JP2014058946A - Gas volume adjusting valve and exhaust gas recirculating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas volume adjusting valve and an exhaust gas recirculating device which prevents abrasion of a seal ring constituting a butterfly valve in a gas volume adjusting valve provided with the butterfly valve, can maintain durability even after repeating a vibration movement, and retains a satisfactory gas volume adjusting function.SOLUTION: In a gas volume adjusting valve provided with a substantially disc-shaped butterfly valve in a substantially circular tube-shaped nozzle, the butterfly valve to which a seal ring arranged so as to freely open/close is attached, a groove continuous in a circumferential direction of an outer circumferential surface of the butterfly valve is formed, a protrusion part of such a form as to close the groove is formed on a part of the groove, one seal ring is fitted into the groove in a C shape, the protrusion part exists on an abutment joint of the seal ring, and one edge surface and the other edge surface of the seal ring abut on respective facing edge surfaces of the protrusion part.

Description

  The present invention relates to a gas amount adjusting valve provided with a butterfly valve and an exhaust gas recirculation device incorporating the gas amount adjusting valve. The gas amount adjusting valve of the present invention can be advantageously used to adjust the flow rate of exhaust gas mixed into the intake passage when a part of the exhaust gas of the internal combustion engine is recirculated to the intake passage in the intake pipe. Even when the sliding operation is repeatedly performed, durability is maintained, and deterioration of the product function over time can be effectively suppressed. In this specification, “valve” and “valve” are synonymous.

  A butterfly valve is used as a flow control valve for adjusting the flow rate of various fluids, and the report has been made in the patent literature. For example, Patent Document 1 describes a forward / reverse pressure sealing device for a butterfly valve that is useful as a water control valve. In this sealing device, a structure in which a circumferential groove is formed on the outer peripheral surface of the valve body of the butterfly valve, and a seal metal and two buffer rings are fitted in the circumferential groove has been proposed. In this water control valve, when the valve body of the butterfly valve is fully closed, the sealing contact surface of the seal metal fitted in the circumferential groove of the valve body of the butterfly valve using the elastic deformation force in the radial direction of the buffer ring Is tightly contacted with the seat contact surface of the valve housing, so that the inner peripheral wall surface of the valve housing and the outer peripheral surface of the valve body of the butterfly valve are hermetically sealed to reduce the total leakage of the fluid.

  In addition, exhaust recirculation gas (EGR gas), which is part of the exhaust gas flowing through the exhaust pipe of the internal combustion engine, is mixed into the intake air flowing through the intake pipe, thereby lowering the maximum combustion temperature and 2. Description of the Related Art An exhaust gas recirculation system (EGR system) that reduces harmful substances (for example, nitrogen oxides) is known. However, since the exhaust gas recirculation is accompanied by a decrease in the output of the internal combustion engine and a decrease in the operability of the internal combustion engine, it is necessary to adjust the exhaust gas recirculation amount (EGR amount) of the EGR gas recirculated to the intake passage in the intake pipe. There is.

  Therefore, conventionally, a flow rate control valve for an exhaust gas recirculation system (“EGR control valve”) for adjusting the opening degree or the opening area of the exhaust gas recirculation passage formed in the exhaust gas recirculation pipe of the exhaust gas recirculation system. , Also referred to as “EGR valve”, etc.). Moreover, what uses a butterfly valve as this EGR control valve is described in patent document 2, for example. This EGR control valve forms a circumferential groove on the inner peripheral wall surface of the housing when the butterfly valve is fully closed, and a seal ring is installed in the circumferential groove so that the seal contact surface of the seal ring is in contact with the seat of the housing. By closely contacting the surface, the inner peripheral wall surface of the housing and the outer peripheral surface of the butterfly valve are hermetically sealed using the elastic deformation force in the radial direction of the seal ring, thereby reducing the total leakage of EGR gas.

  Moreover, what uses a butterfly valve as an EGR control valve is also described in Patent Document 3, for example. This EGR control valve extends along the radial direction of the valve from the radial bottom wall side to the opening side of the circumferential groove on the ring contact surface on one side of the circumferential groove on the outer circumferential surface of the butterfly type valve. By providing a plurality of protrusions, the ring contact surface of the circumferential groove has a non-planar shape, and the contact area between the side contact surface on one side of the seal ring and the limb contact surface on one side of the circumferential groove is reduced. Yes.

