JPH0441110B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a pneumatic booster used to assist the pedal force when operating a brake master cylinder or a clutch master cylinder in automobiles, etc. , relates to an improvement in a device equipped with a mechanism that reduces play in the initial stage of operation.

(Prior Art) The present applicant first proposed a movable body movably inserted into an internal space molded inside a main body, and a movable body that is equipped with a mechanism that reduces or eliminates the play at the initial stage of operation. a low-pressure chamber and a high-pressure chamber respectively partitioned on both sides of the movable body; a cylindrical portion provided on the other side of the movable body and movably penetrating the main body and projecting to the outside; an input member and an output member fitted movably from both sides of the inner hole; a plunger integrally provided with the input member and movable within the inner hole; A poppet valve body having a movable portion facing the provided valve seat and a valve seat provided on the inner wall of the inner hole so as to be seated thereon, respectively, and the plunger are placed in a non-operating position in which the poppet valve body is separated from one valve seat. A valve device includes a biasing valve spring and controls communication between the low-pressure chamber and the high-pressure chamber and an external pressure source by displacement of the plunger relative to the movable body; and a biasing device that biases the poppet valve body to seat on both valve seats in the valve device, and the biasing device is movably fitted into a hole provided in the movable body and has one end. has a shaft-like member that can come into contact with the main body on the high-pressure chamber side and whose other end projects toward the low-pressure chamber side, and an engaging portion that can be movably fitted into the inner hole and engaged with the plunger. An actuating member having a cylindrical portion and an arm portion extending from the cylindrical portion to be connected to the shaft member has been proposed.

To briefly explain the operation of this proposal, when the device is not in operation, when the movable body retreats until it comes into contact with the main body due to the large urging force of the return spring, the shaft-like member of the urging device is also pushed against the main body. As a result, the shaft-like member and the arm portion of the actuating member are positioned so as to move forward relative to the movable body, and naturally the cylindrical portion of the actuating member also moves forward relative to the movable body. The engaging portion of the shaped portion engages with the plunger to move the plunger forward relative to the movable body against the biasing force of the valve spring. Therefore, the poppet valve body moves forward equal to the amount of advance of the plunger, so it remains seated on the valve seat of the plunger.
Either reduce the distance between the valve seat and the valve seat provided on the inner wall of the inner hole, or move forward until it is seated on both valve seats.

When not in operation, the poppet valve body is seated on both valve seats, or is seated on the other valve seat while decreasing the distance from one valve seat, and input is transmitted to the input member. When the plunger moves, the poppet valve body either immediately leaves the other valve seat, or moves a little and then leaves the other valve seat, depending on the movement, and the poppet valve body disengages from the other valve seat after a slight movement. This allows the play in the initial stage of operation to be reduced or eliminated.

Furthermore, in the above proposal, the cylindrical portion of the actuating member that engages with the plunger that controls the valve device is
By being movably fitted into the inner hole of the cylindrical portion of the movable body, the portion of the inner hole that accommodates the valve device is freely communicated with the low pressure chamber through the gap formed on the outer periphery of the cylindrical portion of the actuating member. In order to prevent the movable member from being damaged and unable to function normally, a sealing device is provided between the outer surface of the cylindrical portion of the actuating member and the inner surface of the inner hole of the movable body.

The specific structure of this sealing device is to provide a flange-like part at the end of the cylindrical part on the low-pressure chamber side, and increase the diameter of the open end of the inner hole on the low-pressure chamber side, so that a predetermined distance is established between the two. An annular space is formed, and a rubber sealing member is placed in this annular space in elastic contact with the outer surface of the cylindrical portion and the inner surface of the increased diameter portion of the inner hole, and the moving force generated in the sealing member due to the differential pressure is transferred to the flange. It is supported by a shaped part.

(Problems to be Solved by the Invention) However, by providing the sealing device as described above, it is possible to prevent free communication between the inner hole portion that accommodates the valve device and the low pressure chamber, but the durability of the sealing member is It was found that there was a problem in that the sealing was poor and there was a risk of sealing failure in a short period of time.

