JP2016070283A - Butterfly valve and exhaust system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve sealability even when there is manufacturing variation in a gap of an abutment of a seal ring.SOLUTION: A butterfly valve 4 includes: a housing having a hole through which fluid passes; a valve shaft 42 rotating; a discoid valve body 43 having an outer peripheral edge 433 on which a groove 434 is formed, and connected to the valve shaft 42; a seal ring 44 having an abutment 441, and fitted into the groove 434; and a stationary member 45 fixed at a position of the abutment 441 in the groove 434. The abutment 441 is formed by the end part of the seal ring 44. The stationary member 45 has a first portion wider than the interval of the abutment 441, and a second portion narrower than the interval of the abutment 441, when viewed from in the radial direction of the seal ring 44.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a technique for improving sealing performance in a butterfly valve using a seal ring.

  A butterfly valve is known as a valve for controlling the flow rate of fluid. For example, Patent Document 1 discloses a technique using a butterfly valve as an EGR valve used in an exhaust gas recirculation (EGR) system in which a part of exhaust gas is re-intaken in an internal combustion engine for automobiles. Yes. Patent Document 1 discloses a structure in which a groove is provided on the outer peripheral edge of the valve body and a seal ring is fitted in the groove in order to improve the sealing performance (air tightness) between the valve body and the housing. Here, the seal ring is not a perfect ring shape, but has a C-shape with a notch (a so-called joint) in part. In order to prevent the seal ring from rotating relative to the valve body, a non-rotating pin is provided at the position of the notch (FIG. 5).

JP 2008-223505 A

  When the seal ring is mass-produced, manufacturing variations occur in the gap at the joint. However, depending on the technique described in Patent Document 1, there is a problem in that the sealing performance between the valve body and the housing deteriorates when the gap between the joints is widened due to manufacturing variations.

  On the other hand, the present invention provides a technique for improving the sealing performance even if there is a manufacturing variation in the gap at the joint of the seal ring.

  The present invention includes a housing having a hole through which a fluid passes, a rotating valve shaft, a disk-like shape provided inside the hole and having an outer peripheral edge formed with a groove and connected to the valve shaft. A valve body, a seal ring having a joint, and fitted in the groove; and a fixing member fixed at the position of the joint in the groove, wherein the joint has a first end and a second end of the seal ring. The fixing member includes a first portion wider than a distance between the first end and the second end, as viewed from a radial direction of the seal ring, and the first end and the second end. A butterfly valve having a second portion that is narrower than

  The fixing member further includes a third portion that is wider than a distance between the first end and the second end when viewed from the radial direction of the seal ring, and the second portion includes the first portion and the second portion. The first end and the second end may be engaged with a gap between the first portion and the second portion between the second portions.

  The first portion may be located upstream of the second portion with respect to the fluid flow direction as viewed from the radial direction of the seal ring.

  The fixing member may be fixed at a position where the center of gravity of the fixing member is deviated from the center line of the seal ring as viewed from the radial direction of the seal ring.

  The present invention also provides an exhaust system having an exhaust pipe for flowing exhaust gas of an internal combustion engine, and any one of the butterfly valves attached in the middle of the exhaust pipe.

  According to the present invention, even if there is a manufacturing variation in the gap at the joint of the seal ring, the sealing performance can be improved.

The figure which illustrates the structure of the intake / exhaust system 1000 which concerns on one Embodiment. The perspective view of the valve assembly 1 which concerns on one Embodiment. The perspective view which shows the structure of the valve shaft in the butterfly valve 4, and a valve body. The disassembled perspective view of the butterfly valve 4. FIG. The figure which illustrates the relationship between the abutment 441 and the fixing member 45. The enlarged view of the joint 441. FIG. The figure which illustrates the relationship between the joint which concerns on a comparative example, and the fixing member 45. FIG. VIII-VIII sectional drawing of FIG. The enlarged view of the area | region IX of FIG. Sectional drawing of the valve assembly 1 in a half open state. The figure which shows another example of the shape of the fixing member 45. FIG.

1. Structure FIG. 1 is a diagram illustrating a configuration of an intake / exhaust system 1000 according to an embodiment. The intake / exhaust system 1000 is a system that controls intake / exhaust to the engine 2000. In this example, engine 2000 is an automobile diesel engine. The intake / exhaust system 1000 is a so-called EGR system (EGR device) that recirculates a part of the exhaust gas to the intake system. The intake / exhaust system 1000 includes an intake system 11, an exhaust system 12, an HPL (High Pressure Loop) -EGR system 13, and an LPL (Low Pressure Loop) -EGR system 14.

