JPH0353956Y2 - - Google Patents

Description

[Detailed description of the invention] "Field of industrial application" The present invention relates to a solenoid valve for a brake booster, more specifically a solenoid valve that opens and closes a fluid passage communicating between a variable pressure chamber and a constant pressure chamber of a brake booster. Regarding.

``Prior Art'' Conventionally, as a brake booster, a solenoid is provided in a valve body, and this solenoid is linked via a lever to a valve plunger that constitutes a valve mechanism. When the vehicle is stopped, the valve plunger is actuated by the solenoid. There is a known brake booster in which the flow path of the valve mechanism is switched so that the brake can be applied even when the pedal force is released and the brake can be applied to a stop. Publication No. 105866 (1983).

Furthermore, the present applicant has already provided a solenoid valve in the valve body of the brake booster as a brake booster, and when the solenoid constituting the solenoid valve is deenergized, the valve means is moved away from the valve seat by a spring. thereby opening a fluid passage that communicates the variable pressure chamber and constant pressure chamber of the brake booster via the valve mechanism, and seating the valve means on the valve seat to close the fluid passage when the solenoid is energized. At the same time, it has been proposed that fluid pressure on the variable pressure chamber side is applied to the valve means to press it against the valve seat. issue).

The spring and valve means of the electromagnetic valve have a seat portion seated on the valve seat on the outer periphery, a communication passage communicating with the fluid passageway on the inner periphery, and a valve member that is closed when the solenoid is deenergized. a ring-shaped first valve body that is separated from the valve seat by a spring;
It is interlocked with a plunger that is moved forward and backward by the solenoid, and when the solenoid is energized, it seats on the first valve body and closes the communication passage, and at the same time, the first valve body is moved against the first spring to open the valve. a poppet-shaped second valve body that is seated on the valve seat to close the fluid passage, and that is separated from the first valve body seated on the valve seat by a second spring when the solenoid is deenergized. There is.

``Problem that the invention seeks to solve'' However, in the former brake booster, the valve plunger and the input shaft linked thereto are actuated by the solenoid, and depending on the structure, the valve plunger is also linked to the input shaft. Since it is also necessary to operate the brake pedal, a large solenoid is required, and it is difficult to accommodate such a large solenoid within the shell of the brake booster.

On the other hand, in the latter brake booster, the electromagnetic valve only needs to open and close the fluid passage formed in the valve body, so it can be small and easily accommodated in the shell of the brake booster. .

Moreover, when the fluid passage is opened, the solenoid valve
That is, when the solenoid is de-energized, the poppet-shaped second valve body is first separated from the first valve body by the elastic force of the second spring, thereby opening the fluid passage through the communication path of the first valve body. When the pressure of the fluid biasing the first valve element decreases, the first valve element is unseated from the valve seat by the first spring and completely opens the fluid passage, thereby causing the valve means to open. Compared to the case where the valve body is composed of one valve body, the second spring and the first
It is possible to make the overall elastic force of the spring smaller than the elastic force of the spring that opens one valve body, and as a result, the suction force of the solenoid can be reduced, so that the solenoid valve can be further miniaturized. I can do it.

However, in the electromagnetic valve proposed by the applicant, the seating portion of the poppet-type second valve body on the first valve body is formed in a plane perpendicular to the stem of the second valve body. Since the flat seating portion is seated on the first valve body, for example, when the second valve body is connected to a plunger that is moved forward and backward by the solenoid, the stem is curved and the flat seating portion is seated on the first valve body. If the valve body was inclined with respect to the first valve body, there was a risk that airtight leakage would occur.

"Means for solving the problem" In view of such circumstances, the present invention is provided in the valve body of the brake booster, and when the solenoid is deenergized, the valve means is lifted off the valve seat by a spring. A fluid passage communicating between a variable pressure chamber and a constant pressure chamber of the brake booster via a valve mechanism is opened, and when the solenoid is energized, the valve means is seated on a valve seat to close the fluid passage; A solenoid valve for a brake booster that applies fluid pressure on the variable pressure chamber side to the valve means to press it against the valve seat, the spring and the valve means being arranged on the outer periphery of the valve seat. a ring-shaped first valve having a seat portion seated on the valve seat and having a communication passageway communicating with the fluid passageway formed in the inner peripheral portion thereof, and being unseated from the valve seat by a first spring when the solenoid is deenergized; and a plunger that is moved forward and backward by the solenoid, and when the solenoid is energized, seats on the first valve body to close the communication passage, and at the same time resists the first valve body against the first spring. a poppet-type second valve body, which is seated on the valve seat to close the fluid passage, and is further unseated from the first valve body seated on the valve seat by a second spring when the solenoid is deenergized; The present invention further provides an electromagnetic valve for a brake booster, comprising: a seat portion of the second valve body on the first valve body formed in a spherical surface.

