JPH08135520A - Exhaust gas reflux control valve device for internal combustion engine - Google Patents

Abstract

PURPOSE: To prevent gas leakage when a valve is closed by incresasing air tightness between a valve seat and a valve body. CONSTITUTION: A horizontal sheet surface 51a which is horizontal relative to an axis of a valve body 52 and, successively, a tapered sheet surface 51c which is reduced in diameter gradually toward the closing direction of the valve body 52 are formed on the internal peripheral edges of a valve seat 51 with which a valve face part 52c of a valve body 52 is brought into contact. Also an annular recessed groove 53 which compensates for both seat surface is formed so as to always bring into contact the valve seat 51 and the valve body 52 closely with each other at either of the horizontal and tapered surfaces. Thus air tightness between them can be maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation control valve device mounted in an exhaust system of an internal combustion engine, and more particularly, to an exhaust gas having enhanced airtightness between a valve face portion and a valve seat with which the valve face portion abuts. The present invention relates to a reflux control valve device.

[0002]

2. Description of the Related Art An internal combustion engine is equipped with an exhaust gas recirculation control valve device (EGR valve) which recirculates a part of exhaust gas to an intake system to reduce harmful nitrogen oxides contained in the exhaust gas. Often.

FIG. 3 shows a conventional device disclosed in Japanese Patent Laid-Open No. 5-321770.
It is composed of a control valve (A) and an actuator (B).

The body of the control valve (A) that curves into an elbow shape
The inlet (2) at the lower end of (1) is connected to the exhaust pipe (not shown) of the engine, and the outlet (3) at the right end is connected to the intake pipe (not shown) of the engine.

An annular valve seat (4) is located above the inlet (2).
Is seated, and a seat surface (4a) is formed at the lower end of the inner peripheral surface thereof, the seat surface (4a) diametrically expanding downward.

A horizontal mounting flange (5) is continuously provided on the upper end of the body (1), and a valve shaft (6a) facing upward of a mushroom-shaped valve body (6) provided in the body (1). Penetrates vertically through the centers of the body (1) and the flange (5). Disc
On the outer peripheral surface of the expanding portion (6b) at the lower end of (6), the valve seat
A tapered valve face portion (6c) having the same inclination angle as the seat surface (4a) of (4) is formed.

On the flange (5), a spring bearing (7) and a cylinder (8) having a top surface and a lower surface opened to the lower surface are bolted, and the spring bearing (7) has a plurality of ventilation holes ( 9) is drilled. A ventilation gap (10) is formed in a key portion between the spring bearing (7) and the flange (5).

An air supply hole (11) for supplying compressed air is formed in the center of the upper surface of the cylinder (8), and a cylinder (8) is provided with a topped cylindrical piston (12) having a lower surface opening. It is vertically slidable and fitted with airtightness.
The upper end of (6a) is in contact. The piston (12) is constantly urged downward by a first compression coil spring (13) provided between the piston (12) and the cylinder (8).

The valve body (6) has a pair of cotters (14) at its upper end.
A second compression coil spring (16) having a spring constant larger than that of the first compression coil spring (13), which is contracted between the retainer (15) fixed via It is biased upward. In the normal state, the valve face portion (6c) of the valve body (6) is in close contact with the seat surface (4a) of the valve seat (4) and closes the inflow port (2).

In the above-mentioned device, when compressed air is supplied to the cylinder (8) by a control device (not shown), the piston (12) and the valve body (6) resist the second compression coil spring (16). Are pushed down together and the inlet (2) is opened.

[0011]

As in the conventional device described above, the seat surface (4a) of the valve seat (4) and the valve face portion (6c) of the valve body (6) are simply in surface contact with each other in a tapered shape. If they do, the valve seat (4) may be worn due to uneven wear or thermal expansion of the body (1).
If the roundness (concentricity) of the valve body (6) or the circularity (concentricity) of the valve body (6) changes, a slight gap is created between the seat surface (4a) and the valve face portion (6c), resulting in airtightness when closing the valve. Performance is deteriorated, and the amount of exhaust gas leaked increases.

The present invention has been made in order to solve this problem, so that even if the circularity of the valve seat or the valve disc is distorted due to thermal expansion of the body or the like, high airtightness can be obtained. did,
An object of the present invention is to provide an exhaust gas recirculation control valve device for an internal combustion engine.

