JP2010261410A - Exhaust flow passage control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize an opening-closing characteristic of a valve element by reducing friction when opening-closing the valve element, in an exhaust flow passage control valve having the valve element for opening-closing an exhaust flow passage formed in a housing and a valve spring for energizing this valve element in the closing direction, and opening the exhaust flow passage when pressure of exhaust gas flowing in the exhaust flow passage exceeds a predetermined value. <P>SOLUTION: A guide shaft 47 extending in its axial direction is fixed to a diagonal position of the valve element 31, and a fitting hole 45 is arranged in the housing 30 for slidably fitting its guide shaft 47 in response to the guide shaft 47. An outer peripheral surface of the guide shaft 47 and an inner peripheral surface of the fitting hole 45, always come into point contact with each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust passage control valve provided in an exhaust passage through which exhaust gas from an engine for vehicles or the like flows, and in particular, reduces the friction during opening and closing movement of the valve body to stabilize the opening and closing characteristics of the valve body. It relates to what I did.

  Conventionally, in the exhaust passage control valve 10 (50), which is disposed in the exhaust passage through which the exhaust gas flows and opens when the pressure of the exhaust gas exceeds a predetermined value, the housing 30 (60) in which the exhaust passage is formed; The valve body 20 (70) for opening and closing the exhaust passage and the torsion coil spring 40 for urging the valve body 20 (70) in the valve closing direction are provided, and the valve body 20 (70) with respect to the housing 30 (60). (1) provided with a guide mechanism for guiding opening and closing movements is known (see Patent Document 1 below).

JP 2006-188974 A

  However, what is disclosed in Patent Document 1 is that the guide mechanism is such that the grooves 24a and 24b (74a and 74b) provided in the valve body 20 (70) are engaged with the guide portions 16a and 16b (62 and 66). Since the valve body 20 (70) is guided to move from the valve-closed state to the valve-open state, the grooves 24a and 24b (74a and 74b) and the guide portion are moved when the valve body 20 (70) is moved. 16a, 16b (62, 66) and surface contact or line contact, the friction during the movement of the valve body 20 (70) increases, the smooth and accurate movement of the valve body 20 (70) is hindered, There is a problem that the opening / closing characteristics (valve opening-valve opening load characteristics) are not stable.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a novel exhaust flow path control valve that ensures the smooth and accurate operation of the valve body and can solve the above problems. .

In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that an exhaust passage is formed by seating on a housing in which an exhaust passage through which exhaust gas from an engine flows is formed and a valve seat formed in the housing. The valve body that closes and floats from the valve seat to open the exhaust passage, the valve spring that biases the valve body toward the valve seat, and the position of the valve body in the plane direction perpendicular to the axis of the exhaust passage are regulated An exhaust passage control valve that opens the exhaust passage when the exhaust gas pressure exceeds a predetermined value and the valve body floats from the valve seat against the biasing force of the valve spring. Because
The valve body position regulating mechanism includes a plurality of guide shafts provided on one of the housing and the valve body so as to extend in the axial direction of the exhaust flow passage with a circumferential interval therebetween, and a housing. Provided on either one of the valve bodies corresponding to the plurality of guide shafts, and a plurality of fitting holes into which the plurality of guide shafts are slidably fitted, the guide shaft and the fitting holes Is characterized in that point contact fitting is always performed regardless of the relative position between the valve body and the housing.

  In order to achieve the above object, the invention according to claim 2 is the one according to claim 1, wherein the guide shaft is a straight body having a circular fitting section in the fitting hole, The fitting hole is characterized by a constriction hole having a drum-shaped cross section in which the inner diameter at the center in the axial direction is the smallest and the inner diameter is gradually increased symmetrically toward both ends in the axial direction.

  According to the invention described in the claims, the guide shaft and the fitting hole constituting the position regulating mechanism of the valve body always hit a point (point contact), and they contact a surface (surface contact) or a line contact. Since there is no (line contact), the friction (friction) when the valve body floats is reduced, and the opening / closing characteristics (valve opening-valve opening load characteristics) of the valve body are stabilized. Further, since the contact area between the guide shaft and the fitting hole is reduced, it is possible to reduce abnormal noise when the two contact each other.

