JP2967366B2 - Exhaust switching valve for internal combustion engine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas switching valve for an internal combustion engine that is disposed in an exhaust pipe of an internal combustion engine and switches the flow rate of exhaust gas.

<Prior Art> Conventionally, as shown in FIG. 3, this type of exhaust gas switching valve B0 includes a body 1 interposed in an exhaust pipe.
A valve shaft 3 of a valve body 2 arranged in the exhaust passage 1a is supported. An arm 4 is connected to one end of the valve shaft 3, and a rod 7 of a diaphragm actuator 5 is journaled to the arm 4 (see Japanese Utility Model Laid-Open No. 55-106342).

A diaphragm actuator (hereinafter simply referred to as an "actuator") 5 has a case 6 separated into two chambers by a diaphragm 8, a lower chamber 5B communicates with the atmosphere, and an upper chamber 5A.
Is connected to a pressure source (not shown) so that when the accelerator (not shown) is depressed, the internal pressure rises and the rod 7 can be moved downward together with the diaphragm 8. 10 is a coil spring.

In the exhaust gas switching valve B0, the case 6 of the actuator 5 is held by a bracket 9 connected and fixed to the body 1 using bolts 11 and 12.

When the accelerator (not shown) is released from the exhaust switching valve B0, the internal pressure of the upper chamber 5A of the actuator 5 decreases, and the rod 7 moves downward together with the diaphragm 8 against the urging force of the coil spring 10. Then, the valve shaft 3 rotates through the arm 4, and the valve body 4 tries to close the exhaust passage 1a, thereby functioning as an exhaust brake.

<Problem to be Solved by the Invention> However, in the conventional exhaust switching valve B0, the actuator 5
The heat resistance (about 200 ° C or less) of the diaphragm 8 is low.
In order to prevent heat of the body 1 from being conducted to the diaphragm 8 through the bracket 9, the bracket 9 is connected to the body 1.
It is necessary to connect and fix to a part where the temperature is low.
, The degree of freedom in the arrangement position of the bracket 9 with respect to the internal combustion engine is reduced, and the degree of freedom in mounting the exhaust switching valve B0 on the internal combustion engine is reduced.

Further, in the conventional actuator 5 of the exhaust switching valve B0,
The rod 7 connected to the diaphragm 8 merely penetrated the case 6 through the insertion hole 6a, and was not sufficiently supported.

Therefore, when the actuator 5 is operated, the rod 7 is tilted, which causes a decrease in the durability of the diaphragm 8.

An object of the present invention is to solve the above-described problems, and an object of the present invention is to provide an exhaust gas switching valve that can improve durability and can have a higher degree of freedom in mounting on an internal combustion engine.

<Means for Solving the Problems> In an exhaust gas switching valve according to the present invention, a body provided with an exhaust flow path and having a valve body disposed in the flow path and disposed in an exhaust pipe; A diaphragm actuator for actuating the body, wherein the diaphragm actuator extends from the diaphragm and protrudes from the case, the diaphragm being housed in a case, and is used for the operation of the diaphragm. An exhaust switching valve for an internal combustion engine which is provided on a bracket which is connected and fixed to the body, wherein the diaphragm actuator has a rod for operating the valve body. An air layer is provided at a connection portion, and a guide that is connected to the bracket and that can slide the rod between the bracket and the rod in the case. A cover portion is provided on the internal combustion engine side of the diaphragm actuator, while providing an interval with the diaphragm actuator, and covering the internal combustion engine side of the diaphragm actuator. The cover is attached to the bracket, and the bracket is fixedly connected to the body by providing an air layer at a connection portion with the body.

<Effects and Effects of the Invention> In the exhaust gas switching valve according to the present invention, a guide portion that can slide the rod is disposed between the case and the rod, and when the rod operates, the rod is Since the slider slides and moves within the guide portion, it can move without tilting, and can be prevented from affecting the durability of the diaphragm.

In this exhaust switching valve, since the air layer is provided at the connection portion of the actuator with the bracket, heat from the bracket can be prevented from being conducted to the actuator because the air layer is insulated and the air layer is insulated.

Therefore, in the exhaust gas switching valve according to the present invention, the durability of the diaphragm can be improved, the heat of the body can be prevented from being transmitted to the diaphragm of the actuator, and the degree of freedom of the arrangement position of the bracket with respect to the body can be improved. And the body itself can be arranged in the vicinity of the internal combustion engine, so that the degree of freedom of mounting the device itself on the internal combustion engine can be improved.

