JP2002089259A - Flexible joint structure for exhaust pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact flexible joint structure for exhaust pipes with high degree of freedom in piping of the exhaust pipes by eliminating displacement orientation when absorbing vibration of an exhaust pipe system of an automobile or the like by oscillatory displacement. SOLUTION: In a connecting structure of the exhaust pipes with an upstream exhaust pipe and a downstream exhaust pipe connected via a spherical joint, a sealing member having a spherical slidably contacting face slidably contacting a spherical bearing face is provided on a substantially circular flange provided on the upstream or the downstream exhaust pipe and having the spherical bearing face, the sealing member is sandwiched by a substantially circular flange provided on the corresponding upstream or downstream exhaust pipe, a first leaf spring is provided around an entire circumference between mutually corresponding faces of a pair of the flanges with circular shapes, and back faces of the pair of flanges are sandwiched by a plurality of substantially U-shaped stoppers via a plurality of second leaf springs provided in a back face side of either one of the pair of corresponding flanges. The pair of flanges can also be sandwiched without providing the second leaf springs by using a U-shaped leaf spring instead of the stoppers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure of an exhaust pipe connected to an exhaust manifold or the like of an internal combustion engine when absorbing vibration of an exhaust pipe system caused by transmission of engine vibration while swingingly displacing. The present invention relates to a compact exhaust pipe flexible joint structure having no difference depending on a displacement direction.

[0002]

2. Description of the Related Art In order to prevent the vibration generated from an engine and the vibration generated from a road surface during traveling in an automobile or the like from being transmitted to a vehicle body and thereby deteriorating riding comfort, vibration of an exhaust system is changed by swing displacement. Absorbing spherical joints are widely used. When connecting the upstream exhaust pipe and the downstream exhaust pipe as shown in FIG. 5, a flange 102 having a concave spherical seat surface is attached to one exhaust pipe 101 by welding or the like, as shown in FIG.
Two connection holes 102a are provided in this flange in the direction of 180 degrees on the circumference, and a flange 104 of the other exhaust pipe 103 is provided.
A corresponding connecting hole 104a is also provided, and a sealing member 105 that comes into sliding contact with the spherical surface is interposed therebetween, and a bolt 105 spring-biased by a coil spring 106 is passed through the connecting hole of one flange, and a nut 108 and the like are passed through the other flange. Screwed. In such a joint structure, since the seal member is held by the elastic force of two coil springs arranged in the 180-degree direction, the tension applied to the seal member differs depending on the displacement direction of the exhaust pipe. Directionality is generated in the vibration absorption performance of the. In particular, when large vibrations such as rolling and pitching occur in the engine, the effect is large, and in some cases, uneven wear may occur on the spherical sliding contact portion of the seal member, and furthermore, the cause of exhaust gas sealing failure. In some cases. In addition, the projecting portion of the coil spring is large, which limits the degree of freedom of arrangement of the exhaust pipe.

[0003]

SUMMARY OF THE INVENTION The present invention eliminates the displacement directionality when absorbing the vibration of the exhaust pipe system of an automobile or the like by swinging displacement, and is a flexible exhaust pipe having a high degree of freedom in exhaust pipe piping. The purpose is to provide a joint structure.

[0004]

According to a first aspect of the present invention, there is provided an exhaust pipe connecting structure in which an upstream exhaust pipe and a downstream exhaust pipe are connected via a spherical joint. A substantially circular flange having a seating surface is provided with a seal member having a spherical sliding contact surface that slides on the spherical seating surface, and a substantially circular flange provided on a corresponding upstream exhaust pipe or downstream exhaust pipe. And a plurality of second leaf springs disposed on the back surface of one of the pair of corresponding flanges. The back surfaces of the pair of flanges were sandwiched between a plurality of substantially U-shaped stoppers via a leaf spring. As a result, the second leaf spring opposes the inner surface of the stopper, and a tension acts in the direction of adhesion between the flanges, so that the first leaf spring acts as a stopper when receiving a compressive displacement load. At this time, since the first leaf spring is provided over the entire circumference of the flange, the first leaf spring also functions as a stopper in any direction, so that the directionality of the vibration absorbing displacement is eliminated.