Overall plan view of an exhaust system of a vehicle engine equipped with a silencer having an exhaust flow control valve Broken perspective view of the silencer shown in the arrow 2 in FIG. Sectional view of arrow 3 in FIG. Enlarged cross-sectional view along line 4-4 in FIG. Enlarged sectional view taken along line 5-5 in FIG. 3 is an enlarged cross-sectional view taken along line 6-6 in FIG. Sectional view along line 7-7 in FIG. Sectional view along line 8-8 in FIG. Sectional drawing which follows the 9-9 line of FIG. Perspective view of exhaust flow control valve

  Embodiments of the present invention will be described below based on the embodiments of the present invention shown in the accompanying drawings.

  In this embodiment, the exhaust passage control valve according to the present invention is applied to the exhaust system of a V-type engine for a vehicle. In the following description, front and rear, left and right, and top and bottom are based on the forward direction of the vehicle. Say.

  In FIG. 1, the vehicular engine generally indicated by the symbol E is a V-type multi-cylinder engine, and includes left and right banks BL and BR that form a pair, and the exhaust manifolds of these banks BL and BR include The first exhaust pipe P1 and the second exhaust pipe P2 are connected to each other. The first and second exhaust pipes P1 and P2 are separated from each other in the width direction of the vehicle body F and extend in the front-rear direction. The exhaust pipes P1 and P2 are primary in order from the upstream side to the downstream side. The catalyst CA1, the secondary catalyst CA2, and the auxiliary silencer (prechamber) PC are connected in series. The downstream ends of the first and second exhaust pipes P1, P2 are connected in parallel to the silencer M through joints J, J. The auxiliary silencers PC and PC are connected to each other to regulate the distance between them, and the downstream side of the auxiliary silencers PC and PC of the first and second exhaust pipes P1 and P2 is an elastic support member. The silencer M is suspended and supported by the vehicle body F via the other elastic support members S2 and S2 and is suspended and supported by the vehicle body F via S1 and S1.

  The exhaust gas discharged from the operation of the engine E is purified by the primary and secondary catalytic converters CA1 and CA2 to remove harmful components such as HC, CO and NOx, and then the auxiliary silencer. After being silently silenced through the PC, the sound is silenced by the silencer M and discharged to the outside.

  Next, the configuration of the silencer M will be described in detail with reference to FIGS.

  The silencer M is disposed in such a direction that its longitudinal center axis LL crosses the longitudinal direction of the vehicle body F, and the silencer body 1 that forms the main part of the silencer M and the exhaust gas from the engine E are silenced. A pair of left and right first exhaust gas introduction pipes 2L and second exhaust gas introduction pipes 2R that lead to the main body 1 and a pair of left and right exhausts that exhaust the exhaust gases in the expansion chambers 20, 21, and 21 of the silencer main body 1 to the outside. Exhaust gas discharge pipes 5 and 5 are provided.

  The silencer body 1 constitutes the housing of the silencer M, and includes a cylindrical shell 10 whose left and right end faces are open, a left end wall 11 that is airtightly fixed to the left opening end of the shell 10, and the shell. A right end wall 12 that is airtightly fixed to the right opening end of the right side wall and a cylindrical shape that is more hermetically sealed, and a sound deadening chamber is formed therein. The silencer body 1 is supported by the vehicle body F with its longitudinal center axis LL directed in the left-right direction.

  A pair of left and right inner separators 13, 13 each having a plurality of small holes 15 made of punching holes are fixed substantially parallel to the left and right end walls 11, 12 at the central portion in the longitudinal direction of the inner surface of the silencer body 1. An expansion chamber 20 is formed between the pair of inner separators 13 and 13. A pair of left and right outer separators 14 and 14 are fixed to the left and right end walls 11 and 12 in the longitudinal direction of the inner surface of the silencer body 1 so as to be substantially parallel to the left and right end walls 11 and 12. And expansion chambers 21 and 21 are formed between the inner separators 13 and 13 and the outer separators 14 and 14, and between the outer separator 14 and the left end wall 11 and between the outer separator 14 and the right end wall 12. The resonance chambers 21R are respectively formed.

