JP2010223208A - Exhaust valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust valve using a bent leaf spring with the opening degree of a valve and the energizing force of the bent leaf spring provided nonlinearly, capable of providing a sufficiently large opening degree of the valve body for enabling a further lower back pressure. <P>SOLUTION: The exhaust valve 1 includes a valve 8 swayable around a sway axis 7, and a bent leaf spring 12 for forcing the valve 8 to the closing direction for switching an exhaust path according to the exhaust pressure of an internal combustion engine. A sliding part 10 swayed together with the valve 8 is provided swayably with the concave surface side of the bent leaf spring 12, and the sliding part 10 is formed so that the distance from the center of the sway axis 7 is increased from the close state toward the open state of the valve 8. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust valve that is provided in an exhaust path of an internal combustion engine mounted on a vehicle and opens and closes the exhaust path according to exhaust pressure.

  Conventionally, in order to achieve both low-speed quietness and high-speed mobility of a vehicle equipped with an internal combustion engine, for example, at the exhaust path of the internal combustion engine, for example, at the downstream end of an inner pipe provided in a silencer An exhaust valve that opens and closes depending on the exhaust pressure may be provided. As an example of such an exhaust valve, chattering that occurs when the internal combustion engine runs at low speed by using a curved plate spring as shown in Patent Document 1 and making the opening of the valve body and the closing force by the spring non-linear. An exhaust valve has been proposed that suppresses the above-described problem and also aims to reduce the back pressure during high rotation.

JP 2001-65342 A

  However, the exhaust valve disclosed in the above prior art is configured such that the end face of the valve element that is equidistant from the center of swinging of the valve element is slid by the curved plate spring. For this reason, if the valve body opens beyond a certain opening, the sliding part and the curved plate spring may not be engaged, or the biasing force of the curved plate spring may act in the direction of opening the valve body and the valve body may not close. there were. Therefore, the opening degree of the valve body cannot be increased and it is difficult to reduce the back pressure.

  The present invention has been made in view of the above problems, and in an exhaust valve in which the opening of the valve body and the urging force by the curved plate spring are made nonlinear using a curved plate spring, the opening of the valve body is sufficiently large. The main object of the present invention is to provide an exhaust valve that can achieve the lower back pressure.

  In order to solve the above problems, an invention according to claim 1 is provided with an internal combustion engine comprising: a valve body that can swing about a swing shaft; and a curved plate spring that biases the valve body in a closing direction. In the exhaust valve that opens and closes the exhaust path according to the exhaust pressure of the valve body, a sliding portion that swings with the valve body is provided so as to slide on the concave surface side of the curved plate spring, and the valve body is opened from the closed state. The exhaust valve is characterized in that the sliding portion is formed so that the distance from the center of the swing shaft increases in accordance with the state.

  According to a second aspect of the present invention, in the first aspect of the invention, the curvature of the sliding portion is formed in a curved shape that gradually changes from small to large as the valve body changes from a closed state to an open state. An exhaust valve characterized by

  According to a third aspect of the present invention, there is provided a valve body capable of swinging about a swing shaft, first biasing means for biasing the valve body in the closing direction, and a curve for biasing the valve body in the closing direction. An exhaust valve that opens and closes an exhaust path according to the exhaust pressure of the internal combustion engine, and swings with the valve body so as to slide on the concave surface side of the curved plate spring. The exhaust valve is characterized by being provided with a sliding portion and extending the sliding portion so that a distance from the center of the swing is constant.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, an arm member that swings in synchronization with the valve body is provided on the swing shaft so as to be parallel to the valve body, and the arm member includes An exhaust valve characterized in that the sliding portion is formed.

  According to the present invention, in an exhaust valve in which the opening of the valve body and the urging force by the curved plate spring are made nonlinear using a curved plate spring, the opening of the valve body can be made sufficiently large. Back pressure can be achieved.

The figure which shows an example of the exhaust valve which concerns on this invention. The perspective view which shows an example of the exhaust valve which concerns on this invention. The figure which shows the modification of the sliding part which concerns on this invention.

  A mode for carrying out the present invention will be described based on the embodiment shown in FIGS.

  1A is a front view and FIG. 1B is a side view showing a closed state of an exhaust valve according to a first embodiment of the present invention. The exhaust valve 1 is joined to the downstream end of an inner pipe (exhaust path) of a silencer (not shown). The housing 2 is formed by integrally joining a first housing member 3 and a second housing member 4 formed by pressing a metal plate material. The housing member is provided with burring holes 3a and 4a, respectively, and a rocking shaft 7 having flanges 7a and 7b is inserted through bearing members 5 and 6 formed by interleaving fine metal wires. . The swing shaft 7 has a valve body 8 and an arm member 9 outside the housing 2 so as to close the opening of the housing 2, and the valve body 8 and the arm member 9 swing synchronously about the swing shaft 7. It is fixed so that it can move. The valve body 8 is provided with a buffer member 11 formed by intermingling fine metal wires in order to suppress the hitting sound with the housing 2.