According to a second aspect of the present invention, in an exhaust pipe connection structure in which an upstream exhaust pipe and a downstream exhaust pipe are connected via a spherical joint, a substantially circular shape having a spherical seat surface provided on the upstream exhaust pipe or the downstream exhaust pipe. A seal member having a spherical sliding contact surface that slides on the spherical seating surface is provided on the flange having a shape, and this is sandwiched by a substantially circular flange provided on a corresponding upstream exhaust pipe or downstream exhaust pipe. A first leaf spring is disposed on the entire circumference between corresponding surfaces of a flange having a substantially circular shape, and a plurality of U-shaped leaf springs having a substantially U-shaped cross section are provided between the back surfaces of the corresponding flanges. Pinched.
Accordingly, when tension is exerted between the flanges by the plurality of U-shaped leaf springs in the close contact direction, and a compressive displacement is applied to the first leaf springs provided between the pair of flanges in all circumferential directions, the first leaf springs are pressed. Since the leaf spring is disposed over the entire circumference of the flange, the leaf spring also functions as a stopper in any direction, so that the directionality of the vibration absorbing displacement is eliminated.

According to a third aspect of the present invention, in the exhaust pipe connection structure in which the upstream exhaust pipe and the downstream exhaust pipe are connected via a spherical joint, a substantially circular shape having a spherical seat surface provided on the upstream exhaust pipe or the downstream exhaust pipe. A seal member having a spherical sliding contact surface that slides on the spherical seat surface is disposed on the flange having a shape, and the seal member is sandwiched between substantially corresponding flanges provided on the corresponding upstream exhaust pipe or downstream exhaust pipe. The back surfaces of the pair of flanges holding the member were fitted and clamped by a plurality of U-shaped leaf springs having a substantially U-shaped cross section. Here, a tension in the close contact (compression) direction acts between the flanges of the U-shaped leaf spring, and when a compression displacement is applied in a certain direction,
The leaf spring on the diagonal receives a tensile displacement load and acts to function as a stopper. According to the third aspect of the present invention, the number of restraining points on the circumferential portion of the flange is increased instead of eliminating the leaf spring between the pair of flange surfaces.

[0007]

FIG. 1 shows an embodiment according to the first aspect of the present invention. A substantially circular flange 2 having a spherical seat surface is attached to the upstream or downstream exhaust pipe 1 by welding or the like,
A substantially circular flange 4 is attached to the corresponding exhaust pipe 3 by welding or the like, and a seal member 5 having a spherical sliding contact surface between the pair of flange surfaces and a first leaf spring 6 are provided. A second leaf spring 7 was provided on the back surface of the device in accordance with the position of the stopper 8, and a pair of flanges were sandwiched between the pair of flanges via the second leaf spring. Here, the first leaf spring is preferably provided over the entire circumference of the flange surface.
(A) and (b). The first leaf spring 6 shown in (a) is obtained by punching a circular leaf spring into a ring shape and making it into a corrugated plate shape. The first leaf spring 6 may be a single leaf spring or a laminate of thin plates laminated in multiple layers. A split type in which a leaf spring is connected to form a ring may be used. The first leaf spring 61 shown in (b) is obtained by winding a plate-like spring in a coil shape. As shown in FIG. 2 (c), an example of the second leaf spring is a leaf spring having a corrugated shape, and may be a single sheet or a thin sheet laminated in multiple layers.

FIG. 3 shows an embodiment according to the second aspect of the present invention. A substantially circular flange 2 having a spherical seating surface is attached to the upstream or downstream exhaust pipe 1 by welding or the like, and a substantially circular flange 4 is attached to the corresponding exhaust pipe 3 by welding or the like, and the pair of flange faces is attached. A seal member 5 having a spherical sliding contact surface and a first leaf spring 6 were disposed therebetween, and a back surface of the pair of flanges was sandwiched by a U-shaped leaf spring 9 having a substantially U-shaped cross section. Here, even if the U-shaped leaf spring is fixed to one flange by welding or the like as shown in FIG. 3 and fixed to one side, it is press-fitted like the U-shaped leaf spring 19 shown in FIG. It may be a single type or a type in which thin plates are stacked in multiple layers.