That is, when the actuating member moves relative to the movable body, the cylindrical part moves relative to the inner hole, and when moving in one direction, the cylindrical part moves between the flange of the cylindrical part and the movable body. A relatively large gap is created facing the low-pressure chamber, and this gap narrows when moving to the other side, causing a phenomenon such as sagging. Due to this phenomenon, when the sealing member supported by the flange-like portion enters such a gap due to the moving force or deformation force due to the differential pressure, the intruding portion is eaten away and damaged, resulting in sealing failure such as pressure leakage.

(Means for Solving the Problems) In the present invention, a groove is provided on the outer periphery of the plunger, and a sealing member for sealing between the plunger and the inner hole is attached to the groove.

(Function) Even if the plunger moves within the inner hole during operation,
Since the sealing member is installed in the groove of the plunger, the gap between the plunger and the inner surface of the inner hole, which is opposite to the sealing member, is always constant.
Even if there is a deforming force acting on the sealing member that does not change due to the movement of the plunger, it is prevented from entering the gap.

(Example) FIG. 1 is a side sectional view showing the overall configuration of a negative pressure booster that is an example of the present invention, and FIG. 3 is a view in the direction of arrows showing only the actuating member, and FIG. 3 shows details of the auxiliary member for transmitting force shown in FIG. 1; FIG. be.
Note that in the drawings, those that are substantially the same as those of the conventional system will be briefly explained. Further, the front-rear direction is the left-right direction in FIG.

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, forms a low pressure chamber 11 on the front side and a high pressure chamber 12 on the rear side inside the main body 6. Main body 6 is rear shell 5
is supported by being fixedly attached to the vehicle body (not shown) with bolts and nuts (not shown), and a master cylinder (not shown) is similarly fixed to the front side of this main body 6 with bolts and nuts (not shown). and tightly mounted. The hub member 9 has a cylindrical shape as a whole, and the rear portion 91 has a smaller diameter than the front portion 92.
1 passes through a hole 34 in the center of the rear shell 5 and projects to the outside.

A stepped inner hole 13 passing through the center of the hub member 9 has an output shaft 1 inserted through a retainer 14 on the front end side thereof.
5 are fitted, and the front and rear of the output shaft 15 are brought into contact with the bottom of the recess at the rear of the piston of the master cylinder. The retainer 14 is press-fitted into the end of the hub member 9 and held by its inward elastic claws 141. At the rear of the output shaft 15, a rubber disk 16 as a force transmitting member, a plunger 17, and an input shaft 18 coupled to the plunger 17 in a swingable manner and secured in the axial direction are arranged. A conical valve seat 21 provided on the outer periphery of the rear end of the plunger 17
A poppet valve body 23 is disposed so as to be able to sit on and face a valve seat 22 formed in a stepped portion of the stepped inner hole 13 on the radially outer side thereof. The poppet valve body 23 has its rear end engaged with a step on the rear side of the stepped inner hole 13, and a front side portion 230 is movable. Poppet valve body 23 and input shaft 18
A conical spring-shaped first portion 241 that biases the input shaft 18 rearward, and a second portion 2 that biases the front side portion 230 of the poppet valve body 23 forward.
A valve spring 24, which is made integrally with 42, is stretched. The outer periphery of the front portion 230 of the poppet valve body 23 is constantly communicated with the negative pressure chamber 11 through a passage 25 provided in the hub member 9, and further communicated with a negative pressure source such as an engine intake manifold through piping (not shown). be done. On the other hand, the inner peripheral side of the poppet valve body 23 is always in communication with the atmosphere through a filter 26 disposed at the opening of the stepped inner hole 13. Further, the outer periphery of the rear portion of the plunger 17 on the front side of the poppet valve body 23 is always in communication with the high pressure chamber 12 through the passage 27 of the hub member 9.

