JP2013167192A - Exhaust gas flow control valve for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas flow control valve for an engine which can reduce valve-closing torque applied to the valve plate of a valve spring in accordance with increase of opening degree of the valve plate and moreover, lessens friction of the valve spring and can stabilize opening and closing characteristics of the valve plate.SOLUTION: A valve spring 24 is constituted of a torsion coil spring which includes a coil part 24a and first and second arms 24b, 24c extended from the coil part 24a and exhibits elastic repulsion force in a direction of increasing a setting angle δ between the first and second arms 24b, 24c, the coil part 24a is borne by a valve plate 23 so as to apply valve closing torque to the valve plate 23 by virtue of the elastic repulsion force, at the same time, the first arm 24b is locked to the valve plate 23, and the second arm 24c is connected with a tip end part of a link 25 which is offset to the valve hole 22 side rather than a first fulcrum 29 and is supported turnably at a second fulcrum 30 on a valve seat plate 21 so as to be relatively turnable.

Description

  The present invention is supported by a valve seat plate having a valve hole communicating between an upstream side and a downstream side in an exhaust system of an engine, and a fulcrum on the valve seat plate so as to open and close the valve hole. A valve plate that receives the upstream pressure in the valve opening direction, and a valve that urges the valve plate in the valve closing direction to allow the valve plate to open when the upstream pressure rises above a predetermined value. The present invention relates to an improvement of an engine exhaust flow control valve including a spring.

  Such an exhaust flow control valve of an engine is already known as disclosed in Patent Document 1.

JP 2010-24894 A

  An exhaust flow control valve for an engine described in Patent Document 1 is provided with a valve seat plate having a valve hole, and rotatably supported by the valve seat plate so as to open and close the valve hole. A valve plate that receives the valve plate in the valve opening direction, and a valve spring that is attached to the valve seat plate and biases the valve plate in the valve closing direction. A pressure receiving piece is fixed on one side of the valve plate, The valve spring is provided with a pressing arm that slidably and slidably contacts the pressure receiving piece and biases it in the valve-closing direction of the valve plate. The effective length of this pressing arm depends on the increase in the opening of the valve plate. To increase.

  In such an engine exhaust flow control valve, the valve closing torque applied to the valve plate of the valve spring can be reduced as the opening of the valve plate increases. When the valve starts to open as the upstream pressure rises, the opening degree is immediately increased, and the back pressure can be lowered to contribute to an increase in engine output. However, in the one described in Patent Document 1, since the valve plate rubs with a pressing arm of the valve spring with a relatively long stroke when opening and closing, the frictional resistance therebetween becomes the opening and closing resistance of the valve plate, and the opening and closing characteristics of the valve plate are reduced. May cause instability.

  The present invention has been made in view of such circumstances, and the valve closing torque applied to the valve plate of the valve spring can be reduced according to the increase in the opening degree of the valve plate, and the friction of the valve spring is small. It is an object of the present invention to provide an engine exhaust flow control valve capable of stabilizing the opening / closing characteristics of a valve plate.

  In order to achieve the above object, the present invention provides a valve seat plate having a valve hole communicating between an upstream side and a downstream side in an exhaust system of an engine, and a valve seat plate that opens and closes the valve hole. A valve plate supported rotatably at the first fulcrum and receiving the upstream pressure in the valve opening direction, and urging the valve plate in the valve closing direction, the upstream pressure increased to a predetermined value or more. An engine exhaust flow control valve comprising a valve spring that allows the valve plate to open, and comprises a coil portion and first and second arms extending from the coil portion. The coil spring is constituted by a torsion coil spring that exerts an elastic repulsive force in a direction that increases the sandwiching angle between the second arms, and the coil is applied to apply a valve closing torque to the valve plate by the elastic repulsive force. The first arm is locked to the valve plate, and the second arm is supported by the valve plate. The first pivot point is connected to the tip end of a link which is offset from the first fulcrum to the valve hole side and is pivotally supported by the second fulcrum on the valve seat plate. Features. The exhaust system corresponds to the muffler M in the embodiment of the present invention described later.

  Further, in addition to the first feature, the present invention has a second feature that a part of the coil portion is accommodated in a recess formed on one side surface of the valve plate.

  Furthermore, in addition to the second feature, the present invention is configured such that the opposing inner surfaces of the recess are inclined surfaces that extend toward the outside of the valve plate, and the outer peripheral surface of the coil portion is supported by these inclined surfaces. This is the third feature.