FIG. 4 shows an embodiment according to the third aspect of the present invention. A substantially circular flange 2 having a spherical seating surface is attached to the upstream or downstream exhaust pipe 1 by welding or the like, and a substantially circular flange 4 is attached to the corresponding exhaust pipe 3 by welding or the like, and the pair of flange faces is attached. A seal member 5 having a spherical sliding contact surface is disposed between the pair of flanges, and a back surface of the pair of flanges is clamped by a U-shaped leaf spring 19 having a substantially U-shaped cross section. Here, the U-shaped leaf spring may be one in which one side is fixed by welding or the like as in the second aspect of the invention. In this case, the first leaf spring is not provided between the pair of flange surfaces, and a plurality of U-shaped leaf springs are used to increase the number of constrained portions in the circumferential direction of the flange.

[0010]

According to the present invention, the range of restraint by the leaf spring is wider than that of the conventional two-point restraint by a coil spring. Since the effect of the first leaf spring as a stopper is used, the difference in tension in the displacement direction is reduced, and vibration absorption characteristics with less directivity can be obtained. In addition, a simple structure in which a leaf spring is provided between a pair of flanges allows a high degree of freedom in the arrangement of piping.

[Brief description of the drawings]

FIG. 1 shows an embodiment according to the first aspect of the present invention.

FIGS. 2A and 2B show examples of a leaf spring; FIGS. 2A and 2B show examples of a first leaf spring; and FIG. 2C shows an example of a second leaf spring.

FIG. 3 shows an embodiment according to the second aspect of the present invention.

FIG. 4 shows an embodiment according to the third aspect of the present invention.

FIG. 5 shows a connection example of a conventional exhaust pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust pipe 2 Flange 3 Corresponding exhaust pipe 4 Corresponding exhaust pipe flange 5 Seal member 6, 61 First leaf spring 7 Second leaf spring 8 Stopper 9, 19 U-shaped leaf spring

Claims (3)

[Claims] In an exhaust pipe connection structure in which an upstream exhaust pipe and a downstream exhaust pipe are connected via a spherical joint, a substantially circular flange having a spherical seat surface provided on the upstream exhaust pipe or the downstream exhaust pipe is provided. A seal member having a spherical sliding contact surface that slides on the ball seating surface is provided and sandwiched by a substantially circular flange provided on a corresponding upstream exhaust pipe or a downstream exhaust pipe, and a pair of the pair of circular flanges is provided. A first leaf spring is disposed between the corresponding surfaces, and a plurality of substantially U-shaped portions are formed between the rear surfaces of the pair of flanges via a second leaf spring disposed on the back surface of one of the pair of corresponding flanges. The flexible joint structure of the exhaust pipe, characterized by being held between the stoppers. 2. An exhaust pipe connection structure in which an upstream exhaust pipe and a downstream exhaust pipe are connected via a spherical joint, a substantially circular flange having a spherical seat surface provided on the upstream exhaust pipe or the downstream exhaust pipe. A seal member having a spherical sliding contact surface in sliding contact with the ball seating surface is disposed and sandwiched between corresponding upstream and downstream exhaust pipes or substantially circular flanges provided on the downstream exhaust pipe. A first leaf spring is disposed between corresponding surfaces, and a plurality of U-shaped leaf springs having a substantially U-shaped cross section are sandwiched between the back surfaces of the corresponding flanges. Flexible joint structure. 3. A substantially circular flange having a spherical seat surface provided on an upstream exhaust pipe or a downstream exhaust pipe in an exhaust pipe connection structure in which an upstream exhaust pipe and a downstream exhaust pipe are connected via a spherical joint. A seal member having a spherical sliding contact surface that slides on the ball seating surface is provided and sandwiched by a substantially circular flange provided on the corresponding upstream exhaust pipe or downstream exhaust pipe, and a pair of flanges sandwiching the seal member is provided. A flexible joint structure for an exhaust pipe, wherein a plurality of U-shaped leaf springs each having a substantially U-shaped cross section are fitted and sandwiched between back surfaces.