The poppet valve body 23, plunger 17, etc. constitute a valve device B. This valve device B
There are three types of control: One is a state in which the poppet valve body 23 is seated on the valve seat 21 and separated from the valve seat 22, in other words, the low pressure chamber 11 and the high pressure chamber 12 are communicated, and the high pressure chamber 12 and the atmosphere are in communication with each other. This is a state in which communication is cut off, and is a differential pressure eliminating position where the differential pressure between the high pressure chamber 12 and the low pressure chamber 11 is eliminated. The other is a state in which the poppet valve body 23 is seated on the valve seats 21 and 22, in other words, communication between the high pressure chamber 12 and the low pressure chamber 11, and communication between the high pressure chamber 12 and the atmosphere are both cut off. This is a differential pressure holding position where the differential pressure between the high pressure chamber 12 and the low pressure chamber 11 is kept constant. Furthermore, the poppet valve body 23 is separated from the valve seat 21 and the valve seat 22
In other words, the low pressure chamber 11 and the high pressure chamber 12 are disconnected from each other, and the high pressure chamber 12 is in communication with the atmosphere, and at the position where a differential pressure is generated. be. In particular, at the differential pressure generation position and differential pressure cancellation position, the range of these positions is
They are set at both ends of the movement range of the plunger 17 with respect to the movable body 10. In addition, the input shaft 18
The rear end is swingably pin-coupled to a pedal (not shown).

The center portion of the plunger 17 constituting the valve device B is a large diameter portion 171 that fits into the middle hole portion 130 of the inner hole 13 while forming a relatively small gap. An annular groove 172 is formed on the outer periphery of this large diameter portion 171, into which a sealing member 19 made of an O-ring is attached.
7 and the inner hole 13, thereby blocking communication between the front and rear of the plunger 17. Thereby, the low pressure chamber 11 and the high pressure chamber 12 are related to each other by the above-described control form of the valve device B, and direct communication is prevented. Further, the valve seat 21 of the plunger 17 is seated on a corner 231 formed by forming the opening of the front side portion of the poppet valve body 23 with a cone angle smaller than the cone angle of the valve seat 21. There is,
By allowing the valve seat 21 to sit on the corner 231 and bite into the opening, the plunger 1
Even if valve 7 falls down, the poppet valve body 23 will not hold both valve seats 2.
He is scheduled to sit at the temple on the 1st and 22nd.

A hub member 9 housing such a valve device B inside
As described above, the rear portion 91, which is a cylindrical portion, passes through the hole 34 of the rear shell 5 and projects to the outside. The rear part of the rear shell 5 is narrower than the front part, and a hole 34 is formed inside the narrowed part 51. The movable body 10 is disposed between the inner peripheral surface of the hole 34 and the rear part 91. It is airtight so that it can be moved. That is, the boot 41 is arranged so as to cover almost the entire rear portion 91, and the rear end portion 42 is hooked and supported by the flange 36 of the metal fitting 35 fitted to the rear portion 91, while the front end portion 43 is a U-shaped sealing member that is sandwiched and supported between the constriction portion 51 and the rear portion 91. Further, in order to prevent the front end 43 of the boot 41 from slipping out and to prevent it from slipping, the rear end of the constricted portion 51 of the rear shell 5 is bent inward, and a plastic support is provided on the front surface of the front end 43 of the boot 41. ring 4
4 and a retaining ring 45 made of elastic material.

By the way, such a booster 1 includes a movable body 1
A return spring 32 that biases the front shell 4
and the movable body 10. Therefore, when the movable body 10 is not activated, the strong return spring 3
2, and the rib 33 of the diaphragm 2 is in contact with the inner surface of the rear shell 5.
At this time, the plunger 17 and the input shaft 18
Since the poppet valve body 23 is urged rearward by the valve spring 24, the poppet valve body 23 is conventionally seated on the inner valve seat 21, but unlike the illustrated state, the poppet valve body 23 is seated on the outer valve seat 22. They were seated quite far apart. Such poppet valve body 23 and valve seat 2
2 was the main cause of initial play in the booster 1.

Therefore, in order to eliminate or reduce the initial operation play in the booster 1, the poppet valve body 23 is
It is effective to move the valve so that it is seated on both the inner and outer valve seats 21 and 22. To do this, move the input shaft 18 or the plunger 17 to the movable body so that the amount of separation decreases or becomes zero.
It suffices to move it forward relative to 0.