  A pair of left and right first exhaust gas introduction pipes 2 </ b> L and a second exhaust gas introduction pipe 2 </ b> R are provided in the shell 10 so as to be biased closer to the left and right end walls 11, 12 than the longitudinal center of the sound deadening chamber body 1. Each is through-connected. The upstream end of the first exhaust gas introduction pipe 2L and the upstream end of the second exhaust gas introduction pipe 2R are connected to the downstream end of the first exhaust pipe P1 and the second exhaust pipe P2 outside the silencer body 1. The first exhaust gas introduction pipe 2L and the second exhaust gas introduction pipe 2R are connected to the downstream ends via joints J and J, respectively, in the expansion chambers 21 and 21 of the silencer main body 1. One branch pipe 3, 3 and the other branch pipe 4, 4 are bifurcated. One branch pipe 3, 3 extends toward the center in the silencer main body 1, and its downstream end is penetrated and supported by the central part of the inner separators 13, 13, and the central part of the expansion chamber 20, That is, the silencer body 1 is opened on the longitudinal center axis LL. As shown in FIGS. 2 and 3, the downstream end openings of the pair of left and right one branch pipes 3 and 3 are arranged to face each other with a space in the central portion in the expansion chamber 21. On the other hand, the pair of left and right other branch pipes 4, 4 extend in the silencer body 1 toward the left and right end walls 11, 12, respectively, and their downstream ends are biased in the radial direction of the outer separators 14, 14. And is communicated with an inlet of an exhaust passage control valve V described later.

  At a position that is spaced apart from the exhaust flow path control valve V and deviated in the radial direction, between the pair of left and right outer separators 14 and 14 and the left and right end walls 11 and 12, left and right that penetrate the resonance chamber 21R. A pair of exhaust gas discharge pipes 5 and 5 are respectively supported along the axial direction of the silencer main body 1, and the upstream ends of the exhaust gas discharge pipes 5 and 5 are expanded in a divergent shape so as to be inside and outside. Opened into the expansion chambers 21 and 21 between the separators 13, 13, 14, and 14, and tail pipes 23 and 23 that open to the outside are connected to the downstream ends thereof.

  The pair of left and right outer separators 14 and 14 are supported by a pair of communicating pipes 16 and 17, and these communicating pipes 16 and 17 resonate with the expansion chambers 21 and 21 between the inner and outer separators 13 and 14. The chamber 21R communicates with each other.

  The pair of left and right inner separators 13 and 13 and the pair of left and right outer separators 14 and 14 are respectively connected by a plurality of (three) connecting rods 18 that are fixed to their outer peripheral portions with a circumferential interval therebetween. Yes.

  An exhaust passage pipe 33 having an elliptical cross section is provided in the resonance chamber 21R so as to be cut off from the resonance chamber 21R. The exhaust passage pipe 33 is provided between the outer separator 14 and the left end wall 11 and between the outer separator 14 and the right end wall 12, and an upstream end opening thereof is an opening formed in the outer separator 14. 44 and connected to the downstream end opening of the other branch pipe 4, and the downstream end opening thereof is connected to the tail pipe 24. An exhaust passage control valve V is provided in the exhaust passage pipe 33.

  Next, the structure of the exhaust passage control valve V will be described mainly with reference to FIGS.