  The intake system 11 supplies an air-fuel mixture to the engine 2000. The intake system 11 includes an intake-side turbo bypass valve 111, an intercooler switching valve 112, an intercooler 113, and a throttle valve 114.

  The exhaust system 12 discharges exhaust gas from the engine 2000. The exhaust system 12 includes an exhaust-side turbo bypass valve 121, an exhaust brake valve 122, a DPF (Diesel Particulate Filter) 123, and an exhaust throttle valve 124.

  A first turbocharger 15 and a second turbocharger 16 are provided between the intake system 11 and the exhaust system 12.

  The HPL-EGR system 13 returns a part of the exhaust to the intake system 11. The HPL-EGR system 13 is provided between the exhaust side of the engine 2000 and the intake system 11 (specifically, the downstream side of the throttle valve 114). The HPL-EGR system 13 includes an EGR cooler switching valve 131, an HPL-EGR valve 132, and an EGR cooler 133.

  The LPL-EGR system 14 returns a part of the exhaust gas to the intake system 11. The LPL-EGR system 14 is provided between the exhaust system 12 (specifically, downstream of the DPF 912) and the intake system 11 (specifically, upstream of the second turbocharger 16). The LPL-EGR system 14 includes an LPL-EGR valve 141 and an EGR cooler 142.

  FIG. 2 is a perspective view of the valve assembly 1 according to an embodiment. The valve assembly 1 is a valve used in the intake / exhaust system 1000, for example, a valve used as the exhaust-side turbo bypass valve 121. The valve assembly 1 includes a drive unit 2, a link mechanism unit 3, and a butterfly valve 4. Hereinafter, for the sake of explanation, the direction is defined as follows. In the butterfly valve 4, upstream and downstream in the fluid flow direction are referred to as “front” and “rear”, respectively. The top, bottom, left and right when facing backward from the front toward the butterfly valve 4 are referred to as “upper”, “lower”, “left”, and “right”. This definition is for convenience of explanation, and does not limit the direction and position where the valve assembly 1 is installed in the system.

  The butterfly valve 4 includes a housing 41, a valve shaft (not shown in FIG. 2), and a valve body 43. The housing 41 includes a housing body 411 and a sleeve 412. The housing body 411 is made of, for example, stainless steel and has a rectangular parallelepiped shape. The housing body 411 has a hole extending in the front-rear direction. Fluid passes through this hole. In FIG. 2, the direction in which the fluid flows is indicated by arrows. The sleeve 412 is formed of stainless steel, for example, and has a cylindrical shape. The sleeve 412 is fitted in the hole of the housing body 411.

  FIG. 3 is a perspective view illustrating the structure of the valve shaft and the valve body in the butterfly valve 4, and FIG. 4 is an exploded perspective view of the butterfly valve 4. The butterfly valve 4 includes a valve shaft 42, a valve body 43, a seal ring 44, and a fixing member 45.

  The valve shaft 42 is made of stainless steel, for example, and has a cylindrical shape (round bar shape). In the valve shaft 42, a part of the side surface is cut to connect the valve body 43 to form a flat portion 421.

  The valve body 43 is made of, for example, stainless steel and has a disk shape. That is, the valve body 43 has a flat surface 431, a flat surface 432, and an outer peripheral edge 433. Grooves 434 (hatched portions in FIG. 4) are formed in the outer peripheral edge 433. The groove 434 is formed along the outer peripheral edge 433 and is circular when viewed from the front. Further, the groove 434 extends straight along the outer peripheral edge 433 when viewed from above, below, left, or right. The valve shaft 42 and the valve body 43 are fixed to each other by a bolt 46 on the flat portion 421 and the flat surface 432.

  The seal ring 44 is formed of stainless steel, for example, and has an annular shape. However, the seal ring 44 does not have a complete annular shape, and the ring is partially cut and a gap (gap) is formed. That is, the seal ring 44 has a C shape. The portion where the ring is cut is referred to as an abutment 441. When the abutment 441 is formed, the gap at the abutment becomes a margin, and the seal ring 44 is easily elastically deformed. Note that the seal ring 44 and the valve body 43 may be formed of different materials depending on required characteristics. For example, the seal ring 44 may be formed of SUS631J1, and the valve body 43 may be formed of SUS303.