For this purpose, as proposed earlier, it is configured as follows.

That is, the booster 1 includes a pair of holes 60 provided in the outer peripheral side of the front portion 92 of the hub member 9 in the axial direction (one of them is omitted in FIG. 1 for convenience of drawing). The sealing member 61 can be moved freely to
a pair of movable pin members 62 fitted through the
An actuating member 70 assembled to the end of the pin member 62 on the low pressure chamber 11 side is used. The end of the pin member 62 on the high pressure chamber 12 side is brought into contact with the rear shell 5. Also, referring to FIG. 2, the connection between the pin member 62 and the actuating member 70 is as follows.
A pair of holes 72 provided at both ends of a pair of arm portions 71 of the actuating member 70 are press-fitted and connected to a reduced diameter portion 64 provided at the end of the pin member 62 on the low pressure chamber 11 side. The pin member 62 and the actuating member 70 are movable together. The central part of the actuating member 70 is a cylindrical part 74 that is movably fitted into the front end of the inner hole 13, and inside thereof, the output shaft 15 is arranged in order from the front side to the rear side. A diameter portion 151, a rubber disk 16 which is a force transmission member, and an auxiliary member 81 for force transmission whose detailed shape is shown in FIG. 3 are arranged.

Referring to FIG. 3, the auxiliary member 81 mainly has an annular portion 82 on the front side, and a pair of arc-shaped protrusions 83 are formed protruding from the annular portion 82 on the rear side.

Returning to FIG. 1, the protruding portion 83 of the auxiliary member 81 is located at the small hole portion 1 of the inner hole 13 having the smallest diameter.
31, and the front end of the plunger 17 is fitted into its inner hole so as to be able to come into contact with the rubber disk 16. Further, a pair of inward protrusions 73 formed at the rear end of the actuating member 70 extend inwardly from between the pair of protrusions 83, and the protrusions 73 are spaced apart by 180 degrees.
It is positioned so as to be able to engage from the rear side with a C-ring-shaped stopper 85 attached near the front end of the plunger 17, and has a function as an engaging portion for the plunger 17. Therefore, the plunger 17 is
By engaging the stopper 85 with the protrusion 73 of the actuating member 70, the relative backward limit position with respect to the movable body 10 is defined. Further, the plunger 17 has its intermediate large diameter portion 171 brought into contact with the rear shoulder portion of the small hole portion 131, thereby defining the relative forward movement limit position with respect to the movable body 10.

Such a pin member 62 and operating member 70
is dimensioned to allow the plunger 17 to be advanced relative to the movable body 10 such that in the illustrated inoperative position, the distance between the valve seat 22 and the poppet valve body 23 is zero.

Now, here, the pair of arm portions 71 of the actuating member 70
has an end portion formed with a pair of holes 72 and a cylindrical portion 74.
It not only simply integrates the two, but also serves as a deformable part that deforms elastically when a predetermined force is applied. That is, the entire operating member 70 is
The first portion 241 of the valve spring 24 is made to have such rigidity that it will not be substantially elastically deformed only by the biasing force (the maximum value including the increase proportional to the spring constant due to the change in compression length). In addition, the width of the arm portion 71 in particular is made smaller compared to its length,
The protrusion 73 is set to be elastically deformed with an acting force that is slightly larger than the biasing force of the first portion 241 and that does not cause the protrusion 73 to deform. For example, the biasing force of the first portion 241 is 10 kg.
f, and the deformation starting force of the portion 73 is 20 kgf, the arm portion 73 may have a numerical value between those, for example, 12 to 18 kgf. These numbers are
It is shown as a converted value as an acting force acting on the input shaft 18. Furthermore, when the arm portion 73 actually deforms, the amount of deformation is determined by the stopper 8 of the plunger 17.
5 comes into contact with the left shoulder portion of the small hole portion 131 via the portion 73, and the elastic deformation limit of the arm portion 73 does not need to be so large.