  The exhaust passage control valve V includes a housing 30 provided in the exhaust passage 35 in the exhaust passage pipe 33, a valve body 31 seated on the valve seat 30a of the housing 30, and the valve body 31 on the valve seat 30a side. A valve spring 32 made of a torsion coil spring that urges the valve body 31 and a position restricting mechanism A for the valve body 31 that restricts the position of the valve body 31 in the direction vv of the exhaust passage 34 perpendicular to the axis l-l. ing. The housing 30 is formed in a short cylindrical shape, and an exhaust passage 34 is formed therein, and an upstream end thereof is supported by the opening 44 of the outer separator 14 together with the exhaust passage pipe 33, and the other To the downstream end of the branch pipe 4. Further, the downstream end opening of the housing 30 faces the exhaust passage 35, and an outer flange 30b is integrally formed on the periphery thereof toward the outer side in the radial direction. An annular surface is formed on the outer surface of the outer flange 30b. A valve seat 30a is formed. An annular metal mesh sheet 37 is superimposed on the valve seat 30a. As shown in FIGS. 8 and 9, the metal mesh sheet 37 has an inner peripheral side half portion 37 a bent toward the inner peripheral surface of the housing 30 so that the metal mesh 37 is fixed to the housing 30. A fixing portion F2 is formed, and the fixing portion F2 is crimped to the inner peripheral surface of the housing 30 by a ring-shaped member 36 fixed to the inner peripheral surface of the housing 30. And since this ring-shaped member 36 covers the fixing | fixed part F2 from an inner side, the fixing | fixed part F2 is not directly exposed to the exhaust gas which flows through the inside of the housing 30. FIG.

  As shown in FIGS. 6, 7, and 10, a plurality of caulking pieces 30c are integrally formed on the outer periphery of the outer flange 30b at intervals in the circumferential direction, and these caulking pieces 30c. The metal mesh sheet 37 is crimped and fixed to the valve seat 30a by bending toward the outer peripheral surface of the sheet 37 and caulking there. The metal mesh sheet 37 has a fixing portion F1 crimped by the crimping piece 30c ... on the radially outer side of the outer peripheral surface thereof, and a seal portion on which the valve element 31 is seated on the radially inner side. S is formed.

  As shown in FIGS. 6, 8, and 10, a disc-like valve body 31 that opens and closes the opening is arranged opposite to the downstream end opening of the housing 30. In other words, the spring mounting member 38 is fixed to the central portion of the surface that does not face the exhaust gas flowing through the housing 30. The spring mounting member 38 is formed with a semi-cylindrical spring receiving portion 38a, and a valve spring 32 made of a torsion coil spring is interposed in a concave portion of the spring receiving portion 38a through a cushioning material 39 made of a metal mesh. Contained and supported. On the outer flange 30b of the housing 30, spring mounting tongues 30d, 30d that are paired at diagonal positions thereof are integrally formed upright in the axial direction, and these spring locking tongues 30d, 30d. The both ends 32a, 32a of the valve spring 32 are engaged with the locking holes 40, 40 respectively opened in the first and second openings. The elastic force of the valve spring 32 urges the valve body 31 to be seated on the valve seat 30a. As clearly shown in FIG. 10, a pair of upper and side spring retainers 38b and 38c are integrally formed on the upper and side portions of the spring receiving portion 38a, respectively. These spring retainers 38b and 38c are valve springs. 32 is prevented from moving outward and laterally.

  As shown in FIG. 8, a concave exhaust gas receiving portion 31a is formed at the front surface of the valve body 31, that is, at the center of the surface facing the exhaust gas flowing in the housing 30, toward the exhaust gas flow. Yes. Further, an annular raised portion 31b that protrudes toward the housing 30 is formed integrally with the exhaust gas receiving portion 31a on the outside of the exhaust gas receiving portion 31a on the inner surface of the valve body 31. The housing 30 and the valve body 31 are provided with a position regulation mechanism A for the pair of valve bodies 31 that regulates the position of the valve body 31 in the direction vv of the exhaust passage 34 perpendicular to the axis l-l. .

  Hereinafter, the structure of the position restriction mechanism A of the valve body 31 will be described mainly with reference to FIGS. 6, 9, and 10. In the diagonal position in the radial direction of the outer flange 30 b of the housing 30, A pair of projecting pieces 30f and 30f are integrally projected, and an insertion hole 41 is formed in each of the projecting pieces 30f and 30f. A bush 42 is fitted into the insertion hole 41. The flange 42a of the bush 42 is clamped and fixed by a projecting piece 30f and a clamping plate 43 fixed thereto. A specially shaped fitting hole 45 is formed in the bush 42. That is, as shown in FIG. 9, the fitting hole 45 has a drum-shaped cross section in which the inner diameter d of the center c in the axial direction is minimum and the inner diameter gradually increases symmetrically toward both ends in the axial direction. It is constituted by a constricted hole. A guide shaft 47, which will be described later, is passed through and fitted into the fitting hole 45 formed of the constricted hole.