Japanese Patent Laid-Open No. 01-188772 Japanese National Patent Publication No. 11-502582 JP 2005-113872 A

  In the gas amount adjusting valve provided with the butterfly valve, the wear of the seal ring at the contact portion and the sliding portion in the open / close portion becomes a problem in order to reduce the function of the product. Here, the “seal ring” refers to an inner peripheral wall surface of the nozzle and an outer peripheral surface of the butterfly valve when the exhaust gas recirculation amount adjusting valve is configured by a nozzle and a butterfly valve that can be opened and closed in the nozzle. In order to make it airtight, in other words, in order to eliminate a minute gap existing between the butterfly valve and the nozzle, it is a ring-shaped member that is usually fitted in a groove provided on the surface of the butterfly valve, and has a spring structure. Have. Since the seal ring exhibits tension due to its spring structure, it can be in close contact with the surface of the nozzle to ensure a certain sealing property, and gas leakage when the butterfly valve is closed can be prevented.

  However, during the opening / closing operation of the butterfly valve, the surface of the seal ring may be worn as described above at the contact portion with the nozzle, and as a result, the tension of the seal ring that should not be lowered gradually increases. If the tension is lost and finally the tension cannot be expressed, the sealing performance with the nozzle is lost. If such a problem exists, gas leakage will eventually occur even when the butterfly valve is closed.

  Further, during the opening / closing operation of the butterfly valve, the side surface of the seal ring tends to be worn with the butterfly valve. For this reason, a gap is formed between the butterfly valve and the seal ring, and gas leakage also occurs from there. As a cause of the wear, it is considered that the relative positions of the seal ring and the butterfly valve are shifted during the opening / closing operation of the butterfly valve.

  The present invention has been made in view of the above-described problems in a gas amount adjusting valve equipped with a butterfly valve. Accordingly, an object of the present invention is to prevent wear of a seal ring that occurs during opening and closing operations of a butterfly valve in a gas amount adjusting valve having a butterfly valve and an exhaust gas recirculation device incorporating the gas amount adjusting valve. As a result, there is no change in durability even after the sliding operation is repeated, and a sufficient gas amount adjusting function can be secured in the gas amount adjusting valve.

  As a result of diligent research to achieve the above object, the inventors of the present invention have improved the seal ring attached to the butterfly valve in the gas amount adjusting valve equipped with the butterfly valve, and the nozzle to which the butterfly valve is attached. The present invention was completed by obtaining the knowledge that it is effective to improve both the seal ring and the nozzle.

  The present invention is connected to an exhaust gas recirculation path and is configured to be a part of a substantially tubular nozzle, and is disposed in the nozzle so as to be openable and closable, and the opening degree or the opening area of the exhaust gas recirculation path can be adjusted. An exhaust gas recirculation amount adjusting valve having a substantially disc-shaped butterfly valve attached with a seal ring for airtightly sealing an inner peripheral wall surface of the nozzle and an outer peripheral surface of the butterfly valve, that is, a gas amount adjusting valve .

  In one aspect, the gas amount adjusting valve has a groove continuously formed in the circumferential direction of the outer peripheral surface of the butterfly valve, and a protrusion that closes the groove is formed in a part of the groove. And one seal ring is fitted in the groove in a C-shape, and the protrusion is present between the joints of the seal ring, and one end face and the other end face of the seal ring are Are in contact with the opposing end surfaces of the protrusions.

  According to the present invention, since the relationship between the seal ring and the butterfly valve is configured as described above, the relative position between the seal ring and the butterfly valve during the valve opening / closing operation can be eliminated, and the side surfaces of the butterfly valve and the seal ring can be eliminated. Thus, wear that has conventionally occurred can be prevented.

  In another aspect, in the gas amount adjusting valve, the nozzle is composed of a resin molded product made of polyimide (PI) resin, polyphenylene sulfide (PPS) resin, polyetherimide (PEI) resin, or reinforced resin thereof. It is characterized by that.

  According to the present invention, by using a resin molded product instead of a conventionally used metal such as stainless steel as the material of the nozzle, wear on the seal ring surface that has conventionally occurred at the contact portion with the nozzle can be prevented. can do. At this time, although it is feared that abrasion occurs on the side of the resin nozzle, the present invention avoids this problem by using a resin that is not easily worn such as PI resin, PPS resin, and reinforced resin. be able to.

  When the nozzle is made of a reinforced resin, the reinforced resin can be formed by blending various reinforcing materials with a PI resin, a PPS resin, a PEI resin, or the like. A suitable reinforcement is a filler, as will be described below. Although the amount of the filler can be changed in a wide range, it is usually preferable that the amount is approximately 1 to 80% by weight based on the total amount of the reinforcing resin.

  According to the present invention, in addition to forming the nozzle from PI resin, PPS resin, PEI resin, etc., by adding an appropriate amount of filler to these resins, the wear of the seal ring surface is prevented, and the resin Deformation of the nozzle made can also be suppressed. In addition, since deformation of the resin nozzle in the sliding portion is considered to be due to wear and creep deformation with the seal ring, in order to suppress this, as described above, the filler content is 1% by weight. It is preferable to make it more than this, and it is necessary to mix | blend 30 weight% or more desirably. In addition, when mix | blending a filler, if the compounding quantity is less than 1 weight%, the effect of addition cannot be acquired.

  In another aspect of the present invention, an exhaust gas recirculation pipe connected to the exhaust pipe of the internal combustion engine for recirculating a part of the exhaust gas between the intake air of the internal combustion engine as an exhaust recirculation gas; An exhaust gas recirculation apparatus comprising the gas amount adjusting valve of the present invention attached in the middle of an exhaust gas recirculation pipe and a drive motor for opening and closing a butterfly valve. Here, the exhaust gas recirculation device can also be called an exhaust gas recirculation system.

  According to the present invention, as can be understood from the above description and the following detailed description, the structure of the seal ring in the butterfly valve or the material of the nozzle has been improved. The wear of the inner surface of the nozzle can be suppressed, and therefore, when the butterfly valve is subjected to repeated sliding motions that are required to reduce its durability (in the present invention, this is referred to as “sliding motion”). Even in the “endurance process”), the amount of gas leakage in the butterfly valve can be greatly suppressed. In addition, since the gas leakage of the butterfly valve can be stably suppressed over a long period of time, the EGR system incorporating the butterfly valve can be stably operated with high reliability, and the amount of nitrogen oxide (NOx) emissions can be reduced. It can be effectively reduced.

It is a schematic diagram which shows a part of exhaust gas recirculation apparatus. FIG. 2 is an enlarged schematic view of a gas amount adjusting valve of the exhaust gas recirculation device shown in FIG. 1. It is a schematic cross section explaining the relationship between the nozzle and the butterfly valve in the gas amount adjusting valve. It is sectional drawing of A and B of FIG. It is the graph which plotted the amount of gas leaks in a sliding test.

  The gas quantity regulating valve and exhaust gas recirculation (EGR) device according to the present invention can be advantageously used in EGR systems well known in the art. According to the present invention, the gas amount adjusting valve and the EGR device of the present invention can be used in the system as it is without any special change or improvement in the EGR system.

  Generally speaking, the EGR system is connected to an exhaust pipe of an internal combustion engine (engine), and a part of exhaust gas (referred to as “exhaust gas recirculation gas” or “EGR gas”) is returned to the intake pipe for recycle. This is a well-known technique in which EGR gas, which is non-combustible gas, is mixed into a part of the intake air by circulation. The EGR device includes an EGR passage that returns part of the exhaust gas flowing through the exhaust passage to the intake passage, and an EGR valve that adjusts the gas amount in the EGR passage by adjusting the valve opening (in the present invention, “exhaust gas return”). At least a flow rate adjusting valve "or" gas amount adjusting valve "), and the opening degree of the EGR valve is controlled by an engine control unit (ECU) according to the traveling state of the vehicle. The EGR valve may be a high pressure EGR valve mounted on a high pressure EGR device that returns EGR gas to the intake downstream side of the throttle valve in the intake passage, or an intake upstream side of the throttle valve in the intake passage (for example, a turbocharged vehicle) If so, it may be a low pressure EGR valve mounted on a low pressure EGR device that returns EGR gas to the intake upstream side of the compressor.

  Next, a preferred embodiment of the EGR valve and the EGR device of the present invention will be specifically described with reference to FIGS. In the following description, the components of the EGR valve and the EGR device will be described with a focus on the components related to the present invention. Unless otherwise specified, the described components are the conventional EGR valves. It should be understood that the components, configurations, dimensions, materials, and the like included in the EGR device are the same, and that improvements and changes can be arbitrarily made as necessary.

