JPH07293734A - Flow rate control valve - Google Patents

Abstract

PURPOSE:To prevent foreign matter from sticking to a valve stem, and improve the cooling effect in an atmospheric chamber by providing a protective plate inside a ventilation port opposite to an opening of the ventilation port, and making the projection of the protective plate on the plane to diagonally cross the line orthogonal to the valve stem. CONSTITUTION:A ventilation port 26 of a flow rate control valve 1A is provided with an opening part facing the bottom surface of an actuator case 21 A, a protective plate 44 is provided inside the ventilation port 26 opposite to the opening of the ventilation port 26. The projection of the protective plate 44 on the plane is made to diagonally cross the line orthogonal to a valve stem 15. This constitution guides the air advancing from the ventilation port 26 in an atmospheric chamber 40 at the angle of inclination of the protective plate 44 in a spiral manner to cool the valve stem 15 and the lower surface of a diaphragm 30. Foreign matter such as water and dust to enter collides with the protective plate 44 and are dropped to the lower part on the outer side, and discharged from the opening part of the ventilation port 26 in the bottom of the actuator 21A outside. As a result, the smooth sliding of the valve stem 15 is kept.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate control valve configured to adjust the opening degree by a vacuum type actuator.

[0002]

2. Description of the Related Art Conventionally, a flow control valve equipped with a vacuum actuator is generally used in an exhaust gas recirculation system for an automobile engine or the like.

Such a flow rate control valve includes a control valve having a valve body capable of opening and closing a flow path and having a valve shaft for guiding the valve body in an axial direction, and a negative pressure formed on an upper portion of an actuator case. An actuator having a chamber and an atmospheric chamber formed below the negative pressure chamber and separated by a diaphragm is provided, and the tip of the valve shaft is fixed to the diaphragm so that the control valve is driven to open and close. Was there.

The flow path of the control valve is connected to a recirculation path for recirculating exhaust gas to the intake system, and an intake negative pressure generated corresponding to the operating state of the engine is introduced into the negative pressure chamber, and the negative pressure is introduced. Due to this, the diaphragm was operated and the reflux amount was controlled.

A valve shaft of a control valve fixed to a diaphragm penetrates through the atmosphere chamber of the actuator, and a vent hole is provided on a side surface of the atmosphere chamber for communicating the inside and outside of the actuator case. There is. Then, the outside air is introduced from the ventilation hole to cool the inside of the atmosphere chamber so that the high temperature on the control valve side is not transmitted to the diaphragm or the like.

However, in addition to the outside air, foreign matters such as water and dust may enter through the vent holes and adhere to the valve shaft. As a result, the foreign matter is caught between the valve shaft and the bearing that supports it, which causes a problem that smooth sliding of the valve shaft is obstructed.

Therefore, there has been proposed a flow control valve in which a cylindrical protective cover is provided so as to cover the valve shaft penetrating the atmosphere chamber to prevent foreign matter from adhering to the valve shaft (for example, the actual open valve). 59-119963).

[0008]

However, in the flow control valve having such a conventional structure, since the cylindrical protective cover covers the valve shaft in the atmosphere chamber, the cooling effect of the valve shaft by the outside air is lowered, There was a problem that the heat resistance and reliability of the diaphragm deteriorated.

Further, since the ventilation hole is provided on the side wall of the lower case of the actuator case, foreign matter such as water and dust is accumulated on the bottom surface of the lower case, and the foreign matter is caught between the valve shaft and the bearing. There was a risk of hindering smooth sliding of the valve shaft.

The present invention has been made in view of the above problems, and it is an object of the present invention to prevent foreign matter from adhering to a valve shaft driven by a diaphragm and to improve the cooling effect in the atmosphere chamber. It is intended to provide a flow control valve.

[0011]

The present invention has been made to achieve the above object, and a flow control valve of the present invention has a valve body capable of opening and closing a flow passage, and the valve body has an axial direction. A control valve having a valve shaft for movably guiding to, a negative pressure chamber formed in the upper part of the actuator case, and an atmosphere chamber separated by a diaphragm and communicating with the atmosphere by a ventilation hole. A flow control valve comprising: an actuator provided with a tip of a valve shaft fixed so as to open and close the control valve, wherein the vent hole has an opening facing the bottom surface of the actuator case, A flow rate is characterized in that a protection plate is provided inside the ventilation hole facing the opening of the ventilation hole, and a plane projection of the protection plate intersects obliquely with respect to a line orthogonal to the valve axis. Control It is a valve.

Further, a ridge is formed around the valve shaft penetrating portion on the bottom surface of the actuator case.