  On the other hand, at the diagonal position in the radial direction of the valve body 31, mounting pieces 31c, 31c are formed integrally with the pair of protruding pieces 30f, and each mounting piece 31c has a housing. One end of a guide shaft 47 extending in the axial direction of 30 is fixed. This guide shaft 47 is a straight shaft having a circular cross section, and is slidably fitted into a fitting hole 45 made of a constricted hole. The guide shaft 47 and the fitting hole 45 are always spotted, that is, point-contacted regardless of their relative positions. A stopper 48 is fixed to the free end of the guide shaft 47, and this stopper 48 is engaged with the holding plate 43 to restrict the fully open state of the valve element 31. The position restricting mechanism A of the valve body 31 is a valve in a plane vv direction perpendicular to the axis l-l of the housing 30 so that the valve body 31 opens and closes in parallel on the axis of the housing 30. The position of the body 31 is regulated.

  Thus, the bush 42 is made of graphite (graphite) or SiC (silicon carbide), and more reliably generates abnormal noise when the guide shaft 47 hits the fitting hole 45, that is, when it makes point contact. In order to prevent the friction, when the guide shaft 47 is in point contact with the fitting hole 45, the guide shaft 47 or the fitting hole 45 may have a DLC ( A friction reducing material such as diamond-like carbon) may be coated.

  The exhaust passage control valve V has an inlet directly connected to the downstream opening of the other branch pipe 4, and an outlet connected to an exhaust passage pipe 33 provided in the resonance chamber 21R. Without going through, it opens directly to the outside. When the exhaust gas pressure in the first and second exhaust gas introduction pipes 2L, 2R is equal to or lower than a predetermined value, the valve body 31 closes the downstream opening of the other branch pipe 4 by the elastic force of the valve spring 32. When the other branch pipe 4 and the outside are maintained in a shut-off state, and the exhaust gas pressure in the first and second exhaust gas introduction pipes 2L and 2R exceeds a predetermined value, the valve body 31 is floated and opened against the resilient force of the valve spring 32, and the downstream opening of the other branch pipe 4 is opened to the outside through the exhaust passage pipe 33. At this time, the guide shaft 47 of the position restricting mechanism A of the valve body 31 slides with the valve body 31 while making point contact in the fitting hole 45 to reduce friction when the valve body 31 is lifted. To do. When the valve body 31 is fully opened, the stopper 48 engages with the clamping plate 43 fixed to the housing 30 to restrict the fully opened position.

  The downstream ends of the exhaust gas discharge pipes 5 and 5 and the downstream end of the exhaust passage 33 are communicated with tail pipes 23 and 24 connected to the left end plate 11 and the right end plate 12, respectively, and are opened to the outside. Further, a side branch (resonance silencer) 25 is connected to the tail pipe 23 (see FIG. 1).

  Next, the operation of this embodiment will be described.

  Now, according to the operation of the V-type engine E, the exhaust gas discharged from the left and right banks BL, BR flows through the first exhaust pipe P1 and the second exhaust pipe P2, and passes through the primary and secondary catalysts CA1, CA2, respectively. After flowing and purifying harmful components such as Nx, CO, and HC, they enter the prechambers PC and PC, where they are primarily silenced, and then pass through the first exhaust gas introduction pipe 2L and the second exhaust gas introduction pipe 2R. The sound is guided to the silencer M, and after being mainly silenced as described later, it is discharged to the outside.

