JP5400682B2 - Exhaust flow control valve sliding part structure - Google Patents

Description

  The present invention relates to a sliding portion structure of an exhaust flow rate control valve provided in an exhaust passage of an internal combustion engine (engine) and capable of controlling the flow rate of exhaust gas flowing through the exhaust passage.

  Conventionally, for example, an on-off valve is provided in an exhaust passage of an automobile engine, and the flow rate of exhaust gas flowing through the exhaust passage is controlled by the on-off valve biased in a valve closing direction by a spring. Has been done. For example, Patent Document 1 discloses a spring mounting structure of a torsion coil spring that urges an exhaust flow control valve incorporated in a control silencer for an automobile toward a closing side. In this spring mounting structure, the urging force of the torsion coil spring is applied to the maximum at the valve closing position, and the urging force of the torsion coil spring is reduced as the exhaust flow control valve rotates to the valve opening side. It can be made to.

  In the spring mounting structure disclosed in Patent Document 1, a bent hook portion is provided at one end of a torsion coil spring supported by a fixed shaft, and a cylindrical roller for rotation support is freely rotatable on the hook portion. It is attached to. In this case, in Patent Document 1, the cylindrical roller attached to the hook portion rolls on the sliding surface of the plate portion when the exhaust flow control valve is opened and closed, so that the hook portion can be displaced with a small resistance. It is said.

Japanese Patent No. 4141601

  However, in the exhaust flow control valve disclosed in Patent Document 1, the torsion coil spring constituting the spring mounting structure, the plate portion having the sliding surface, the roller component accuracy (dimensional accuracy), and the exhaust gas load (load) The contact angle between the roller mounted on the hook portion and the sliding surface of the plate portion changes due to deformation of the bending angle of the hook portion of the torsion coil spring due to being applied, and the cylindrical roller There is a possibility that a uniform contact state cannot be obtained on the contact surface between the outer peripheral surface of the plate and the sliding surface of the plate portion, and the contact state is biased to one of the rollers in the axial direction.

  In such a biased contact state between the roller mounted on the hook portion and the sliding surface of the plate portion, uneven wear occurs on a part of the outer peripheral surface of the cylindrical roller that rolls along the sliding surface. In addition, since smoothness of relative movement between the sliding surface and the roller is lost, the opening / closing operation of the exhaust flow control valve may become unstable.

  The present invention has been made in view of the above points, and an exhaust flow rate capable of ensuring a stable opening / closing operation of a valve body by smoothly rolling a rolling element along a sliding portion. It aims at providing the sliding part structure of a control valve.

In order to achieve the above-mentioned object, the present invention is provided in an exhaust system that exhausts exhaust gas discharged from an internal combustion engine to the outside. In the sliding part structure of the exhaust flow control valve to be controlled, the valve body, a torsion coil spring for biasing the valve body disposed inside the valve body to a valve closed state, and the valve body are rotatable. A valve shaft that is pivotally supported by the valve body and rotates integrally with the valve body, a rolling element that is rotatably mounted on the movable end of the torsion coil spring, and one end side And a stay member that is fixed to the valve shaft and rotates integrally with the valve shaft. Are provided so as to make point contact with the sliding portion of the stay member at two locations. The features.
In this case, the rolling element is a sphere, and an engagement surface including two arc surfaces having a radius of curvature larger than the radius of the sphere and the same curvature radius may be formed on the sliding portion.

  According to the present invention, the one end of the stay member is provided with a sliding portion on which the rolling element rolls or slides, and the rolling element is in point contact with the sliding portion at two locations. Is provided. Therefore, in the present invention, component accuracy (dimensional accuracy) such as a torsion coil spring, a stay member having a sliding portion, a rolling element, etc. constituting a sliding portion structure, or a load (load) is applied by exhaust gas. Even if the contact angle between the rolling element pivotally attached to the movable end and the sliding portion changes due to deformation of the movable end of the torsion coil spring caused by the A uniform point contact state between the outer surface and the sliding portion (for example, an engagement surface including two arc surfaces) is obtained.

