with respect to the first valve seat 27, and also allows the movable body 10 to be moved by the pedal force applied to the operating shaft 19 in the event of vacuum failure. possible.

Now, in the position defining member 33, the circular back portion 34 surrounds the outer periphery of the cylindrical portion 91, and each tooth portion 35, 36 crosses the cylindrical portion 91. As a result, the outer periphery of the back portion 34 and the tips of the teeth 35 and 36 can come into contact with the inner surface of the rear shell 5. In this case, in order to adapt to the shape of the rear shell 5, the corresponding portions 34a, 35a, 3 of the back portion 34 and the teeth 35, 36 are
6a is bent, each portion of which serves to prevent the position defining member 33 from coming off. In contrast to the outer end, the inner end of the position defining member 33 is connected to the movable portion 22 of the poppet valve body 20, specifically the reinforcing member 24.
It is possible to engage with the back surface of the portion 22a reinforced by. Therefore, considering the non-operating return state, the movable portion 22 of the poppet valve body 20, especially the portion 22a, has a retracting limit defined by the position defining member 33, and the operating shaft 19 and the valve plunger 18
The biasing force of the valve spring 26 is received through the valve spring 26. Therefore, the biasing force of the valve spring 26 is effectively used as a seating force for the poppet valve body 20 against the first valve seat 27. In this case, since the poppet valve body 20 is relatively moved from the non-operating position side to the neutral position side by the reaction force from the position defining member 33, a strong biasing force from the return spring 32 is applied to the movable body 10.
It may be applied to the poppet valve body 20 side through the second valve seat 28 on the side. This is the poppet valve body 20
From the viewpoint of durability, this is not desirable. Therefore, as a countermeasure, the rib 2a or other portion of the diaphragm 2 is brought into contact with the inner surface of the rear shell 5 slightly earlier than the position defining member 33 is brought into contact with the inner surface of the rear shell 5. In short, the biasing force of the strong return spring 32
In order to prevent the movable body 10 from applying to the poppet valve body 20 side through the second valve seat 28 on the 0 side,
It is important that the return position of itself is defined by a return position defining means different from the position defining member 33.

By the way, the movable part 22 of the poppet valve body 20 is
Since the seal portion 39 comes into elastic contact with the inner periphery of the cylindrical portion 91, the inner periphery of the cylindrical portion 91 is guided by the seal portion 39. As a result, the movable portion 22 of the poppet valve body 20 hardly tilts against the movable body 10, and the seating ability on the second valve seat 28 provided on the movable body 10 side can be improved.

In addition, in the illustrated example, the openings 37 and 38 are connected to the cylindrical portion 91.
However, it can also be provided in the front portion 92 of the hub member 9 or in the rear cylindrical portion 91 from there.

Furthermore, in order to more effectively prevent the poppet valve body 20 from falling down, the seal portion 39 may have a structure with relatively little elastic deformation, or the seal portion 39 may be provided with guiding projections. You can also.

Furthermore, in order to improve the seating ability of the poppet valve body 20 on the first valve seat 27 on the valve plunger 18 side, a guide portion that fits into the inner peripheral portion of the movable portion 22 is provided inside the first valve seat 27. You can also do it like this. By doing so, together with the increase in the seating force, the seating ability of the poppet valve body 20 on the first valve seat 27 can be made extremely good.

(Effect of the invention) In this invention, the position of the valve plunger 18 is not directly determined in the non-operating return state, but is indirectly determined via the movable portion 22 of the poppet valve body 20. The biasing force of the valve spring 26 can be effectively used as a seating force for the poppet valve body 20 against the first valve seat 27. Therefore, good seating comfort can be maintained, and unnecessary consumption of an external pressure source such as a negative pressure source can be effectively prevented.

Furthermore, since the position regulating member 33 is made to act on the poppet valve body 20 side, the length of the valve plunger 18 in the axial direction can be shortened, and the booster 1 can be made smaller by that amount. can.

Furthermore, since the seal portion 39 is provided on the outer periphery of the movable portion 22 of the poppet valve body 20, the structure of the seal can be simplified, and at the same time, the poppet valve body 20 is prevented from falling with respect to the movable body 10. The seating properties of the poppet valve body 20 can also be improved.

The good seating performance of the poppet valve body 20 is due to the fact that the poppet valve body 20 and the position defining member 33 are separate bodies, and the movable body 10 is provided with return position defining means separate from the position determining member 33. The fact that both of these provisions are in place increases the effectiveness of the Act.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing the overall structure of an embodiment of this invention, and FIG. 2 is a sectional view of the main parts along the line - in FIG. 1. 1... Negative pressure booster, 6... Main body, 91...
Cylindrical part, 10... Movable body, 11... Negative pressure chamber (low pressure chamber), 12... Variable pressure chamber (high pressure chamber), 14... Inner hole,
16... Output shaft (output member), 18... Valve plunger, 19... Operation shaft (input member), 20... Poppet valve body, 22... Movable part, 26... Valve spring,
27...first valve seat, 28...second valve seat, 32...
Return spring, 33... Position regulating member, 37, 38...
...Opening, 39...Seal portion.

Claims (1)

[Claims for Utility Model Registration] 1. A movable body movably inserted into an internal space formed in a main body, a low pressure chamber and a high pressure chamber formed on both sides of the movable body, and a high pressure chamber formed on the high pressure chamber side of the movable body. a cylindrical part that movably penetrates the main body and protrudes to the outside; an inner hole that passes through the cylindrical part and the movable body; an input member that fits separately on both sides of the inner hole; an output member, a valve device disposed between the two members for controlling communication between the low pressure chamber and the high pressure chamber and an external pressure source, and a return spring for biasing the movable body to a non-operating position; The valve device includes a valve plunger that is interlocked with the input member, and a movable portion that faces two valve seats such as a first valve seat provided on the valve plunger and a second valve seat provided in the inner hole so as to be seated on each valve seat. a poppet valve body with a poppet, and a valve spring that urges the valve device to a non-operating position, and the valve device eliminates the differential pressure between the low pressure chamber and the high pressure chamber by movement of a valve plunger interlocked with the input member. In a pneumatic booster that can be switched from a non-operating position, through a neutral position where a differential pressure between these two chambers is maintained, to an operating position where a differential pressure is generated between these two chambers, a seal is provided on the outer periphery of the movable part of the poppet valve body. The seal portion is slidably and elastically contacted with the inner wall of the inner hole, and an opening extending in the radial direction is provided in the movable body or the cylindrical portion near the movable portion, and the inner end side of the opening is provided with an opening extending in the radial direction. A position defining member which can be engaged with the movable part and whose outer end side abuts the main body when the movable body returns to the non-operating position is movably fitted, and when the movable body returns to the non-operating position, the position defining member is movably fitted. The poppet valve body can be moved from a non-operating position to a neutral position, and the position defining member and the poppet valve body are separate bodies, and
A pneumatic booster further comprising a return position defining means that defines a return position of the movable body, in addition to the position defining member. 2. The return position defining means includes a part of the movable body;
The pneumatic booster according to claim 1, which is constituted by a part of the main body against which a part of the movable body comes into contact.