JP4670819B2 - Exhaust system valve structure - Google Patents

Description

  The present invention relates to an exhaust system valve structure applied to an exhaust system for exhausting exhaust gas from, for example, an automobile.

In an automobile exhaust silencer with a valve that switches the exhaust flow path in response to the exhaust pressure, the apparent spring constant of the return spring that urges the valve in the closing direction is set to a predetermined value. What is made to reduce when exceeding is known (for example, refer patent document 1).
JP-A-8-109815

  However, in the conventional technology as described above, since the valve is held in the closed position mainly by the urging force of the return spring, the spring constant of the return spring is large, so that the strength of the return spring is ensured and high-temperature exhaust gas is discharged. In order to prevent settling (permanent deformation) due to exposure, there was a problem that a large return push ring had to be used.

  In view of the above fact, an object of the present invention is to obtain an exhaust system valve structure that can reduce the urging force of the urging means.

  The exhaust system valve structure according to the first aspect of the present invention is a tubular member that forms a flow path of exhaust gas, and a valve seat provided in the tubular member to close the flow path, A valve body that opens away from the valve seat portion by the pressure of exhaust gas, and a biasing means that imparts a biasing force to the valve body to bias the valve body toward the closing posture; In a separate predetermined opening range in which the opening of the flow path by the valve body is equal to or less than a predetermined opening, than the opening range in which the opening of the flow path by the valve body exceeds the predetermined opening, And a frictional force applying means for increasing the frictional force generated when the valve body is driven.

  In the exhaust system valve structure according to the first aspect, when the pressure of the exhaust gas is low, the valve body comes into contact with the valve seat portion by the biasing force of the biasing means, and the exhaust gas flow path is closed. The biasing means may use, for example, a restoring force of an elastic member such as a spring, or may have a structure (arrangement) that presses the valve body against the valve seat portion using gravity. When the pressure of the exhaust gas increases, the valve body moves away from the valve seat against the urging force of the urging means, and the exhaust gas flow path is opened at an opening degree corresponding to the pressure (flow rate) of the exhaust gas. The

  Along with this operation, a frictional force by the frictional force applying means acts on the valve body. That is, the valve body receives a frictional resistance in a predetermined opening range (part or all of the opening range of the predetermined opening or less) within the opening range of the predetermined opening or less. Thereby, in the initial region where the valve body is moved to the open side of the flow path, the resistance of the operation of the valve body due to the pressure of the exhaust gas can be increased, and the urging force of the urging means can be reduced. Further, since the frictional force becomes relatively small when the opening degree of the flow path by the valve body exceeds a predetermined opening degree, the valve body can be driven to a position where the required opening degree is obtained by the pressure of the exhaust gas.

  Thus, in the exhaust system valve structure according to claim 1, the urging force of the urging means can be reduced. In addition, it is sufficient that the predetermined opening range is within a range below the predetermined opening, and it may coincide with the entire range below the predetermined opening.

  An exhaust system valve structure according to a second aspect of the present invention is the exhaust system valve structure according to the first aspect of the present invention, wherein the valve body is rotated about a rotation axis to change the opening degree of the flow path. The frictional force applying means is supported between the rotating shaft and the cylindrical member, or between the valve body and the rotating shaft. Is provided.

  In the exhaust system valve structure according to the second aspect, a frictional force is generated with a relative angular displacement between the rotating shaft and the valve body or the cylindrical member. For example, in a configuration in which the rotation shaft rotates integrally with the valve body, a frictional force is generated between the support portion of the rotation shaft and the rotation shaft (supported portion of the valve body) in the cylindrical member. In the configuration in which the body is rotatably supported by the rotation shaft, a frictional force is generated between the supported portion by the rotation shaft of the valve body and the rotation shaft (tubular member). Thus, the frictional force applying means generates a frictional force between the supported portion (guided portion) of the valve body that contacts and separates from the valve seat portion and the cylindrical member, and thus can be configured compactly. .

  An exhaust system valve structure according to a third aspect of the present invention is the exhaust system valve structure according to the second aspect, wherein the opening of the flow path by the valve body is equal to or less than a predetermined opening degree. In addition, in a predetermined opening range, friction caused by driving the valve body by bringing a bearing provided on the cylindrical member or the valve body and the rotating shaft supported by the bearing in contact in the thrust direction. It is designed to generate power.

  In the exhaust system valve structure according to claim 3, for example, a bearing provided on the cylindrical member and a rotation shaft (supported portion of the valve body) abut in the thrust direction to generate a frictional force accompanying a relative angular displacement, Further, for example, a bearing provided on the valve body and a rotating shaft (cylindrical member) abut on each other in the thrust direction, and a frictional force accompanying relative angular displacement is generated. For this reason, in this exhaust system valve structure, the state with a large frictional force and the state with a small frictional force can be switched according to the relative position of the bearing and the rotating shaft in the thrust direction.

  The exhaust system valve structure according to a fourth aspect of the present invention is the exhaust system valve structure according to the third aspect, wherein the frictional force applying means is provided on the cylindrical member and supports the rotating shaft at least in a radial direction. One end in the circumferential direction from the other end of the bearing in the axial direction end face and the facing portion that protrudes from the rotating shaft and supports the rotating shaft at least in the radial direction. Is provided on the other of the stepped portion formed so as to protrude in the thrust direction, the axial end surface of the bearing and the opposed portion of the rotating shaft, and the opening degree of the flow path by the valve body is a predetermined opening degree. A contact portion that contacts a range on one side in the circumferential direction with respect to the stepped portion of the end surface of the bearing or the facing portion of the rotating shaft in at least a part of a predetermined opening range that is the following. Has been.

  In the exhaust system valve structure according to claim 4, the one where the stepped portion is formed in the end face of the bearing or the opposed portion of the rotating shaft has a rotating shaft on one side in the circumferential direction with the stepped portion as a boundary in the thrust direction. Close to the contact portion, the other side in the circumferential direction is separated from the contact portion of the rotating shaft. Then, in at least a part of the predetermined opening range where the opening degree of the flow path by the valve body is equal to or less than the predetermined opening degree, the contact part provided on the end face of the bearing or the opposing part of the rotating shaft is opposed. Since the abutting portion is in contact with one side in the circumferential direction with respect to the stepped portion on the bearing portion or the bearing end surface, for example, the contact opening portion is larger than the opening range in which the other end in the circumferential direction with respect to the stepped portion on the bearing end surface or the facing portion A frictional force is obtained.