  As a result, in the present invention, uneven wear occurs on a part of the outer peripheral surface of the cylindrical roller that rolls along the sliding surface in the prior art, and smooth relative movement between the sliding surface and the roller occurs. Loss of thickness can be preferably avoided, and by smoothly rolling a rolling element (for example, a sphere) along a sliding portion (for example, an engagement surface including two arc surfaces), A stable opening and closing operation of the valve body can be ensured.

  In the present invention, the sliding part structure of the exhaust flow control valve capable of ensuring a stable opening / closing operation of the valve body can be obtained by smoothly rolling the rolling element along the sliding part. .

FIG. 3 is an exploded perspective view in which an exhaust flow control valve according to an embodiment of the present invention is incorporated in an exhaust system of an automobile engine and a cover member is removed from the exhaust flow control valve. (A) is a schematic perspective view of the exhaust flow control valve in which the cover member is omitted, and (b) is a longitudinal sectional view taken along line II-II in (a). (A) is the perspective view seen from the diagonal direction of the front side, (b) is the transparent perspective view seen from the diagonal direction of the rear side. It is a principal part disassembled perspective view which abbreviate | omitted the inner pipe | tube. It is a side perspective view which shows the positional relationship of a spring mechanism and a valve body. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. It is operation | movement explanatory drawing of the exhaust flow control valve which concerns on this embodiment, Comprising: (a) shows the valve closed state of a valve body, (b) and (c) have shown the valve open state of the valve body. . (A)-(d) is principal part sectional drawing which showed the contact state of the sliding part which concerns on this embodiment and a modification, and a spherical body, and the left figure toward each part figure is a normal contact state The right diagram in each drawing shows the contact state when the contact angle changes. It is explanatory drawing of the engaging surface which is formed in the sliding part which concerns on this embodiment, and makes a point contact with a spherical body. (A) is principal part sectional drawing which shows the contact state of the sliding part which concerns on a comparative example, and a roller, (b) is a contact state when the contact angle of the sliding part which concerns on a comparative example, and a roller changes. It is principal part sectional drawing which shows these.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is an exploded perspective view in which an exhaust flow control valve according to an embodiment of the present invention is incorporated in an exhaust system of an automobile engine, and a cover member is removed from the exhaust flow control valve.

  As shown in FIG. 1, the exhaust system 10 is connected to an exhaust port of an automobile engine (internal combustion engine) (not shown) and is provided so as to extend along the front-rear direction of the automobile 11. A first silencer 12, a pair of second silencers 14a and 14b, and a pair of third silencers 16a and 16b are disposed along the downstream side from the upstream side of the exhaust system 10, respectively. The third silencers 12, 14a, 14b, 16a, 16b are integrally connected via a plurality of pipe members. An exhaust flow control valve 30 according to an embodiment of the present invention is provided in front of the second silencers 14a and 14b and on the output side of the first silencer 12.

  In the present embodiment, the exhaust system 10 in which the exhaust flow control valve 30 is disposed between the first silencer 12 and the second silencers 14a and 14b is illustrated, but the present invention is not limited to this. The exhaust flow control valve 30 may be disposed at another part of the exhaust system 10.

  2A is a schematic perspective view of an exhaust flow control valve in which a cover member is omitted, FIG. 2B is a longitudinal sectional view taken along line II-II in FIG. 2A, and FIG. FIG. 3B is a perspective view seen from the front oblique direction, FIG. 3B is a perspective view seen from the rear oblique direction, FIG. 4 is an exploded perspective view of the main part with the inner tube omitted, and FIG. FIG. 6 is a side perspective view showing the positional relationship between the spring mechanism and the valve body, and FIG. 6 is a cross-sectional view taken along line VI-VI in FIG.

  As shown in FIG. 2, the exhaust flow control valve 30 has an inlet port 32a connected to the first silencer 12 and an outlet port 32b connected to a branched pipe member on the second silencer 14a, 14b side. An inner pipe (valve body) 34 to be formed, and a pair of cover members 36a and 36b (see FIG. 1) that are formed of a rectangular body formed in a pair of upper and lower parts and surround the inner pipe 34 are included.