  The fixing member 45 functions as a stopper that prevents the seal ring 44 from rotating with respect to the valve body 43. The fixing member 45 is fixed to the valve body 43 at a position corresponding to the joint 441 in the groove 434. As a method of fixing the fixing member 45 to the valve body 43, for example, press-fitting or screwing is used. The fixing member 45 is a pin made of, for example, stainless steel and having a column shape with a predetermined cross-sectional shape.

  FIG. 5 is a diagram illustrating the relationship between the joint 441 and the fixing member 45. The upper part of FIG. 5 shows a cross section of the valve element 43 and the seal ring 44 as viewed from the front (the VV cross section of the lower part of FIG. 5). The lower view of FIG. 5 is a view of the valve body 43 and the seal ring 44 as viewed from below. That is, the lower diagram of FIG. 5 shows the shape of the abutment 441 and the positional relationship with the fixing member 45 as seen from the radial direction of the seal ring 44. In this figure, the groove 434 and the seal ring 44 are drawn large for explanation. The joint 441 is formed by one end (end portion 442) and the other end (end portion 443) of the seal ring 44. The seal ring 44 is not fitted to the bottom surface of the groove 434, and a gap (gap G3 in FIG. 9) is provided between the bottom surface of the seal ring 44 and the bottom surface of the groove 434. A part of the fixing member 45 is fitted into (or screwed into) the valve body 43 and is fixed. The valve body 43 has a hole (concave portion) for fixing the fixing member. The diameter of the fixing member 45 may be equal to or smaller than the width of the groove 434, or may be wider than the width of the groove 434. When the diameter of the fixing member 45 is wider than the width of the groove 434, the portion of the groove 434 where the fixing member 45 is fixed is wider than the others. The seal ring 44 is not entirely fitted in the groove 434, and a part of the seal ring 44 protrudes from the groove 434. As an example, the outer diameter of the seal ring 44 is 40 to 70 mm, the height (the length in the radial direction) d1 is 1.8 to 2.0 mm, and the height d2 of the portion protruding from the groove 434 is included. Is 0.8 to 1.1 mm.

  FIG. 6 is an enlarged view of the joint 441. In this example, the fixing member 45 has a shape in which two concave portions (notches) are formed in a cylinder. The recesses are formed on the left and right sides in the direction along the groove 434, respectively. The end 442 and the end 443 are engaged with these recesses. The cross-sectional shape of the fixing member 45 is the first portion 451 and the third portion 453 that are longer than the interval G1 between the end portion 442 and the end portion 443, and the second portion that is shorter than the interval G1, in terms of the length in the left-right direction. 452 may also be included. The second portion 452 is sandwiched between the first portion 451 and the third portion 453. The width of the second portion 452 is wider than the width of the seal ring 44 (specifically, the width of the end portion 442 and the width of the end portion 443). Here, “width” refers to the length in the front-rear direction.

  6A shows a state where no pressure is applied by the fluid, and FIG. 6B shows a state where the pressure is applied. When pressure is applied by the fluid, the seal ring 44 is pressed against the fixing member 45. At this time, since the end portion 442 and the end portion 443 are engaged with the concave portion of the fixing member 45, the first portion 451, the end portion 442, and the end portion 443 come into contact with each other to be in an airtight state. Here, from the viewpoint of further improving the airtightness, it is desirable that the surface of the concave portion of the fixing member 45 that meshes with the end portion y442 and the end portion 443 has a flat portion parallel to the circumferential direction of the seal ring 44. Further, at this time, the fixing member 45 is located at a position where the center of gravity C of the fixing member 45 is shifted (forward) from the center line of the seal ring 44 (a chain line in the drawing) when viewed from the radial direction of the seal ring 44. .

  Refer to FIG. 5 again. If the vertical dimension of the fixing member 45 is formed together with the seal ring 44, that is, if the outer peripheral edge (outer peripheral surface) of the seal ring 44 and the fixing member 45 draws a smooth arc, the sealing performance is improved. Can do.