In such a negative pressure booster 1, the stopper function of the pin member 62 and the actuating member 70 allows the retraction limit of the plunger 17 to be slightly advanced, thereby causing the poppet valve to close when not in operation. The body 23 comes to sit on both the inner and outer valve seats 21 and 22. This means that the operating play in the booster 1 itself is eliminated.

Therefore, when the input shaft 18 is moved forward by depressing a pedal (not shown), the valve device B is immediately switched to the differential pressure generating position. Then, the movable body 10 moves forward against the force of the return spring 32 due to ear pressure, and the output shaft 1
5 is the moving force of the movable body 10 via the rubber disk 16 and the auxiliary member 81, and the rubber disk 1
6 and the plunger 17, and a pressing force, which is the sum of both moving forces, advances a piston of a master cylinder (not shown) to generate pressure. And input shaft 18
When the moving force (input) and the reaction force acting on the plunger 17 from the rubber disk 16 are balanced, the valve device B switches to the differential pressure holding position and the pressure generated in the master cylinder becomes constant.

During this time, the pin member 62 and the actuating member 70 are in a relatively free state, but are subjected to a forward biasing force due to an external force acting on them, that is, a differential pressure acting on the pin member 62, and furthermore, Due to the compression of the rubber disk 16 that occurs during operation, the frictional bonding force between the actuating member 70 and the rubber disk 16 increases, and as a result, the actuating member 70 tends to move together with the rubber disk 16. No trouble occurs in the operation of the booster 1.

On the other hand, when the pedal is no longer depressed, the input shaft 18 is returned to the rear by the force of the valve spring 24. This rearward moving force causes the plunger 17 to retreat, causing the stopper 85 and the protrusion 73 of the actuating member 70 to move backward.
The actuating member 70 and the pin member 62 engage with each other and move the actuating member 70 and the pin member 62 backward. At this time,
The pin member 62 and the actuating member 70 are connected to the plunger 17
, the plunger 17 moves back until it comes into contact with the front shoulder of the small hole 131 , and the plunger 17 reaches the maximum retreat position where it comes into contact with the front shoulder of the small hole 131 via the stopper 85 and the protrusion 73 . and switch the valve device B to the differential pressure eliminating position. In this switching state, the low pressure chamber 11 and the high pressure chamber 12 communicate with each other and the differential pressure is eliminated, so that the movable body 10 returns to the spring 32.
This is continued until just before it comes into contact with the rear shell 5 which has moved rearward due to the acting force. Therefore, the hyperbaric chamber 12
The atmospheric air sufficiently moves to the low pressure chamber 11 side, and is further suctioned sufficiently by a negative pressure source which is an external pressure source. As a result, both chambers 11 and 12 have approximately the same pressure and sufficient vacuum pressure.

Just before the movable body 10 abuts the rear shell 5, the rear end of the pin member 62 abuts the rear shell 5 and stops moving backward integrally with the movable body 10. Thereafter, the movable body 10 retreats until it comes into contact with the rear shell 5. Due to this retraction, the plunger 17 itself is moved by the actuating member 7.
0 and stopping the retraction, the distance between the poppet valve body 23 and the valve seat 22 decreases, and finally the poppet valve body 23 touches both the valve seats 21 and 22. The seat is in the state shown in the figure.

In this series of operations, when the atmosphere is supplied to or discharged from the high pressure chamber 12 according to the switching of the valve device B, the pressure difference between the atmospheric pressure and the negative pressure is generated before and after the plunger 17, especially before and after the sealing member 19. occurs,
Due to this differential pressure and the frictional force between the sealing member 19 and the inner hole 13, the sealing member 19 tries to fit into the gap created between the plunger 17 and the inner hole 13, but this gap is only relatively small. Since it does not change to become larger, it is possible to prevent erosion and greatly improve durability compared to the previously proposed one.

Although this invention has been specifically described above based on Examples, it goes without saying that this invention is not limited to the above-mentioned Examples, and can be modified in various ways without departing from the gist thereof. Examples of changes are as follows.

(1) Although a pair of pin members 62, that is, two pin members are used, only one pin member 62 may be used. In this case, there is only one arm, so you can use this arm as the deformed part, or
Alternatively, the engaging portion may be a deformable portion.

