CN1236199C - Flexible joint structure for exhaust structure - Google Patents

Abstract

The invention discloses a flexible joint structure of an exhaust system, which connects an upstream exhaust pipe (1) and a downstream exhaust pipe. The structure includes: a flexible pipe (7) having many raised portions (P) with the same height; an outer braid (8) covering the outer peripheral surface of the flexible pipe (7); Inner plate (9) between one end of the flexible tube (7) and one end of the outer braid (8). The inner plate (9) includes a plate-like portion (9a) facing the outer surface of the raised portion (Po) at the outermost end, and an annular portion (9c) along the The direction of the starting portion (Po) is bent into a ring shape from the radially outer side of the plate-like portion (9a). Said annular portion (9c) has a higher height than the raised portion (P, Po) of the flexible pipe (7).

Description

Flexible joint structure for exhaust system

technical field

The present invention relates to a flexible joint structure of an exhaust system which is connected halfway in the exhaust system from an engine for running ( engine for travel) extends to the rear of the car body.

Background technique

Generally, in a vehicle (such as an automobile) with a running engine installed at the front of the vehicle body, since the exhaust system of the engine extends rearward from the front of the vehicle body and has a long overall length, during the running of the vehicle, The generated operating vibration of the engine and driving vibration are not uniformly transmitted to the exhaust system, and stresses such as bending, twisting and shearing act locally on the part of the exhaust pipe forming the exhaust system, causing Cracks etc. occur in the tube.

Usually, as shown in Fig. 5, in order to avoid cracks, a flexible pipe with a corrugated section should be connected to the exhaust pipe along the middle, and the stress can be absorbed through the flexible pipe. In addition, in order to prevent the flexible pipe from being damaged by the impact of flying stones (eg, carried by wheels), etc., the outer peripheral surface of the flexible pipe is covered with a tubular outer braid during the running of the car. In addition, an inner plate is provided at a portion between the outer peripheral surface of the outer end of the flexible pipe and the inner peripheral surface of the outer end of the outer braid where severe friction occurs, so that abrasion, cracking, etc. can be avoided.

In this conventional structure, as shown in Figure 5, since an inner plate is provided between the outer peripheral surface of the outer end of the flexible pipe and the inner peripheral surface of the outer end of the outer braid, in order to prevent the flexible pipe and the outer friction between the braids, and make the inner plate bend towards the raised portion at the outermost end of the flexible pipe so as to cover the raised portion, therefore, it is necessary to at least make the raised portion at the outermost end more than the other raised portion part short.

Generally, in a flexible pipe with a corrugated cross-section, reducing the height of the raised portion increases the spring constant in the bending and extension directions. In particular, the spring constant becomes larger in the bending direction closer to the position of the raised portion which decreases in height toward either end of the tube. As described above, if the convex portion at the outermost end of the flexible pipe is set shorter than the other convex portions, the flexible pipe has a higher spring constant in the bending and extending directions. As a result, there is a problem that the flexible joint cannot properly perform its inherent function of absorbing stress such as bending and elongation due to vibration of the exhaust system. In order to solve this problem, measures must be taken to increase the number of raised parts, increase the height of the raised parts, reduce the wall thickness of the flexible pipe, etc., thus causing other problems of higher cost and increased size of the flexible joint.

In addition, the conventional flexible joint has the following problems: Since the edge at the end of the inner plate is close to the inner peripheral surface of the outer braid, this edge may interfere with the inner peripheral surface of the outer braid, thereby damaging the outer braid. taping.

Contents of the invention

The present invention has been achieved having considered the above circumstances, and an object of the present invention is to provide a novel flexible joint structure of an exhaust system which has solved the above-mentioned problems by improving the above-mentioned flexible pipe and inner plate .