  The exhaust system valve structure according to a fifth aspect of the present invention is the exhaust system valve structure according to the fourth aspect, wherein at least a part of the stepped portion in the circumferential direction has a predetermined opening degree of the flow path by the valve body. It is set as the inclined surface which can contact | abut the said contact part in at least one part of the separately predetermined opening range which is below this opening degree.

  In the exhaust system valve structure according to the fifth aspect, the frictional force is gradually reduced in an opening range in which the contact portion passes (slids) in the opening direction while the contact portion contacts the stepped portion which is an inclined surface. That is, a sudden change in the frictional force is prevented. Further, when the valve body returns from the opening range exceeding the predetermined opening to the closing side, interference between the stepped portion and the contact portion is prevented.

  An exhaust system valve structure according to a sixth aspect of the present invention is the exhaust system valve structure according to the third aspect, wherein the frictional force applying means is provided so as to rotate integrally with the valve. Displacement direction converting means for moving in the thrust direction with rotation about its own axis, and a bearing provided on the cylindrical member for supporting the rotation shaft at least in the radial direction, The rotating shaft is configured to include a contacted portion in which the rotation shaft contacts in the thrust direction in a separately predetermined opening range where the opening of the flow path is equal to or less than the predetermined opening.

  In the exhaust system valve structure according to the sixth aspect, when the valve body is rotated around the rotation shaft by the exhaust pressure (variation thereof), the rotation shaft is displaced in the thrust direction by the displacement direction converting means. Then, in a separate predetermined opening range where the opening of the flow path by the valve body is equal to or less than the predetermined opening, the rotating shaft is in contact with the contacted portion of the bearing. A friction force larger than the opening range in which the rotating shaft is separated can be obtained.

  An exhaust system valve structure according to a seventh aspect of the present invention is the exhaust system valve structure according to the sixth aspect, wherein the displacement direction converting means is one of an outer peripheral surface of the rotating shaft and an inner peripheral surface of the bearing. And a projection that protrudes from the other of the outer peripheral surface of the rotating shaft and the inner peripheral surface of the bearing and enters the cam groove.

  In the exhaust system valve structure according to the seventh aspect, since the displacement direction converting means is constituted by the cam groove provided on one of the rotating shaft and the bearing and the projection provided on the other, the structure is simple. The rotating shaft can be displaced in the thrust direction.

  An exhaust system valve structure according to an eighth aspect of the present invention is the exhaust system valve structure according to any one of the first to seventh aspects, wherein the frictional force applying means is configured to open the flow path by the valve body. In the range where the degree is equal to or less than the predetermined opening, the separately predetermined opening range does not include an opening degree that fully closes the flow path by the valve body, and an opening that fully closes the flow path by the valve body. The frictional force generated when the valve body is driven is smaller than the separate predetermined opening range in the opening range from the degree to the lower limit of the separately predetermined opening range. Yes.

  In the exhaust system valve structure according to claim 8, the valve body has a small frictional force from the position where the flow path is closed to the lower limit of the predetermined opening range, and the frictional force is large in the separate predetermined opening range. The frictional force is reduced in the opening range exceeding the upper limit of the predetermined opening range (which may separately coincide with the upper limit of the predetermined opening range). Since the frictional force (static friction) is reduced at the closed position (opening degree 0) of the flow path by the valve body, sticking between the valve body and the cylindrical member (rotating shaft and bearing) is easily prevented.

  The exhaust system valve structure according to the ninth aspect of the invention closes the flow path by contacting a tubular member that forms an exhaust gas flow path and an annular valve seat provided in the tubular member. A valve body that is spaced apart from the valve seat portion by the pressure of the exhaust gas and opens the flow path; a biasing means that generates a biasing force for biasing the valve body toward the closed posture; and the valve body The one side is provided on the cylindrical member side and the other side is provided on the valve body side so that the one and the other slide by the opening / closing operation of the flow path by the heating, and heated by the exhaust gas. And a frictional force applying means that separates each other in a direction intersecting the sliding direction due to a difference in thermal expansion.

  In the exhaust system valve structure according to claim 9, when the temperature of the exhaust system is low, for example, immediately after starting the internal combustion engine, when the valve body is driven by the pressure of the exhaust gas, one and the other of the frictional force applying means Slides and generates a large frictional force. On the other hand, when the temperature of the exhaust system rises due to the heating by the exhaust gas, one of the frictional force applying means and the other are separated by the difference in thermal expansion between each other, and the frictional force does not act between them. Thus, chattering can be suppressed by the frictional force applying means without relying on the urging force of the urging means at a low temperature of the exhaust system in which chattering is likely to occur between the valve body and the valve seat portion. Therefore, the urging force of the urging means can be reduced. On the other hand, when the exhaust system is at a high temperature, it is possible to reduce the frictional force accompanying the operation of the valve body and ensure the required valve opening.

  Thus, in the exhaust system valve structure according to the ninth aspect, the urging force of the urging means can be reduced. Moreover, the frictional force applying means can be configured without providing a movable part.

  An exhaust system valve structure according to a tenth aspect of the present invention is the exhaust system valve structure according to the ninth aspect, wherein the valve body is rotated about a rotation axis to change the opening degree of the flow path. The frictional force applying means is supported between the rotating shaft and the cylindrical member, or between the valve body and the rotating shaft. Is provided.

  In the exhaust system valve structure according to the tenth aspect, a frictional force is generated along with the relative angular displacement between the rotating shaft and the valve body or the cylindrical member. For example, in a configuration in which the rotation shaft rotates integrally with the valve body, a frictional force is generated between the support portion of the rotation shaft and the rotation shaft (supported portion of the valve body) in the cylindrical member. In the configuration in which the body is rotatably supported by the rotation shaft, a frictional force is generated between the supported portion by the rotation shaft of the valve body and the rotation shaft (tubular member). Thus, the frictional force applying means generates a frictional force between the supported portion (guided portion) of the valve body that contacts and separates from the valve seat portion and the cylindrical member, and thus can be configured compactly. .

  An exhaust system valve structure according to an eleventh aspect of the present invention is the exhaust system valve structure according to the tenth aspect, wherein the frictional force applying means is a bearing provided on the rotating shaft and the cylindrical member or the valve body. Are brought into contact with each other in the thrust direction to generate a frictional force accompanying the driving of the valve body.

