JPH04159446A - Exhaust gas recirculation control valve - Google Patents

Abstract

PURPOSE:To always ensure normal contact action of an adjusting valve with a valve seat by bearing-supporting a shaft part of the adjusting valve, which adjusts an amount of exhaust gas recirculated to an intake pipe from an exhaust pipe, with two upper and lower parts of a guide member and a sliding plate. CONSTITUTION:An EGR valve 5 has an adjusting valve 6 for adjusting an opening of an exhaust gas passage and a diaphragm 7 for actuating the adjusting valve 6 by a differential pressure in a negative pressure chamber 8. A shaft part 14, integrally molded with the adjusting valve 6, is guided by a guide member 15, fixed into a housing 10, and made slidable in a vertical direction. Here, a sliding plate 23, serving concurrently as a shield plate, is fixed to extend in a flange shape in an axial orthogonal direction relating to a shaft part 14, in the shaft part 14 further below the guide member 15. On the other hand, a guide plate 24 is provided in a diameter spread surface 25 formed in an internal wall of the housing 10, so that an internal wall surface of this guide plate 24 is brought into slide-contact with an external edge of the sliding plate 23. Thus by supporting the shaft part 14 by upper and lower two part bearings, a tilt of the shaft part 14 is eliminated to ensure normal contact action of the adjusting valve 6 with a valve seat 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an exhaust gas recirculation control valve in an exhaust gas recirculation system of an internal combustion engine such as an automobile.

[Prior art] Figure 2 shows Utility Application No. 62-5543, which was previously filed by the present applicant.
In the system diagram of the exhaust gas recirculation control valve (hereinafter referred to as EGR valve) shown in the specification of No. 0, 1 is an engine having a combustion chamber 2, 3 is an exhaust pipe connected to the combustion chamber 2, 4 is an EGR cooler that is connected to this exhaust pipe 3 and cools the exhaust gas from the combustion chamber 2; 5 is connected to this EGR cooler 4, and introduces the exhaust gas cooled by the EGR cooler 4 to the intake pipe of the engine 1 ( 6 is an EGR valve that adjusts the amount of exhaust gas recirculation to the exhaust gas i
! The control valve 7 has 11 openings, and is a diaphragm that operates the control valve 6 by the differential pressure in the negative pressure chamber 8.

After the exhaust gas from the exhaust pipe 3 is cooled by the EGR cooler 4, the EGR valve 5 described above
will be introduced in Thereafter, the exhaust gas whose recirculation amount has been adjusted by the control valve 6 is supplied to the engine from the intake pipe. As a result, the exhaust gas is re-combusted within the engine 1, and harmful nitrogen oxides (N0x) in the exhaust gas are reduced. Note that although the exhaust gas led from the exhaust pipe 3 is at a high temperature, it is cooled by the EGR cooler 4 and the temperature of the exhaust gas is reduced by the time it is led to the EGR valve 5, so that deterioration of the diaphragm 7 due to heat is prevented. It can be prevented.

FIG. 3 shows a detailed configuration diagram of the EGR valve 5.
9 indicates the flow direction of the exhaust gas, 1o is a housing formed by aluminum die-casting and has an exhaust gas passage 11 inside, and lla is the housing into which exhaust gas is introduced from the exhaust pipe 3 of the engine 1 (Fig. 2). The inlet passage, 12 is an outlet that leads exhaust gas to the intake pipe (not shown) of the engine 1! It is a road. 1
3 is a valve seat provided in the middle of the exhaust gas passage 11 and on which the control valve 6 approaches and separates; 14 is a shaft integrally molded with the control valve 6, and is guided by a guide member 15 fixed in the housing 10; It is slidable in the vertical direction.

A holder 16 is supported on the lower surface of the guide member 15 and located above the exhaust gas passage 11 to prevent carbon, etc. contained in the exhaust gas from entering the guide member 15 side. Reference numerals 17 and 18 sandwich the diaphragm 7 from above and below, and 20 holds the periphery of the diaphragm 7 with the housing 10. The diaphragm 7
In this case, a negative pressure chamber 8 is formed in the space between the two. 21 is stretched between the case 20 and the holding plate 17,
a spring 22 that biases the diaphragm 7 downward;
9 is a negative pressure introducing pipe that introduces negative pressure from the intake pipe of the engine 1.The EGR valve 5 configured as described above is configured such that the exhaust gas 9 led from the exhaust pipe 3 of the engine is introduced into the exhaust gas from the inlet passage 11a. It is introduced into the passage 11. This exhaust gas is then guided from the outlet passage 12 to the intake pipe of the engine according to the opening degree of the control valve 6, which operates according to the magnitude of the negative pressure introduced from the negative pressure introduction pipe 22 to the negative pressure chamber 8. Then, the exhaust gas is mixed with a mixture of fuel and air and combusted. This reduces the amount of nitrogen oxides (N0x), which are harmful components in the exhaust gas. Further, although carbon and the like in the exhaust gas enters the outlet passage 12 through the inlet passage If, the holder 16 prevents carbon from entering the guide member 15.

[Problem to be solved by the invention]

The conventional exhaust gas recirculation control valve is constructed as described above, and since the shaft portion 14 is supported only at one location on the guide member 15, the shaft portion 14 tends to tilt. The control valve 6 does not come into contact with the correct position, which may cause engine malfunction due to exhaust gas leakage, or carbon, etc. in the exhaust gas may enter through the gap with the holder 16 due to the inclination of the shaft portion 14, and as a result, the guide There was a problem in that it adhered to the sliding surface between the member 15 and the shaft portion 14, making it impossible for the shaft portion to operate smoothly.