"Function" According to such a configuration, not only can the solenoid valve be downsized as described above, but also the stem of the poppet-type second valve body is curved so that the seating portion of the spherical surface is connected to the first valve body. Even when the seat is tilted with respect to the body, airtight leakage can be better prevented from occurring than when the seat is flat.

"Example" The present invention will be explained below with reference to the illustrated example.
In FIG. 4, a shell 1 of the brake booster consists of a front shell 1a and a rear shell 1b. A power piston 2 is slidably provided in the shell 1, and a diaphragm 3 is stretched on the rear surface of the power piston 2. The power piston 2 and diaphragm 3 divide the interior of the shell 1 into a constant pressure chamber 4 at the front and a variable pressure chamber 5 at the rear.

Further, a valve body 6 is integrally provided on the shaft portion of the power piston 2, and a valve mechanism 7 for switching the flow path is housed in the valve body 6. Further, the power piston 2, the valve body 6, etc. are normally connected by a return spring 8. and is held in the inoperative position shown.

The valve mechanism 7 has a first valve formed in the valve body 6.
A valve seat 10, a second valve seat 12 formed on the valve plunger 11, and a power piston 2 on both valve seats 10, 12.
The valve body 14 is seated from the rear side, that is, from the right side in FIG. 4, by the elastic force of a spring 13. The outside of the seat portion of the first valve seat 10 and the valve body 14 is communicated with the constant pressure chamber 4 via a passage 15 and a solenoid valve 16, and the constant pressure chamber 4 is provided in the shell 1 for negative pressure introduction. The pipe 17 communicates with a negative pressure source such as an engine intake manifold (not shown).

On the other hand, the first valve seat 10 and the valve body 14, and the intermediate portions of the seals of the second valve seat 12 and the valve body 14 are communicated with the variable pressure chamber 5 through a passage 18 formed in the valve body 6. Second valve seat 12 and valve body 1
The inner side of the seat portion with 4 is communicated with the atmosphere through a passage 20 provided with a filter 19. In addition,
The variable pressure chamber 5 is kept airtight from the outside by a seal member 21 that slidably penetrates the valve body 6.

The valve plunger 11 constituting the valve mechanism 7 is prevented from being pulled out from the valve body 6 by a key member 24, and its distal end is connected to an input shaft 25 that is linked to a brake pedal (not shown).
Further, the distal end surface of the valve plunger 11 is opposed to the distal end surface of the output shaft 26, and a reaction disk 27 is interposed between the opposing surfaces. Further, a cylindrical portion 1c is formed on the shaft portion of the front shell 1a to protrude toward the inside of the shell 1, and the output shaft 26 is slidably passed through a seal member 28 disposed inside the cylindrical portion 1c. It is made to protrude outside the shell 1, and its protruding end is interlocked with a piston of a master cylinder (not shown).

The above-mentioned solenoid valve 16 is disposed within the constant pressure chamber 4 and is attached to the valve body 6 at a position outside and below the coiled return spring 8, and the passage formed in the valve body 6 by the solenoid valve 16 is 15 can be opened and closed.

As shown in an enlarged view in FIG. 1, the electromagnetic valve 16 includes a generally dish-shaped case 30 that covers the opening of the passage 15 into the constant pressure chamber 4 and is airtightly attached to the valve body 6. It is equipped with a generally cup-shaped case 31 whose opening side is integrally connected to a dish-shaped case 30, and a positioning plug 32 attached to the center of the bottom inside the cup-shaped case 31 is connected to the solenoid 3.
The solenoid 3 is fitted into the spool 34 of the solenoid 3.
3 is positioned and housed in the shaft portion of the cup-shaped case 31.

The cup-shaped case 31 is formed with a stepped portion 31a whose opening side is enlarged in diameter. By overlappingly contacting the end face of the solenoid 31a, a magnetic circuit of the solenoid 33 is formed by the cup-shaped case 31, the plug 32, the plunger 36 and the spacer 35 slidably provided in the spool 34.