  In the low speed operation region including the idling operation and the start operation of the engine E, the combustion pressure of the engine E is low and the pressure of the exhaust gas discharged from the engine E is also low. Therefore, the first exhaust gas introduction pipe 2L and the second exhaust gas Since the pressure of the exhaust gas flowing into the silencer body 1 from the introduction pipe 2R is weaker than the elastic force of the valve spring 32 of the exhaust flow path control valve V, the valve body 32 of the exhaust flow path control valve V is shown in FIG. , 9 as indicated by the solid line position, the exhaust passage 34 is kept closed by being seated on a valve seat 30a formed in the housing 30. Therefore, the exhaust gas introduced into the first and second exhaust gas introduction pipes 2L and 2R expands through the one of the left and right branch pipes 3 and 3 as shown by the solid line arrow a in FIG. The left and right inner separators 13 and 13 pass through the small holes 15 and then divert to the left and right expansion chambers 21 and 21. Through the exhaust gas discharge pipes 5 and 5. In this process, the exhaust sound of the exhaust gas is effectively silenced by the silencing effect due to expansion in the expansion chambers 20, 21, and 21 and the silencing effect due to resonance in the resonance chambers 21R and 21R.

  By the way, in the low-speed operation region of the engine E, the exhaust gas introduced into the first and second exhaust gas introduction pipes 2L and 2R passes through the one of the left and right branch pipes 3 and 3, and the expansion chamber 20 Since the amount of exhaust gas flowing into the expansion chamber 20 increases, the downstream end openings of the left and right branch pipes 3 and 3 face each other in the expansion chamber 20. Therefore, the amount of exhaust gas involved in interference increases as much as possible, and the amount of interference of exhaust gas also increases. As a result, the silencing effect based on the interference of exhaust gas is greatly enhanced.

  In particular, as shown in FIGS. 2 and 3, the downstream end opening of one branch pipe 3 of the first exhaust gas introduction pipe 2L and the downstream of one branch pipe 3 of the second exhaust gas introduction pipe 2R. The side end openings are on the longitudinal center axis LL of the silencer M main body, and are opposed to each other with a space at the center of the expansion chamber 20, so that the exhaust gas after interference is made. It can be expanded uniformly in the expansion chamber 20, and the silencing effect due to the expansion of the exhaust gas can be enhanced.

  On the other hand, when the combustion of the engine E reaches a complete explosion state and reaches the high-speed operation range, the combustion pressure increases, and when the pressure of the exhaust gas discharged from the engine E increases, the first exhaust gas introduction pipe 2L The pressure of the exhaust gas flowing into the second exhaust gas introduction pipe 2R also increases, and when this exceeds a predetermined value, the pressure of the exhaust gas flowing into the housing 30 is reduced by the valve spring 32 of the exhaust flow path control valve V. 8 and 9, the valve body 31 floats against the urging force of the valve spring 32, and the valve body 31 of the exhaust passage control valve V is opened. The

  At this time, the position restriction mechanism A of the valve body 31 restricts the position in the plane vv direction perpendicular to the axis line l-l of the valve body 31. That is, the pair of guide shafts 47 and 47 slide while being guided by the fitting holes 45 of the bush 42. At that time, since the guide shafts 47 and 47 and the fitting holes 45 and 45 are always in contact (point contact) as described above, the friction when the valve body 31 floats is reduced, and the valve The opening and closing of the body 31 is stabilized. Further, the contact area between the guide shafts 47 and 47 and the fitting holes 45 and 45 is reduced, and the abnormal noise generated when they slide in contact with each other is extremely small. When the exhaust flow control valves V, V are opened, most of the exhaust gas flowing into the first exhaust gas introduction pipe 2L and the second exhaust gas introduction pipe 2R is expanded into the expansion chambers 20, 21, 21. Without being routed through the other branch pipes 4 and 4, the exhaust flow path control valve V, and the exhaust flow path pipe 33, the exhaust gas is directly discharged to the outside, and the exhaust gas flow resistance is greatly reduced. .

  Further, since the exhaust gas receiving portion 31a formed in the valve body 31 faces the exhaust gas flowing in the housing 30, the pressure of the exhaust gas rises, the valve body 31 is opened, and the exhaust gas flows out. Sometimes, the resistance against the exhaust gas flow pressure (dynamic pressure) is increased to increase the force in the valve opening direction received by the valve body 31 by the exhaust gas flow. Therefore, the valve body 31 moves at a stroke from the start of the valve opening to the fully opened state, and the responsiveness of each exhaust flow path control valve V is enhanced.