[0013]

According to the present invention, there is provided a valve face portion which is accommodated in a body so as to be vertically slidable and which abuts a valve seat provided at an exhaust gas flow port at a lower end thereof. In an exhaust gas recirculation control valve device for an internal combustion engine, comprising: a valve body having a valve body and an actuator for driving the valve body to open and close, an axial line of the valve body is provided at an inner peripheral edge of the valve seat where the valve face portion of the valve body contacts. A horizontal seat surface that is horizontal with respect to it, and a tapered seat surface that continuously reduces in diameter in the closing direction of the valve body are formed continuously, and both seats are formed on the valve face portion of the valve body. The solution is to form an annular groove that is complementary to the surface.

[0014]

According to the present invention, since the valve seat and the valve body are in contact with each other on both the horizontal surface and the tapered surface, even if uneven wear or the like occurs on one of the contact surfaces, the The airtightness is maintained because one of the contact surfaces is always in close contact.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Since the present invention is an improvement of a part of the above-described conventional example, each member having the same or the same function as that of the conventional example is denoted by the same reference numeral, and the detailed description thereof will be omitted.

At the lower end surface of the valve seat (51) of the control valve (A), a horizontal seat surface (51a), which is horizontal to the axis of the valve body (52), is shown on an enlarged scale in FIG. Formed, the inner peripheral surface (51
b) bulges inward toward the inside. Inner surface (51
At the lower edge of b), a tapered seat surface (51c) is formed which is continuous with the horizontal seat surface (51a) and is inclined by about 45 °. The tapered seat surface (51c) and the horizontal seat surface (51a) are formed. ) Forms an obtuse-angled seat surface (51d).

The inclination angle of the valve face portion (52c) formed on the umbrella portion (52b) of the valve body (52) is determined by the taper seat surface (51c).
Smaller than that, and in the middle portion of the inclined surface, an annular groove (53) that is a complement to the seat surface (51d), that is, a narrow face surface (53a) that closely contacts the horizontal seat surface (51a). And a narrow tapered face surface (53b) contacting the tapered seat surface (51c) are continuously formed.

As described above, the valve seat (51) is attached to the horizontal seat surface (51
If a seat surface (51d) consisting of a) and a tapered seat surface (51c) is formed, and face surfaces (53a) (53b) that closely contact with them are formed on the valve body (52) side, for example, The valve seat (51) and the valve body (52) contact each other with uneven wear, or the body (1), the valve seat (51) and the valve body (52) are thermally expanded, so that the valve Even if the circularity between the seat (51) and the valve body (52) slightly changes, the horizontal contact surface and the tapered contact surface of the valve seat (51) and the valve body (52) There is almost no gap formed in both of them, and since one of the contact surfaces is always in close contact, there is no fear of impairing the airtightness.

The present invention can be applied not only to the push-open type control valve device as in the above embodiment but also to the push-close type. At this time, the valve face portion (52c) of the valve seat (51) and the valve body (52).
Should be turned upside down.

[0020]

According to the device of the present invention, since the valve seat and the valve body are in contact with each other on both the horizontal surface and the tapered surface, even if uneven wear occurs on the contact surface, either of them will occur. The contact surface of No. 1 has a high probability of being in close contact with each other at all times, and the airtightness is higher than that of a conventional device in which only the tapered surface is in contact, and the amount of exhaust gas leakage is significantly reduced.

[Brief description of drawings]

FIG. 1 is a central longitudinal front view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a portion X in FIG.

FIG. 3 is a central longitudinal front view of a conventional device.

[Explanation of symbols]

 (A) Control valve (B) Actuator (1) Body (2) Inlet (3) Outlet (4) Valve seat (4a) Seat surface (5) Flange (6) Valve body (6a) Valve shaft (6b) Umbrella part (6c) Valve face part (7) Spring bearing (8) Cylinder (9) Vent hole (10) Gap (11) Air supply hole (12) Piston (13) First compression coil spring (14) Cotter (15) Retainer (16) Second compression coil spring (51) Valve seat (51a) Horizontal seat surface (51b) Inner peripheral surface (51c) Tapered seat surface (51d) Seat surface (52) Valve body (52a) Valve shaft (52b) ) Umbrella part (52c) Valve face part (53) Annular groove (53a) (53b) Face surface

Claims (1)

[Claims] 1. A valve body which is housed in a body so as to be slidable up and down and has a valve face portion at a lower end which abuts a valve seat provided in an exhaust gas passage, and the valve body is opened and closed. In an exhaust gas recirculation control valve device for an internal combustion engine, comprising an actuator, a horizontal seat surface that is horizontal to an axis of the valve body, and an inner peripheral edge of the valve seat that contacts the valve face portion of the valve seat, A tapered seat surface that gradually reduces in diameter in the closing direction of the valve body, and an annular groove that compliments the two seat surfaces is formed in the valve face portion of the valve body. An exhaust gas recirculation control valve device for an internal combustion engine, comprising: