JP4064390B2 - Exhaust gas recirculation valve and its sealing device - Google Patents

Description

  The present invention relates to an exhaust gas recirculation valve and a sealing device therefor, and more particularly, to an exhaust gas recirculation valve capable of preventing leakage of exhaust gas flowing through a valve base and a sealing device therefor.

  Conventionally, for example, an exhaust gas recirculation valve has been used to remove harmful components discharged from an internal combustion engine. The exhaust gas recirculation valve recirculates the exhaust gas discharged from the internal combustion engine to the intake system and reduces harmful components such as NOx contained in the exhaust gas to reduce the harmful components such as NOx. Has the function of communicating with the system.

  For example, such an exhaust gas recirculation valve includes a housing having an exhaust gas passage for communicating an intake system and an exhaust system of an internal combustion engine, an adjustment valve for switching the communication state of the exhaust gas passage, and a pressure fluid supply action. The diaphragm comprises a diaphragm for displacing the adjusting valve along the axial direction.

  The regulating valve is inserted into a sliding member provided inside the housing, and is displaced by the pressure difference of the pressure fluid supplied to the diaphragm provided at the upper portion of the housing, thereby being connected to the central portion of the diaphragm. The adjusting valve is displaced along the axial direction under the guide action of the sliding member. A cylindrical sealing member made of a resin material through which an adjustment valve is inserted is provided above the sliding member, and the sealing member abuts against the end surface of the sliding member by the spring force of the compression coil spring. The structure is kept airtight (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 5-52251

  By the way, in the prior art which concerns on patent document 1, it is set as the structure which hold | maintains the airtightness in the exhaust-gas channel | path of a housing with the cylindrical seal member by which an adjustment valve is penetrated, and prevents the exhaust gas to leak to the diaphragm side. .

  However, the sealing member used as the sealing device is merely brought into contact with the end surface of the sliding member, and when the regulating valve is separated from the valve seat, the shaft portion of the regulating valve is used. The seal member is forcibly displaced in a direction away from the sliding member, and the exhaust gas flowing from the passage inlet of the housing to the passage outlet through the valve seat is located between the shaft portion of the regulating valve and the sliding member. There is a problem of leakage from the gap to the diaphragm side.

  The present invention has been made in view of the above problems, and provides an exhaust gas recirculation valve and a sealing device for the exhaust gas recirculation valve that can reliably prevent leakage of exhaust gas flowing through the valve base. Objective.

In order to achieve the above object, the present invention provides a valve base having a circulation passage for exhaust gas and a valve seat provided in the circulation passage.
A valve body that opens and closes the circulation passage by being seated and separated from the valve seat;
A drive unit connected to the valve base and displacing the valve body along an axial direction under supply of pressure fluid;
A guide member that is provided inside the valve base and holds the valve body in an axially displaceable manner;
A first hermetic holding member provided between the valve base and the drive unit and preventing leakage of the exhaust gas flowing through the valve base;
A second airtight holding member provided on the guide member so as to surround an outer peripheral surface of the valve body, and preventing leakage of the exhaust gas flowing through the valve base;
With
The second airtight holding member is formed on an inner peripheral surface facing the valve body and is formed to extend toward the drive unit side, and a first seal portion that contacts the outer peripheral surface of the valve body. And a single or a plurality of second seal portions that contact the end face of the drive portion.

  According to the present invention, the first airtight holding member is provided between the valve base portion and the drive portion, and the second airtight holding member is provided on the guide member so as to surround the outer peripheral surface of the valve body. When exhaust gas flows through the circulation passage of the valve base, the exhaust gas flowing between the valve base and the drive unit is blocked by the first airtight holding member, and the exhaust gas leaks to the outside of the valve base. Can be prevented. Further, the exhaust gas flowing between the valve body and the guide member is blocked by the first seal portion of the second hermetic holding member that comes into contact with the outer peripheral surface of the valve body, and the guide member and the drive portion The exhaust gas flowing in between can be blocked by the single or plural second seal portions in contact with the end face of the drive unit, thereby preventing the exhaust gas from leaking out from the valve base.

  Therefore, by providing the exhaust gas recirculation valve with the first and second airtight holding members, it is possible to reliably prevent the exhaust gas flowing through the circulation passage of the valve base from leaking outside.

  In addition, the guide member is formed of a sintered material (for example, a carbon sintered body), and the second airtight holding member is formed of a rubber material, whereby the valve member is held displaceably by the guide member. The sliding resistance is reduced, the sliding performance of the valve body can be improved, and when exhaust gas flows into the gap formed between the guide member made of the sintered material and the valve body, The flow of the exhaust gas can be blocked by a second hermetic holding member made of a rubber material. Therefore, both the slidability of the valve body and the exhaust gas sealing performance by the second airtight holding member can be improved.

Further, the first seal portion is formed on the inner annular portion that bulges radially inward toward the valve body side, and is formed on the drive portion side from the inner annular portion, and has a predetermined angle toward the direction approaching the valve body. It consists of a skirt that extends at an incline,
The inner annular portion and the skirt portion may be brought into contact with the outer peripheral surface of the valve body.

  As a result, the inner annular portion of the first seal portion comes into contact with and closely contacts the outer peripheral surface of the valve body, and at the same time, the skirt portion contacts and comes into close contact with the outer peripheral surface of the valve body. When the exhaust gas flows in between the valve body and the guide member toward the drive unit side, the exhaust gas is blocked by the inner annular portion and can be further reliably blocked by the skirt portion. Therefore, it is possible to prevent the exhaust gas from flowing to the driving side through between the valve body and the guide member, and it is possible to reliably prevent leakage of the exhaust gas to the outside.

  Furthermore, the exhaust gas recirculation valve may be used for a diesel engine in which exhaust gas is supplied to the circulation passage at a positive pressure. That is, since exhaust gas is supplied into the circulation passage at a positive pressure in a diesel engine, the exhaust gas is under the pressure and the gap between the valve body and the guide member or the gap between the valve base and the guide member. Will flow into. In that case, the exhaust gas flowing into each gap can be reliably blocked by the first and second hermetic holding members, and the exhaust gas can be prevented from leaking outside the valve base.

Further, the present invention is formed so as to seal between the valve body and a guide member that holds the valve body movably along the axial direction, and surrounds the outer peripheral surface of the valve body in the guide member. A sealing device mounted in an annular recess,
The sealing device includes a first seal portion that contacts an outer peripheral surface of the valve body;
A single or a plurality of second seal portions provided on the inner peripheral surface side of the annular recess and abutting against an end surface of the first casing that closes the opening of the annular recess;
The first seal portion includes an inner annular portion that bulges radially inward toward the valve body,
A skirt portion formed on the first casing side from the inner annular portion and extending at a predetermined angle toward a direction approaching the valve body;
A planar portion that is formed radially inward from the second seal portion and has a small axial length with respect to the second seal portion in a state before the sealing device is attached to the annular recess;
The planar portion is in contact with an end surface of the first casing when the sealing device is mounted.

  According to the present invention, the sealing device includes a first seal portion formed so as to surround the valve body, and a single or a plurality of second seal portions formed so as to contact the end surface of the first casing. The bulge portion and the skirt portion of the first seal portion suitably surround the outer peripheral surface of the valve body to improve the sealing performance, and provide a planar portion having a smaller length in the axial direction than the second seal portion. Thus, when the sealing device is mounted in the annular recess and comes into contact with the first casing, the planar portion comes into contact with the end surface of the first casing and the displacement in the axial direction is restricted. Excessive deformation of the seal portion can be prevented, and the sealing performance by the sealing device can be further improved by forming the planar portion in an annular shape.

  According to the present invention, the following effects can be obtained.

  That is, the first airtight holding member is provided between the valve base and the drive portion, and the second airtight holding member is provided on the guide member so as to surround the outer peripheral surface of the valve body, whereby the circulation passage of the valve base is exhausted. When the gas flows, the exhaust gas flowing between the valve base and the drive unit is blocked by the first airtight holding member, and the exhaust gas flowing between the valve body and the guide member is blocked by the second airtight holding member. The exhaust gas leaks to the outside of the valve base by shutting off the exhaust gas flowing between the guide member and the drive portion by the single seal seal or the plurality of second seal portions. This can be reliably prevented.

  In addition, by providing a bulging portion and a skirt portion in the first seal portion formed so as to surround the valve body, it is possible to suitably surround the outer peripheral surface of the valve body and improve the sealing performance. The sealing device is attached to the annular recess by providing a second seal portion formed so as to contact the end surface of the first casing and a planar portion having a length smaller in the axial direction than the second seal portion. When the first casing comes into contact with the first casing, excessive deformation of the second seal portion can be prevented, and the sealing performance of the sealing device can be further improved.

  Preferred embodiments of an exhaust gas recirculation valve and its sealing device according to the present invention will be described below and described in detail with reference to the accompanying drawings.

  In FIG. 1, reference numeral 10 denotes an exhaust gas recirculation valve to which a sealing device according to an embodiment of the present invention is applied.

  As shown in FIGS. 1 and 2, the exhaust gas recirculation valve 10 includes a valve base 14 having a passage (circulation passage) 12 for recirculating exhaust gas discharged from an internal combustion engine (not shown) to the intake system, A drive unit 16 connected to the upper portion of the valve base 14 and supplied with a pressure fluid from a pressure fluid supply source (for example, a vacuum pump) (not shown), and the exhaust gas communication state with each other under the drive action of the drive unit 16 are mutually connected. It comprises a valve body 18 for switching.

  The valve base 14 is formed with an inlet port (circulation passage) 20 connected to an exhaust system of an internal combustion engine (not shown) at a substantially central portion of the lower surface, and on the side of the valve base 14 that is separated from the inlet port 20. Is formed with an outlet port (circulation passage) 22 connected to an intake system of an internal combustion engine (not shown). The inlet port 20 and the outlet port 22 are communicated with each other by a valve chamber (circulation passage) 24 and a passage 12 defined on the upper side of the inlet port 20.

  An annular valve seat 26 is disposed in the inlet port 20, and a communication hole 28 through which exhaust gas flows is formed in the approximate center of the valve seat 26. The communication hole 28 is formed in a tapered shape that gradually decreases in diameter toward the valve chamber 24 side (arrow A direction). The seat portion 30 of the valve body 18 abuts the end face of the valve seat 26 facing the valve chamber 24.

  The valve chamber 24 of the valve base 14 is provided with a valve cover 34 made of a metal material through a step 32 formed on the inner peripheral surface thereof.

  The valve cover 34 is formed, for example, from a thin plate with a substantially U-shaped cross section, and a hole 38 through which the valve shaft 36 of the valve body 18 is inserted in a substantially central portion protruding toward the inlet port 20. Is formed. That is, the valve cover 34 prevents carbon or the like contained in the exhaust gas introduced into the valve chamber 24 of the valve base 14 from entering the drive unit 16 side (in the direction of arrow A) and prevents high-temperature exhaust gas from flowing. Heat is prevented from being transmitted to the drive unit 16 (arrow A direction). The valve body 18 is mounted such that its axis coincides with the axis of the hole 38, and the diameter of the hole 38 is such that the valve shaft 36 of the valve body 18 is displaced in the axial direction. It is formed to be slightly larger than the outer peripheral diameter of the valve shaft portion 36 so as not to contact the valve.

  On the other hand, the valve base portion 14 is provided with a guide member 40 formed of a sintered material such as a carbon sintered body at an opening portion opened upward of the valve chamber 24, and the radius of the guide member 40 is increased. A diameter-expanded portion 42 that is expanded in the outward direction is engaged with the opening. The end of the valve cover 34 extending in the radially outward direction is sandwiched between the stepped portion 32 of the valve base portion 14 by the enlarged diameter portion 42 of the guide member 40. When the guide member 40 is attached to the valve base portion 14, the upper surface of the enlarged diameter portion 42 of the guide member 40 and the upper surface of the valve base portion 14 are substantially flush with each other.

  A guide hole 44 penetrating along the axial direction is formed in a substantially central portion of the guide member 40, and the valve shaft portion 36 of the valve body 18 is inserted into the guide hole 44. Since the inner peripheral diameter of the guide hole 44 is substantially the same as the outer peripheral diameter of the valve shaft portion 36, the valve shaft portion 36 of the valve body 18 is supported by the guide hole 44 so as to be displaceable along the axial direction. Is done.

  In this case, it is preferable to employ a sintered material such as a carbon sintered body for the guide member 40 so that the valve body 18 has good slidability when displaced along the axial direction under the guide action of the guide hole 44. Is obtained.

  One end portion of the guide member 40 is inserted into the valve cover 34 having a substantially U-shaped cross section, and the other end portion bulges so as to engage with the convex portion 48 of the first casing 46 of the drive unit 16. Is formed. An annular recess 50 is formed at the other end of the guide member 40 so as to face the guide hole 44, and the annular recess 50 has a seal that functions as a sealing device capable of maintaining airtightness in the valve base 14. A member (second airtight holding member) 52 is mounted so as to be coaxial with the guide hole 44.

  The seal member 52 is formed in an annular shape from, for example, a rubber material such as fluoro rubber, and the valve shaft portion 36 of the valve body 18 is inserted through a substantially central portion thereof.

  3 and 4, the seal member 52 is formed on the inner peripheral surface side of the seal member 52, and is an inner annular shape that bulges toward the outer peripheral surface of the valve shaft portion 36 that is radially inward. Part (first seal part) 54 and formed on the inner peripheral surface on the drive unit 16 side (in the direction of arrow A) from the inner annular portion 54, and inclined at a predetermined angle toward the outer peripheral surface of the valve stem 36. A first skirt portion (first seal portion) 56 that extends, and after extending a predetermined length from the base portion of the first skirt portion 56 in a radially outward direction, toward the valve base portion 14 (in the direction of arrow B) The outer annular portion 58 to be bent, and a second skirt portion (second seal portion) extending at a predetermined angle from the corner portion 60 of the outer annular portion 58 toward the driving portion 16 (arrow A direction). 62.

  The inner annular portion 54 is formed at a position on the valve base 14 side (in the direction of arrow B) when the seal member 52 is mounted in the annular recess 50 of the guide member 40, and the inner annular portion 54 is on the valve shaft portion 36 side. Are formed from a set of tapered surfaces that are inclined at a predetermined angle toward each other and approach each other. And the site | part where one set of taper surfaces cross | intersected the valve stem part 36 side most. That is, as shown in FIG. 3, when the valve shaft portion 36 of the valve body 18 is inserted through the seal member 52, the seal member 52 is centered on the portion of the inner annular portion 54 that protrudes most toward the valve shaft portion 36. As a result of contacting the outer peripheral surface of the valve stem 36, the inner annular portion 54 is crushed outwardly and deformed to be in close contact with the valve stem 36.

  On the other hand, a ring member 64 is mounted on the outer peripheral side of the inner annular portion 54 of the seal member 52 via an annular groove, and the ring member 64 is tightened with a predetermined force toward the radially inward direction. Therefore, a pressing force is always applied to the inner annular portion 54 of the seal member 52 in the radially inward direction, and the ring member 64 restricts the inner annular portion 54 from being deformed in the radially outward direction. . That is, it is desirable that the ring member 64 has a tensile force for tightening inside the radius.

  As shown in FIG. 4, the first skirt portion 56 extends so as to protrude a predetermined length toward the valve shaft portion 36 with respect to the inner peripheral surface of the seal member 52, and the first skirt portion The amount of protrusion 56 in the radially inward direction is set to be substantially equal to the amount of protrusion in the radially inward direction of the most protruding portion of the inner annular portion 54.

  Further, the first skirt portion 56 is formed so as to protrude from the upper end surface of the seal member 52 facing the drive unit 16 to the drive unit 16 side (arrow A direction) by a predetermined length. That is, the first skirt portion 56 is formed so as to protrude from each of the inner peripheral surface and the upper end surface of the seal member 52.

  That is, as shown in FIG. 3, when the valve shaft portion 36 of the valve body 18 is inserted through the seal member 52, the first skirt portion 56 is pushed slightly outward in the radial direction by the outer peripheral surface of the valve shaft portion 36. Abuts in an unfolded state. Therefore, the inner peripheral surface of the first skirt portion 56 is always held in contact with the outer peripheral surface of the valve shaft portion 36.

  Further, on the inner peripheral surface of the seal member 52, an arcuate recess portion 66 is formed between the inner annular portion 54 and the first skirt portion 56, which is recessed by a predetermined depth in the radially outward direction of the seal member 52. ing. The recessed portion 66 is inserted into the seal member 52 through the valve shaft portion 36 of the valve body 18, and when the inner annular portion 54 and the first skirt portion 56 contact the outer peripheral surface of the valve shaft portion 36, It is formed so as to be separated from the surface by a predetermined interval. That is, the recessed portion 66 is provided for the purpose of reducing the sliding resistance generated between the inner annular portion 54 and the valve shaft portion 36.

  The outer annular portion 58 is bent at a substantially right angle with respect to a plane portion 68 extending substantially horizontally outward from the base of the first skirt portion 56 and a plane portion 68 extending substantially horizontally. The orthogonal part 70 is configured to extend substantially in parallel with the inner peripheral surface of the seal member 52. The outer peripheral surface of the orthogonal portion 70 is formed so as to slightly bulge outward in the radial direction, and when the seal member 52 is attached to the annular recess 50, the bulged portion of the outer annular portion 58 is the annular shape. It contacts the inner wall surface of the recess 50 (see FIG. 3).

  The planar portion 68 is provided on the inner peripheral side of the second skirt portion 62, and the height dimension T1 along the axial direction from the end surface of the seal member 52 is first before the seal member 52 is mounted in the annular recess 50. The height is set smaller than the height dimension T2 of the two skirt portions 62 (T1 <T2) (see FIG. 4). Thereby, when the seal member 52 is mounted on the guide member 40 via the annular recess 50, the planar portion 68 abuts against the wall surface of the convex portion 48 of the first casing 46 in the same manner as the second skirt portion 62 ( (See FIG. 3).

  Therefore, since the displacement in the axial direction (arrow A, B direction) is restricted by the flat portion 68 coming into contact with the first casing 46, the second skirt portion 62 can be prevented from being excessively deformed. In other words, the planar portion 68 functions as a stopper that restricts the displacement of the second skirt portion 62 in the axial direction to a predetermined amount.

  Further, by providing the flat surface portion 68 in an annular shape, the second skirt portion 62 and the flat surface portion 68 can be brought into contact with the end surface of the first casing 46, so that the sealing performance can be further improved. it can.

  On the other hand, a reinforcing member 72 formed in a substantially L-shaped cross section from a metal material (for example, cold-rolled material) is integrally disposed inside the outer annular portion 58. That is, the rigidity of the sealing member 52 is enhanced by installing the annular reinforcing member 72 along the planar portion 68 and the orthogonal portion 70 bent at a substantially right angle in the outer annular portion 58. Specifically, the rigidity of the outer annular portion 58 with respect to the inner peripheral surface of the seal member 52 is improved. The reinforcing member 72 is integrally formed with the seal member 52 by molding or the like.

  Further, a second skirt portion 62 extending from the corner portion 60 toward the drive portion 16 side is formed at the corner portion 60 where the planar portion 68 and the orthogonal portion 70 intersect in the outer annular portion 58, and the second skirt portion 62 is formed. The tip of the two skirt portion 62 protrudes so as to have substantially the same diameter as the outer peripheral diameter of the orthogonal portion of the outer annular portion 58, and the amount of protrusion of the second skirt portion 62 toward the driving portion 16 is the first amount. It is set to be smaller than the protruding amount of the skirt portion 56.

  The second skirt portion 62 is held in contact with the convex portion 48 of the first casing 46 in the driving unit 16 and always in close contact therewith.

  In the above description, the second skirt portion 62 is formed as a single unit at the corner portion 60 where the planar portion 68 and the orthogonal portion 70 intersect, but the present invention is not limited to this. A plurality of the skirt portions 62 may be provided in the plane portion 68 at a predetermined interval in the radial direction. As a result, the plurality of second skirt portions 62 can be brought into contact with the end surface of the first casing 46, so that the sealing performance can be further enhanced.

  As shown in FIGS. 1 and 2, the driving unit 16 is provided on the upper portion of the valve base 14 and the guide member 40, and has a first casing 46 formed in a bottomed shape, and an upper portion of the first casing 46. A second casing 74 to be mounted; a connection port 76 provided on a side of the second casing 74 and supplied with pressure fluid from a pressure fluid supply source (not shown); the first casing 46 and the second casing 74; And a driving force urging mechanism 78 that is displaced by the pressure fluid.

  The first casing 46 is formed in a curved concave shape opening upward, and the other end portion of the guide member 40 is engaged with a convex portion 48 formed at a substantially central portion, and the first casing 46 is radially outward from the convex portion 48. The first casing 46 is fixed to the valve base 14 by a plurality of bolts 80 through bolt holes (not shown) formed at predetermined intervals.

  A thin gasket (first airtight holding member) 82 is sandwiched between the upper surfaces of the guide member 40 and the valve base 14 and the first casing 46. The gasket 82 is formed of, for example, a metal material. By providing the gasket 82, exhaust gas flowing through the valve base portion 14 is passed from between the valve base portion 14 and the enlarged diameter portion 42 of the guide member 40 to the outside. And the airtightness in the valve chamber 24 and the passage 12 of the valve base 14 can be maintained.

  A plurality of air windows 84 are formed on the side surface of the first casing 46 at a predetermined interval, and the inside and the outside of the first casing 46 communicate with each other through the air window 84.

  The second casing 74 is formed in a curved concave shape that is open like the first casing 46, and is disposed so that the inner wall surface thereof faces the first casing 46. Then, the first casing 46 and the second casing 74 are formed by caulking flange portions 86 a and 86 b formed on the outermost diameter portion of the first casing 46 and the outermost diameter portion of the second casing 74, respectively. Are connected together.

  At that time, a peripheral edge portion 90 of a diaphragm 88 (to be described later) of the driving force biasing mechanism 78 is sandwiched between the flange portions 86a and 86b of the first and second casings 46 and 74 and integrally crimped. Therefore, the peripheral edge 90 of the diaphragm 88 is held by the first and second casings 46 and 74.

  The connection port 76 is made of a tubular tube material and is press-fitted into the hole of the second casing 74. A pipe connected to a pressure fluid supply source (for example, a vacuum pump) (not shown) is connected to the connection port 76, and pressure fluid (for example, negative pressure fluid) from the pressure fluid supply source is connected to the connection port 76. To the inside of the second casing 74.

  The driving force urging mechanism 78 is sandwiched between the first casing 46 and the second casing 74 and connected to the valve shaft portion 36 in the valve body 18, and a set of the diaphragm 88 that holds the diaphragm 88. The first and second diaphragm plates 92 and 94, and the spring 96 interposed between the second diaphragm plate 94 and the second casing 74.

  The diaphragm 88 is formed from a flexible elastic material (for example, rubber) into a thin disk shape, and its peripheral portion 90 is integrally added to the flange portions 86 a and 86 b of the first and second casings 46 and 74. The substantially central portion is inserted into the end portion of the valve shaft portion 36 in the valve body 18 through the insertion hole 98. Thereby, a diaphragm chamber 100 surrounded by the second casing 74 and the diaphragm 88 is formed, and the inside of the diaphragm chamber 100 is kept airtight.

  A disk-shaped first diaphragm plate 92 made of a thin metal material is disposed on the first casing 46 side of the diaphragm 88. A substantially central portion of the first diaphragm plate 92 is provided with a hole. The valve shaft portion 36 is inserted therethrough. And the 1st diaphragm plate 92 is latched by the latching | locking part 104 which was formed in the valve-shaft part 36 and expanded radially outward. Thereby, the displacement of the first diaphragm plate 92 toward the valve base 14 is restricted by the locking portion 104.

  On the other hand, on the second casing 74 side of the diaphragm 88, a second diaphragm plate 94 formed from a thin plate-like metal material and having a substantially U-shaped cross section is disposed, and at a substantially central portion of the second diaphragm plate 94. The valve stem 36 is inserted through the formed hole. Then, the diaphragm 88 is sandwiched between the first diaphragm plate 92 and the second diaphragm plate 94, and the valve shaft portion 36 is crimped via the washer 106, whereby the diaphragm 88, the first diaphragm plate 92, and the second diaphragm plate 92 are clamped. Since the diaphragm plate 94 is sandwiched between the crimped portion of the valve shaft portion 36 and the locking portion 104, the diaphragm 88, the first diaphragm plate 92, and the second diaphragm plate 94 connect the valve shaft portion 36 to each other. Are connected together.

  The second diaphragm plate 94 is formed with an annular first spring guide 108 that protrudes by a predetermined height toward the second casing 74 (in the direction of arrow A), and on the inner wall surface of the second casing 74. A second spring guide 110 that protrudes toward the second diaphragm plate 94 (in the direction of arrow B) is formed at a position facing the first spring guide 108. A spring 96 is interposed between the first and second spring guides 108 and 110, and the spring force of the spring 96 causes the second diaphragm plate 94 to move away from the second casing 74 (in the direction of arrow B). ).

  That is, the diaphragm 88 and the valve body 18 connected to the diaphragm 88 are always urged toward the valve base 14 (in the direction of arrow B) by the elastic force of the spring 96. Since the spring 96 is restricted from being displaced in the radial direction by the first and second spring guides 108 and 110, the spring 96 is not displaced in the radial direction inside the second casing 74.

  The valve body 18 is formed of a metal material and is disposed in the valve chamber 24 of the valve base 14, and is formed at a long valve shaft portion 36 supported by the guide member 40 and a lower end portion of the valve shaft portion 36. The seat portion 30 can be seated on the valve seat 26. The seat portion 30 is formed so as to expand radially outward from the valve shaft portion 36, and the diameter of the seat portion 30 is formed to be larger than the diameter of the communication hole 28 of the valve seat 26. Further, the end portion of the valve shaft portion 36 is formed in a narrow shaft shape whose diameter is reduced radially inward, and the diaphragm 88 and the first and second diaphragm plates 92 and 94 are inserted therethrough.

  The exhaust gas recirculation valve 10 to which the sealing device according to the embodiment of the present invention is applied is basically configured as described above. Next, its operation and effects will be described. The valve closed state in which the seat portion 30 of the valve body 18 shown in FIG. 1 is seated on the valve seat 26 and the communication state between the inlet port 20 and the outlet port 22 is blocked will be described as an initial position.

  In such a valve closed state, a negative pressure fluid is supplied to a connection port 76 of the drive unit 16 through a pipe from a vacuum pump (not shown) serving as a pressure fluid supply source. By introducing this negative pressure fluid into the diaphragm chamber 100 inside the second casing 74, the diaphragm 88 is bent under the negative pressure action of the negative pressure fluid and resists the elastic force of the spring 96. 2. It is sucked and displaced toward the casing 74 side (arrow A direction). Therefore, the first and second diaphragm plates 92 and 94 are displaced along with the displacement of the diaphragm 88, and the valve body 18 connected to the diaphragm 88 is axially moved under the guide action of the guide hole 44 of the guide member 40. Along the top (in the direction of arrow A).

  As a result, the seat portion 30 of the valve body 18 is separated from the valve seat 26, and the valve is in an open state in which the inlet port 20 and the outlet port 22 communicate with each other through the valve chamber 24 and the passage 12. As a result, exhaust gas flowing from the inlet port 20 is discharged from the outlet port 22 through the valve chamber 24 and the passage 12.

  When the exhaust gas recirculation valve 10 is used in a diesel engine, in the exhaust gas recirculation system in the diesel engine, the exhaust gas is supplied from the inlet port 20 at a positive pressure. Under the action, it flows from the valve chamber 24 between the valve shaft portion 36 of the valve body 18 and the guide hole 44, and from the valve chamber 24 to between the valve base portion 14 and the enlarged diameter portion 42 of the guide member 40. In particular, when the guide member 40 is a sintered material, there is a possibility that the guide member 40 may permeate into the enlarged diameter portion 42 side.

  At that time, the exhaust gas that has infiltrated between the enlarged diameter portion 42 of the guide member 40 and the valve base portion 14 is separated from the valve base portion 14 by the gasket 82 sandwiched between the valve base portion 14 and the first casing 46. Leakage from between the first casing 46 and the outside of the exhaust gas recirculation valve 10 is prevented.

  Further, the exhaust gas flows from between the enlarged diameter portion 42 of the guide member 40 and the valve base portion 14 to the inner peripheral side of the gasket 82 and penetrates between the other end portion of the guide member 40 and the first casing 46. In this case, since the second skirt portion 62 of the seal member 52 is in contact with the wall surface of the convex portion 48 of the first casing 46, the exhaust gas is prevented from flowing into the valve body 18 side.

  Further, the exhaust gas that has flowed from the valve chamber 24 into the space between the valve shaft portion 36 of the valve body 18 and the guide hole 44 has an inner annular shape of the seal member 52 that is in contact with the outer peripheral surface of the valve shaft portion 36 of the valve body 18. The flow is blocked by the portion 54, and the exhaust gas that has passed between the inner annular portion 54 and the valve shaft portion 36 is reliably blocked by the first skirt portion 56 of the seal member 52. Therefore, the exhaust gas flowing from the valve chamber 24 into the space between the valve shaft portion 36 and the guide hole 44 of the valve body 18 leaks into the first casing 46 from between the valve shaft portion 36 and the guide hole 44. I can prevent it.

  Thus, when the exhaust gas recirculation valve 10 according to the embodiment of the present invention is employed in, for example, a diesel engine, the exhaust gas flowing through the valve chamber 24 is between the valve base 14 and the guide member 40. Exhaust gas that has entered the gas is blocked by the gasket 82, and exhaust gas flowing from the gasket 82 and the guide member 40 to the first casing 46 side is blocked by the second skirt portion 62 of the seal member 52, and the valve body The exhaust gas flowing from the space 18 and the guide member 40 toward the first casing 46 is blocked by the inner annular portion 54 and the first skirt portion 56 of the seal member 52.

  That is, in the exhaust gas recirculation valve 10, the guide member 40 is provided with the seal member 52 capable of contacting the valve body 18 and the convex portion 48 of the first casing 46, and between the valve base portion 14 and the first casing 46. By sandwiching the gasket 82, the seal member 52 and the gasket 82 block the flow of exhaust gas that permeates into the gaps between the valve body 18, the valve base 14, and the guide member 40, and pass through the air window 84 of the first casing 46. Further, leakage of the exhaust gas to the outside can be reliably prevented.

  Next, by stopping the supply of the negative pressure fluid supplied to the drive unit 16, the diaphragm 88 and the first and second diaphragm plates 92 and 94 are pressed toward the valve base 14 by the elastic force of the spring 96. Then, as the diaphragm 88 is displaced downward, the valve body 18 is integrally displaced downward under the guide action of the guide member 40. At that time, the air in the first casing 46 is discharged to the outside through the air window 84.

  As a result, the seat portion 30 of the valve body 18 is seated on the valve seat 26, and the communication hole 28 is closed by the seat portion 30, thereby closing the communication state between the inlet port 20 and the outlet port 22. Become.

  In the above description, the case where the exhaust gas recirculation valve 10 to which the sealing device according to the embodiment of the present invention is applied is employed in a diesel engine. However, the exhaust gas recirculation valve 10 is employed in a gasoline engine. It is also possible.

  In general, in an exhaust gas recirculation system in a gasoline engine, exhaust gas flows from the inlet port 20 to the outlet port 22 under the suction action by the negative pressure supplied from the outlet port 22 of the exhaust gas recirculation valve 10. To do. That is, in the valve open state in which the valve body 18 is separated from the valve seat 26, negative pressure is applied to the inlet port 20, the outlet port 22 and the valve chamber 24.

  As described above, also in the exhaust gas recirculation valve 10 in the gasoline engine, the exhaust gas flowing through the valve chamber 24 is exhausted from between the valve base 14 and the guide member 40 to the outside, similarly to the case where it is adopted in the diesel engine. Gas flow is blocked by the gasket 82, and exhaust gas flowing from between the gasket 82 and the guide member 40 to the first casing 46 side is blocked by the second skirt portion 62 of the seal member 52, and the valve body 18 The exhaust gas flowing from the space between the guide member 40 to the first casing 46 side can be blocked by the inner annular portion 54 and the first skirt portion 56 of the seal member 52. As a result, even in a gasoline engine, the exhaust gas that permeates into the gaps between the valve body 18, the valve base 14, and the guide member 40 is blocked by the seal member 52 and the gasket 82, and the leakage of the exhaust gas to the outside is ensured. Can be prevented.

  Further, by forming the guide member 40 for supporting the valve body 18 along the axial direction from a sintered material such as a carbon sintered body, the guide of the valve shaft portion 36 of the valve body 18 and the guide member 40 is provided. The sliding resistance with respect to the hole 44 is reduced, and the slidability when the valve body 18 is displaced along the axial direction can be improved. In this case, a slight clearance is generated between the valve body 18 made of a metal material and the guide member 40 made of a sintered material such as a carbon sintered body. However, a seal member 52 is provided on the guide member 40 to provide a valve. By sealing the shaft portion 36, the exhaust gas flowing between the valve body 18 and the guide member 40 can be reliably blocked by the seal member 52.

  For this reason, the guide member 40 made of a sintered material such as a carbon sintered body ensures the slidability at the time of the displacement operation of the valve body 18 and improves the sealing performance with respect to the valve body 18 so that the exhaust gas is discharged to the outside. Leakage can be prevented.

  On the other hand, FIG. 5 shows a case where the sealing member 52 applied to the exhaust gas recirculation valve 10 according to the embodiment of the present invention described above is applied to the exhaust gas cooling bypass valve 200 as a reference example. The same components as those in the exhaust gas recirculation valve 10 according to this embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the exhaust gas cooling bypass valve 200 according to this reference example, an inlet port 204 connected to the exhaust system of the internal combustion engine is formed in the valve base 202, and is separated from the inlet port 204 and is not shown in the drawing. A pair of first and second outlet ports 206a, 206b are formed which are connected to each other. Then, valve seats 208a and 208b are formed at connection portions between the inlet port 204 and the first and second outlet ports 206a and 206b, respectively.

  A valve body 210 is provided in the valve chamber 24 of the valve base portion 202 so as to be displaceable along the axial direction by a guide member 212. One seating portion 214a of the valve body 210 is seated on one valve seat 208a. As a result, the exhaust gas from the inlet port 204 flows to the first outlet port 206a, and conversely, the other seating portion 214b of the valve body 210 is seated on the other valve seat 208b. The exhaust gas flow path is switched so that the exhaust gas from the exhaust gas flows to the second outlet port 206b.

  In this case, the exhaust gas flowing from the inlet port 204 to the first outlet port 206a is sealed by the seal member 52 provided on the guide member 212 and the gasket 82 provided between the valve base 202 and the drive unit 16. Then, it is reliably prevented from flowing into the drive unit 16 side and the outside through a gap around the guide member 212.

It is a longitudinal cross-sectional view which shows an exhaust-gas recirculation valve in the exhaust-gas recirculation valve which concerns on embodiment of this invention, and its sealing device. FIG. 2 is a partially enlarged longitudinal sectional view showing a valve open state in which the valve body in the exhaust gas recirculation valve of FIG. 1 is separated from the valve seat. It is a partial expanded longitudinal cross-sectional view which shows the seal member vicinity provided in the exhaust-gas recirculation valve. It is an expanded longitudinal cross-sectional view which shows the seal member of the state which is not mounted | worn with an exhaust-gas recirculation valve. FIG. 2 is a reference longitudinal sectional view showing an exhaust gas cooling bypass valve to which a seal member in the exhaust gas recirculation valve of FIG. 1 is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Exhaust gas recirculation valve 14, 202 ... Valve base 16 ... Drive part 18, 210 ... Valve body 20, 204 ... Inlet port 22, 206a, 206b ... Outlet port 24 ... Valve chamber 26, 208a, 208b ... Valve seat 30 214a, 214b ... Seating part 34 ... Valve cover 36 ... Valve shaft part 40, 212 ... Guide member 44 ... Guide hole 46 ... First casing 50 ... Annular recess 52 ... Seal member 54 ... Inner annular part 56 ... First skirt part 58 ... outer annular portion 62 ... second skirt portion 64 ... ring member 72 ... reinforcing member 74 ... second casing 78 ... driving force biasing mechanism 82 ... gasket 84 ... air window 88 ... diaphragm 92 ... first diaphragm plate 94 ... first 2 Diaphragm plate 96 ... Spring 100 ... Diaphragm chamber

Claims (5)

A valve base having a circulation passage for exhaust gas and a valve seat provided in the circulation passage;
A valve body that opens and closes the circulation passage by being seated and separated from the valve seat;
A drive unit connected to the valve base and displacing the valve body along an axial direction under supply of pressure fluid;
A guide member that is provided inside the valve base and holds the valve body in an axially displaceable manner;
A first hermetic holding member provided between the valve base and the drive unit and preventing leakage of the exhaust gas flowing through the valve base;
A second airtight holding member provided on the guide member so as to surround an outer peripheral surface of the valve body, and preventing leakage of the exhaust gas flowing through the valve base;
With
The second airtight holding member is formed on an inner peripheral surface facing the valve body and is formed to extend toward the drive unit side, and a first seal portion that contacts the outer peripheral surface of the valve body. An exhaust gas recirculation valve comprising: a single or a plurality of second seal portions that abut against the end face of the drive portion. The exhaust gas recirculation valve according to claim 1,
The exhaust gas recirculation valve, wherein the guide member is made of a sintered material, and the second hermetic holding member is made of a rubber material. The exhaust gas recirculation valve according to claim 1,
The first seal portion is formed on an inner annular portion that bulges radially inward toward the valve body side, and is formed on the drive portion side from the inner annular portion, and has a predetermined angle toward the direction approaching the valve body. It consists of a skirt that extends at an incline,
The exhaust gas recirculation valve, wherein the inner annular portion and the skirt portion are in contact with an outer peripheral surface of the valve body. The exhaust gas recirculation valve according to claim 1,
The exhaust gas recirculation valve is used for a diesel engine in which the exhaust gas is supplied to the circulation passage at a positive pressure. The valve body and a guide member that holds the valve body movably along the axial direction are sealed, and the guide member is attached to an annular recess formed so as to surround the outer peripheral surface of the valve body. A sealing device,
The sealing device includes a first seal portion that contacts an outer peripheral surface of the valve body;
A single or a plurality of second seal portions provided on the inner peripheral surface side of the annular recess and abutting against an end surface of the first casing that closes the opening of the annular recess;
The first seal portion includes an inner annular portion that bulges radially inward toward the valve body,
The skirt portion is formed on the first casing side from the inner annular portion and extends at a predetermined angle toward the direction approaching the valve body,
A planar portion that is formed radially inward from the second seal portion and has a small axial length with respect to the second seal portion in a state before the sealing device is attached to the annular recess;
The sealing device according to claim 1, wherein the flat portion abuts against an end surface of the first casing when the sealing device is mounted.

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