  In the exhaust system valve structure according to the eleventh aspect, the rotating shaft expands and contracts in the axial direction according to temperature (the amount of expansion and contraction in the longitudinal direction becomes the largest), and extends in the axial direction to become a bearing. Separated in the thrust direction. For this reason, in this exhaust system valve structure, it is possible to create a relatively large relative displacement without providing a movable part, and to switch between a state where the frictional force is large and a state where the frictional force is small.

  As described above, the exhaust system valve structure according to the present invention has an excellent effect that the urging force of the urging means can be reduced.

  An exhaust system valve device 10 to which an exhaust system valve structure according to a first embodiment of the present invention is applied will be described with reference to FIGS. 1 to 3. In the following description, when the terms upstream and downstream are simply used, they indicate upstream and downstream in the flow direction of the exhaust gas.

  FIG. 2 shows the overall configuration of the exhaust system valve device 10 in a plane cross-sectional (side cross-sectional) view. As shown in this figure, the exhaust system valve device 10 includes, as main components, an exhaust pipe 12 as a cylindrical member and a valve 14 as a valve body for opening and closing one side opening end of the exhaust pipe 12. . The exhaust pipe 12 constitutes an exhaust gas passage 16 for exhausting exhaust gas generated by an automobile engine (internal combustion engine). The exhaust pipe 12 may be the exhaust pipe itself or a separate member (valve body) attached to the exhaust pipe.

  A valve seat 18 as a valve seat portion is formed in an annular shape on the periphery of the open end 12 </ b> A of the exhaust pipe 12. In this embodiment, the valve seat 18 is formed in a tapered shape (conical shape) in which the diameter of the open end 12A of the exhaust pipe 12 is increased toward the downstream side. The valve 14 has a disc-shaped valve main body 14A corresponding to the inner diameter of the exhaust pipe 12, and an annular seal portion 14B formed on the peripheral edge of the valve main body 14A. The seal portion 14B is formed in a taper shape corresponding to the valve seat 18, and makes contact (surface contact) with the valve seat 18 over a substantially entire surface in a fully closed posture for closing the exhaust gas flow path 16 of the exhaust pipe 12. It is configured.

  Further, the valve 14 is formed with an extending portion 14C extending in a radial direction from a part in the circumferential direction of the seal portion 14B, and the rotating shaft 20 is fixedly provided on the extending portion 14C. ing. The rotating shaft 20 is formed in a cylindrical shape that is long in the axial direction, and is supported rotatably with respect to the exhaust pipe 12. Specifically, as shown in FIG. 1, the rotary shaft 20 is rotatably supported by bearings 22 and 24 that are different at both ends in the longitudinal direction. As shown in FIG. 2, the bearings 22 and 24 are The exhaust pipe 12 is fixedly supported via the bracket 26.

  In addition, as shown in FIG. 2, the exhaust system valve device 10 includes an urging means for urging the valve 14 toward the closing posture and a return spring 28 as an urging member. In this embodiment, the return spring 28 is a torsion coil spring in which one end portion 28A is locked to the bracket 26 and the other end portion 28B is locked to the valve 14, and an intermediate annular portion 28C includes The rotating shaft 20 is inserted.

  In the exhaust system valve device 10 described above, when the pressure of the exhaust gas is small, the valve 14 is held in the fully closed position by the urging force of the return spring 28, and when the pressure of the exhaust gas rises, the valve 14 is returned to the return spring 28. The exhaust gas passage 16 of the exhaust pipe 12 is opened by rotating in the direction of the arrow R around the rotation shaft 20 against the urging force. As shown in FIG. 2, the valve 14 is configured to open the exhaust gas passage 16 by rotating in the direction of arrow R around the rotation shaft 20 from the fully closed posture. The valve 14 can be rotated about the rotation shaft 20 at least until the valve 14 is fully opened as shown by an imaginary line in FIG.

  As shown in FIG. 1, the exhaust system valve device 10 includes a friction force applying structure 30 as a friction force applying means. The frictional force imparting structure 30 includes a frictional force adjusting surface 32 formed on an end surface of the one bearing 24 on the bearing 22 side in the axial direction, and a contact provided on the rotary shaft 20 toward the frictional force adjusting surface 32. And a projection 34 as a part. In this embodiment, the protrusion 34 is provided on a disc-like flange 36 projecting radially outward from the outer periphery of the rotating shaft 20 so as to protrude toward the friction force adjusting surface 32. In this embodiment, the bearing 22 supports the rotating shaft 20 in the radial direction and the thrust direction, and the bearing 24 supports the rotating shaft 20 only in the radial direction.

  The frictional force adjusting surface 32 is formed with a stepped portion 32A at a predetermined portion in the circumferential direction, and one side in the circumferential direction with respect to the stepped portion 32A is a high friction side sliding surface 32B that protrudes most in the axial direction. Further, the portion of the frictional force adjusting surface 32 opposite to the stepped portion 32A in the circumferential direction opposite to the high friction side sliding surface 32B has the smallest amount of protrusion in the axial direction (the amount of protrusion is zero). 32C. In this embodiment, the stepped portion 32A is an inclined surface that is inclined so as to continuously reduce the protruding amount from the high friction side sliding surface 32B toward the low friction side end surface 32C.

  In the exhaust system valve device 10, when the valve 14 is in the fully closed position, the protrusion 34 comes into contact with the high friction side sliding surface 32B. In this embodiment, the protrusion 34 is configured to abut on the high friction side sliding surface 32 </ b> B in a state compressed in the axial direction of the rotation shaft 20 (an interference fit state). A thrust force (mainly elastic restoring force) acting on the protrusion 34 becomes a frictional drag force of friction accompanying the sliding between the protrusion 34 and the high friction side sliding surface 32B.

  Further, in the exhaust system valve device 10, when the valve 14 is rotated by a predetermined angle in the arrow R direction (reached to a predetermined opening), the relative angular position (range) of the protrusion 34 with respect to the frictional force adjusting surface 32 is the step portion 32A. It comes to become. This predetermined angle is an angle (for example, 5 °) that is sufficiently smaller than the rotation angle (for example, 45 °) when the valve 14 reaches the fully open position. Further, the protrusion 34 comes into contact with a part on the high friction side sliding surface 32B side in the circumferential direction of the stepped portion 32A in a compressed state (an interference fit state) in the axial direction (thrust) direction. Yes. When the valve 14 further rotates in the arrow R direction, the relative angular position of the protrusion 34 with respect to the friction force adjusting surface 32 becomes the low friction side end surface 32C. In this embodiment, the protrusion 34 is configured to be in non-contact with the low friction side end face 32C.