[0013]

The present invention is configured as described above, and the air that is about to enter the atmosphere chamber through the vent hole is guided by the oblique angle of the protective plate and spirally enters the atmosphere chamber, and the valve shaft And cool the bottom surface of the diaphragm.

Further, foreign matter such as water, dust, and the like, which is about to enter, hits the protective plate and falls to the lower portion of the outer surface thereof, and is discharged to the outside from the vent hole opening on the bottom surface of the actuator case.

Further, the raised portion around the valve shaft penetrating portion on the bottom surface of the actuator case prevents the foreign matter dropped on the bottom surface of the actuator case from flowing to the periphery of the valve shaft, and prevents the foreign matter from entering between the valve shaft and the bearing. To prevent.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view of a flow control valve according to an embodiment of the present invention, and FIGS. 2 and 3 are a plan cross-sectional view and a partial front view showing a vent hole and a protective plate.

In the drawing, 1A is a flow control valve, and the flow control valve 1A is provided with a control valve 10 having a valve shaft 15 for guiding the valve element 14 in the axial direction, and a negative pressure chamber 3 having a diaphragm 30.
5, an actuator 20 having an atmosphere chamber 40,
The vent hole 26 of the atmosphere chamber 40 is provided in the actuator case 21.
A protective plate 44 is provided so as to face the bottom surface 25 of A and open inside the vent hole 26.

The control valve 10 is provided in a valve housing 11 and has a flow passage 12 having an inlet port 12a at one end and an outlet port 12b at the other end, and a valve seat 1 provided in the middle of the flow passage 12.
3 and a valve body 14 and the like that can contact the valve seat 13 when lowered.

A valve shaft 15 extending upward is provided upright in the center of the valve body 14, and the valve shaft 15 is guided and supported by a bearing 18 supported by a bush 17 so as to be movable in the axial direction. There is. An actuator 20 is fixed to the upper portion of the valve housing 11 via a gasket (not shown), and a tip end portion of the valve shaft 15 is formed so as to project into the actuator 20.

The actuator 20 is composed of the upper case 2
2, actuator case 2 consisting of lower case 23A
1A and a diaphragm 30 and the like, and a negative pressure chamber 35 is provided between the diaphragm 30 and the upper case 22.
And an atmosphere chamber 40 is formed between the diaphragm 30 and the lower case 23A. The lower case 23A is provided with three vent holes 26 opened from the side surface 24 to the bottom surface 25, and the atmosphere chamber 4 is opened through the vent holes 26.
0 is in communication with the atmosphere.

[0021] Taiafuramu 30, depending however prospect Me of the outer peripheral portion is an upper case 22 and the lower case 23A,
It is sandwiched between the two while maintaining airtightness, further sandwiched between the upper shell 31 and the lower shell 32, and integrally connected to the tip end portion of the valve shaft 15 via a shim (not shown) in the central portion. It is fixed. Further, a diaphragm spring 37 is interposed between the upper shell 31 and the upper case 22 via a connecting member 36, and the valve shaft 15 is urged in the direction of closing the valve body 14.

The negative pressure chamber 35 is formed so that the negative pressure from the negative pressure source is transmitted through the negative pressure port 38, and the urging force of the diaphragm spring 37 is generated by the negative pressure. A spring force that is smaller than the power is applied. Then, the actuator 20 is fixed to the control valve 10 by bolts 39 together with a protection member 43A described later.

The protective member 43A has three protective plates 44 bent and formed. The protective plate 44 is a protective member 43.
When A is attached to the bottom surface of the lower case 23A, it is erected in parallel with the valve shaft 15 and the plane projection (see FIG. 2) of the protective plate 44 with respect to the line in the centrifugal direction orthogonal to the valve shaft 15. And are formed to intersect at an oblique angle θ = 65 degrees. Further, each protection plate 44 is located inside each ventilation hole 26, and is provided so as to block linear flow of air, water, etc. between the outside of the ventilation hole 26 and the valve shaft 15.

A lift sensor 50 and a connector terminal 51 are integrally formed in the upper case 22, and the lift sensor 50 electrically detects the opening degree of the valve body 14 via the connecting member 36. Is configured.

Next, the flow rate control valve 1 thus constructed
The operation of the protection plate 44 of A will be described.

The air (indicated by the dotted arrow in FIG. 2) entering the atmosphere chamber 40 through the vent hole 26 and the foreign substances such as water and dust (indicated by the solid arrow in FIG. 2) flying together with the air are Upon hitting the protection plate 44, the air is guided by the oblique angle θ to change its course and enters the atmosphere chamber 40. Then, the air hits the inner wall of the lower case 23A, turns to form a spiral, flows in the atmosphere chamber 40, and cools the valve shaft 15 and the lower surface side of the diaphragm 30.