  The inner tube 34 is formed of a substantially oval cylindrical body in which a through hole 38 is formed. The inner tube 34 is an intermediate portion of the inner tube 34 along the inlet port 32a and the outlet port 32b, and the inner tube 34 is perpendicular to the axis. Concave portions 40 that are recessed inward are formed on both sides.

  Further, as shown in FIG. 3, the inner pipe 34 includes a valve mechanism 44 having a valve body 42 for controlling the flow rate of exhaust gas introduced from the inlet port 32a and led out from the outlet port 32b, and the valve A spring mechanism 48 including a torsion coil spring (coil spring) 46 that urges the body 42 to the valve closed state, and an urging force (spring force) of the torsion coil spring 46 that urges the valve body 42 toward the valve closed state. ) Is transmitted to the valve body 42. The urging force (spring force) of the torsion coil spring 46 refers to a force that causes the valve body 42 to rotate in a direction in which the valve body 42 abuts against the stopper member 60 with a valve shaft 52 described later as a rotation fulcrum.

  The valve mechanism 44 extends in a direction orthogonal to the axis connecting the inlet port 32a and the outlet port 32b, and is pivotally supported through a pair of support holes so as to pass through both side portions of the inner tube 34. The shaft 52 and a valve body 42 made of a rectangular plate body as viewed from the axial direction of the inner pipe 34 (see FIG. 2B) and provided so as to be rotatable at a predetermined angle with the valve shaft 52 as a fulcrum, And a weight member 56 fixed to a portion in the vicinity of one long side of the rectangular valve body 42.

  In this case, the valve shaft 52 is provided with a connecting portion 52a that extends along the axial direction and is formed by cutting out a part of the outer periphery in a planar shape (FIG. 3B, FIG. 4, FIG. 6). The other long side vicinity part of the valve body 42 which consists of a rectangular-shaped board body is fixed to the valve shaft 52 via the screw member 58 by making the said connection part 52a into a mating surface. Further, an annular flange portion 52b that protrudes along the radially outward direction is provided on one end portion side of the valve shaft 52.

  Further, the valve mechanism 44 is composed of a member having a substantially L-shaped cross section fixed to the inner wall of the inner pipe 34, and a valve member 42 which comes into contact with the valve member 42 to be in a closed state. A buffer member 62 that cushions an impact when the body 42 abuts against the stopper member 60, and a metal that is provided on both sides of the valve shaft 52 and outside the inner tube 34, and rotatably supports the valve shaft 52. A bearing member 64 made of a mesh is provided, and a ring body 66 for preventing deformation of the bearing member 64 (see FIG. 6). When the valve body 42 is in the valve closed state in contact with the stopper member 60, it is formed by a gap 67 between the inner wall of the inner tube 34 and the outer surface of the valve body 42 as shown in FIG. The exhaust gas passage area is the most constricted (minimum area).

  Both end portions of the valve shaft 52 projecting outward from the inner tube 34, the torsion coil spring 46, and the like are disposed in a recess 40 that is recessed inwardly outside the inner tube 34 formed of a substantially elliptical cylindrical body. (See FIGS. 2 and 6). For this reason, even if the inner pipe 34 is covered with the pair of upper and lower cover members 36a and 36b, the torsion coil spring 46 and the like do not get in the way, and the exhaust flow control valve 30 in a state where the cover members 36a and 36b are mounted. The overall shape is configured in a substantially rectangular parallelepiped shape.

  As shown in FIG. 6, the spring mechanism 48 includes a torsion coil spring 46, and the torsion coil spring 46 includes a coil portion 46 a formed of a substantially cylindrical spiral body and a coil portion 46 a that is separated from the inner tube 34. A fixed side arm 46b which is provided on one side and extends in a direction substantially orthogonal to the axial direction of the coil part 46a and which is a fixed end; and the coil part provided on the other side of the coil part 46a adjacent to the inner tube 34 The movable arm 46c includes a movable end that extends in a direction substantially orthogonal to the axial direction of 46a.