  As shown in FIG. 3, in the exhaust system valve device 10, the friction force is large and substantially constant in the opening range A of the valve 14 in which the protrusion 34 is in contact with the high friction side sliding surface 32 </ b> B. In the opening range B of the valve 14 in contact with the stepped portion 32A, the frictional force gradually decreases, and in the opening range C of the valve 14 in which the protrusion 34 is not in contact with the frictional force adjusting surface 32, the frictional force is small. And it is almost constant. In the opening range C, the generated frictional force is mainly the frictional force between the inner periphery of the bearings 22 and 24 and the outer periphery of the rotating shaft 20.

  In the exhaust system valve device 10 described above, in the exhaust system, for example, the exhaust system path in the muffler (silencer) is switched, or the DC exhaust path is simply opened and closed (exhaust gas is circulated at a predetermined flow rate or higher). ), Switching between a plurality of catalyst devices and bypass passages, or switching between exhaust heat recovery and bypass in a configuration in which an exhaust heat recovery device is provided in parallel to the exhaust system.

  Next, the operation of the first embodiment will be described.

  In the exhaust system valve device 10 configured as described above, when the pressure of the exhaust gas is low, the valve 14 is closed by the urging force of the return spring 28, so that the exhaust gas passage 16 formed in the exhaust pipe 12 is closed. It is closed. When the pressure of the exhaust gas rises, the valve 14 rotates in the arrow R direction against the urging force of the return spring 28 and the frictional force between the rotating shaft 20 and the bearings 22 and 24. As a result, the exhaust gas passage 16 (open end 12 </ b> A of the exhaust pipe 12) is opened, and the exhaust gas flows through the exhaust gas passage 16.

  Here, in the exhaust system valve device 10, the valve 14 is fully closed to a minute predetermined opening (in this embodiment, an opening corresponding to a rotation angle of approximately 5 °, which is generally considered to cause chattering). In the opening range A, the protrusion 34 and the high friction side sliding surface 32B of the rotation shaft 20 are in contact with each other, so that a large amount of friction is caused by the rotation of the valve 14 in the direction of the arrow R and in the direction opposite to the arrow R. Force acts. Since this frictional force acts as a damping force (frictional damping) against the vibration movement in the opening / closing direction of the valve 14 with respect to the exhaust pipe 12, occurrence of abnormal noise (chattering) due to resonance vibration of the valve 14 is suppressed or prevented. . That is, since the damping ratio is large, the amplitude of the valve 14 is suppressed, and the contact between the seal portion 14B and the valve seat 18 is suppressed or prevented. This effect has been confirmed experimentally.

  Thereby, in the exhaust system valve device 10 including the frictional force applying structure 30, chattering can be prevented without increasing the biasing force based on the spring constant of the return spring 28, that is, the restoring force of the return spring 28. Since the return spring 28 has a small spring constant, demands on strength and durability (sag resistance) are alleviated, and the return spring 28 can be made compact. For example, in the case of the return spring 28 that is a torsion coil spring, the number of turns of the annular portion 28C can be reduced, or the wire diameter can be reduced.

  On the other hand, in the opening range C, the protrusion 34 and the friction force adjusting surface 32 (low friction side end surface 32C) are not in contact with each other, and the friction between the rotating shaft 20 and the bearings 22 and 24 is reduced. The opening degree of the valve 14 is increased with respect to this pressure, and the back pressure of the exhaust system is reduced. In particular, when the spring constant of the return spring 28 is reduced as described above, the opening degree of the valve 14 can be further increased and the back pressure of the exhaust system can be further reduced.

  As described above, the exhaust system valve device 10 can achieve both prevention of chattering (abnormal noise) and reduction of back pressure.

  Further, in the exhaust system valve device 10, since a large frictional force acts in the opening range A of the valve 14 by the friction force applying structure 30 as described above, the flow rate of the exhaust gas is within a range in which the opening range A is maintained. If it is the same, the opening degree of the valve 14 becomes small. Thereby, the effect which the silence volume of exhaust sound increases can be acquired.

  Further, in the exhaust system valve device 10, since the stepped portion 32 </ b> A of the frictional force adjusting surface 32 is an inclined surface, when the valve 14 shifts from the opening range C to the opening range A, the protrusion 34 has a stepped portion. It is guided to 32A and reliably returns to the contact state with the high friction side sliding surface 32B. That is, the catch (interference) between the step portion 32A and the protrusion 34 is prevented. Moreover, in the exhaust system valve device 10, the frictional force between the rotating shaft 20 and the bearings 22 and 24 gradually changes due to the stepped portion 32A being an inclined surface. For this reason, the vibrational behavior such as the transient response to the step input is prevented like the structure in which the frictional force changes suddenly.

  In the exhaust system valve device 10, the friction force applying structure 30 is configured by the protrusion 34 provided on the disk-like flange 36 of the rotating shaft 20 and the friction force adjusting surface 32 provided on the bearing 24. The above-described effects such as reduction of the urging force of the return spring 28 and prevention of chattering can be obtained with a simple structure.

  In the exhaust system valve device 10, the example in which the step portion 32A is set outside the range of about 5 ° in the rotation angle that is likely to cause the above chattering is shown, but the present invention is not limited to this. Alternatively, at least a part of the stepped portion 32A that is an inclined surface (a range in which the projection 34 abuts) may be set within a range of approximately 5 ° (within a range of a predetermined opening or less in the present invention). In this case, the frictional force according to the opening degree of the valve 14 can be adjusted by the inclination angle of the stepped portion 32A.

  Further, in the exhaust system valve device 10, the example in which the protrusion 34 as the contact portion is provided on the rotating shaft 20 and the friction force adjusting surface 32 having the stepped portion 32A is formed on the bearing 24 is shown. For example, the frictional force adjusting surface 32 may be provided on the disc-shaped flange 36 of the rotating shaft 20, and the protrusion 34 may be protruded from the end surface of the bearing 24.

  Next, another embodiment of the present invention will be described. Note that parts and portions that are basically the same as those in the first embodiment or the previous configuration are denoted by the same reference numerals as those in the first embodiment or the previous configuration, and the description thereof is omitted. May be omitted.