  In addition to the second feature of the present invention, a part of the inner peripheral surface of the coil portion is supported by a support shaft fixed to the valve seat plate, and the outer peripheral surface of the coil portion is made to be less than the inner peripheral surface of the recess. The fourth feature is that it is floated.

  Furthermore, in addition to any one of the first to fourth features, the present invention includes a pair of first arms of the valve spring extending from both ends of the coil portion, and the second arm serving as the coil portion. The fifth feature is that the central portion is extended from the center.

  According to the first feature of the present invention, the elastic repulsive force acting on the second fulcrum from the second arm of the valve spring via the link is the first component force perpendicular to the straight line connecting the first and second fulcrums. And the second component force parallel to the straight line, and the product of the first component force and the distance between the first and second fulcrum is the valve closing torque exerted on the valve plate. This valve closing torque decreases when the valve plate is opened because the link tilt angle is larger than the valve plate opening angle. In addition, the change in the angle between the first and second arms accompanying the change in the opening degree of the valve plate is small, and therefore the friction generated between the coil portion and the valve plate supporting it is very small. The opening / closing characteristics of the can be stabilized.

  According to the second feature of the present invention, the amount of protrusion of the coil portion from the valve plate can be reduced, and the exhaust flow control valve can be made compact.

  According to the third aspect of the present invention, the coil portion can be stably supported by the opposing inclined surfaces of the recess, and it is not necessary to provide a special support member for the support, thereby simplifying the structure. be able to.

  According to the fourth feature of the present invention, a part of the inner peripheral surface of the coil portion is supported by the support shaft fixed to the valve plate, and the outer peripheral surface of the coil portion is floated from the inner peripheral surface of the recess. Thus, there is only one friction part between the coil part and its support part, and when the opening of the valve plate is changed, the friction generated between the coil part and the support shaft can be kept small. It can be done smoothly.

  According to the fifth aspect of the present invention, a valve closing torque can be applied to the entire valve plate by a single valve spring, which can contribute to stabilization of the opening / closing posture of the valve plate.

The longitudinal cross-sectional view of the muffler of the engine for motor vehicles provided with the exhaust flow control valve which concerns on 1st Embodiment of this invention. FIG. 2 is an enlarged view of part 2 of FIG. 1. FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG. 2 and shows a closed state of the exhaust flow control valve. FIG. 4 is a view corresponding to FIG. 3 showing an open state of the exhaust flow control valve. The exploded perspective view of an exhaust flow control valve. FIG. 4 is a view corresponding to FIG. 3 showing a second embodiment of the present invention. FIG. 7 is a view corresponding to FIG. 6 showing a second embodiment of the present invention. The valve closing torque characteristic diagram of the exhaust flow control valve of the present invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  First, the description starts with the description of the first embodiment of the present invention shown in FIGS.

  In FIG. 1, an exhaust muffler M constituting a part of an exhaust system of an automobile engine E includes a muffler body 2, an upstream exhaust pipe 10, and a downstream exhaust pipe 11. The muffler main body 2 is configured in a sealed drum shape by a body portion 3 and a front end plate 4 and a rear end plate 5 which are welded to both front and rear ends of the body portion 3. The inside of the muffler body 2 is divided into a front silencing chamber 7 and a rear silencing chamber 8 by a partition plate 6 welded to the inner peripheral surface of the middle portion of the trunk portion 3. A number of first silencing holes 13, 13... Communicating between the eight are provided.

  The upstream exhaust pipe 10 has an upstream end connected to the exhaust port of the engine E, and passes through the front end plate 4 and the partition plate 6 so that the downstream end faces the rear muffler chamber 8. Although the end is closed by a welded end plate 16, a plurality of second silencing holes 14, 14... Communicating with the rear silencing chamber 8 are provided in the peripheral wall of the upstream exhaust pipe 10 in the rear silencing chamber 8. It is done. The upstream exhaust pipe 10 and the front end plate 4 and the partition plate 6 are connected by welding.

  The upstream end of the downstream exhaust pipe 11 starts from the front silencing chamber 7, passes through the front end plate 4, goes out of the front silencing chamber 7, and is bent into a U-shape, and then again returns to the front end. It is formed so as to penetrate the plate 4 and further penetrate the front silencer chamber 7, the partition plate 6, the rear silencer chamber 8 and the rear end plate 5 to open the downstream end to the atmosphere. The upstream end of the downstream exhaust pipe 11 is closed by a non-hole portion of the partition plate 6, and a number of third silencer holes communicating with the front silencer chamber 7 are formed on the upstream peripheral wall of the downstream exhaust pipe 11. 15, 15 ... are provided. The downstream exhaust pipe 11 and the front end plate 4, the partition plate 6 and the rear end plate 5 are joined together by welding.