This invention was made to solve the above-mentioned problems, and by supporting the shaft at two locations, upper and lower, it prevents tilting, thereby stabilizing the contact of the control valve with the valve seat. An object of the present invention is to obtain an exhaust gas recirculation control valve in which carbon, etc. in the exhaust gas does not enter the sliding surface between the guide member and the details.

[Means to solve the problem]

The exhaust gas recirculation control valve according to the present invention includes a housing provided with an exhaust gas passage therein, and a housing that controls the amount of exhaust gas that is circulated from the exhaust pipe of the engine to the intake pipe via the exhaust gas passage. a control valve, a valve seat on which the control valve approaches and separates, a shaft portion connected to the control valve and slidably supported by a guide member fixed in the housing, and an end portion of this detail. In the exhaust gas recirculation control valve, the exhaust gas recirculation control valve includes a diaphragm that is attached to the valve and operates to open and close the control valve based on a differential pressure, and a case that is connected to the housing and forms a negative ring together with the diaphragm; The present invention is characterized in that a sliding plate that also serves as a plate is provided in a direction perpendicular to the axis, and the outer edge of this sliding plate makes sliding contact with a guide plate provided on the inner wall surface of the housing. A guide plate in which the details of the control valve are supported by a guide member, and a guide plate that also serves as a shield plate is fixed to the shaft below the guide member in a direction perpendicular to the axis, and the outer edge of this guide plate is provided on the inner wall surface of the housing. Since the valve is slidably in contact with the valve seat along the guide member and the guide plate, the shaft is supported at two locations, and the control valve can stably contact the valve seat without tilting the shaft.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a configuration diagram of the exhaust gas recirculation control valve according to the present invention, and in the figure, 6 to 15 and 17 to 22 are the same as the conventional exhaust gas recirculation control valve shown in FIG. In FIG. 0, reference numerals are given and duplicate explanations are omitted. Reference numeral 23 denotes a sliding plate that also serves as a shielding plate and is fixed to the lower shaft portion 14 of the guide member 15. On the other hand, it extends in the direction perpendicular to the axis in the shape of a flange.

Reference numeral 24 denotes a guide plate provided on an enlarged-diameter surface 25 formed on the inner wall of the housing 10, and the outer edge of the sliding plate 23 slides on the inner wall surface of the guide plate 24.

In the exhaust gas recirculation control valve according to the present invention configured as described above, the shaft portion 14 of the control valve 6 is supported by the guide member 15 at the upper portion, and the lower portion of the shaft portion 14 has a sliding plate 23 fixed thereto. Since it is in sliding contact with the guide plate 24 provided on the inner wall surface of the housing 10 through the shaft part 14, the shaft part 14 is supported at two places, upper and lower.
4 is above.

Normal contact operation between the control valve 6 and the valve seat 13 is possible without tilting during the downward movement.

Further, when the control valve 6 is opened, carbon and the like in the exhaust gas enters, but the step 25a and the sliding plate 23 on the inner wall of the housing 10 prevent carbon and the like from entering. ing. That is, the exhaust gas that enters when the control valve 6 is opened hits the inner circumferential surface 10a of the housing 10 and the stepped portion 25.
There is almost no adhesion of carbon or the like to a. Further, the exhaust gas that is about to flow in does not enter any further because there is a small gap between the sliding plate 23 and the guide plate 24, and as a result, the sliding surface between the guide member 15 and the shaft portion 14 is made of carbon. The shaft portion 14 can operate smoothly without any adhesion.

[Effects of the Invention] As explained above, according to the present invention, the shaft of the control valve is supported at two locations, above and below the guide member and the sliding plate, so that the shaft does not tilt during operation. Normal contact operation between the control valve and the valve seat can be performed without any problems, and as a result, when the control valve is closed, exhaust gas will not leak from between the valve seat and the valve seat.
Even when the control valve is open, the exhaust gas is blocked by the sliding plate that also serves as a shielding plate, allowing smooth movement of the shaft without intrusion into the guide plate, making it a highly reliable exhaust gas recirculation control valve. Become.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an exhaust gas recirculation control valve according to an embodiment of the present invention, Fig. 2 is a system diagram of a conventional exhaust gas recirculation system, and Fig. 3 is a configuration diagram of a conventional exhaust gas recirculation control valve. It is a diagram. In the figure, 6... control valve, 7... diaphragm, 8...
・Negative pressure chamber, 10...Housing, 13...Valve seat, 1
4... Shaft portion, 15... Guide member, 23... Sliding plate, 24... Guide plate. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa 1st figure 23 2nd sliding plate 24 2nd guide plate 2nd figure

Claims (1)

[Claims] A housing having an exhaust gas passage therein, a control valve disposed within the housing that adjusts the amount of exhaust gas circulated from the exhaust pipe of the engine to the intake pipe via the exhaust gas passage, and the control valve coming into contact with and separating from each other. a valve seat; a shaft part connected to the control valve and slidably supported by a guide member fixed in the housing; A diaphragm that opens and closes the valve;
In an exhaust gas recirculation control valve including a case connected to the housing and forming a negative pressure chamber together with a diaphragm, a sliding plate that also serves as a shielding plate is provided on the shaft in a direction perpendicular to the axis, and the sliding plate An exhaust gas recirculation control valve characterized in that an outer edge of the valve is in sliding contact with a guide plate provided on an inner wall surface of the housing.