(2) The engagement between the plunger 17 and the operating member 70 is as follows:
Although this is done using two protrusions 73, it may be three (120 degrees apart), four (90 degrees apart), or more. However, when the number of protrusions is small, it is preferable to provide them at equal intervals, and it goes without saying that at least the protrusions must have sufficient strength.

(3) Since the small holes 131 of the hub member 9 repeatedly come into contact with the front and rear shoulders of each member, a metal protection ring or the like may be arranged to strengthen the small holes 131 of the hub member 9.

(4) Although it is most convenient to use the arm portion of the actuating member as the deforming portion, it is of course possible to use other parts as the deforming portion.

(5) The basic configuration of the booster is such that the input-output relationship is a pressing force, but the tow type that the applicant has already proposed (for example, the
58-85749).

(6) Sealing member 1 attached to the outer periphery of plunger 17
Instead of an O-ring, 9 may be a lip-type seal, for example, and in this case, the lip may be mounted with the lip facing toward the poppet valve body 23.

(7) Although the gaps created facing the sealing member 19 are made equal in the embodiment, the differential pressure, which is the main cause of deforming the sealing member 19, is pressed from the right to the left in Fig. 1. Therefore, the gap on the right side may be made somewhat larger, and the gap on the left side may be made smaller.

(Effects of the Invention) In this invention, a groove is formed on the outer periphery of the plunger, and a sealing member for sealing between the plunger and the inner hole is attached to this groove. Not only can the durability of the plunger be improved, but compared to installing it in other parts, it is only necessary to change the shape of the plunger, and the structure does not become particularly complicated.

[Brief explanation of drawings]

FIG. 1 is a side cross-sectional view showing the overall configuration of a booster according to an embodiment of the present invention, FIG. 2 is a directional view of only the actuating member from the direction indicated by arrow A in FIG. 1,
FIG. 3 is a diagram showing details of the auxiliary member shown in FIG. 1, with FIG. 3A showing a side sectional view and FIG. 3B showing a front view. DESCRIPTION OF SYMBOLS 1... Negative pressure booster, 6... Main body, 91... Rear part (cylindrical part), 10... Movable body, 11... Low pressure chamber, 12
...High pressure chamber, 13...Inner hole, 15...Output shaft (output member), 17...Plunger, 172...Groove, 18...Input shaft (input member) 19...Sealing member, 21...Valve seat (plunger side), 22... Valve seat (inner hole side), 23...
poppet valve body, 24...valve spring, 32...return spring,
70... Actuation member, 71... Arm part, 74... Cylindrical part, B
...Valve device.

Claims (1)

[Claims] 1. A movable body movably inserted into an internal space formed inside the main body, a low-pressure chamber and a high-pressure chamber partitioned on both sides of the movable body, and a movable body provided on the other side of the movable body so that the main body can be moved. a cylindrical portion that penetrates through the tube and projects to the outside; an inner hole that penetrates the cylindrical portion and the movable body; and an input member and an output member that are movably fitted into each other from both sides of the inner hole; A poppet having a plunger integrally provided with the input member and movable within the inner hole, and a movable portion facing the valve seat provided on the plunger and the valve seat provided on the inner wall of the inner hole so as to be able to sit on each of them. The movement of the plunger includes a valve spring that urges the valve body and the plunger to a non-operating position in which the poppet valve body is separated from one valve seat, and controls communication between the low pressure chamber and the high pressure chamber and an external pressure source. and a biasing device that moves a plunger against a valve spring when not actuated to urge the poppet valve body to seat on both valve seats in the valve device. The biasing device includes a shaft-like member that is movably fitted into a hole provided in the movable body, one end of which can abut against the main body on the high-pressure chamber side, and the other end of which protrudes toward the low-pressure chamber side. , a cylindrical part having an engaging part movably fitted into the inner hole and capable of engaging with the plunger; and an arm part extending from the cylindrical part to be connected to the shaft member. A pneumatic booster having a member, wherein a groove is provided on the outer periphery of the plunger, and a sealing member is attached to the groove to seal between the plunger and the inner hole.