(Second Embodiment)
The principal part of the exhaust system valve device 40 which concerns on the 2nd implementation type | system | group of this invention is shown by FIG. 4 with the front view corresponding to FIG. As shown in this figure, the exhaust system valve device 40 moves in the axial direction from the position indicated by the solid line to the position indicated by the imaginary line so that the friction is made according to the opening range of the valve 14. The exhaust system valve device 10 according to the first embodiment is different from the exhaust system valve device 10 in that a frictional force imparting structure 42 for different forces is provided. This will be specifically described below.

  The frictional force imparting structure 42 constituting the exhaust system valve device 40 includes a rotational shaft 44 that does not have the protrusion 34 and the flange 36 instead of the rotational shaft 20, and replaces the bearing 24 with the frictional force adjustment surface 32. A bearing 46 that does not have the A protrusion (contactor) 48 protrudes from the inner peripheral surface of the bearing 46, and a cam groove 50 into which the protrusion 48 is inserted is formed on the outer peripheral surface of the rotating shaft 44.

  The cam groove 50 is formed so as to maintain the state in which the protrusion 48 enters in the entire range from the fully closed position to the fully open position of the valve 14 along the circumferential direction of the rotating shaft 44. The cam groove 50 is a high friction cam in which the projection 48 enters the opening range A of the valve 14 and is the farthest away from the end surface 44A on the bearing 22 side of the rotating shaft 44 in the axial direction of the rotating shaft 44. The portion where the projection 48 enters in the opening range C of the valve 14 is the low friction cam portion 50B closest to the end surface 44A of the rotating shaft 44 in the axial direction of the rotating shaft 44. The portion where the projection 48 enters in the opening range B of the valve 14 (which may include a part of the opening range C) smoothens the high friction cam portion 50A and the low friction cam portion 50B. It is set as the continuous switching cam part 50C.

  In the frictional force imparting structure 42, as shown by the solid line in FIG. 4, the end surface 44 </ b> A of the rotation shaft 44 is in contact with the contacted portion of the bearing 22 in a state where the protrusion 48 is inserted into the high friction cam portion 50 </ b> A. It contacts the thrust receiving surface 22A. In this state, the rotation shaft 44 is slightly compressed in the axial direction. Further, in the frictional force imparting structure 42, as shown by an imaginary line in FIG. 4, the end surface 44 </ b> A of the rotating shaft 44 is the thrust receiving surface of the bearing 22 in a state where the protrusion 48 is inserted into the low friction cam portion 50 </ b> B. It is separated from 22A (not contacted). Further, in a state where the protrusion 48 enters a part (on the high friction cam portion 50A side) of the switching cam portion 50C until the rotation shaft 44 is released from the compressed state described above, the rotation shaft 44 Contact between the end surface 44A and the thrust receiving surface 22A of the bearing 22 is maintained.

  Therefore, in the exhaust system valve device 40, as shown in FIG. 3, in the opening range A of the valve 14 where the projection 48 enters the high friction cam portion 50A, the frictional force is large and substantially constant, and the projection 48 In the opening range B of the valve 14 that has entered a portion of the switching cam portion 50C on the high friction cam portion 50A side, the frictional force gradually decreases, and the valve 14 in which the protrusion 48 has entered the low friction cam portion 50B. In the opening range C, the frictional force is small and substantially constant. In the opening range C, the generated frictional force is mainly the frictional force between the inner periphery of the bearing 22 and the bearing 46 and the outer periphery of the rotating shaft 20 and the frictional force between the protrusion 48 and the cam groove 50.

  In the present embodiment, the projection 48 and the cam groove 50 constitute a displacement direction conversion means for converting the direction of rotation of the valve 14 in the direction of arrow R or the direction opposite to the arrow R into the direction of movement of the rotation shaft 44 in the axial direction. is doing. Other configurations of the exhaust system valve device 40 are the same as the corresponding configurations of the exhaust system valve device 10, including portions not shown.

  Therefore, in the exhaust system valve device 40 according to the second embodiment, the same effect can be obtained by basically the same operation as the exhaust system valve device 10 according to the first embodiment.

(Third embodiment)
The principal part of the exhaust system valve | bulb apparatus 55 which concerns on FIG. 5 at the 3rd implementation type | system | group of this invention is shown with the front view corresponding to FIG. As shown in this figure, the exhaust system valve device 40 includes a bearing 58 in which a flange 56 extending in the radial direction from the rotating shaft 44 is provided in place of the bearing 22 in the opening range A of the valve 14. The exhaust system valve device 40 according to the second embodiment is different from the exhaust system valve device 40 according to the second embodiment in that a frictional force imparting structure 58 is configured in contact with the end surface 56A.

  Other configurations of the exhaust system valve device 55 are the same as those of the exhaust system valve device 40 (exhaust system valve device 10) according to the second embodiment, including a portion not shown.

  Therefore, the exhaust system valve device 40 according to the second embodiment can obtain the same effect by basically the same operation as the exhaust system valve device 40 according to the second embodiment.

  In the second and third embodiments, the example in which the protrusions 48 are provided on the bearing 46 and the cam grooves 50 are provided on the rotation shaft 44 to configure the frictional force applying structures 42 and 58 has been described. The present invention is not limited to this. For example, the cam groove 50 may be formed on the inner peripheral surface of the bearing 46, and the protrusion 48 may protrude from the outer peripheral surface of the rotating shaft 44.

  In the second and third embodiments, the cam groove 50 is elongated along the circumferential direction of the rotating shaft 44 and the projection 48 is short in the circumferential direction. For example, the protrusion 48 is formed along the circumferential direction on the outer periphery of the rotation shaft 44 or the inner periphery of the bearing 46, and a short cam groove that extends in the axial direction of the long protrusion 48 in the circumferential direction is formed on the bearing 46. May be provided on the inner periphery of the rotating shaft 44 or on the outer periphery of the rotating shaft 44.

(Fourth embodiment)
The principal part of the exhaust system valve | bulb apparatus 60 which concerns on the 4th implementation type | system | group of this invention is shown by the front view corresponding to FIG. As shown in this figure, the exhaust system valve device 60 has a frictional force adjusting surface 62 having two step portions 62A and 62B formed on the end surface of the bearing 24 in place of the frictional force adjusting surface 32. The exhaust system valve device 10 according to the first embodiment is different from the exhaust system valve device 10 in that the provision structure 64 is provided.