Further, in the exhaust gas switching valve according to the present invention, since the cover covers the internal combustion engine side of the actuator, the radiant heat of the internal combustion engine is insulated by the cover and can be prevented from being transmitted to the actuator. Further, since the cover covers only the internal combustion engine side of the actuator, on the opposite side of the internal combustion engine side, the actuator is exposed to the flow of air without being blocked by the cover, thereby cooling the actuator. It becomes possible. Further, since the cover is attached to the bracket, even if the cover is heated by the radiant heat of the internal combustion engine, the heat of the cover itself is arranged at the connection portion between the bracket and the actuator, similarly to the heat from the body. The air layer is insulated and prevented from conducting to the actuator.

Therefore, in the exhaust gas switching valve according to the present invention, cooling by the flow of air is made possible and transmission of radiant heat of the internal combustion engine to the actuator can be prevented, so that the degree of freedom of mounting on the internal combustion engine is further improved. Can be.

Furthermore, in the exhaust gas switching valve according to the present invention, since the bracket is provided with an air layer at a connection portion with the body and is connected and fixed to the body, the bracket partially comes into contact with the body. Therefore, the heat of the body is hardly transmitted, and the influence of the heat on the diaphragm can be further reduced.

An embodiment of the present invention will be described below with reference to the drawings.

In the exhaust switching B1 of the embodiment shown in FIGS. 1 and 2, the body 1 interposed in the exhaust pipe pivotally supports the valve shaft 3 in which the valve element 2 is disposed in the exhaust flow path 1a, as in the prior art. A rod 7 of an actuator 5 is mounted on an arm 4 connected to one end of the valve shaft 3.

Reference numeral 13 denotes a bearing for the valve shaft, and reference numeral 14 denotes a seal portion provided with a seal ring and the like. 15 and 16 are lid plates fixed to the body 1.

The actuator 5 is connected to a lower chamber 5B in which the inside of the case 26 is separated by the diaphragm 8 and in which a coil spring 10 that communicates with the atmosphere and urges the diaphragm 8 upward is connected, and a pressurizing source (not shown). An upper chamber 5A capable of moving the rod 7 downward together with the diaphragm 8 when the internal pressure rises when the accelerator (not shown) is depressed.
Room.

The case 26 includes an upper case 27 and a lower case 28, each made of stainless steel, a corrosion-resistant metal plating steel plate, or the like.
It is composed of At the lower part of the lower case 28, a step 28a for reducing the diameter is formed, and the step 28a of the lower case 28 is formed.
In a lower portion, vent holes 28b are formed at a plurality of locations on the outer peripheral wall.

Further, on the upper surface of the step portion 28a in the lower case 28, a bottom plate 29 made of three plate members and supporting a lower end of the coil spring 10 is provided.
Is arranged.

The air between the bottom plate 29 and the bottom wall of the lower case 28 transfers heat from the bracket 19 described later to the actuator 5.
To insulate it so that it is not transmitted to the diaphragm 8
It becomes the air layer A1.

At the lower portion of the bottom plate 29, a cylindrical tubular portion 29a is formed around the rod 7 with a space therebetween, and the lower end of the tubular portion 29a protrudes downward from the lower case 28. On the upper part of the bottom plate 29, a substantially cylindrical storage portion 29b for forming a guide portion 30 for guiding the reciprocating linear motion of the rod 7 is formed.

The guide portion 30 is made of a material such as fluororesin, and has a through hole 30a formed at the center thereof so that the outer diameter and the inner diameter of the rod 7 can be substantially matched with each other so that the rod 7 can slide on the inner peripheral surface.

Reference numeral 31 denotes a packing for sealing the guide section 30 and the storage section 29b. 17 and 18 are diaphragm 8
When the diaphragm 8 moves up and down, the diaphragm 8 comes into contact with the lower surface of the upper wall of the upper case 27 and the upper surface of the bottom plate 29 of the lower case 28, respectively.
The position restricting plates 17 and 18 hold the diaphragm 8 therebetween, and the nut 32 is screwed into the male screw portion 7a at the upper end of the rod 7 so that the diaphragm 8 It is integrated with.

An upper mounting seat 19A of a bracket 19 for holding the actuator 5 is connected to the lower surface of the bottom wall of the lower case 28 of the actuator 5 by using bolts and welding. 1
9a is a cylindrical portion projecting from the lower case 28 of the actuator 5
Reference numeral 29a denotes an insertion hole through which an interval is provided.

The bracket 19 is made of stainless steel, a corrosion-resistant metal plated steel plate, or the like, and uses a bolt 11 to fix the lower mounting seat 19B at the lower portion to the body 1.

The bracket 19 also has bent mounting seats 19b, 19b formed on the sides of the portion extending in the vertical direction.
A cover 20 is fixed to bolts 21 at 19b and 19b.

The cover 20 is formed in a substantially half-cylindrical shape from stainless steel, a corrosion-resistant metal plating steel plate, or the like. Covered and arranged.