  As shown in FIGS. 1 to 3, a portion from the intermediate portion disposed in the rear silencing chamber 8 of the downstream side exhaust pipe 11 to the downstream end is formed in a flat shape, and is formed on a flat wall 11 a on one side of the flat portion. The exhaust flow control valve 20 of the present invention is provided.

  2 to 6, the exhaust flow control valve 20 includes a valve seat plate 21 having a valve hole 22, a valve plate 23 that opens and closes the valve hole 22, and a valve spring 24 that applies a valve closing torque to the valve plate 23. And a link 25 that controls the valve closing torque to decrease in accordance with an increase in the opening degree of the valve plate 23.

  The flat wall 11a of the downstream exhaust pipe 11 is provided with a rectangular opening 17 passing therethrough. The valve seat plate 21 also has a square shape, and is joined to the outer surface of the flat wall 11a along the periphery thereof by welding or the like so as to close the opening portion 17, and the rectangular valve hole 22 is formed on the opening portion 17. It arrange | positions so that the said rear muffler chamber 8 and the inside of the downstream exhaust pipe 11 may be connected inside.

  The valve seat plate 21 is formed with a raised portion 27 that protrudes toward the rear silencing chamber 8 and has a fulcrum groove 28 on the inside. The fulcrum groove 28 forms a cross-sectional mountain shape in the lateral direction of the downstream exhaust pipe 11. It extends and is disposed at a position closer to the upstream side of the exhaust pipe 11 on the downstream side than the valve hole 22. The groove bottom of the fulcrum groove 28 becomes the first fulcrum 29. Further, the valve seat plate 21 is formed so that a second fulcrum 30 is raised between the first fulcrum 29 and the valve hole 22 toward the rear silencing chamber 8.

  The valve plate 23 is also formed in a square shape, and at one end thereof, a projection 31 that engages with the first fulcrum 29 and a pair of stopper pieces 32 that are arranged across the projection 31 are formed. Thus, the valve plate 23 has a fully closed position C (see FIG. 3) for closing the valve hole 22 around the first fulcrum 29, and the stopper piece 32 is brought into contact with the valve seat plate 21 so that the valve hole 22 is closed. It can be rotated between the fully open position O (see FIG. 4) to be fully opened.

  Further, a raised portion 35 is formed in the central portion of the valve plate 23 so as to protrude toward the valve hole 22 and have a recessed portion 36 on the inner side. The recessed portion 36 forms a trapezoidal cross section in the lateral direction of the downstream side exhaust pipe 11. It extends in a groove shape and closes both ends. Therefore, the opposing inner side surfaces of the recess 36 are composed of slopes 36 a and 36 a that spread toward each other toward the open surface of the recess 36.

  The valve spring 24 includes a coil portion 24a, a pair of rod-like first arms 24b extending from both ends of the coil portion 24a, and a single U-shaped second extending from the center portion of the coil portion 24a. It comprises an arm 24c and is constituted by a torsion coil spring that exhibits an elastic repulsion force in a direction that increases the sandwiching angle δ between the first and second arms 24b, 24c. The coil portion 24a is arranged such that the outer peripheral surface thereof is supported by the slopes 36a, 36a. Thus, a part of the coil portion 24a is accommodated in the recess 36. The distal ends of the pair of first arms 24 b are locked by a pair of locking claws 37 provided at the free ends of the valve plate 23, and the distal ends of the U-shaped second arms 24 c are transparent to the valve plate 23. It penetrates the hole 26 and is connected to the tip end portion of the link 25 rotatably supported by the second fulcrum 30 so as to be relatively rotatable. The link 25 has U-shaped first and second connecting grooves 25a and 25b at both ends, and the first connecting groove 25a is rotatably connected to the first fulcrum 29, and the second connecting groove 25b. In addition, the U-shaped bent portion of the second arm 24c is rotatably connected.

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

  When the valve spring 24 is mounted, the coil portion 24a is supported on both inclined surfaces 36a, 36a of the concave portion 36 on the opposite side of the valve hole 22 of the valve plate 23, and the sandwiching angle δ between the first and second arms 24b, 24c. The first arm 24b is locked to the locking claw 37 at the free end of the valve plate 23 against the elastic repulsive force to spread the second arm 24c, and the second arm 24c is connected to the valve seat plate 21 via the link 25. Since the first fulcrum 29 is supported, an elastic repulsive force that attempts to widen the sandwiching angle δ between the first and second arms 24b and 24c urges the valve plate 23 in the valve closing direction via the coil portion 24a.