  A sliding portion 10 is formed integrally with the arm member 9. The sliding portion 10 is formed such that one end 10a is formed in a straight line having a constant distance from the center of the swing shaft 7 and extends in a curved line toward the other end 10b. More specifically, the sliding portion 10 is formed in an involute curve shape with a gradually increasing curvature toward the other end 10b so that the distance from the center of the swing shaft 7 increases. A curved plate spring 12 formed of a tape-like thin metal plate material having a transverse cross-section curved in an arc shape so that the concave side abuts on one end 10a of the sliding portion 10 in the closed state is provided on the housing 2 via the bracket 13. Is provided. The curved plate spring 11 biases the arm member 9 to bias the valve body 8 in the closing direction via the swing shaft 7. The curved plate spring 11 is formed by bending and bending a thin plate of an arbitrary metal material having appropriate elasticity into an arc shape or a dogleg shape, and a resin material or the like can be used when the operating temperature is low. . Further, a plurality of them may be overlapped and used.

  The effect of the exhaust valve 1 according to the first embodiment will be described. 2A and 2B are perspective views showing the exhaust valve according to the first embodiment of the present invention in the closed state (a) and the open state (b). Until the internal combustion engine reaches a predetermined rotational speed, the urging force of the curved plate spring 12 is set to be larger than the exhaust pressure exerted by the exhaust gas on the valve body 8, so that the closed state of the valve body 8 is maintained. Since the curved plate spring 12 has a circular cross section and is set to have high rigidity, the valve element 8 can be kept closed against a larger exhaust pressure. Thereafter, when a predetermined number of revolutions of the internal combustion engine is exceeded, the exhaust pressure becomes larger than the urging force of the curved plate spring 12, the curved plate spring 12 bends in the vicinity of the bracket 13, and the valve body 8 is opened. At this time, since the curved plate spring 12 becomes flat at the bent portion, the rigidity is lowered and the urging force of the curved plate spring 11 is reduced. Therefore, chattering of the valve body 8 can be suppressed at low rotation, and back pressure can be reduced at high rotation.

  Further, since the sliding portion 10 and the curved plate spring 12 extending in a curved shape slide as the opening degree of the valve body 8 increases, the valve body opening degree becomes larger. The sliding portion 10 and the curved plate spring 12 can be engaged. Further, since the sliding portion 10 is formed so that the distance from the center of the swing shaft 7 increases with the opening of the valve body 8, the urging force of the curved plate spring 12 is always closed. Can work in any direction. Accordingly, since the valve body 8 can be set to open up to a larger valve body opening degree, the back pressure can be further reduced at high rotation. In addition, since it is not necessary to provide a separate urging body for closing the valve body 8, it is effective in reducing cost and mass. Furthermore, by providing the sliding portion 10 on the arm member 9 as in this embodiment, it is not necessary to consider the gas hitting on the valve body 8 as compared with the case where the sliding portion 10 is provided on the valve body 8. The shape of the sliding part 10 can be set arbitrarily.

  FIG. 3 is a view showing a modification of the sliding portion. In (a), one end 20a is formed in a linear shape with a constant distance from the center of the swing shaft 7, and is formed in an arc shape so that the distance from the center of the swing shaft 7 increases toward the other end 20b. It is an example. In (b), one end 30a is formed in a linear shape with a constant distance from the center of the swing shaft 7, and the distance from the center of the swing shaft 7 is increased to the other end 30b via the bent portion 30c. It is an example formed in a straight line. In (c), one end 40a is formed in a straight line having a constant distance from the center of the swinging shaft 7, and the distance from the center of the swinging shaft 7 is extended to the other end 40b in a circular arc shape. This is an example of formation. In the case of this modification, it is necessary to provide a separate urging body in order to close the valve body.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and design changes within a range that does not depart from the spirit of the present invention are included in the present invention. For example, in the above embodiment, the example of the inner pipe in the silencer is shown as the exhaust path, but it may be provided at the end of the pipe or the exhaust pipe provided in an arbitrary exhaust device or in the middle.

DESCRIPTION OF SYMBOLS 1 Exhaust valve 2 Housing 5, 6 Bearing member 7 Oscillating shaft 8 Valve body 9 Arm member 10, 20, 30, 40 Sliding part 12 Curved plate spring

Claims (4)

  An exhaust valve comprising: a valve body that can swing about a swing shaft; and a curved plate spring that biases the valve body in a closing direction, and that opens and closes an exhaust path according to an exhaust pressure of the internal combustion engine. The sliding portion that swings with the body is provided so as to slide on the concave surface side of the curved plate spring, and the distance from the center of the swing shaft increases from the closed state to the open state of the valve body. An exhaust valve characterized by forming a sliding portion.   2. The exhaust valve according to claim 1, wherein the curvature of the sliding portion is formed in a curved shape that gradually changes from small to large as the valve body changes from a closed state to an open state.   A second urging force comprising a valve body that can oscillate about an oscillating shaft, first urging means for urging the valve body in the closing direction, and a curved plate spring that urges the valve body in the closing direction. An exhaust valve that opens and closes an exhaust path according to an exhaust pressure of the internal combustion engine, and a sliding portion that swings with the valve body so as to slide on the concave surface side of the curved plate spring, and An exhaust valve formed by extending the sliding portion so that the distance from the center of oscillation is constant.   4. An arm member that swings in synchronization with the valve body is provided on the swing shaft so as to be parallel to the valve body, and the sliding portion is formed on the arm member. Exhaust valve.

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