  Further, the spring mechanism 48 is fixed to the outer wall of the intermediate portion along the axial direction of the inner tube 34 by welding or the like, and is fixed to the plate 68 having a rectangular shape when viewed from the side, and the torsion coil spring 46. A cylindrical support member 70 that supports the coil portion 46 a from the inner peripheral side and a bolt 71 that is screwed into a screw hole of the support member 70 are attached to the support member 70, and And a disc-shaped pressing plate 72 that prevents the torsion coil spring 46 from being detached. In the present embodiment, the shape of holding the coil portion 46a of the torsion coil spring 46 from the inner peripheral side is illustrated as the support member 70, but the shape is not limited to this, for example, the outer wall of the inner tube 34 The outer peripheral surface of the coil portion 46a may be gripped by a curved portion formed in a substantially Ω shape when viewed from the side.

  In this case, a portion of the support member 70 adjacent to the plate 68 is provided with a deformation absorbing portion 73 formed by cutting a part of the outer peripheral surface along the axial direction into a substantially arc shape in cross section. . When the deformation absorbing portion 73 tries to switch from the valve closed state (initial state) in which the valve body 42 contacts the stopper member 60 to the valve open state due to the pressure of the exhaust gas flowing through the inner pipe 34, A force (compression force) applied to the coil portion 46a of the torsion coil spring 46 through the movable arm 46c is absorbed.

  As shown in FIGS. 2 to 6, the biasing force transmission mechanism 50 is formed on one end side along the axial direction of the valve shaft 52 exposed to the outside from the inner tube 34, and from the fixed end of the torsion coil spring 46. An annular groove 74 to which the fixed arm 46b is locked, a C clip 76 attached to an annular step adjacent to the annular groove 74, and a folding of the movable arm 46c comprising the movable end of the torsion coil spring 46. It has a sphere 78 that is pivotally attached to the curved portion 46d and functions as a rotator, a sliding portion 80a on which the sphere 78 rolls or slides on one end, and a valve shaft on the other end. A fixing member 80b having a substantially arc-shaped cross section fixed to 52 is provided, and a stay member 80 that rotates integrally with the valve shaft 52 with the valve shaft 52 as a fulcrum is provided.

  As shown in FIG. 4, the movable side arm 46 c of the torsion coil spring 46 is substantially continuous with the straight line portion extending in a direction substantially orthogonal to the axis of the valve shaft 52 and parallel to the axis of the valve shaft 52. It has a bent portion 46d formed by bending in an L shape. On the sliding portion 80a of the stay member 80 on which the sphere 78 rolls, there are two arc surfaces ARC1 and ARC2 (which are larger than the radius R1 of the sphere 78 and have the same curvature radius R2 (R1 <R2)). Even if the engagement surface 81 including the later-described FIG. 9) is formed and the contact angle between the sphere 78 and the engagement surface 81 changes, the sphere 78 slides on the stay member 80. It is provided so as to make point contact with the engaging surface 81 of the portion 80a at two locations (contact points C1, C2). This will be described in detail later. A bending portion 80c that is curved in an arc shape and prevents the sphere 78 from being detached is provided at the tip of the stay member 80 that is continuous with the sliding portion 80a.

  The rolling element that rolls or slides along the sliding portion 80a (engagement surface 81) of the stay member 80 is preferably a sphere 78, but is not limited to the sphere 78, and the stay member 80 is not limited thereto. A non-spherical body may be used as long as it rolls or slides while making point contact with the sliding portion 80a (engagement surface 81) of the two. As shown in FIG. 6, a disc member 82 is fixed to the other end portion along the axial direction of the valve shaft 52 via a hole portion, and the disc member 82 supports the support hole of the inner tube 34. The valve shaft 52 is prevented from coming off.

  In this case, as shown in FIG. 6, a fixed side arm 46 b of the torsion coil spring 46 that is locked in the annular groove 74 of the valve shaft 52 and a fixed portion 80 b of the stay member 80 that is fixed to the valve shaft 52. A C clip 76 is interposed therebetween, and the C clip 76 functions as a partition wall, so that the non-contact state between the fixing portion 80b of the stay member 80 and the fixing side arm 46b of the torsion coil spring 46 is preferably maintained. Is done. As a result, even if the stationary arm 46 of the torsion coil spring 46 is locked by the annular groove 74 of the valve shaft 52, the smooth rotation operation of the stay member 80 that rotates integrally with the valve shaft 52 is achieved. Can be secured.