  The frictional force adjusting surface 62 is formed with a stepped portion 62A at a predetermined portion in the circumferential direction, and one side in the circumferential direction with respect to the stepped portion 62A is a high friction side sliding surface 62C that protrudes most in the axial direction. Further, the portion of the friction force adjustment surface 62 opposite to the stepped portion 62A in the circumferential direction opposite to the high friction side sliding surface 62C has the smallest axial projection amount (the projection amount is zero) and the low friction side end surface. 62D. In this embodiment, the stepped portion 62A is an inclined surface that is inclined so as to continuously reduce the protrusion amount from the high friction side sliding surface 62C toward the low friction side end surface 62D.

  Further, the stepped portion 62B is formed on the opposite side in the circumferential direction to the stepped portion 62A side with respect to the high friction side sliding surface 62C. A portion opposite to the high friction side sliding surface 62C in the circumferential direction with respect to the stepped portion 62B is a low friction side end surface 62E having a smaller amount of protrusion in the axial direction than the high friction side sliding surface 62C. In this embodiment, the low friction side end surface 62E has the same amount of protrusion toward the protrusion 34 as the low friction side end surface 62D (the amount of protrusion is 0).

  In the frictional force imparting structure 64 of the exhaust system valve device 40, when the valve 14 is in the fully closed posture, the protrusion 34 faces the vicinity of the stepped portion 62B on the low friction side end surface 62E. In the frictional force imparting structure 64, when the valve 14 is slightly rotated in the direction of the arrow R, the protrusion 34 comes into contact with the stepped portion 62B, and is guided by the stepped portion 62B to be in contact with the high friction side sliding surface 62C. It is set as the structure which leads to. In this embodiment, the rotation angle until the protrusion 34 comes into contact with the high friction side sliding surface 62C is set to approximately 1 °.

  Further, in this embodiment, the opening range of the valve 14, the stepped portion 62A (upper limit of the high friction side sliding surface 62C), and the setting range of the low friction side end surface 62D are the exhaust system valve device 10 (friction force applying structure 30). The opening degree of the valve 14 and the setting range of the step portion 32A and the low friction side end face 62D are set to be the same. That is, in the frictional force imparting structure 64, the high friction side sliding surface 62C is formed corresponding to the range in which the rotation angle of the valve 14 is approximately 1 ° to approximately 5 °.

  Therefore, as shown in FIG. 8, in the exhaust system valve device 60, the opening range A is more fully closed than the opening range A of the valve 14 in which the protrusion 34 is in contact with the high friction side sliding surface 62C. An opening range D in which a frictional force smaller than the frictional force is generated is set. In this opening range D, that is, a minute opening corresponding to a rotation angle of 1 ° or less, the frictional force is small at a part of the fully closed side compared with the frictional force in the opening range A, and the projection 34 The frictional force gradually increases with sliding with the stepped portion 62B (a part thereof). The above opening range is shown in a side sectional view of the exhaust system valve device 60 as shown in FIG.

  Other configurations of the exhaust system valve device 60 are the same as the corresponding configurations of the exhaust system valve device 10.

  Therefore, in the exhaust system valve device 60 according to the fourth embodiment, basically the same effect can be obtained by the same operation as the exhaust system valve device 10. Further, in the exhaust system valve device 60, since the frictional force is small with a small opening degree of the valve 14 of 1 ° or less, in this embodiment, the frictional force adjusting surfaces 62 and 34 are not in contact with each other in the fully closed state. Therefore, the bearing 24 and the rotating shaft 20 are prevented from sticking. That is, these countermeasures for sticking can be made unnecessary.

  On the other hand, at a minute opening corresponding to a rotation angle of 1 ° or less, the generation of noise is suppressed even when the seal portion 14B comes into contact with the valve seat 18, and the frictional force increases when the opening exceeds the opening. Therefore, chattering suppression or prevention performance is not deteriorated.

(Fifth embodiment)
FIG. 9 shows a main part of an exhaust system valve device 70 according to the fifth embodiment of the present invention in a front view corresponding to FIG. As shown in this figure, the exhaust system valve device 70 has a structure similar to the frictional force applying structure 42 instead of the frictional force applying structure 64 of the exhaust system valve device 40 having a structure similar to the frictional force applying structure 30. It differs from 60 which concerns on 4th Embodiment by the point comprised so that the relationship between the opening degree shown in FIG.

  The frictional force imparting structure 72 is configured by forming a cam groove 74 into which the protrusion 48 enters the outer peripheral portion of the rotating shaft 44. The cam groove 74 includes a high friction cam portion 50A, a low friction cam portion 50B, a high friction cam portion 74A corresponding to the switching cam portion 50C, a low friction cam portion 74B, and a switching cam portion 74C. Low friction cam portion 74D formed on the fully closed side with respect to cam portion 74A, and switching cam portion 74E smoothly connecting low friction cam portion 74D and high friction cam portion 74A. Yes.

  In the frictional force imparting structure 72, the region where the projection 48 enters the low friction cam portion 74D is such that the end surface 44A of the rotating shaft 44 is spaced apart from the thrust receiving surface 22A of the bearing 22 in the axial direction. The opening range D is such that the frictional force is smaller than the opening range A entering the friction cam portion 74A. Therefore, the relationship between the opening degree and the frictional force shown in FIG. 8 can be obtained by the exhaust system valve device 70 provided with the frictional force imparting structure 72.

  Other configurations of the exhaust system valve device 70 are the same as the corresponding configurations of the exhaust system valve device 60.

  Therefore, in the exhaust system valve device 70 according to the fifth embodiment, basically the same effect can be obtained by the same operation as the exhaust system valve device 60. Further, in the exhaust system valve device 60, since the frictional force is small with a very small opening corresponding to the rotation angle of the valve 14 of 1 ° or less, in this embodiment, the end surface 44A of the rotation shaft 44 and the bearing are fully closed. Since the thrust receiving surface 22A of 22 is not in contact, the bearing 24 and the rotating shaft 20 are prevented from sticking to each other. That is, these countermeasures for sticking can be made unnecessary.

(Sixth embodiment)
FIG. 10 shows a main part of an exhaust system valve device 80 according to the sixth embodiment of the present invention in a front view corresponding to FIG. As shown in this figure, the exhaust system valve device 80 is different from the exhaust system valve device 10 according to the first embodiment in that a friction force generation structure 82 is provided instead of the friction force application structure 30.

  The frictional force generating structure 82 is provided in the radial direction from the rotary shaft 84 to the bearings 86 and 88 that support the rotary shaft 84 provided in the radial direction instead of the rotary shaft 20. A pair of flanges 90 extending outward are slidably brought into contact with each other. Here, each flange 90 is in contact with the end surfaces 86A and 88A on the end side in the longitudinal direction of the rotation shaft 84 of the corresponding bearings 86 and 88 at normal temperature.