In order to achieve the above object, the first aspect of the present invention provides a flexible joint structure of an exhaust system connecting an upstream exhaust pipe and a downstream exhaust pipe, the structure comprising: a flexible pipe having a corrugated section and It is formed by a number of alternating convex and concave parts, which have the same height; an outer braid covering the outer peripheral surface of the flexible pipe; and an inner plate arranged on the flexible pipe between the raised portion at the outermost end and an end wall portion of the outer braid. The inner plate has a connection end fixedly fixed between the outer braid and the flexible pipe; a plate-like portion radially protrudes from the inside of the connection end so as to face the protrusion at the outermost end of the flexible pipe the outer surface of the portion; and an annular portion bent into a ring shape from the radially outer side of the plate portion in a direction away from the raised portion at the outermost end. The height of the annular portion is higher than the raised portion of the flexible pipe to form an annular space between the outer braid and the flexible pipe.

According to this structure, since the flexible tube is formed with many convex portions and concave portions so as to have a uniform diameter over the entire length, the spring constant in the bending direction and extending direction of the flexible tube is kept low. In addition, since the many convex and concave portions of the flexible pipe do not contact the outer braid, the efficiency of absorbing and mitigating stresses such as torsion and bending applied to the upstream and downstream exhaust pipes can be improved as well as absorbing vibrations efficiency and the ability to easily manufacture the flexible pipe itself. In addition, although the raised portion at the outermost end has the same height as the other raised portions of the flexible pipe, since the direct contact between the raised portion at the outermost end and the outer braid can be avoided by the inner plate, , can avoid the wear of their mutual contact parts. In addition, since the annular portion of the inner plate is bent away from the raised portion at the outermost end, the edge portion of the inner plate does not contact the inner surface of the outer braid so as not to damage the outer braid.

In addition, according to the second aspect of the present invention, in addition to the first aspect, there is proposed a flexible joint structure for an exhaust system, wherein: the outer surface and the surface of the convex portion at the outermost end of the flexible pipe A space is formed between the plate-shaped portions of the inner plate to the outer surface.

According to this structure, in addition to the effect of the first aspect of the present invention, since the presence of the space allows the raised portion at the outermost end of the flexible pipe to also move toward the inner plate, the spring of the flexible pipe can be further reduced. constant, thereby improving its efficiency in absorbing vibrations.

The above objects, other objects, features and advantages of the present invention will be understood from the description of the preferred embodiment described in detail below with reference to the accompanying drawings.

Description of drawings

Fig. 1 is an overall side view of a first embodiment in which the flexible joint structure of the present invention is included in an engine of an automobile.

FIG. 2 is a longitudinal cross-sectional view of the flexible joint taken along line 2-2 of FIG. 1. FIG.

FIG. 3 is an enlarged view of a portion encircled by a dash-dotted line in FIG. 2 .

Fig. 4 is a partial longitudinal sectional view of the flexible joint in the second embodiment.

Fig. 5 is a longitudinal sectional view of a portion of a conventional flexible joint.

Detailed ways

Next, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3 .

The first embodiment is the case where the exhaust system flexible joint structure of the present invention is installed in an automobile engine.

In FIG. 1, an engine E for traveling is installed transversely on the front portion of an automobile body B (along its crankshaft Sc perpendicular to the longitudinal direction of the automobile). An intake system In is connected to an intake port opened on the front surface of the engine E head. An exhaust system Ex is connected to an exhaust port opened on the rear surface of the engine E. The exhaust system Ex comprises an exhaust manifold Me integrally connected with the exhaust port, and an exhaust pipe Pe. The exhaust pipe Pe extends longitudinally below the floor of the vehicle and includes an upstream exhaust pipe 1 and a downstream exhaust pipe 2 . A ball joint Jb is provided between the exhaust manifold Me and the upstream exhaust pipe 1 . Between the upstream exhaust pipe 1 and the downstream exhaust pipe 2, a flexible joint Jf of the present invention is provided. A catalytic converter Ca is provided halfway along the downstream exhaust pipe 2 . The downstream side of the catalytic converter Ca leads to the outside through a muffler (not shown). The housing part of the ball joint Jb is supported on the main part of the engine E by means of a stay 3 . The portion where the downstream exhaust pipe 2 and the catalytic converter Ca are connected to each other is elastically supported on a cross member of the vehicle body B by a stay 4 .