  When the engine E is operating at a low speed and under a low load, the exhaust gas of the engine E is, as indicated by the arrow A, the upstream side exhaust pipe 10, the second silencing holes 14, 14,..., The rear silencing chamber 8, the first silencing holes 13, 13 ..., passing through the front silencing chamber 7, the third silencing holes 15, 15 ..., and the downstream exhaust pipe 11 in sequence, are released into the atmosphere while being silenced. During this time, since the pressure of the rear silencing chamber 8 acting on the valve plate 23 of the exhaust flow control valve 20 is relatively low, the valve plate 23 is held at the fully closed position C by the urging force of the valve spring 24 and the valve hole 22 is opened. Since it is closed, the exhaust gas passes through the relatively long downstream exhaust pipe 11 over its entire length, and low frequency noise can be reduced.

  When the engine E shifts to a high speed and high load operation state, the flow rate of the exhaust gas flowing through the above path increases and the pressure in the rear silencing chamber 8 rises, and the valve opening torque of the valve plate 23 due to the pressure increases to the valve spring 24. When the valve closing torque of the valve plate 23 is exceeded, the valve plate 23 rotates toward the fully open position O and increases the opening degree of the valve hole 22. Then, according to the opening degree of the valve hole 22, the exhaust gas discharged from the upstream side exhaust pipe 10 to the rear muffler chamber 8 is short-circuited to the valve hole 22 as indicated by an arrow B and is guided to the inclined valve plate 23. However, it passes through the short downstream exhaust pipe 11 after the valve hole 22 and is released to the atmosphere. As a result, it is possible to improve engine output by reducing back pressure and reduce airflow noise.

  The valve closing torque applied to the valve plate 23 by the valve spring 24 will now be considered.

  In FIG. 3, the elastic repulsive force F acting on the second fulcrum 30 from the second arm 24 c of the valve spring 24 via the link 25 is the first perpendicular to the straight line S connecting the first and second fulcrums 29 and 30. The product is divided into a component force F1 and a second component force F2 parallel to the straight line S. The product of the first component force F1 and the distance L between the first and second fulcrums 29, 30 is the valve plate 23. The valve closing torque is

  3 and 4, when the valve plate 23 opens from the fully closed position C, the second fulcrum 30 that supports the link 25 has a valve hole from the first fulcrum 29 that supports the valve plate 23. Since the link 25 is offset by the distance L toward the side 22, the tilt angle β at which the link 25 falls around the second fulcrum 30 toward the valve seat plate 21 in response to the opening of the valve plate 23 is greater than the opening angle α of the valve plate 23. It ’s big. Accordingly, the angle θ formed between the elastic repulsive force F acting on the second fulcrum 30 from the second arm 24c and the first component force F1 increases in accordance with the opening of the valve plate 23. The force F1 will decrease. As a result, the valve closing torque of the valve plate 23 due to the first component force F1 decreases as the opening of the valve plate 23 increases as shown in FIG. In addition, the change in the sandwiching angle δ between the first and second arms 24b and 24c due to the change in the opening degree of the valve plate 23 is small, and therefore the friction generated between the coil portion 24a and the inclined surfaces 36a and 36a of the recess 36 is also small. Very small.

  Thus, when the valve plate 23 starts to open due to the pressure of the rear silencing chamber 8, it automatically and smoothly rotates to the fully open position O, and it is possible to reliably reduce the back pressure and the airflow noise. In addition, when the exhaust gas moves from the upstream exhaust pipe 10 through the valve hole 22 to the rear muffler chamber 8, the inclined valve plate 23 smoothly guides the flow of the exhaust gas, thereby further reducing the back pressure and the air flow noise. Can be planned.

  When the engine E returns to the low speed and low load operation state, the valve opening torque of the valve plate 23 due to the pressure in the rear silencing chamber 8 becomes smaller than the valve closing torque, and the valve plate 23 returns to the fully closed position C. .

  In such an exhaust flow control valve 20, a part of the coil portion 24 a of the valve spring 24 is accommodated in the recess 36 of the valve plate 23, thereby reducing the amount of protrusion of the coil portion 24 a from the valve plate 23, The exhaust flow control valve 20 can be made compact. In addition, the coil portion 24a can be stably supported by the opposing inclined surfaces 36a, 36a of the recess 36, and it is not necessary to provide a special support member for the support, and the structure can be simplified.