  The C clip 76 prevents the stationary arm 46 b of the torsion coil spring 46 locked in the annular groove 74 of the valve shaft 52 from moving toward the stay member 80 along the axial direction of the valve shaft 52. It also has a stopper function. Further, an annular flange portion 52b is interposed between the fixed portion 80b of the stay member 80 fixed to the valve shaft 52 and the bearing member 64, so that the stay member 80 and the inner portion adjacent to the stay member 80 are disposed. The side wall of the pipe 34 is brought into a non-contact state, and the smooth rotation operation of the stay member 80 can be ensured.

  The fixed side arm 46b of the torsion coil spring 46 extends linearly and engages the lower side of the annular groove 74 formed in the valve shaft 52, and the fixed side arm 46b of the torsion coil spring 46 has its spring force. To prevent displacement upward.

The exhaust system 10 in which the exhaust flow control valve 30 according to the present embodiment is incorporated is basically configured as described above. Next, the function and effect will be described.
FIG. 7 is an explanatory view of the operation of the exhaust flow control valve according to the present embodiment. FIG. 7 (a) shows the valve closed state of the valve body, and FIG. 7 (b) and FIG. The valve state of the valve body is shown.

  When an engine (not shown) is driven (operated), exhaust gas discharged from the engine is introduced into the exhaust system 10. After the exhaust gas flow rate is controlled through the first silencer 12 and the exhaust flow rate control valve 30, the exhaust gas is exhausted by the second silencer 14a, 14b and the third silencer 16a, 16b on the downstream side. The sound is muted and discharged to the outside.

  At this time, for example, when the engine rotation speed including idling operation and start operation is in a low speed region, the combustion pressure of the engine (combustion chamber) is low, and the exhaust pressure of the exhaust gas discharged from the engine also decreases. Therefore, the exhaust pressure of the exhaust gas introduced into the exhaust system 10 is also low.

  Therefore, as shown in FIG. 7A, the exhaust flow control valve 30 is held in the valve closed state in which the valve element 42 abuts against the stopper member 60 by the urging force (spring force) of the torsion coil spring 46. Therefore, the exhaust gas passage area formed by the gap 67 (see FIG. 2B) between the inner wall of the inner pipe 34 and the outer surface of the valve body 42 is the most constricted state (minimum area). As a result, the exhaust flow control valve 30 reduces the exhaust energy of the exhaust gas exhausted from the output side of the first silencer 12 and preliminarily silences the exhaust noise before the second silencers 14a and 14b. And the filling efficiency of the engine is increased.

  In other words, in the exhaust flow control valve 30 according to the present embodiment, even if the valve body 42 is biased to the closing side by the biasing force of the torsion coil spring 46, the exhaust passage of the inner pipe 34 is the valve. The exhaust gas having a reduced flow rate flows through a gap 67 formed between the inner wall of the inner pipe 34 and the outer surface of the valve body 42 without being completely sealed by the body 42.

  On the other hand, when the combustion state of the engine becomes a complete explosion state and the engine rotation speed reaches the high speed region, the combustion pressure of the engine (combustion chamber) increases and the exhaust pressure of the exhaust gas discharged from the engine also increases. Become. Therefore, the exhaust gas dynamic pressure introduced into the exhaust flow control valve 30 from the inlet port 32a in the exhaust system 10 also increases, and the force that presses the valve element 42 against the biasing force of the torsion coil spring 46 increases. As a result, the force that presses the valve body 42 overcomes the urging force of the torsion coil spring 46, whereby the valve body 42 rotates counterclockwise by a predetermined angle with the valve shaft 52 as a rotation fulcrum (FIG. 7 ( b), the valve body 42 is switched from the valve closed state in which the valve body 42 is in contact with the stopper member 60 to the valve open state in which the valve body 42 is tilted by a predetermined angle in a direction away from the stopper member 60.

