JPH0410454Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a negative pressure control valve that variably controls negative pressure from a negative pressure source.

Conventional negative pressure control valves are equipped with 1 input from a negative pressure source.
Next, apply negative pressure to the diaphragm (or bellows, etc.),
A negative pressure regulating chamber made up of springs, valves, etc. outputs a constant negative pressure, and a mechanism for varying the spring force is added to variably control the output negative pressure. However, this conventional negative pressure control valve has the following problems. The control speed when outputting the desired negative pressure by varying the spring force is such that as the secondary negative pressure approaches the desired negative pressure, the opening distance between the primary negative pressure inlet and the valve narrows, and the negative pressure increases. There was a drawback that it took time to reach the desired negative pressure because the amount introduced was reduced.

The present invention was devised in view of the above points, and aims to improve the control speed by keeping the primary negative pressure inlet and valve always open even when the forces are in equilibrium. purpose. Therefore, in the present invention, by providing a communication passage that communicates the atmospheric negative pressure source port and the negative pressure regulation chamber, a configuration is adopted in which the valve is always open regardless of the force equilibrium state.

Next, one embodiment of the present invention will be described based on the drawings.

In Figure 1, 1 is a diesel engine, 2 is a fuel tank, 3 is a fuel injection pump, 4 is a fuel injection nozzle, and 5 is a fuel adjustment lever for adjusting the fuel injection amount of the fuel injection pump 3. This fuel adjustment lever 5 is connected to an accelerator pedal 7 via a rod 6. 8 is the exhaust system 9 and intake system 1 of engine 1
0, and 11 is an exhaust gas flow rate adjustment valve provided in this EGR passage 8. This exhaust gas flow rate adjustment valve 11 adjusts the EGR amount (return) according to the negative pressure introduced into its diaphragm chamber 12. control the circulating exhaust gas flow rate). Further, 13 is a vacuum pump driven by the engine 1 or an electric motor (not shown).

A negative pressure control valve 15 according to this invention is provided in the middle of the signal path 14 connecting the vacuum pump 13 and the exhaust gas flow rate adjustment valve 11.The configuration of the negative pressure control valve 15 will be explained below. do.

The main body of the negative pressure control valve 15 is composed of a cover 16 and a housing 17. The cover 16 and the housing 17 are fixed by ultrasonic welding with the outer edge of the diaphragm 18 in between, and the diaphragm 18 separates the cover 16 and the housing 17 from each other. As a result, the cover 16 and the diaphragm 18 form a negative pressure chamber 19 that regulates the output negative pressure, and the cover 16 has a negative pressure chamber source port 20 communicating with the negative pressure chamber 19 and an output port. 21 are provided.
These negative pressure source port 20 and output port 21 are connected to the vacuum pump 13 and the exhaust gas flow rate adjustment valve 1.
1 via a signal path 14.

A valve tube 22 is provided in the center of the diaphragm 18, passing through the diaphragm 18 in an airtight manner. The lower end of this valve cylinder 22 is connected to the closing plate 2
The valve chamber 24 is closed by press-fitting the valve chamber 24 . A valve hole 25 is formed in the valve chamber 24, and a movable valve body 26 made of an elastic material is disposed therein. The movable valve body 26 is urged toward the valve seat 28 of the valve chamber 24 with a relatively weak force by a spring 27, so that the valve hole 25 can be opened and closed. The valve seat 28 of the valve cylinder 22 has a valve hole 2 as shown in FIG.
A passage 53 is formed that constantly communicates between the valve chamber 5 and the valve chamber 24.

In addition, the lower part of the valve cylinder 22, that is, the housing 1
A small hole 29 communicating with the valve chamber 24 is formed on the 7 side, and this valve chamber 24 communicates with the inside of the housing 17 via the small hole 29 and the air hole 30 of the housing 17 .

A first spring 31 is disposed in the negative pressure chamber 19 between the cover 16 and the diaphragm 18, that is, between the cover 16 and the valve cylinder 22. Further, the negative pressure chamber 19 has a negative pressure source port 20.
The opening end 20a of the negative pressure source port 20 in the negative pressure chamber 19 is connected to the valve cylinder 2.
2, and its open end 20a faces the movable valve body 26.

A movable body 32 is provided inside the housing 17.
The movable body 32 is composed of, for example, a plate 33 and a cam 34. Three projections 35 are provided on the outer periphery of the plate 33, and these projections 35 are connected to the housing 17.
They are slidably fitted into guide grooves 36 on the inner surface, respectively. Therefore, the plate 33 is connected to the guide groove 3.
6... and is movable in the direction toward and away from the diaphragm 18, that is, in the vertical direction. The cam 3 is placed below the plate 33.
4 is disposed, and the bottom side of the plate 33, that is, the bottom portions 35a of the protrusions 35 ride on the three cam surfaces 37 of the cam 34, respectively. The cam 34 connects the fastener 38 and the fastening bolt 3
9, it is connected to the rotation shaft 5a of the fuel adjustment lever 5 so as to rotate together with this rotation shaft 5a. The cam surface 37 is formed such that as the cam 34 rotates in the forward direction, the height of the cam on which the bottom portion 35a rides increases. Therefore, the cam surface 3 changes depending on the rotation angle of the cam 34.
7... are adapted to move the plate 33 up and down via the bottom portion 35a. The cam 34 is urged in the opposite direction by a return spring 40, and the maximum amount of rotation of the cam 34 in the opposite direction is determined by a stopper 34a formed on the outer periphery of the cam 34 and a stopper 34a (not shown) provided on the housing 17. It is regulated by coming into contact with.