  As shown in the figure, the EGR device of the present embodiment is connected to an exhaust pipe of an engine, and an exhaust gas recirculation path (gas flow path) 2 for recirculating a part of exhaust gas (EGR gas) to the intake pipe. A valve body (housing) 3 constituting a part, a butterfly valve 6 accommodated in the valve body 3 so as to be openable and closable, and a seal ring installed in a circumferential groove 7 provided on the outer peripheral surface of the butterfly valve 6 8. A flow control valve (EGR valve) 1 for an exhaust gas recirculation device having a valve shaft 10 that operates integrally with the butterfly valve 6 in the rotational direction, and the butterfly valve 6 of the EGR valve 1 are attached in the valve closing direction. A coil spring (return spring) 21 to be energized, a drive motor for driving the butterfly valve 6 in the valve opening direction (or the valve closing direction), and the rotational power of the drive motor for the valve shaft of the EGR valve 1. Power unit configured to include a power transmission mechanism for transmitting the bets 10, and an engine control unit for electronically controlling the drive motor of the power unit (hereinafter, referred to as. "ECU") and a.

  The EGR device converts the valve opening of the butterfly valve 6 into an electrical signal, and how much EGR gas is mixed in the intake air flowing through the intake pipe, that is, the exhaust gas recirculation amount (EGR amount of EGR gas into the intake pipe). ) Is output to the ECU. By the way, the EGR amount sensor 22 of the present embodiment is a magnetic sensor commonly used in this technical field, and can have any usual configuration. Further, in this embodiment, the drive current to the drive motor is such that the command EGR amount (target valve opening) commanded by the ECU and the detected EGR amount (valve opening) detected by the EGR amount sensor substantially coincide. The value is feedback controlled. The control command value (drive current value) for the drive motor is desirably controlled by, for example, duty (DUTY) control. That is, the control pulse signal ON / OFF ratio (energization ratio / duty ratio) per unit time is adjusted according to the deviation between the command EGR amount (command valve opening) and the detected EGR amount (valve opening). The duty (DUTY) control for changing the valve opening degree of the butterfly valve 6 of the EGR valve 1 is preferably used.

  Referring to FIGS. 1 and 2 again, the EGR valve 1 of this embodiment forms a gas flow path 2 for recirculating a part of engine exhaust gas to the intake side as described above. A main body 3, a circular tube-shaped nozzle 9 fitted and held in the valve main body 3, and the nozzle 9 is accommodated in the nozzle 9 so as to be freely opened and closed within a rotation angle range between a valve fully closed position and a valve fully opened position. A substantially disc-shaped butterfly valve 6 for adjusting the opening degree or opening area of the gas flow path 2 formed in the inside 9, and a circumferential groove (seal fitting groove) 7 formed on the outer peripheral surface of the butterfly valve 6 A substantially annular seal ring 8 held in a plate thickness direction orthogonal to its own radial direction so that it can move in the radial direction inside, a butterfly valve 6 and a valve shaft 10 operating integrally in the rotational direction. ing. The nozzle 9 of this embodiment is composed of an outer metal ring 4 and a resin nozzle 5 inside thereof, and the resin nozzle 5 is made of a specific resin according to the present invention. When the EGR valve 1 is fully closed, the seal contact surface 8a of the seal ring 8 is brought into close contact with the seat contact surface 9a of the nozzle 9 by utilizing the elastic deformation force of the seal ring 8 in the radial direction. The peripheral wall surface and the outer peripheral surface of the butterfly valve 6 are configured to be airtight (seal).

  The valve body 3 is a device that holds the butterfly valve 6 in the gas flow path 2 formed in the nozzle 9 so as to be rotatable in the rotational direction from the valve fully closed position to the valve fully open position. It is fastened and fixed to the engine intake pipe using a fastener such as a bolt. The valve body 3 is integrally formed with a nozzle fitting portion 14 that fits and holds a circular tube-shaped nozzle 9 that accommodates the butterfly valve 6 so as to be freely opened and closed. Further, the nozzle 9 and the nozzle fitting portion 14 are integrally formed with a shaft bearing portion that rotatably supports the right end portion of the valve shaft 10 via a bearing 16. Here, the valve body 3 is formed by die casting of an aluminum alloy.

  Further, the valve shaft 10 is integrally formed of a heat resistant material resistant to high temperatures, such as stainless steel, and a valve mounting portion for holding and fixing the butterfly valve 6 using a fixing means such as welding is provided at the tip of the shaft. And is supported rotatably or slidably on the shaft bearing portion.