  FIG. 7 is a diagram illustrating the relationship between the fixing member 55 and the joint according to the comparative example. The cross-sectional shape of the fixing member 55 is a circle, and no notch (concave portion) is formed. Due to factors such as manufacturing errors and manufacturing variations, the gap of the joint 441 cannot be made the same size as the diameter of the fixing member 55. If the gap of the joint 441 is larger than the diameter of the fixing member 55, the joint 441 and the fixing member 55 are not sealed, and fluid leaks.

  On the other hand, if the fixing member 45 of this embodiment is used, a sealing performance can be improved compared with the case where the fixing member 55 is used.

  Refer to FIG. 2 again. The drive unit 2 rotates the valve shaft 42 (that is, drives the valve shaft 42). The drive unit 2 includes a motor 21 and a bracket 22. The motor 21 is fixed to the bracket 22. The link mechanism unit 3 transmits driving force (rotational force) from the motor 21 to the valve shaft 42. The link mechanism unit 3 connects the rotating shaft (not shown) of the motor 21 and the valve shaft 42.

  FIG. 8 shows a cross-sectional view taken along the line VIII-VIII in FIG. In this figure, the butterfly valve 4 is fully closed. In this state, the valve body 43 is located in front of the valve shaft 42 (upstream side). That is, the radial center O2 of the valve body 43 is located forward with respect to the axis O1 of the valve shaft 42.

  A hole serving as a fluid path through which a fluid passes is formed in the sleeve 412. A sliding surface 4121 is formed on a part of the wall surface of the hole. The sliding surface 4121 is a surface that slides with the valve body 43 (seal ring 44), and has a part of a spherical surface with a radius of curvature r1. The curvature radius r <b> 1 is a length corresponding to the radius of the valve body 43 including the seal ring 44. The sliding surface 4121 is formed upstream of the axis O1 when viewed from above. On the downstream side of the axis O1, the hole of the sleeve 412 is constant or has a taper widening toward the downstream.

FIG. 9 is an enlarged view of a region IX in FIG. The seal ring 44 is an outer peripheral edge 433 of the valve body 43.
Is fitted into a groove 434 formed in In this example, the cross-sectional shape of the seal ring 44 is a rectangle. In this example, the seal ring 44 is not completely pushed into the groove 434 (the seal ring 44 and the bottom surface of the groove 434 are not in contact), and the seal ring 44 and the groove 434 are not in contact with each other. There is a gap G3 between the bottom surface. If there is a gap G3, this becomes a margin, and the seal ring 44 is more easily elastically deformed.

  Refer to FIG. 8 again. Ideally, the axis O <b> 1 of the valve shaft 42 passes through the center of the sphere that forms the sliding surface 4121. Further, ideally, the radius of curvature r1 of the sliding surface 4121 and the distance from the axis O1 of the valve shaft 42 to the outer peripheral edge of the valve body 43 (seal ring 44) are the same. In such an ideal state, the outer peripheral edge of the valve body 43 and the sliding surface 4121 do not shift and contact with no gap.

  However, in actuality, due to various factors such as the shape accuracy of the valve body 43 and the sliding surface 4121, the assembly error between the valve shaft 42 and the valve body 43, and the thermal contraction of the valve body 43 and the housing 41, the valve body 43 There is a deviation between the outer peripheral edge of the lens and the sliding surface 4121.

  The seal ring 44 of the present embodiment can be elastically deformed from an unloaded state by the gaps G1 to G3. In a portion where the distance between the axis O1 and the sliding surface 4121 is shorter than the design value, the seal ring 44 is elastically deformed so that the sliding between the valve element 43 and the sliding surface 4121 is not impaired. Can do. That is, in the fully closed state, the sliding surface 4121 can be brought into contact with the entire circumference of the outer peripheral edge of the seal ring 44. A contact portion between the seal ring 44 and the sliding surface 4121 is illustrated as a seal portion S (the same applies to the following drawings).

  FIG. 10 shows a cross-sectional view of the valve assembly 1 in a half-open state. FIG. 10 shows the same cross section as FIG. In this state, the valve body 43 is inclined as compared with the fully opened state, and the fluid path A is partially opened. The outer peripheral edge of the valve body 43 is in contact with the sliding surface 4121 at a part of the upper and lower portions. In other words, the upper and lower portions of the seal ring 44 are supported by the sliding surface 4121. The same applies to the fully opened state.

2. Modifications The present invention is not limited to the above-described embodiments, and various modifications can be made. Hereinafter, some modifications will be described. A plurality of the following modifications may be used in combination.