A lip seal 41 is placed around the outer periphery of the cam 34. This lip seal 41 is in sliding contact with the inner surface of the housing 17, and by this lip seal 41 an atmospheric chamber 42 surrounded by the diaphragm 18 and the cam 34 is formed inside the housing 17.
is formed.

A second spring 45 is spanned between the diaphragm 18 and the plate 33 in the atmospheric chamber 42 via a spring holder 44 . That is, the spring holder 44 consists of a rod portion 46 and a flange portion 47, and the second spring 45 is spanned between the flange portion 47 and the plate 33.
The rod portion 46 is slidably fitted into the guide hole 48 of the housing 17, and its tip abuts against the lower end of the valve cylinder 22, that is, the closing plate 23, thereby reducing the mounting load of the second spring 45. is connected to the valve cylinder 22 via the spring holder 44.
It is something that can be added to. Furthermore, the mounting load on the second spring 45 is the same as that on the first spring 31.
The installation load is set to be weaker than that of the Therefore, if the negative pressure chamber 19 is close to atmospheric pressure, the valve cylinder 22 and diaphragm 18 are pushed down by the first spring 31 until the bottom of the valve cylinder 22 contacts the stopper part 49 in the housing 17. It's becoming like that.

Further, the housing 17 is provided with an atmospheric port 50 that communicates with the atmospheric chamber 42, and this atmospheric port 50 is connected to an air cleaner 51 together with the intake system 10. Note that 52 is a long hole for mounting the negative pressure control valve 15.

Next, the operation of the negative pressure control valve having the above structure will be explained.

When the fuel adjustment lever 5 is in the full position,
The cam 34 is rotated as much as possible in the forward direction via the rotation shaft 5a, and the plate 33 is raised to the highest position by its cam surface 37. Therefore, the distance between the plate 33 and the flange portion 47 of the spring holder 44 is narrowed, and the mounting load on the second spring 45 increases accordingly, and the resultant force of the first spring 31 and the second spring 45 is small. It's summery. Therefore, even if the negative pressure in the negative pressure chamber 19 evacuated by the vacuum pump 13 is relatively low, the diaphragm 18 and the valve cylinder 22 rise against the first spring 31.

Then, these further rise, and the movable valve body 26
When the valve is separated from the valve seat 28 and the valve hole 25 is opened, the atmosphere enters the valve chamber 24 from the atmospheric chamber 42 through the atmospheric hole 30 and the small hole 29, and negative pressure is generated from the valve chamber 24 through the valve hole 25. Infiltrate room 19. The movable valve body 26 comes into contact with the open end 20a of the negative pressure source port 20 in the negative pressure chamber 19 when it is separated from the valve seat 28, thereby closing the open end 20a.

Therefore, by communicating the valve chamber 24 and the negative pressure chamber 19, the pressure in the negative pressure chamber 19 approaches atmospheric pressure, so that the valve tube 22 and the diaphragm 1
8 is lowered by the first spring 31, whereby the movable valve body 26 moves away from the opening end 20a and comes into contact with the valve seat 28, closing the valve hole 25 and opening the valve chamber 24 and the negative pressure chamber. Cut off communication with 19. At the same time, the negative pressure chamber 19 is also connected via the negative pressure source port 20.
Negative pressure is supplied to the negative pressure chamber 19, and the negative pressure in the negative pressure chamber 19 increases until the valve chamber 24 and the negative pressure chamber 19 communicate with each other again.

In this way, the diaphragm 18 and the valve cylinder 22 repeatedly rise and fall, and the negative pressure in the negative pressure chamber 19 is maintained at a constant negative pressure mainly determined by the mounting loads of the first spring 31 and the second spring 45. is maintained. The low negative pressure maintained at a relatively low constant pressure in this manner is supplied from the output port 21 to the diaphragm chamber 12 of the exhaust gas flow rate adjustment valve 11, and a small amount of exhaust gas is passed through the exhaust gas flow rate adjustment valve 11. and is recirculated into the cylinders of the engine 1.

Next, when the fuel adjustment lever 5 is in the idle position, the cam 34 is rotated as much as possible in the opposite direction via the rotating shaft 5a, and the plate 33 is rotated on its cam surface 3.
7 to the lowest position. Therefore, the distance between the plate 33 and the flange portion 47 of the spring holder 44 is widened, and the second
The mounting load on the spring 45 is reduced, and the resultant force of the first spring 31 and the second spring 45 is increased. Therefore, the valve chamber 2
4 and the negative pressure chamber 19 is relatively high negative pressure. Therefore, the negative pressure in the negative pressure chamber 19 maintained at a relatively high constant pressure is transferred to the output port 21.
From the diaphragm chamber 1 of the exhaust gas flow rate adjustment valve 11
2, and a large amount of exhaust gas is refluxed.