  In the EGR valve 1 of this embodiment, the nozzle 9 is preferably configured integrally with the outer metal ring 4 and the inner resin nozzle 5 as described above. As with the valve shaft 10, the outer metal ring 4 is preferably formed in a circular tube shape from a heat-resistant material that is resistant to high temperatures, such as stainless steel.

  The resin nozzle 5 is made of a specific resin according to the present invention. As described above, a suitable nozzle can be formed from a resin molded product made of polyimide resin, polyphenylene sulfide resin, polyetherimide resin or its reinforced resin.

  When the resin nozzle 5 is made of a reinforced resin, the reinforced resin can be formed by blending various reinforcing materials into a PI resin, a PPS resin, a PEI resin, or the like. A suitable reinforcing material is a filler, and examples of suitable fillers include, for example, carbon fiber, graphite, potassium titanate, talc, fluorine-containing resin (such as PTFE), talc, and molybdenum disulfide. These fillers may optionally contain conventional additives. Moreover, these fillers can be used in arbitrary forms, for example, forms, such as a powder, a granule, a whisker. Furthermore, the compounding quantity of these fillers can be changed in a wide range. Usually, the blending amount of the filler is in the range of about 1 to 80% by weight, desirably in the range of about 30 to 60% by weight, based on the total amount of the reinforcing resin. When the blending amount of the filler is less than 1% by weight, the slidability of the resin nozzle cannot be sufficiently improved, so that wear cannot be prevented, deformation becomes large, and sealability cannot be obtained. On the other hand, when the blending amount of the filler exceeds 80% by weight, the viscosity of the resin increases, resulting in poor moldability and a desired resin molded product cannot be obtained.

  By configuring the nozzle 9 as described above, in the present invention, for example, the seal ring 8 made of stainless steel slides on the resin nozzle 5 made of resin, and the sliding portion between the seal ring 8 and the nozzle 9 is moved. Wear can be suppressed. For this reason, even if the EGR valve 1 is used over a long period of time, the occurrence of wear can be suppressed, and the reliability of the EGR valve 1 can be improved.

  Further, like the outer metal ring 4, the butterfly valve 6 is preferably formed in a substantially disk shape from a heat-resistant material resistant to high temperatures, such as stainless steel. The butterfly valve 6 is a butterfly-type rotary valve that controls the EGR amount of EGR gas mixed into the intake air flowing in the intake pipe, and is held and fixed at the tip of the valve shaft 10. The end surface (outer peripheral surface) of the radially outer end of the butterfly valve 6 is held in the thickness direction perpendicular to the radial direction of the seal ring 8 so that the seal ring 8 can be moved in the radial direction. An annular circumferential groove (also referred to as “seal ring groove”, “seal fitting groove”, etc.) 7 is formed continuously in the circumferential direction. On the groove wall surfaces on both sides of the circumferential groove 7, ring contact surfaces are formed so that the side contact surfaces on both sides of the seal ring 8 can contact each other.

  As shown in FIGS. 2 to 4, the EGR valve of this embodiment is formed with a circumferential groove 7 that is continuous in the circumferential direction of the outer circumferential surface 6 a of the butterfly valve 6. A protrusion 60 is formed to close the groove. In addition, a single seal ring 8 is fitted in the groove 7 in a C-shape, and a protrusion 60 exists between the joints of the seal ring 8, that is, between the spaces defined by the opposing end surfaces. Yes. Therefore, one end surface 8 b and the other end surface 8 c of the seal ring 8 are in contact with the opposing end surfaces of the protrusion 60. Here, the protrusion 60 is preferably integrally formed from the same material as the butterfly valve 6, but is formed from a material different from the butterfly valve 6 as necessary and embedded in the groove 7. It may be. With this configuration, in the present invention, the relative position between the seal ring 8 and the butterfly valve 6 during the opening / closing operation is eliminated, and the wear that has occurred on the side surfaces of the butterfly valve 6 and the seal ring 8 in the prior art. By preventing the occurrence of this, even if the EGR valve is used for a long time, the occurrence of wear can be suppressed, and the reliability of the EGR valve can be improved.

  The seal ring 8 has a spring structure and, like the butterfly valve 6, is preferably formed in a substantially annular plate shape from a heat-resistant material resistant to high temperatures, such as stainless steel. The seal ring 8 has an outer peripheral side end portion 8a protruding outward (outer diameter side) in the radial direction from an end surface (outer peripheral surface) 6a of the outer diameter side end portion of the butterfly valve 6. Is held in the plate thickness direction so that it can move in the radial direction in the circumferential groove 7. The seal ring 8 is formed in a substantially C shape with a gap at the joint. The joint shape of the seal ring 8 is arbitrary, and may be any of a pad joint shape, a taper joint shape, and a lap joint shape, for example.

  Next, the operation of the EGR device of this embodiment will be described with reference to FIGS. 1 and 2 again.

  For example, when an engine such as a diesel engine is started and the intake valve of the intake port of the cylinder head of the engine is opened, the intake air filtered by the air cleaner passes through the intake pipe and the throttle body to the intake manifold of each cylinder. Distributed and taken into each cylinder of the engine. In the engine, air is compressed until it reaches a temperature higher than the temperature at which the fuel burns, and fuel is sprayed on the air to be combusted. The combustion gas burned in each cylinder is discharged from the exhaust port of the cylinder head, and is discharged through the exhaust manifold and the exhaust pipe. At this time, when the drive motor is energized by the ECU so that the butterfly valve 6 of the EGR valve 1 has a predetermined opening, the motor shaft of the drive motor rotates.

  When the motor shaft rotates, for example, the attached pinion gear rotates and torque is transmitted to the large diameter gear of the intermediate reduction gear. When the small-diameter gear rotates about the support shaft as the large-diameter gear rotates, the valve-side gear having a gear portion that meshes with the small-diameter gear rotates. As a result, the valve side gear rotates about the valve shaft 10, so that the valve shaft 10 rotates by a predetermined rotation angle, and the butterfly valve 6 of the EGR valve 1 opens from the valve fully closed position to the valve fully open position side. It is rotationally driven in the (open direction). Then, a part of the exhaust gas of the engine flows into the gas flow path 2 of the valve body and the nozzle 9 as EGR gas through the exhaust gas recirculation pipe. The EGR gas that has flowed into the gas flow path 2 flows into the intake passage of the intake pipe and is mixed with the intake air from the air cleaner.

  In this embodiment, the EGR amount of EGR gas is feedback-controlled so that a predetermined value can be held by detection signals from the intake air amount sensor (air flow meter), the intake air temperature sensor, and the EGR amount sensor 22. Therefore, the intake air sucked into each cylinder of the engine and passing through the intake pipe has the EGR amount set for each operating state of the engine so as to reduce the emission of the butterfly valve 6 of the EGR valve 1. The valve opening is controlled linearly, and is mixed with the EGR gas recirculated from the exhaust pipe through the gas flow path 2 into the intake pipe.

  On the other hand, when the valve is fully closed, the valve shaft 10 is returned to the initial position using the rotational power of the drive motor or the urging force of the coil spring 21. For this reason, the butterfly valve 6 is rotationally driven in the direction (closed direction) to be closed from the valve fully open side to the valve fully closed position side. Thereby, the seal contact surface of the seal ring 8 held in the circumferential groove 7 on the outer peripheral surface of the butterfly valve 6 is pressed against the seat contact surface 9a of the nozzle 9 by the elastic deformation force in the radial direction of the seal ring 8 itself. Therefore, the seal contact surface of the seal ring 8 is in close contact with the sheet contact surface 9 a of the nozzle 9. Accordingly, the inner peripheral wall surface of the nozzle 9 and the outer peripheral surface of the butterfly valve 6 are hermetically sealed (sealed), so that EGR gas does not enter the intake passage of the intake pipe.

  In this example, the EGR valve shown in FIGS. 1 to 4 is manufactured according to the present invention, and the gas leakage characteristics when this EGR valve is used in the illustrated EGR device are evaluated by a sliding test in which a fully closed and fully opened operation is repeated. did.

  The butterfly valve 6 used in this example was a stainless steel disc having a diameter of 24 cm, and had a seal fitting groove 7 continuous in the circumferential direction on the outer peripheral surface thereof. The seal fitting groove 7 is of two types, one having a protrusion 60 that entirely closes the groove and the other having no protrusion 60 formed. Here, in the case where the protrusion 60 is formed, the protrusion 60 is integrally formed of stainless steel like the butterfly valve 6.

  The seal ring 8 is made of stainless steel like the butterfly valve 6. The seal ring 8 is embedded and fitted in the seal fitting groove 7, and when buried, the outer peripheral surface slightly protrudes from the seal fitting groove 7, and the abutment of the seal ring 8 sandwiches the protruding portion 60 to seal the seal ring 8. Both ends of the ring 8 have a shape and size sufficient to abut against both ends of the protrusion 60.

The nozzle 9 was produced by integrally joining the following three different nozzles 5 to the outer metal ring 4 made of stainless steel for comparison.
Nozzle I: Stainless steel nozzle (no protrusion in groove 7; comparative example)
Nozzle II: Resin nozzle (no protrusion in groove 7; example of the present invention)
Nozzle III: Resin nozzle (protrusion in groove 7; example of the present invention)
In the resin nozzle of the present invention example, a polyetherimide resin (trade name “Vespel (registered trademark)”, manufactured by DuPont) is filled with 50% by weight of carbon fiber and fluorine-containing resin (both compounding ratio: 25/15) as fillers. The amount is blended and molded.

  When the test body provided with each of the nozzles I to III was subjected to a sliding test of 3 million times and the gas leakage amount (L) measured during the test was plotted, a measurement result as shown in FIG. 5 was obtained. It was. In the case of this example, when the amount of gas leakage is less than 6 L, it can be evaluated that an acceptable wear prevention effect has been achieved. Therefore, from the obtained measurement results, the nozzle II suppresses wear on the seal ring surface. It was considered that the nozzle III was effective in suppressing the wear on the surface of the seal ring and at the same time suppressing the wear on the side surface.

  According to the present invention, the amount of gas leakage in the butterfly valve can be greatly suppressed, and the gas leakage of the butterfly valve can be stably suppressed over a long period of time, so that more accurate flow control and sealing performance can be achieved. Improvement can be achieved. In addition, the EGR system incorporating the butterfly valve can be stably operated with high reliability, and the amount of nitrogen oxide (NOx) emission can be effectively reduced.

1 EGR valve 2 Gas flow path 3 Valve body 4 Outer metal ring 5 Resin nozzle 6 Butterfly valve 7 Seal fitting groove 8 Seal ring 9 Nozzle 10 Valve shaft

Claims (5)

A substantially circular nozzle connected to the exhaust gas recirculation path and constituting a part thereof;
A seal ring that is disposed in the nozzle so as to be openable and closable and is capable of adjusting an opening degree or an opening area of the exhaust gas recirculation path is provided to hermetically seal the inner peripheral wall surface of the nozzle and the outer peripheral surface of the butterfly valve. A gas amount adjusting valve having a substantially disc-shaped butterfly valve,
A groove that is continuous in the circumferential direction of the outer peripheral surface of the butterfly valve is formed, a protrusion that closes the groove is formed in a part of the groove, and one seal is formed in the groove. A ring is fitted in a C-shape, and the protrusion is present between the joints of the seal ring, and one end face and the other end face of the seal ring are in contact with the opposite end faces of the protrusion, respectively. Gas amount adjustment valve characterized by being in contact. A substantially circular nozzle connected to the exhaust gas recirculation path and constituting a part thereof;
A seal ring that is disposed in the nozzle so as to be openable and closable and is capable of adjusting an opening degree or an opening area of the exhaust gas recirculation path is provided to hermetically seal the inner peripheral wall surface of the nozzle and the outer peripheral surface of the butterfly valve. A gas amount adjusting valve having a substantially disc-shaped butterfly valve,
The gas amount adjusting valve, wherein the nozzle is composed of a resin molded product made of polyimide resin, polyphenylene sulfide resin, polyetherimide resin or reinforced resin thereof.   The gas amount adjusting valve according to claim 1, wherein the nozzle is made of a resin molded product made of polyimide resin, polyphenylene sulfide resin, polyetherimide resin or reinforced resin thereof.   The gas amount adjusting valve according to claim 2 or 3, wherein the reinforced resin is reinforced with 1 to 80% by weight of a filler based on the total amount of the reinforced resin. An exhaust gas recirculation pipe connected to the exhaust pipe of the internal combustion engine for recirculating a part of the exhaust gas between the intake air of the internal combustion engine as an exhaust recirculation gas;
The gas amount adjusting valve according to any one of claims 1 to 4, attached in the middle of the exhaust gas recirculation pipe,
An exhaust gas recirculation device comprising: a drive motor that opens and closes the butterfly valve.

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