Then, the dish-shaped case 30 is attached to the spacer 35.
The plunger 36 is attached to the spool 34 by integrally connecting the dish-shaped case 30 and the cup-shaped case 31 by caulking in a state where they are superimposed on each other.
When the plug 3 is slidably stored inside the
2. The spool 34 and the spacer 35 are integrally connected and fixed.

In this way, the stepped portion 3 is attached to the cup-shaped case 31.
1a and bring the outer periphery of the spacer 35 into overlapping contact with the stepped portion 31a, the stepped portion 31a is omitted and the outer periphery of the spacer 35 is attached to the cup-shaped case 31.
Compared to the case where the spacer 35 is brought into close contact with the inner circumferential surface of the cup-shaped case 31, even if there is a dimensional error, the spacer 35 cannot be fitted into the cup-shaped case 31, or the outer circumferential surface of the spacer 35 and the inner circumference of the cup-shaped case 31 may not fit properly. It is possible to reliably prevent a situation where a large gap is formed between the magnetic circuit and the peripheral surface and the efficiency of the magnetic circuit is reduced.

Further, since the axial position of the spacer 35 with respect to the cup-shaped case 31 can be determined by the stepped portion 31a, when the dish-shaped case 30 and the cup-shaped case 31 are connected together by caulking, It is also possible to prevent the spacer 35 from compressing the spool 34 strongly and damaging it, thereby improving the ease of assembly.

Next, a stepped portion is formed in the dish-shaped case 30, and the right end surface of the stepped portion serves as a valve seat 30a. Seated valve means 40
has been established.

As shown in FIGS. 1 and 3, the valve means 40 includes a large-diameter ring-shaped first valve body 41 made of an elastic body 41A as a sealing material and a metal holding plate 41B that holds the elastic body 41A. and this first valve body 4
a poppet-shaped second valve body 42 that is press-fitted into the plunger 36 through the shaft portion of the second valve body 42 in a slidable manner;
The first valve body 41 has a seat portion 41a on its outer periphery that is seated on the valve seat 30a of the dish-shaped case 30, and the passage 15 on its inner periphery.
Further, the communication path 41b communicates with the communication path 41b.
A valve seat 41c is formed around each valve seat 41c, and the poppet-shaped second valve body 42 has a seating portion 42a formed at its head portion to sit on the valve seat 41c around the communication passage 41b.

A first spring 43 is loaded between the first valve body 41 and the dish-shaped case 30, and a second spring 44 is loaded between the plug 32 and the plunger 36.
Normally, the plunger 36 is brought into contact with the dish-shaped case 30 by the second spring 44 to hold the second valve body 42 in the non-operating position, and the first valve body 42 is held in the inoperative position.
The spring 43 causes the valve seat 41c of the first valve body 41 to come into contact with the second valve body 42 located in the non-operating position, thereby holding the first valve body 41 in the non-operating position.

In this state, the seat portion 41a of the first valve body 41
is spaced apart from the valve seat 30a formed in the dish-shaped case 30, so the passage 15 is separated from the first valve body 4.
1 and the valve seat 30a and through a passage 45 formed in the dish-shaped case 30 to the constant pressure chamber 4.

On the other hand, when the solenoid 33 is energized to move the plunger 36 to the left, the second poppet type
The seating portion 42a of the valve body 42 is seated on the valve seat 41c formed on the inner circumference of the first valve body 41 to close the communication passage 41b, and at the same time, the first valve body 41
is integrally moved to the left so that its seat portion 41a is seated on the valve seat 30a of the dish-shaped case 30, thereby making it possible to close the passage 15.

At this time, as shown in FIG.
While forming an engaging portion 42c that protrudes to the side,
The holding plate 41B constituting the first valve body 41 has the engaging portion 4 protruding toward the center of the communicating path 41b.
2c is formed, and when the seating part 42a of the second valve body 42 is seated on the valve seat 41c of the first valve body 41, the engaging part 42c and the contact part 41d are formed. By bringing the valve seat 4 into contact with
This prevents the elastic body 41A of 1c from being excessively elastically deformed.