On the other hand, the foreign matter hitting the protective plate 44 adheres to the outer surface of the protective plate 44 and falls to the lower part thereof,
It is discharged to the outside from the opening of the vent hole 26 on the bottom surface of the lower case 23A. Therefore, the foreign matter is prevented from adhering to the valve shaft 15, and the foreign matter is prevented from staying or accumulating in the lower case 23A.

FIGS. 4 and 5 show a second embodiment of the present invention, which is characterized by the structure of a protective member having a raised portion. In the following description, the same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The flow rate control valve 1B according to the second embodiment is provided with a bearing 18A which is slightly longer in the axial direction than the bearing 18, and the upper end portion of the bearing 18A projects into the atmosphere chamber 40 by a long distance. Lower case 23B constituting the actuator case 21B
Has a vent hole 26 and is formed with a conical trapezoidal raised portion (not shown in the figure) that abuts against the bearing 18A.
The protective plate member 43B has a protective plate 44, and a conical trapezoidal raised portion 45 is formed in the penetrating portion of the valve shaft 15.

As a result, similarly to the first embodiment, the protective plate 44 guides the outside air from entering the atmosphere chamber 40 and prevents foreign matter from entering, and the raised portion 45 allows the bottom surface of the lower case 23B and the protective member. The foreign matter that has fallen on the mounting surface of 43B is prevented from flowing around the valve shaft 15 to prevent the foreign matter from further entering between the valve shaft 15 and the bearing 18A.
The smooth sliding of the valve shaft 15 is maintained.

6 and 7 show a third embodiment of the present invention, which is characterized in that the lower case and the protective plate are integrally formed.

In the flow control valve 1C of the third embodiment, the lower case 23C which constitutes the actuator case 21C.
Is partially bent to form a protection plate 44, and a conical trapezoidal raised portion 46C is formed at the penetrating portion of the valve shaft 15. According to the lower case 23C, the flow control valve 1 including the protection plate 44 and the raised portion 46C can be simply configured.

Even if the actuator case 21D is constructed by the lower case 23D having the conical protrusion 46D as in the flow control valve 1D of the fourth embodiment shown in FIGS. .

[0034]

As described above, according to the flow rate control valve of the present invention, the ventilation hole is opened so as to face the bottom surface of the actuator case, and the protective plate is obliquely provided inside the ventilation hole. It is possible to prevent foreign matter such as water and dust from entering the atmosphere chamber and to discharge the foreign matter from the bottom surface of the case. Therefore, it is possible to prevent the foreign matter from being attached to the outside and maintain the smooth sliding of the valve shaft.

Further, the air is guided by the protective plate and spirally enters the atmosphere chamber, the cooling effect of the valve shaft and the diaphragm is enhanced, and the reliability of the diaphragm can be improved.

Further, the raised portion can prevent foreign matter from flowing on the bottom surface of the actuator case and prevent foreign matter from being caught between the valve shaft and the bearing.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a flow control valve according to an embodiment of the present invention.

FIG. 2 is a sectional plan view taken along the line II-II of FIG.

FIG. 3 is a view on arrow III in FIG.

FIG. 4 is a vertical sectional view of a flow rate control valve according to a second embodiment.

5 is a cross-sectional plan view taken along the line VV of FIG.

FIG. 6 is a vertical sectional view of a flow rate control valve according to a third embodiment.

7 is a plan sectional view taken along the line VII-VII of FIG.

FIG. 8 is a vertical sectional view of a flow rate control valve according to a fourth embodiment.

9 is a plan sectional view taken along the line IX-IX of FIG.

[Explanation of symbols]

1A, 1B, 1C, 1D Flow control valve 10 Control valve 14 Valve body 15 Valve shaft 20 Actuator 21A, 21B, 21C, 21D Actuator case 25 Bottom face 26 Vent hole 30 Diaphragm 35 Negative pressure chamber 40 Atmosphere chamber 44 Protective plate 45 Raised part 46C, 46D Raised part

Claims (2)

[Claims] 1. A control valve having a valve body which can open and close a flow path and which guides the valve body movably in an axial direction; a negative pressure chamber formed in an upper part of an actuator case; A flow control valve comprising: an atmosphere chamber separated by a diaphragm and communicating with the atmosphere by a ventilation hole; and an actuator in which the tip of the valve shaft is fixed to the diaphragm so that the control valve can be opened and closed. The ventilation hole has an opening facing the bottom surface of the actuator case, a protection plate is provided inside the ventilation hole so as to face the opening of the ventilation hole, and a planar projection of the protection plate is provided. Is obliquely intersecting with a line orthogonal to the valve axis, the flow control valve. 2. The flow control valve according to claim 1, wherein a raised portion is formed on the bottom surface of the actuator case around the valve shaft penetrating portion.