As shown in Figure 2, the opposite ends along the longitudinal direction of the flexible joint Jf of the present invention are connected by welding between the downstream end of the upstream exhaust pipe 1 and the upstream end of the downstream exhaust pipe 2, the upstream exhaust pipe 1 Both the downstream end of the downstream exhaust pipe 2 and the upstream end of the downstream exhaust pipe 2 are formed in a cylindrical shape. Both the end portion on the downstream side of the upstream exhaust pipe 1 and the end portion on the upstream side of the downstream exhaust pipe 2 are tapered toward their respective ends. The downstream and upstream ends having the smallest diameter are connected in a sealed and communicating manner by a flexible inner tube 5 . The exhaust gas flowing through the upstream exhaust pipe 1 flows into the downstream exhaust pipe 2 through the inner pipe 5 .

The flexible inner tube 5 is formed by helically winding and joining a strip-shaped tube forming material 5a and covering its outer surface with a tube material 5b. Since the inner tube 5 is generally known, a detailed description thereof is omitted.

The structure of the flexible joint Jf of the present invention will be described in detail with reference to FIGS. 2 and 3 . This flexible joint Jf consists of a flexible pipe 7, an outer braid 8 covering the outer peripheral surface of the flexible pipe 7, disposed on the outer peripheral surface at the opposite end of the flexible pipe 7 and on the inner peripheral surface at the opposite end of the outer braid 8. The front and rear inner panels 9 between them and the front and rear end panels 10 covering the outer peripheral surfaces at the front and rear ends of the outer braid 8 are formed, all of which are made of stainless steel sheet.

The flexible pipe 7 is formed of a tubular portion 7a constituting its main body, and front and rear cylindrical connecting end portions (mounting portions) 7b. The tubular portion 7a is formed by successively alternating many convex portions P and concave portions D so as to have a corrugated form in longitudinal section and have a uniform diameter along the entire length. The connecting end portion 7b extends in the axial direction from the bottom of the protruding portion Po at the outermost end of the tubular portion 7a. The flexible tube 7 has sufficient flexibility. As can be clearly seen in FIG. 3, the cross-sectional shape of each convex portion P and each concave portion D is such that their width gradually increases from the bottom to the tip so that the tip is wider than the bottom. Bottoms of the raised portions Po at the left and right outermost ends are integrally connected to the connecting end portion (mounting portion) 7b of the flexible pipe 7 .

The outer braid 8 consists of a linear cylindrical portion 8a covering the bellows portion 7a of the flexible pipe 7, end wall portions 8b bent radially inwardly from opposite ends at the front and rear of the cylindrical portion 8a, and extending from the ends at both ends. A small-diameter cylindrical connection end portion (mounting portion) 8c protruding axially inside the wall portion 8b is formed. The inner plate 9 has a connecting end portion 9b, a plate portion 9a and a ring portion 9c. The connection end 9b is firmly fixed between the outer braid 8 and the connection ends 8b and 7b of the flexible tube 7 . The plate portion 9a extends radially from the inside to the outside in the axial direction of the connection end portion 9b so as to face the outer surface of the raised portion Po at the outermost end of the flexible pipe 7 . The annular portion 9c is bent in a ring shape from the radially outer end of the plate portion 9a in a direction away from the outermost convex portion Po. The annular portion 9c is higher than the raised portion P, Po of the flexible pipe 7, i.e. it should be formed so as to be larger in the radial direction so that the linear cylindrical portion of the outer braid 8 covering the bellows-like portion 7a of the flexible pipe 7 An annular space S is formed between the inner peripheral surface of 8a and the outer peripheral surface of the bellows portion 7a of the flexible pipe 7 so that they are not brought into contact with each other even when the flexible joint Jf is bent.

The longitudinal outer end portion of the outer braid 8 including the connecting end portion 8c and the end wall portion 8b is covered with the end plate 10 .

As clearly shown in Fig. 3, the connecting ends 7b, 9b and 8b of the flexible tube 7, the inner plate 9 and the outer braid 8 are sequentially layered, and additionally, the connecting ends of the end plates 10 are overlapped. On the outer surface of the connecting end portion 8b of the outer braid 8 . The opposite edges are connected together by welding to the outer periphery of the downstream end of the upstream exhaust pipe 1 and the outer periphery of the upstream end of the downstream exhaust pipe 2 .

The operation of the first embodiment is explained below.