  Thereby, in the exhaust system valve device 80 provided with the frictional force generating structure 82, when the exhaust gas flows through the exhaust gas passage 16 and the temperature of each part rises, the rotating shaft 84 thermally expands in the axial direction, and this heat The amount of expansion is larger than the amount of thermal expansion of the bracket 26 in the direction in which the bearings 86 and 88 are separated. Therefore, in the exhaust system valve device 80, the flange 90 is separated from the end surfaces 86A and 88A of the bearings 86 and 88 in the axial direction due to a difference in thermal expansion between the rotating shaft 84 and the bracket 26 (exhaust pipe 12). Yes.

  In the exhaust system valve device 80 described above, at normal temperature, as shown in FIG. 11A, each flange 90 is connected to the end face 86A of the bearings 86, 88 as the valve 14 rotates in the direction of the arrow R. , 88A, a larger frictional force is generated as compared with the case where it does not slide. On the other hand, when the temperature is high, as shown in FIG. 11B, the flange 90 is axially separated from the end faces 86A and 88A of the bearings 86 and 88, so that frictional force is generated along with the friction between the flange 90 and the bearings 86 and 88. Is not generated, and the frictional force associated with driving the valve 14 is reduced as compared with normal temperature. Other configurations of the exhaust system valve device 80 are the same as the corresponding configurations of the exhaust system valve device 10 including a portion not shown.

  Next, the operation of the sixth embodiment will be described.

  In the exhaust system valve device 80 configured as described above, when the pressure of the exhaust gas is low, the valve 14 is closed by the urging force of the return spring 28 so that the exhaust gas passage 16 formed in the exhaust pipe 12 is closed. It is closed. When the pressure of the exhaust gas rises, the valve 14 rotates in the arrow R direction against the urging force of the return spring 28 and the frictional force between the rotating shaft 20 and the bearings 22 and 24. As a result, the exhaust gas passage 16 (open end 12 </ b> A of the exhaust pipe 12) is opened, and the exhaust gas flows through the exhaust gas passage 16.

  Here, in the exhaust system valve device 10, when the temperature of the exhaust system is low, for example, immediately after the engine is started, the flange 90 of the frictional force generating structure 82 is in contact with the end faces 86A, 88A of the bearings 86, 88. A large frictional force acts with the opening / closing operation of the valve 14. For this reason, the exhaust pulsation is likely to be unstable (it is easy to grow into a shock wave) immediately after the start of the engine, a large frictional damping can be applied, and the generation of abnormal noise (chattering) due to the resonance vibration of the valve 14 is suppressed or Is prevented. That is, since the damping ratio is large, the amplitude of the valve 14 is suppressed, and the contact between the seal portion 14B and the valve seat 18 is suppressed or prevented. This effect has been confirmed experimentally.

  As a result, the exhaust system valve device 10 having the frictional force generating structure 82 prevents chattering that is likely to occur immediately after the engine is started without increasing the biasing force based on the spring constant of the return spring 28, that is, the restoring force of the return spring 28. can do. Since the return spring 28 has a small spring constant, demands on strength and durability (sag resistance) are alleviated, and the return spring 28 can be made compact. For example, in the case of the return spring 28 that is a torsion coil spring, the number of turns of the annular portion 28C can be reduced, or the wire diameter can be reduced.

  On the other hand, after the temperature of the exhaust system rises (after completion of engine warm-up), the exhaust pulsation is stable and chattering is difficult to occur, and the flange 90 is separated from the bearings 86 and 88 and the friction accompanying the opening / closing operation of the valve 14 occurs. Even if the force is reduced, chattering does not become a problem. And since the frictional force accompanying the opening / closing operation | movement of the valve 14 is reduced, the opening degree of the valve 14 becomes large with respect to the pressure of exhaust gas, and reduction of the back pressure of an exhaust system is achieved. In particular, when the spring constant of the return spring 28 is reduced as described above, the opening degree of the valve 14 can be further increased and the back pressure of the exhaust system can be further reduced.

  In each of the above-described embodiments, the frictional force imparting structures 30, 42, 58, 64, 72, 82 are the rotation shafts 20, 44, 84 (projections 34, flange 90) and the bearings 24, 22, 86, 88. However, the present invention is not limited to this, and the frictional force generated by the opening / closing operation of the valve 14 in any part on the valve 14 side and any part on the exhaust pipe 12 side is shown. May be generated.

  Further, in each of the above-described embodiments, the rotation shafts 20, 44, 84 are provided so as to rotate integrally with the valve 14, and the rotation shafts 20, 44, 84 are supported by the bracket 26, In the example shown in FIGS. 22, 86, and 88, the exhaust pipe 12 is rotatably supported. However, the present invention is not limited to this, and for example, the rotary shaft 20 or the like is fixed to the exhaust pipe 12 side. In addition, the valve 14 is rotatably supported with respect to the exhaust pipe 12 by inserting the rotating shaft 20 through a bearing 22 (which may be a simple support hole) provided in the extending portion 14C. Also good. Further, the valve 14 is not limited to a configuration that rotates around the rotation shaft 20 to open and close the exhaust gas passage 16.

  Further, in each of the fourth and fifth embodiments, the protrusion 34 and the frictional force adjusting surface 32 are separated from each other when the valve 14 is fully closed, or the end surface 44A of the rotating shaft 44 and the thrust receiving surface 22A of the bearing 22 are separated. However, the present invention is not limited to this, for example, by providing a wire mesh or lubricating means at these contact portions. You may make it prevent sticking. As the lubricating means, for example, a solid lubricant such as expanded graphite in which a wire mesh is embedded can be used. By using a solid lubricant, it is possible to reduce sliding noise as compared with the case of using only a wire mesh.