  That is, when the valve body 42 is pressed by the pressing force of the exhaust gas dynamic pressure introduced from the inlet port 32a of the inner pipe 34, the valve body 42 is in the direction of arrow A (counterclockwise direction) with the valve shaft 52 as a fulcrum. The stay member 80 fixed to the valve shaft 52 integrally rotates in the direction of arrow A (counterclockwise direction) with the valve shaft 52 as a fulcrum. In this case, the sphere 78 pivotally supported by the bent portion 46d of the movable arm 46c of the torsion coil spring 46 has two points along the sliding portion 80a of the stay member 80, as shown in FIG. Move while touching and rolling. The fixed arm 46 b of the torsion coil spring 46 is held in a state of being locked in the annular groove 74 of the valve shaft 52.

  The valve body 42 is switched from the valve closed state to the valve open state, and the exhaust gas passage area of the exhaust gas flowing through the inner pipe 34 gradually increases. As shown in FIG. When is fully opened, the exhaust gas passage area becomes the maximum area. Therefore, the exhaust pressure loss when the engine speed is in the high speed region is reduced by appropriately controlling the exhaust gas flow rate by the exhaust flow rate control valve 30.

  8 (a) to 8 (d) are main part cross-sectional views showing the contact state between the sliding part and the sphere according to the present embodiment and the modified example, and the left figure in each part view is a normal one. The contact state is shown, and the right diagram in each drawing shows the contact state when the contact angle changes. Moreover, FIG. 9 is explanatory drawing of the engagement surface which is formed in the sliding part which concerns on this embodiment, and is a point contact with a spherical body, FIG.10 (a) is a contact state of the sliding part which concerns on a comparative example, and a roller. FIG. 10B is a main part sectional view showing a contact state when the contact angle between the sliding part and the roller according to the comparative example changes.

  As shown in FIG. 8A, in the present embodiment, a slidable portion 80a is provided on one end of the stay member 80 so that the sphere 78 can roll or slide. It is provided so as to make point contact with the part 80a at two locations (contact points C1, C2). In this case, as shown in FIG. 9, the sliding portion 80a of the stay member 80 has two arcuate surfaces ARC1 and arcs that are larger than the radius R1 of the sphere 78 and have the same radius of curvature R2 (R1 <R2). An engagement surface 81 including a surface ARC2 is formed, and the sphere 78 is in point contact with the two arcuate surfaces ARC1 and ARC2.

  8A to 8D is a cross section taken along the line VIII-VIII in FIG. 5, and the two arcuate surfaces ARC1 and ARC2 are spherical bodies. It is formed so as to extend along the rolling direction 78 (the axial direction of the sliding portion 80a).

  As shown in the right figure of FIG. 8A, even when the contact angle between the sphere 78 and the engagement surface 81 is changed (the bent portion 46d for axially attaching the sphere 78 is removed from the axis T1). When changing to the axis T2), the spherical body 78 has two locations (contact points C1, C2) with respect to the engagement surface 81 (two arc surfaces ARC1 and ARC2) of the sliding portion 80a of the stay member 80. Are provided so as to be in point contact with each other.

  In this embodiment, for example, the torsion coil spring 46, the stay member 80 having the sliding portion 80a, the component accuracy (dimensional accuracy) of the sphere 78, and the torsion coil spring 46 by applying a load (load) with exhaust gas. The contact angle between the spherical body 78 pivotally attached to the bent portion 46d of the movable arm 46c and the engagement surface 81 of the sliding portion 80a has changed due to the deformation of the bent angle of the bent portion 46d. Even in this case, a load is uniformly applied to the contact points C1 and C2 between the outer surface of the sphere 78 and the sliding portion 80a (engagement surface 81), and a stable point contact state is obtained.

  Therefore, in this embodiment, uneven wear occurs on a part of the outer peripheral surface of the cylindrical roller that rolls along the sliding surface in the prior art, or the relative movement between the sliding surface and the roller is smooth. Loss can be suitably avoided, and the spherical body 78 smoothly rolls along the engagement surface 81 of the sliding portion 80a, thereby ensuring a stable opening / closing operation of the valve body 42. it can.

