JPH02185657A - Valve for controlling recirculation of exhaust gas - Google Patents

Abstract

PURPOSE:To facilitate assembling at a low cost by fittingly fixing an annular valve seat which is formed into a thin metal plate type to a housing. CONSTITUTION:An annular valve seat 34 is formed with a thin plate and further, a roundness which is necessary for forming is provided on the end portion 34a. The top end portion 34c is finished slightly larger than the fit-in portion 34b which is brought into contact with the inner face of a hole portion 10a by means of a spring back at the time of forming. Hence, at the time of inserting the valve seat 34 into a housing 10, higher pressing force can be obtained even with the same interference as in the conventional one. Also, since the roundness on the end portion 34a is by far larger than the conventional cut product, press-fitting can be easily carried out.

Description

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

(Prior art) Regarding the exhaust gas recirculation control valve device, for example,
1104, and FIGS. 4 and 5 show a conventional exhaust gas recirculation control valve [hereinafter referred to as EGR (1!
Fig. 4 is a schematic configuration diagram thereof, and in Fig. 4, l indicates the combustion chamber 2. The engine 3 is connected to the combustion chamber 2 and is an exhaust pipe through which exhaust gas passes.

A BGR cooler 4 is installed between this exhaust pipe 3 and the BGR valve 5.
are connected. The EGR cooler 4 is for cooling exhaust gas.

The BGR valve 5 introduces the exhaust gas cooled by the EGR cooler 4 and adjusts the amount of exhaust gas recirculated to the intake pipe (not shown) of the engine 1.

A control valve 6 is provided in the 1CR pulp 5, and the second control valve 6 responds to a negative pressure signal from the intake pipe 3 to control the opening degree of the exhaust gas passage.

A rubber diaphragm 7 is provided above the EGR pulp 5. This diaphragm 7 forms a negative pressure chamber 8 of the EGR valve 5, and operates the control valve 6 based on the differential pressure.

The conventional BGR pulp 5 is configured as described above, and the exhaust gas from the exhaust pipe 3 is cooled by the EGR cooler 4 and then guided to the EGR pulp 5. Then, the exhaust gas whose recirculation amount is adjusted by the control valve 6 is supplied to the intake pipe.

As a result, the exhaust gas is re-combusted within the engine 1, and harmful nitrogen oxides in the exhaust gas are reduced.

Note that although the exhaust gas led from the exhaust pipe 3 is high temperature,
By being cooled by the EGR cooler 4, the temperature of the exhaust gas is reduced when it is guided to the EGR pulp 5, so that deterioration of the diaphragm 7 due to heat is reduced.

FIG. 5 is a front sectional view of the BGR pulp 5 of the fourth Bll, and in FIG. 5, 10 is a housing formed by aluminum die-casting and having an exhaust gas passage 11 inside. This housing lO has a passage inlet 12.
is provided. Exhaust gas from the exhaust pipe of the engine I is introduced into the passageway 12.

Further, the housing lO is provided with a passage outlet 13. The passage outlet 13 is for introducing exhaust gas into an intake pipe (not shown) of the engine l.

The annular valve seat 14 is fitted into the housing IO in the middle of the exhaust gas passage 11 so that the control valve 6 comes into contact with it. A shaft portion 17 is connected to the control valve 6, and the shaft portion 17 is connected to a sliding member 18 mounted on the housing lO.
It is designed to slide up and down inside.

A holder 19 is placed below the sliding member 18. This holder 19 is further located above the exhaust gas passage 11, and has a U-shaped cross section to prevent carbon and the like contained in the exhaust gas from entering.

The diaphragm 7 has a pair of disc-shaped pressing plates 20.2.
1, and these holding plates 20 and 21
The center portion of the shaft portion 17 is attached to the upper end portion 22 of the shaft portion 17 .

Reference numeral 24 denotes a lower negative pressure case constituting a negative pressure case with a locking hole formed at the bottom. The negative pressure case 24 is screwed onto the sliding member 1B with a tapping screw 33.

The upper negative pressure case 25 constitutes a negative pressure case with the lower negative pressure case 24, and the peripheral edge of the diaphragm 7 is connected to the lower negative pressure case 2.
A negative pressure chamber 8 is formed by the diaphragm 72 and the upper negative pressure case 25.

The compression spring 27 is connected to the upper negative pressure case 25 and the holding plate 2.
0, and presses the temporary presser 2o downward.