It is a front view which shows the principal part of the exhaust system valve | bulb apparatus which concerns on the 1st Embodiment of this invention. 1 is a side sectional view of an exhaust system valve device according to a first embodiment of the present invention. It is a diagram which shows the relationship between the valve opening degree and frictional force of the exhaust valve apparatus which concerns on the 1st Embodiment of this invention. It is a front view which shows the principal part of the exhaust system valve | bulb apparatus which concerns on the 2nd Embodiment of this invention. It is a front view which shows the principal part of the exhaust system valve | bulb apparatus which concerns on the 3rd Embodiment of this invention. It is a front view which shows the principal part of the exhaust system valve | bulb apparatus which concerns on the 4th Embodiment of this invention. It is a sectional side view of the exhaust system valve | bulb apparatus which concerns on the 4th Embodiment of this invention. It is a diagram which shows the relationship between the valve opening degree and frictional force of the exhaust valve apparatus which concerns on the 4th Embodiment of this invention. It is a front view which shows the principal part of the exhaust system valve | bulb apparatus which concerns on the 5th Embodiment of this invention. It is a front view which shows the principal part of the exhaust system valve | bulb apparatus which concerns on the 6th Embodiment of this invention. It is a figure which shows the low temperature friction force generation | occurrence | production structure which comprises the exhaust system valve | bulb apparatus which concerns on the 6th Embodiment of this invention, Comprising: (A) is a front view which shows the state at normal temperature, (B) is at the time of high temperature It is a front view which shows a state.

Explanation of symbols

10 Exhaust system valve device (exhaust valve device)
12 Exhaust pipe (tubular member)
14 Valve (Valve)
16 Exhaust gas flow path (flow path)
18 Valve seat (valve seat)
20 Rotating shaft 22 Bearing 22A Thrust receiving surface (contacted part)
24 Bearing 28 Return spring (biasing means)
30 Friction force applying structure (friction force applying means)
32 Friction force adjustment surface (end surface of bearing)
32A Step part 34 Projection (contact part)
40, 55, 60, 70, 80 Exhaust valve device (exhaust valve device)
42, 58, 64, 72, 82 Friction force application structure (friction force application means)
44/84 Rotating shaft 46/56/86 Bearing 48 Protrusion (displacement direction conversion means)
50 Cam groove (displacement direction conversion means)
62 Friction force adjustment surface (end surface of bearing)
62A Stepped portion 74 Cam groove 84 Rotating shaft

Claims (11)

A cylindrical member that forms a flow path for exhaust gas;
A valve body that abuts on a valve seat provided in the tubular member to close the flow path, and is separated from the valve seat by the pressure of the exhaust gas to open the flow path;
A biasing means for imparting a biasing force to the valve body for biasing the valve body toward the closing posture;
In a separate predetermined opening range in which the opening of the flow path by the valve body is equal to or less than a predetermined opening, than the opening range in which the opening of the flow path by the valve body exceeds the predetermined opening, Frictional force applying means for increasing the frictional force generated when the valve body is driven;
Exhaust system valve structure with The valve body is supported by the cylindrical member via the rotation shaft so as to rotate around the rotation shaft and change the opening of the flow path.
The exhaust system valve structure according to claim 1, wherein the frictional force applying means is provided between the rotating shaft and the cylindrical member, or between the valve body and the rotating shaft.   The frictional force applying means includes a bearing provided on the cylindrical member or the valve body and a bearing in the predetermined opening range in which the opening of the flow path by the valve body is equal to or less than a predetermined opening. The exhaust system valve structure according to claim 2, wherein a frictional force accompanying the driving of the valve body is generated by bringing the supported rotating shaft into contact in the thrust direction. The frictional force applying means is
An axial end surface of a bearing provided on the cylindrical member and supporting the rotating shaft at least in the radial direction; and an axial end surface of a bearing protruding from the rotating shaft and supporting the rotating shaft at least in the radial direction; A stepped portion formed so that one of the circumferential sides protrudes in the thrust direction more than the other side in any one of the opposed portions,
Provided on the other of the axial end face of the bearing and the opposed portion of the rotating shaft, and at least a part of a predetermined opening range where the opening of the flow path by the valve body is a predetermined opening or less, An abutting portion that abuts a range on one side in the circumferential direction with respect to the stepped portion at the end surface of the bearing or the facing portion of the rotating shaft;
The exhaust system valve structure according to claim 3, comprising:   The stepped portion is in contact with the abutting portion at least in a circumferential direction at least in a part of a predetermined opening range in which the opening degree of the flow path by the valve body is equal to or less than a predetermined opening degree. The exhaust system valve structure according to claim 4, wherein the exhaust system valve structure is an obtained inclined surface. The frictional force applying means is
A displacement direction conversion means for moving the rotation shaft provided to rotate integrally with the valve in a thrust direction along with rotation about the own axis;
In a separate predetermined opening range in which the opening of the flow path by the valve body is not more than a predetermined opening, provided in a bearing that is provided in the tubular member and supports the rotating shaft at least in a radial direction, A to-be-contacted portion with which the rotation shaft contacts in the thrust direction;
The exhaust system valve structure according to claim 3, comprising:   The displacement direction converting means includes a cam groove formed on one of the outer peripheral surface of the rotating shaft and the inner peripheral surface of the bearing, and the other of the outer peripheral surface of the rotating shaft and the inner peripheral surface of the bearing. The exhaust system valve structure according to claim 6, wherein the exhaust system valve structure includes a protrusion protruding into the cam groove.   The frictional force applying means includes an opening degree at which the predetermined opening degree range in which the opening degree of the flow path by the valve body is equal to or less than a predetermined opening degree fully closes the flow path by the valve body. In addition, the valve body is driven more than the separately predetermined opening range in the opening range from the fully opening degree of the flow path by the valve body to the lower limit of the separately predetermined opening range. The exhaust system valve structure according to any one of claims 1 to 7, wherein the exhaust system valve structure is configured to reduce a frictional force generated along with the above. A cylindrical member that forms a flow path for exhaust gas;
A valve body that abuts an annular valve seat provided in the tubular member to close the flow path, and that is separated from the valve seat part by the pressure of the exhaust gas and opens the flow path;
A biasing means for generating a biasing force for biasing the valve body toward the closing posture;
The one is provided on the cylindrical member side and the other is provided on the valve body side so that the one and the other slide by the opening and closing operation of the flow path by the valve body, and the exhaust Friction force applying means that are separated from each other in a direction intersecting the sliding direction due to a difference in thermal expansion when heated by gas;
Exhaust system valve structure with The valve body is supported by the cylindrical member via the rotation shaft so as to rotate around the rotation shaft and change the opening of the flow path.
The exhaust system valve structure according to claim 9, wherein the frictional force applying means is provided between the rotating shaft and the cylindrical member or between the valve body and the rotating shaft.   The frictional force applying means generates a frictional force accompanying the driving of the valve body by bringing the rotating shaft and a bearing provided on the tubular member or the valve body into contact in the thrust direction. The exhaust system valve structure according to claim 10.

Images