  As a result, in the present embodiment, it is possible to prevent uneven wear of the sphere 78 functioning as a rolling element, improve the durability of the sphere 78, and reduce the uneven load caused by a dimensional error or the like. it can.

  On the other hand, as shown in FIG. 10, the sliding portion according to the comparative example has a cylindrical roller that is rotatably mounted on a hook portion of a torsion coil spring, and the cylindrical roller is a valve. It is comprised so that it may move along the flat sliding surface formed in the plate. In this case, in the comparative example, in the normal state, as shown in FIG. 10A, the spring force of the torsion coil spring is smoothly applied to the valve plate in a state where the outer peripheral surface of the roller and the sliding surface are in line contact. As shown in FIG. 10B, for example, the contact angle between the roller and the sliding surface has changed due to the dimensional accuracy (product accuracy) of the torsion coil spring or the roller. (When the roller axis is displaced from T1 to T2), an unbalanced load is applied to the sliding surface. As a result, in the comparative example, a part of the outer peripheral surface of the roller may be partially worn, and the opening / closing operation of a valve body (not shown) continuing to the valve plate may be unstable.

Next, based on FIGS. 8B to 8D, a modification of the present embodiment will be described below.
FIG. 8B shows a first modification of the sliding portion 80a (described as modification 1 in the figure), and includes two arc surfaces ARC1 and ARC2 having the same curvature radius R2. This embodiment is different from the present embodiment in which the mating surface 81 is formed in that the engaging surface 81 is configured by connecting a pair of adjacent flat inclined surfaces 81a in a substantially U-shaped cross section. The first modified example has an advantage that the engaging surface 81 can be easily manufactured.

  FIG. 8C shows a second modified example of the sliding portion 80a (denoted as modified example 2 in the drawing), and is a folding support for supporting the sphere 78 with respect to the first modified example. The difference is that a pair of bearing portions 83 is provided in the curved portion 46d. By providing the pair of bearing portions 83, it is possible to reduce rolling resistance when the sphere 78 rolls with the bent portion 46d as the rotation center.

  FIG. 8D shows a third modification of the sliding portion 80a (described as modification 3 in the figure), and is flat between a pair of inclined surfaces 81a that are in point contact with the sphere 78. This is different from the first modification in that the engagement surface 81 is configured with the surface 81b interposed. In the third modified example, by interposing the flat surface 81b between the contact point with the sphere 78, the separation distance between the contact points C1 and C2 can be set large, and the sphere 78 is further stabilized. 2 points can be supported.

10 Exhaust system 30 Exhaust flow control valve 34 Inner pipe (valve body)
42 Valve body 46 Torsion coil spring 46a Movable arm (movable end)
52 Valve shaft 78 Sphere (roller)
80 Stay member 80a Sliding part 81 Engaging surface ARC1, ARC2 Arc surface

Claims (2)

In a sliding part structure of an exhaust flow control valve that is provided in an exhaust system that exhausts exhaust gas discharged from an internal combustion engine to the outside and controls the flow rate of exhaust gas that flows through the exhaust passage by opening and closing the valve body,
A valve body;
A torsion coil spring that biases the valve body disposed inside the valve body to a valve closed state;
A valve shaft pivotally supported by the valve body, connected to the valve body and rotated integrally with the valve body;
A rolling element rotatably mounted on the movable end of the torsion coil spring;
A stay member that has a sliding portion on which the rolling element rolls or slides on one end side, and the other end portion of which is fixed to the valve shaft and rotates integrally with the valve shaft;
With
The sliding part structure of an exhaust flow control valve, wherein the rolling element is provided so as to make point contact with the sliding part of the stay member at two locations. The exhaust flow control valve according to claim 1,
The rolling element is a sphere, and the sliding portion is formed with an engagement surface including two arc surfaces that are larger than the radius of the sphere and have the same radius of curvature. The sliding part structure of the flow control valve.

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