  The valve spring 24 includes a coil portion 24a, a pair of first arms 24b extending from both ends of the coil portion 24a, and a second arm 24c extending from the central portion of the coil portion 24a. 24 a is supported on the valve plate 23, the distal ends of the pair of first arms 24 b are locked to the pair of locking claws 37 of the valve plate 23, and the distal end of the second arm 24 c is connected to the distal end of the link 25. By being connected, a valve closing torque can be applied to the entire valve plate 23 by a single valve spring 24, and the opening and closing posture of the valve plate 23 can be stabilized.

  Next, a second embodiment of the present invention shown in FIGS. 6 and 7 will be described.

  In the second embodiment, the support shaft 40 having a U-shaped cross section penetrating through the hollow portion of the coil portion 24a of the valve spring 24 is fixed to the valve plate 23 so as to vertically cut the open surface of the recess 36 of the valve plate 23. The outer circumferential surface of the coil portion 24 a is floated from the inner circumferential surface of the recess 36 by supporting a part of the inner circumferential surface of the coil portion 24 a by the arc surface of the support shaft 40. Since other configurations are the same as those of the previous embodiment, portions corresponding to those of the previous embodiment in FIG. 6 and FIG. 7 are denoted by the same reference numerals, and redundant description is omitted.

  According to the second embodiment, a part of the inner peripheral surface of the coil portion 24a is supported by the support shaft 40 fixed to the valve plate 23, and the outer peripheral surface of the coil portion 24a is supported from the inner peripheral surface of the recess 36. Due to the floating, the frictional portion between the coil portion 24a and its support portion becomes one place, and when the sandwiching angle δ of the first and second arms 24b, 24c changes with the opening change of the valve plate 23, The friction generated between the coil portion 24a and the support shaft 40 can be kept small, and the valve plate 23 can be opened and closed more smoothly.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, the flat wall 11 a itself of the downstream exhaust pipe 11 can be used as the valve seat plate 21.

E ... Engine M ... Exhaust system (muffler)
δ ··· Angle between first and second arms of valve spring 20 · Exhaust flow control valve 21 · Valve seat plate 22 · Valve hole 23 · · · .... Valve plate 24 ... Valve spring 24a ... Coil part 24b ... First arm 24c ... Second arm 25 ... Link 29 ... First Fulcrum 30... Second fulcrum 36... Recess 36 a... Slope 40.

Claims (5)

A valve seat plate (21) having a valve hole (22) communicating between the upstream side and the downstream side in the exhaust system (M) of the engine (E), and the valve seat so as to open and close the valve hole (22) A valve plate (23) supported rotatably at the first fulcrum (29) on the plate (21) and receiving the upstream pressure in the valve opening direction, and the valve plate (23) is attached in the valve closing direction. An exhaust flow control valve for an engine comprising a valve spring (24) that allows the valve plate (23) to open when the upstream pressure rises above a predetermined value,
A coil portion (24a) and first and second arms (24b, 24c) extending from the coil portion (24a), and a sandwiching angle (δ) between the first and second arms (24b, 24c) The valve spring (24) is composed of a torsion coil spring that exhibits an elastic repulsive force in the direction of increasing
The coil portion (24a) is supported on the valve plate (23) and the first arm (24b) is mounted on the valve plate (23) so as to apply a valve closing torque to the valve plate (23) by the elastic repulsive force. And the second arm (24c) is rotated at the second fulcrum (30) on the valve seat plate (21) offset from the first fulcrum (29) toward the valve hole (22). An exhaust flow control valve for an engine, characterized in that it is connected to the tip of a link (25) movably supported so as to be relatively rotatable. The exhaust flow control valve for an engine according to claim 1,
An exhaust flow control valve for an engine, wherein a part of the coil portion (24a) is housed in a recess (36) formed on one side surface of the valve plate (23). The exhaust flow control valve for an engine according to claim 2,
Both opposing inner side surfaces of the recess (36) are formed as slopes (36a, 36a) extending outwardly of the valve plate (23), and the coil parts (24a The exhaust flow control valve of the engine, characterized by supporting the outer peripheral surface of The exhaust flow control valve for an engine according to claim 2,
A part of the inner peripheral surface of the coil portion (24a) is supported by the support shaft (40) fixed to the valve seat plate (21), and the outer peripheral surface of the coil portion (24a) is supported by the recess (36). The engine exhaust flow control valve is characterized by floating from the inner peripheral surface. The exhaust flow control valve for an engine according to any one of claims 1 to 4,
The first arm (24b) of the valve spring (24) is a pair extending from both ends of the coil part (24a), and the second arm (24c) is extended from the center part of the coil part (24a). An exhaust flow control valve for an engine characterized by being released.

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