Therefore, the elastic body 4 in the valve seat 41c
The amount of elastic deformation of 1A can always be maintained in an optimal state, and the elastic body 41A will not be excessively deformed and prematurely aged as in the case where the abutting portion 41d and the engaging portion 42c are omitted. Furthermore, in the worst case, even if the plunger 36 comes into contact with the plug 32, the valve seat 41c and the valve seat 30a cannot be completely sealed. Note that the engaging portion 4
In order to prevent hitting noises when the contact portion 2c and the contact portion 41d contact each other, an elastic body having an appropriate thickness may be provided on either one of the contact portions 2c and the contact portion 41d.

Further, the seating portion 42a of the second valve body 42 is formed into a spherical surface, so that, for example, the stem 42b of the poppet-shaped second valve body 42 can be attached to the plunger 36, as shown in an exaggerated manner in FIG. Even if the stem 42b is curved and the seating portion 42a is inclined during press-fit connection, the entire circumference of the seating portion 42a is seated on the valve seat 41c to ensure that the communication path 4
1b can be closed.

Next, as shown in FIG. 4, the harness 50 drawn out from the electromagnetic valve 16 is drawn out through a sealing means 51 provided in the front shell 1a, and connected to a control device (not shown) including a microcomputer. . Further, the variable pressure chamber 5 is communicated with the atmosphere as a pressure fluid source through a pressure fluid introduction pipe 52 provided in the rear shell 1b, a solenoid valve 53, and an air cleaner (not shown), without going through the valve mechanism 7. The valve 53 is also connected to the control device (not shown).

At this time, as described above, since the solenoid valve 16 is attached to the valve body 6 at a position outside and below the coiled return spring 8,
The harness 50 can be prevented from interfering with the return spring 8. In addition, in FIG. 2, a notch 35a formed in a part of the spacer 35 is used to provide a space for installing a connector 54 (see FIG. 1) that connects the harness 50 and the solenoid 33 of the electromagnetic valve 16. It was formed.

In the above configuration, under normal conditions, the control device closes the solenoid valve 53 on the atmosphere side and opens the solenoid valve 16 on the negative pressure side, that is, deenergizes the solenoid 33. When the solenoid 33 is deenergized, the second valve body 42 and the plunger 36
The plunger 36 is held in the non-operating position by the second spring 44, and the first valve body 41 is held in the non-operating position by the first spring 43. It is held in an inoperative position abutting the body 42.

When the brake booster is not operating in this state, the negative pressure introduced into the constant pressure chamber 4 via the negative pressure introduction pipe 17 is transmitted via the negative pressure side solenoid valve 16.
That is, it is introduced into the passage 15 via the passage 45 and between the first valve body 41 and the valve seat 30a, and further supplied to the variable pressure chamber 5 via the valve mechanism 7 and the passage 18. Therefore, in this state, no fluid pressure difference occurs before and after the power piston 2, so the brake booster is not shown in the figure, like the conventionally known brake booster that does not have the electromagnetic valves 16, 53. remains in working condition.

It is clear that when the brake pedal is depressed from the above-mentioned non-operating state, it is possible to generate a braking force corresponding to the depression force of the brake pedal, similarly to a conventionally known brake booster. When the valve body moves forward due to the operation of the brake booster, the solenoid valve 16 attached to the valve body 6
By forming the cylindrical portion 1c on the shaft portion of the brake booster, the shaft portion of the brake booster is positioned within the empty space 55 formed within the constant pressure chamber 4. It becomes possible to keep the directional dimensions small.

Next, in contrast to the general operation of the brake booster, for example, when operating the brake booster as a stop brake device, the control device detects operating conditions from various sensors (not shown) and maintains a certain level of control. When the operating conditions are satisfied, the solenoid 33 of the negative pressure side solenoid valve 16 is energized. Then, plunger 3
6 is moved to the left, the two valve bodies 41 and 42 are integrally moved to the left against the respective springs 44 and 43, and the first valve body 4
The first seat portion 41a is seated on the valve seat 30a, and the second valve body 42 is seated on the valve seat 41c.
Then, when the opening of the passage 15 is closed and a fluid pressure difference is generated before and after the two valve bodies 41 and 42, that pressure further presses each of the valve bodies 41 and 42 against the valve seats 30a and 41c, respectively. A reliable seal is achieved.

At the same time, the control device operates the atmospheric side solenoid valve 5.
3 is opened for a predetermined time, atmospheric pressure corresponding to the predetermined time is introduced into the variable pressure chamber 5 via the pressure fluid introduction pipe 52, and therefore no pedal force is applied to the input shaft 25. Even if there is no brake, the braking action is performed with a braking force corresponding to the atmospheric pressure.