Exhaust gas generated by the operation of the engine E flows through the exhaust manifold Me, the ball joint Jb, the upstream exhaust pipe 1, the flexible joint Jf, the downstream exhaust pipe 2, the catalytic converter Ca, and the muffler (not shown ), during which noxious components such as HC and CO can be removed and exhaust sound suppressed, and the exhaust gas is released to the outside.

The exhaust system Ex is placed under the floor of the car; since the exhaust system Ex has a long overall length, the vibration generated during the running of the car and the operating vibration of the engine E are not evenly transmitted to the entire exhaust system , although stresses in the direction of torsion and bending are generated in the upstream and downstream exhaust pipes 1, 2, these stresses can be absorbed and relieved by the flexible joint Jf. In particular, in the embodiment of the present invention, since the tubular portion 7a of the flexible pipe 7 having a large number of convex portions P and concave portions D has a uniform diameter along its entire length, that is, the convex portion at the outermost end Po is not shorter than the other protruding portions P (unlike the conventional structure), so the spring constant in the bending and extending directions of the flexible tube 7 remains low. In addition, since the tubular portion 7a of the flexible pipe 7 does not contact the outer braid 8, the efficiency of absorbing stress and mitigating stress such as twists and bends exerted on the upstream and downstream exhaust pipes 1, 2 can be improved and the absorption The efficiency of the vibrations so as to be able to easily manufacture the flexible pipe 7 itself. Since the direct contact between the raised portion Po at the outermost end and the outer braid 8 can be avoided by the inner plate 9, although the raised portion Po at the outermost end has the same The height, however, still avoids wear on the contact parts between these parts. In addition, since the annular portion 9c of the inner plate 9 is bent in a direction away from the raised portion Po at the outermost end, the edge portion of the inner plate 9 does not interfere with the inner surface of the outer braid 8, thereby Any damage to the outer braid 8 can be avoided.

Next, a second embodiment of the present invention is explained with reference to FIG. 4 .

Fig. 4 is a partial sectional view of a flexible joint in the present invention. In this figure, the same components as those of the first embodiment are denoted by the same reference numerals and symbols.

In the case of the second embodiment, an annular distance d is formed between the outside of the raised portion Po at the outermost end of the flexible pipe 7 and the radially extending plate portion 9a of the inner plate 9, and the arrangement of other components Same as the first embodiment.

In the second embodiment, the presence of the distance d allows the raised portion Po at the outermost end of the tubular portion 7 a of the flexible tube 7 to also move towards the inner plate 9 . This makes it possible to further reduce the spring constant of the flexible tube 7, thereby improving the efficiency of absorbing vibrations.

Although the embodiments of the present invention have been explained in detail above, the present invention can be modified in various ways without departing from the spirit and scope of the present invention.

Claims (2)

1. flexible coupling structure that connects the vent systems of upstream exhaust pipe (1) and downstream row tracheae (2), this structure comprises:

A flexible pipe (7), it has one and connects an end (7b) and a tubular portion (7a), described tubular portion has the corrugated section and is formed by many alternately convex portions (P) and recessed portion (D), and these convex portions have identical height with recessed portion;

One outer braid (8), it has covered the outer circumferential face of flexible pipe (7); And

An inner panel (9), its be arranged at the convex portion (Po) at flexible pipe (7) outermost end place and outside between the end wall portion (8b) of braid (8);

Wherein, inner panel (9) has: a connection end (9b) that firmly fixes between braid outside (8) and the flexible pipe (7); A plate portion (9a), it extends radially out from connecting inboard, end (9b), so that face the outer surface at the convex portion (Po) at flexible pipe (7) outermost end place; And an annulus (9c), this part is along the direction of leaving the convex portion (Po) at outermost end place, curve ring-type by the radial outside of plate portion (9a); And the height of described annulus (9c) be higher than flexible pipe (7) convex portion (P, Po) so that form an annulus (s) between braid outside (8) and the flexible pipe (7).

2. the flexible coupling structure of vent systems according to claim 1, wherein: form spacing (d) at the outer surface of the convex portion (Po) at flexible pipe (7) outermost end place with between the plate portion (9a) of the inner panel (9) of described outer surface.

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