  The first and second exhaust gas introduction pipes 2L and 2R pass through the shell 10 between the left and right end walls 11 and 12, and are connected to the silencer main body 1. The exhaust gas introduction pipes 2L and 2R Since the other branch pipes 4 and 4 on the side where the exhaust flow control valves V and V are provided open directly from the left and right end walls 11 and 12 to the outside of the silencer body 1, the exhaust flow control valves V and V When the valve is opened, the pipe length until the exhaust gas in the first and second exhaust gas introduction pipes 2L and 2R reaches the external opening of the silencer body 1 via the other branch pipes 4 and 4 is short. Thus, the flow resistance of the exhaust gas can be reduced, and further, the flow resistance to the external opening when the exhaust flow control valves V and V are opened reduces the flow resistance of the exhaust flow control valves V and V. When the valve is opened, the other branch pipes 4, 4 are connected without passing through the expansion chambers 20, 21, 21. As a result, the amount of exhaust gas discharged directly from the external opening increases, and flows into the expansion chambers 20, 21, and 21 via one branch pipes 3, 3 that do not have the exhaust flow control valves V, V. Since the amount of exhaust gas is reduced, an increase in the flow resistance due to the exhaust gas being discharged via the expansion chambers 20, 21, 21 can be greatly reduced. As a result, as a whole, the flow resistance of the exhaust gas flowing through the silencer body 1 can be reduced as much as possible, thereby enhancing the output improvement effect of the engine.

  As mentioned above, although the Example of this invention was described, this invention is not limited to the Example, A various Example is possible within the scope of the present invention.

  For example, in the above-described embodiment, the case where the silencer M of the present invention is implemented in the exhaust system of the V-type engine E for vehicles has been described, but it can be applied to the exhaust system of engines for other purposes such as general purpose. It is.

  In the embodiment, the guide shaft 47 is fixed to the valve body 31 and the fitting hole 45 is provided in the housing 30. However, the guide shaft 47 is fixed to the housing 45 and the fitting hole 45 is formed in the valve body 31. In the embodiment, a pair of the position restriction mechanisms A of the valve body 31 are provided at diagonal positions in the radial direction of the housing 30 and the valve body 31. Three or more may be provided at intervals in the direction.

30 ... Housing 30a ... Valve seat 31 ... Valve body 32 ... Valve spring 34 ... Exhaust flow path 45 ... Fitting hole 47 ... Guide shaft A・ ・ ・ ・ ・ Valve position regulating mechanism E ・ ・ ・ ・ ・ Engine

Claims (2)

A housing (30) having an exhaust passage (34) through which exhaust gas from the engine (E) flows;
A valve body (31) that closes the exhaust passage (34) by sitting on a valve seat (30a) formed in the housing (30) and opens the exhaust passage (34) by floating from the valve seat (30a). )When,
A valve spring (32) for urging the valve body (31) toward the valve seat (30a);
A position restricting mechanism (A) for the valve element (31) for restricting the position of the valve element (31) in the surface direction perpendicular to the axis of the exhaust passage (34);
When the pressure of the exhaust gas exceeds a predetermined value, the valve body (31) floats from the valve seat (31a) against the urging force of the valve spring (32) and opens the exhaust passage (34). A valve,
The position restricting mechanism (A) of the valve body (31) is provided in either the housing (30) or the valve body (31) in the axial direction of the exhaust passage (34) with an interval in the circumferential direction. A plurality of guide shafts (47) provided to extend, and provided on either the other of the housing (30) and the valve body (31) in correspondence with the plurality of guide shafts (47). The guide shaft (47) includes a plurality of fitting holes (45) into which the guide shaft (47) is slidably fitted. The guide shaft (47) and the fitting hole (45) include a valve body (31) and a housing ( 30) An exhaust flow path control valve characterized in that point contact fitting is always performed regardless of the relative position to 30).   The guide shaft (47) is a straight body having a circular fitting section in the fitting hole (45), while the fitting hole (45) has a minimum inner diameter at the center in the axial direction. 2. The exhaust flow path control valve according to claim 1, wherein the exhaust flow path control valve is a constriction hole having a drum-shaped cross section whose inner diameter gradually increases symmetrically toward both ends in the axial direction.

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