Further, a negative pressure introduction pipe 28 is installed through the upper negative pressure case 25 to introduce negative pressure from the intake pipe of the engine l.

Note that 29 is a non-metallic packing that is interposed between the lower negative pressure case 24 and the housing 10 and blocks heat from the housing IO.

In the conventional EGR pulp 5 configured as described above, first, the exhaust pipe 3 of the engine l. The exhaust gas led from the exhaust gas enters the exhaust gas passage 11 from the passage entrance 12.

This exhaust gas is guided from the passage outlet 13 to the intake pipe according to the opening degree of the control valve 6, which operates according to the magnitude of the negative pressure introduced into the negative pressure chamber 8 through the negative pressure introduction pipe 28. This exhaust gas is mixed with a mixture of fuel and air, which is introduced into the combustion chamber 2 and combusted. This reduces the amount of nitrogen oxides, which are harmful components in the exhaust gas.

(Problem III to be Solved by the Invention) Since the conventional exhaust gas recirculation control valve is constructed as described above, the annular valve seat 14 is fitted into the bottom of the housing 10, so that the It is necessary to make the upper hole larger than the valve seat 14, and there are also problems in that it is difficult to apply pressure to fit the valve seat into the housing.

This invention was made to solve the above-mentioned problems, and aims to provide an exhaust gas recirculation control pulp that is inexpensive, easy to assemble, and has excellent fitting force.

(1! Means for Solving the Problem) The exhaust gas recirculation control pulp according to the present invention is provided with an annular valve seat that is fitted and fixed to the housing and formed in the shape of a thin sheet metal.

(Function) Since the annular valve seat in the present invention is formed of a thin plate, it is fitted and fixed to the housing by the spring action of the thin plate shape.

(Example) Hereinafter, an example of the exhaust gas recirculation control pulp of the present invention will be described with reference to the drawings. FIG. 1 is a front sectional view showing one embodiment, and FIGS. 2 and 3 are partially detailed views thereof. The same or equivalent parts as in FIGS. 4 and 5 are designated by the same reference numerals, and the explanation thereof will be omitted.

1 to 3, numeral 34 is an annular valve seat press-fitted into a hole 10a in the housing IO, replacing the conventional valve seat 14.

The other configurations are the same as those in FIGS. 4 and 5.

In the exhaust gas recirculation control pulp of the present invention configured as described above, the annular valve seat 34 is formed of a thin plate, and the tip portion 34a is further formed with a necessary radius.

Further, due to springback during formation, the upper end portion 34c is finished slightly thicker than the fitting portion 34b that contacts the inner surface of the hole portion 10a.

Therefore, when inserting the valve seat 34 into the housing 10, a high pressing force can be obtained even with the same tightening margin as in the conventional case. Furthermore, since the radius of the tip 34a is much larger than that of conventional cut products, press-fitting can be easily performed.

〔Effect of the invention〕

As described above, according to the present invention, the annular valve seat is formed of a thin sheet metal shape and is fitted into the housing, so the outer diameter does not have to be strictly controlled to ensure press force as in the past. Since a pressing force above a certain level can be obtained even when the press is pressed, it can be manufactured at low cost, and the large radius at the tip makes it easy to perform straight-up work.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of an exhaust gas recirculation control pulp according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view showing details of the annular valve seat in the embodiment, and FIG. 3 is an embodiment of the same. Enlarged front view showing the annular valve seat taken out, No. 4
The figure is a schematic configuration diagram of a conventional exhaust gas recirculation control pulp, and FIG. 5 is a front sectional view showing the exhaust gas recirculation control pulp of FIG. 4. 6... Control valve, 7... Diaphragm, 10... Housing, 11... Exhaust gas passage, 17... Shaft portion, 18... Sliding member, 24... Lower negative pressure case, 2
5... Upper negative pressure case, 34... Valve seat. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A housing having an exhaust gas passage therein, a control valve provided in the housing to adjust 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. an annular valve seat formed of a thin sheet metal shape and in contact with the control valve, and a shaft portion that is slidable on a sliding member that is connected to the control valve and press-fitted into the housing;
An exhaust gas comprising: a diaphragm attached to the end of the shaft portion and operated by differential pressure to open and close the control valve; and a negative pressure case attached to the sliding member and forming a differential pressure via the diaphragm. Recirculation control valve.