Therefore, according to the negative pressure control valve 15 configured as described above, the magnitude of the output negative pressure can be changed according to the rotation angle of the cam 34, and as in this embodiment, the cam 34 can be connected to the fuel adjustment lever. 5, it is possible to obtain an output negative pressure corresponding to the load of the engine 1. As a result, a pressure source that changes with the load of the engine 1 can be obtained in the diesel engine 1 as well, so that measures against exhaust gas can be easily taken.

In addition, in the case of this embodiment, since the small groove 53 that communicates the negative pressure chamber 19 and the valve chamber 24 is provided in the valve seat 28 of the valve cylinder 22, the negative pressure chamber is Atmospheric air is constantly introduced into the negative pressure chamber 19, and the negative pressure in the negative pressure chamber 19 decreases (approaches atmospheric pressure). Therefore, the valve cylinder 22 is placed in the atmospheric chamber 22.
The force urging the side (downward in Figure 1) increases,
When the cam 34 is stationary, the valve cylinder 22 and the movable valve body 26 are connected to the open end 20a of the negative pressure source port 20.
It remains balanced in an open state, and an amount of negative pressure commensurate with the atmospheric air introduced into the negative pressure chamber 19 is always introduced into the negative pressure chamber 19.

Since the valve seat 28 is always open in this way, a quick response to the rotational movement of the cam 34 can be taken. That is, there is an effect that a negative pressure control valve with excellent responsiveness can be obtained.

FIG. 3 is a diagram showing the effect of providing this communication passage 53. As is clear from this figure, the one provided with the communication passage 53 (indicated by the broken line A) is The control time required to generate output negative pressure is significantly reduced compared to the one without it (indicated by the solid line B).

Although the above-mentioned embodiments are the preferred embodiments of the present invention, the present invention should not be limited to this one example, and there are various other embodiments.

That is, as shown in FIG. 4, a passage 54 communicating between the inside of the port 20 and the negative pressure chamber 19 may be provided in the protrusion 20b of the negative pressure source port 20 into the negative pressure chamber 19. Even in this case, the valve seat 28 can always be opened as in the previous embodiment.

Further, as shown in FIGS. 5a and 5b, a protrusion 20b of the negative pressure source port 20 in the negative pressure chamber 19 and an open end surface 20a
A communication passage 20c that communicates the negative pressure source port 20 and the negative pressure chamber 19 may be formed by making the negative pressure source port 20 and the negative pressure chamber 19 have an uneven shape.

Furthermore, as shown in FIGS. 6a and 6b, the movable valve body 26
A communication passage 26b that communicates the negative pressure source port 20 with the valve chamber 24 and the negative pressure chamber 19 may be formed by providing unevenness on the valve seat surface 26a.

As explained above, in the negative pressure control valve of the present invention, since the opening end of the negative pressure source port is not blocked by the movable valve body, the amount of negative pressure introduced into the negative pressure chamber that regulates the output negative pressure is significantly reduced. It is no longer decreasing. Therefore, the present invention has an excellent effect in that the control speed of the negative pressure control valve can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the negative pressure control valve of the present invention, Fig. 2 is a sectional view showing the movable valve body shown in Fig. 1, and Fig. 3 is an explanation of the effect of the negative pressure control valve shown in Fig. 1. 4, 5a and 5b, and 6a and 6b are a sectional view and a perspective view, respectively, showing essential parts of other examples of the negative pressure control valve of the present invention. 18...Diaphragm, 19...Negative pressure chamber, 20
... Negative pressure source port, 21 ... Output port, 22 ...
...Valve tube, 26...Movable valve body, 42...Atmospheric chamber, 50...Atmospheric port, 53, 54, 20c,
20b...Communication passage.

Claims (1)

[Scope of claims for utility model registration] (1) A negative pressure chamber with a diaphragm arranged on one side,
A negative pressure source port that introduces negative pressure from a negative pressure source into the negative pressure chamber, an output port that outputs the pressure inside the negative pressure chamber, and a large port provided on the opposite side of the negative pressure chamber with the diaphragm in between. an atmospheric pressure chamber, an atmospheric port for introducing atmospheric pressure into the atmospheric pressure chamber, a valve cylinder having a valve hole provided in the diaphragm and communicating the negative pressure chamber and the atmospheric pressure chamber; A negative pressure control valve comprising a movable valve body disposed opposite to the opening end of the pressure source port and opening and closing the valve hole, and provided with communication means for constantly communicating the negative pressure chamber and the negative pressure source port. . (2) The negative pressure control valve according to claim 1, wherein the communication means is a communication passage that opens the valve hole formed in the valve cylinder. (3) The negative pressure control valve according to claim 1, wherein the communication means is a communication passage formed in the negative pressure source port and connecting the negative pressure source port and the negative pressure chamber. (4) The negative pressure control valve according to claim 1, wherein the communication passage is formed on a surface of the movable valve body facing the opening end of the negative pressure source port.