  FIG. 11 is a diagram illustrating another example of the shape of the fixing member 45. The shape of the fixing member 45 is not limited to the cylinder having the recess described in the embodiment. FIG. 11 shows an example in which the fixing member 45 does not have the third portion 453 but has only the first portion 451 and the second portion 452. In this case, the first portion 451 is preferably positioned in front of the second portion 452.

  Further, the shape of the fixing member 45 may be other than those illustrated in FIGS. 6 and 11. For example, the fixing member 45 may be a rectangular column formed with a notch (concave portion).

  The structure of the intake / exhaust system 1000 is not limited to that illustrated in FIG. As long as a part of the exhaust from the engine 2000 is recirculated to the intake pipe, the specific structure of the intake / exhaust system 1000 may be any. Engine 2000 is not limited to a diesel engine for automobiles. It may be an engine used for applications other than automobiles, such as ships, and may be a gasoline engine.

  The use of the valve assembly 1 is not limited to the exhaust-side turbo bypass valve 121 of the intake / exhaust system 1000. It may be used for other valves of the intake / exhaust system 1000. Further, the valve assembly 1 may be used in an exhaust system (exhaust device) other than the EGR system. In another example, the valve assembly 1 is not limited to one that controls the flow of gas (eg, air-fuel mixture and exhaust), and may be used for applications that control the flow of liquid or gas.

  The materials of the components of the valve assembly 1 are not limited to those described in the embodiment. Each of the component parts may be formed of a single metal such as aluminum or iron, an alloy thereof, or a resin other than stainless steel. Further, the shapes of the valve assembly 1 and its components are not limited to those illustrated in the embodiment. The size described in the embodiment is merely an example.

DESCRIPTION OF SYMBOLS 1000 ... Intake / exhaust system 11 ... Intake system 111 ... Intake side turbo bypass valve 112 ... Intercooler switching valve 113 ... Intercooler 114 ... Throttle valve 12 ... Exhaust system 121 ... Exhaust side turbo bypass valve 122 ... Exhaust brake valve 123 ... DPF
124 ... Exhaust throttle valve 13 ... HPL-EGR system 131 ... EGR cooler switching valve 132 ... HPL-EGR valve 133 ... EGR cooler 14 ... LPL-EGR system 141 ... LPL-EGR valve 142 ... EGR cooler 15 ... First turbocharger 16 ... Second turbocharger engine 2000
Valve assembly 1
DESCRIPTION OF SYMBOLS 2 ... Drive part 3 ... Link mechanism part 4 ... Butterfly valve 41 ... Housing 411 ... Housing main body 412 ... Sleeve 42 ... Valve shaft 421 ... Flat part 43 ... Valve body 431 ... Flat surface 432 ... Flat surface 433 ... Outer peripheral edge 434 ... Groove 44 ... Seal ring 441 ... Joint 442 ... End 443 ... End 45 ... Fixed member 451 ... First part 452 ... Second part 453 ... Third part 55 ... Fixed member 551 ... Joint

Claims (5)

A housing having holes through which fluid passes;
A rotating valve stem,
A disc-shaped valve body provided inside the hole, having an outer peripheral edge formed with a groove, and connected to the valve shaft;
A seal ring having a joint and fitted in the groove;
A fixing member fixed to the position of the joint in the groove,
The joint is formed by a first end and a second end of the seal ring,
The fixing member has a first portion wider than the interval between the first end and the second end and a interval smaller than the interval between the first end and the second end when viewed from the radial direction of the seal ring. A butterfly valve having a second portion. The fixing member further includes a third portion that is wider than a distance between the first end and the second end when viewed from a radial direction of the seal ring;
The second part is sandwiched between the first part and the second part;
The butterfly valve according to claim 1, wherein the first end and the second end mesh with a gap between the first portion and the second portion. 3. The butterfly according to claim 1, wherein the first portion is located upstream of the second portion with respect to the fluid flow direction when viewed from a radial direction of the seal ring. valve. 2. The butterfly valve according to claim 1, wherein the fixing member is fixed at a position where a center of gravity of the fixing member deviates from a center line of the seal ring as viewed from a radial direction of the seal ring. . An exhaust pipe for flowing the exhaust gas of the internal combustion engine;
The exhaust apparatus which has a butterfly valve as described in any one of Claim 1 thru | or 4 attached in the middle of the said exhaust pipe.

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