As described above, in the exhaust switching valve B1 of the embodiment, the lower case
A guide portion 30 slidable on the rod 7 is provided between the rod 7 and the bottom plate 29 of the bottom plate 29. When the rod 7 reciprocates linearly, the rod 7 passes through the guide portion 30. Since the inner peripheral surface of the hole 30a slides and moves, it can move without tilting and can be prevented from affecting the durability of the diaphragm 8.

Further, since the air layer A1 is formed at the connection portion of the actuator 5 with the bracket 19, the bracket 19
From the air is insulated by the air layer A1 and the actuator 5
Is prevented from being transmitted to the diaphragm 8, and the same effect as described in the above-mentioned section of operation and effect can be obtained.

Further, in the exhaust switching valve B1 of this embodiment, the lower case 28
A cylindrical portion 29a extending downward from the bottom plate 29 is provided with an interval from the rod 7 and protrudes from the insertion hole 19a of the bracket 19 with an interval. Therefore, between the inner peripheral surface of the insertion hole 19 a of the bracket 19 and the rod 7,
Since the air layer A2 that shields the rod 7 is provided, heat from the bracket 19 (the upper mounting seat 19A) is removed.
And the heat from the bracket 19 can be further prevented from being transmitted to the diaphragm 8. Since the air layer A2 makes it difficult for the heat from the bracket 19 to be transmitted to the rod, the heat resistance of the guide portion 30 does not need to be considered so much, and the degree of freedom in selecting the material of the guide portion 30 can be improved. In addition, the guide portion 30 is less likely to be worn by the sliding rod 7, and an effect of preventing the rod 7 from falling down can be obtained.

Furthermore, in the exhaust gas switching valve B1 of this embodiment, the cover
Since the actuator 20 covers the periphery of the actuator 5 on the side of the internal combustion engine E, the radiant heat of the internal combustion engine E is insulated by the cover 20 and can be prevented from being transmitted to the actuator 5. Further, since the cover 20 covers only the internal combustion engine E side of the actuator 5, the cover 20 is provided on the opposite side of the internal combustion engine E side.
Without being blocked by 20, the actuator 5 is exposed to the flow of air, so that the actuator 5 can be cooled. Further, since the cover 20 is attached to the bracket 19, even if the cover 20 is heated by the radiant heat of the internal combustion engine E, the heat of the cover 20 itself, like the heat from the body 1, is also attached to the bracket 19 and the actuator 5 The air layer A <b> 1 disposed at the connection portion with the air-conditioner is insulated, and is prevented from being transmitted to the Aqueuator 5. Therefore, in the exhaust gas switching valve B1 of the embodiment, cooling by the flow of air is enabled, and the radiant heat of the internal combustion engine E is reduced by the actuator 5
To the internal combustion engine E, so that the degree of freedom in mounting on the internal combustion engine E can be further improved.

Furthermore, in the exhaust switching valve B1 of the embodiment, the bracket
In the vicinity of each mounting hole 19c of the bolt 11 of the lower mounting seat 19B in 19, a boss portion 1b for fixing the bolt 11 from the body 1 is formed. Therefore, an air layer A3 that can be insulated is formed, and the bracket 19 partially contacts the body 1, so that the heat of the body 1 is hardly transmitted, and the heat to the diaphragm 8 is further reduced. The effect of reducing the influence is exerted.

[Brief description of the drawings]

FIG. 1 is a sectional view of an exhaust gas switching valve showing an embodiment of the present invention, FIG. 2 is a partial plan view of the embodiment, and FIG. 3 is a sectional view showing a conventional example. 1 ... Body, 1a ... Exhaust flow path, 2 ... Valve body, 5 ... Actuator, 6/26 ... Case, 7 ... Rod, 8 ... Diaphragm, 9/19 ... Bracket, E ... Internal combustion engine, A1 ... Air layer.

Continuation of the front page (56) References JP-A 57-172133 (JP, U) JP-A 56-150830 (JP, U) JP-A 58-139544 (JP, U) (58) Fields surveyed (Int) .Cl. ⁶ , DB name) F02D 9/04 F02D 9/10 F01N 7/14

Claims (1)

(57) [Claims] A body provided with an exhaust flow passage and having a valve body disposed in the flow passage, and a diaphragm actuator for operating the valve body. The diaphragm actuator includes: a diaphragm housed in a case; and a rod extending from the diaphragm, protruding from the case, and operating the valve body following the operation of the diaphragm. An exhaust switching valve for an internal combustion engine, which is held by a bracket connected and fixed to the body, wherein the diaphragm actuator provides an air space at a connection portion with the bracket and connects to the bracket. A guide portion slidable on the rod is provided between the rod and the case in the case; On the side of the internal combustion engine, while providing an interval with the diaphragm actuator,
A cover is provided to cover the internal combustion engine side of the diaphragm actuator, the cover is attached to the bracket, and the bracket is connected to the body by providing an air layer at a connection portion with the body. An exhaust switching valve for an internal combustion engine, which is fixed.