When the control device deenergizes the solenoid 33 of the negative pressure side electromagnetic valve 16 when the stop brake is released, pressure acts on each valve body 41, 42, causing each valve body 41, 42 to move to the valve seat. 30a, 41
Although I am pressing each of them. First, the poppet-shaped second valve body 42 having a small pressure receiving area and a small diameter is moved to the right by the elastic force of the second spring 44 and separated from the valve seat 41c of the first valve body 41.

Then, the passage 15 comes to communicate with the constant pressure chamber 4 via the communication passage 41b formed in the shaft portion of the first valve body 41, so the pressure on the passage 15 side decreases,
When the pressure becomes lower than a predetermined value, the ring-shaped first valve body 41 is easily removed from the valve seat 30a by the first spring 43, so that the passage 15 has a large flow area and becomes a constant pressure chamber. 4, and therefore the pressure within the passage 15, that is, within the variable pressure chamber 5, quickly decreases.

In this way, if the valve means 40 of the solenoid valve 16 is composed of the two valve bodies 41 and 42, the valve means
The second spring 4
4 and the first spring 43 can be reduced, the attraction force of the solenoid 33 can be reduced, and the solenoid valve 16 can therefore be made smaller.

In addition, in the negative pressure type brake booster, the solenoid valve 16 in the constant pressure chamber 4 is placed in a vacuum atmosphere, so compared to the case where it is installed in the atmosphere, rust prevention and insulation treatment is required. can be simplified or omitted.

Note that even if the pressure fluid introduction pipe 52 and the electromagnetic valve 53 are omitted, if necessary, the input shaft 25 is moved forward to switch the flow path of the valve mechanism 7, and atmospheric pressure is introduced into the variable pressure chamber 5. Of course, it is possible to perform a braking action.

"Effects of the invention" As described above, according to the solenoid valve according to the present invention,
Even if the suction force of the solenoid is smaller than in the past, the valve means pressed against the valve seat by fluid pressure can be moved away from the valve seat.
The solenoid valve can be made smaller, and the seating part of the poppet-type second valve body is a spherical surface.
Even if the stem is curved and the spherical seating part is inclined with respect to the first valve body, the occurrence of airtight leakage is better prevented than when the seating part is flat. The effect of being able to do this is obtained.

[Brief explanation of the drawing]

1 is an enlarged sectional view of the main part of FIG. 4, FIG. 2 is a perspective view of the spacer 35, FIG.
The figure is a sectional view showing an embodiment of the present invention. 4... Constant pressure chamber, 5... Variable pressure chamber, 6... Valve body, 7... Valve mechanism, 15, 18... Passage, 16
... Solenoid valve, 30, 31 ... Case, 30a, 4
1c... Valve seat, 33... Solenoid, 36... Plunger, 40... Valve means, 41... First valve body 1
41a... Seat portion, 41b... Communication path, 42...
...Second valve body, 42a...Seating portion, 43...First spring, 44...Second spring.

Claims (1)

[Scope of claim for utility model registration] Provided in the valve body of the brake booster,
When the solenoid is deenergized, the valve means is moved away from the valve seat by a spring to open a fluid passage communicating the variable pressure chamber and the constant pressure chamber of the brake booster via the valve mechanism, and the solenoid is energized. At the same time, the valve means is seated on the valve seat to close the fluid passage, and the fluid pressure on the variable pressure chamber side is applied to the valve means to press it against the valve seat. The solenoid valve is a solenoid valve, wherein the spring and the valve means are connected to each other, a seat part is formed on the outer periphery to sit on the valve seat, and a communication passage communicating with the fluid passage is formed on the inner periphery, and when the solenoid is deenergized, a ring-shaped first valve body that is unseated from the valve seat by a first spring; and a ring-shaped first valve body that is interlocked with a plunger that is moved forward and backward by the solenoid and is seated on the first valve body when the solenoid is energized. At the same time, the first valve body is seated on the valve seat against the first spring to close the fluid passage, and when the solenoid is deenergized, the valve seat is closed by the second spring. a poppet-shaped second valve body that is separated from the first valve body seated on the valve body, and further characterized in that a seating portion of the second valve body on the first valve body is formed into a spherical surface. Solenoid valve for brake booster.