JPH06307239A - Exhaust pipe structure - Google Patents

Abstract

PURPOSE:To absorb turning movement, oscillating motion and axial displacement generated at an exhaust pipe. CONSTITUTION:A joint 1 by which the rear end portion of a connection pipe 2 passing exhaust gas and the front end portion of an inner pipe 3 are coaxially connected to each other, is composed of two pairs of inside ball support grooves 4a, 4b provided on the outer periphery surface of the rear end portion of the connection pipe 2 so as to form a pair dimetrically at 90 degree pitches in regard to a peripheral direction; two pairs of outside ball support grooves 6a, 6b provided on the inner periphery surface of the front end portion of the inner pipe 3 so as to be able to oppose respective inside ball support grooves 4a, 4b; and balls 5 interpossingly provided between respective mutually-facing fellow ball support grooves so as to be able to roll. As a result, at the connection portions of both pipes, grooves and balls are provided at point symmetry positions in the peripheral direction, and both fellow pipes can conduct oscillating motion mutually and relatively like universal joints, and can be displaced axially, and the structure of an exhaust pipe can be simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust pipe structure, and more particularly to an exhaust pipe structure for absorbing displacement of a pipe connecting portion of an exhaust pipe during a swinging motion due to engine vibration or the like.

[0002]

2. Description of the Related Art In recent years, an exhaust silencer in an exhaust pipe structure of an internal combustion engine is made of a synthetic resin material having excellent corrosion resistance and sound insulation as disclosed in, for example, Japanese Utility Model Laid-Open No. 3-63715. There are an outer shell as an outer plate member, an inner pipe that requires heat resistance formed of a metal material and a combination of both, and a combination of both formed of a synthetic resin material.

Among the conventional exhaust silencers as described above, there is one shown in FIG. 3, for example. In FIG.
A connecting pipe 21 is connected to an exhaust manifold connected to an engine (not shown), and a portion from an intermediate portion to a rear end of an inner pipe 22 flange-connected to the connecting pipe 21 is fixed to a vehicle body (not shown) of the exhaust silencer. It is received in the outer shell 23 made of synthetic resin.

When the engine vibrates in the above structure,
Vibration is transmitted from the connecting pipe 21 to the inner pipe 22, but as described above, the connecting pipe 21 is directly connected to the engine, and the inner pipe 22 is supported by the vehicle body via the outer shell 23. Since there is a displacement gap between the inner pipe 22 and the inner pipe 22, the joint 24, which is the connecting portion between the both, is
It is necessary to have a structure that can absorb the relative displacement between them.

In the structure of the conventional joint 24,
For example, there is one shown in FIG. In FIG. 4, a support ring 25 is fitted to the rear end of the outer peripheral surface of the rear end of the connecting pipe 21, and an outward flange 26 is continuously provided to the front of the support ring 25. . Support ring 25
In the connected state, the peripheral portion on the inner pipe 22 side is formed so as to form a part of a spherical surface.

At the front end of the inner pipe 22, an annular taper body 27 formed so as to expand toward the front is coaxially fixed. The inner peripheral surface of the annular taper body 27 is curved so as to form a shape complementary to the partial spherical surface portion of the support ring 25, and the partial spherical surface of the support ring 25 in the connected state of both pipes 21 and 22. The portion and the inner peripheral surface of the annular taper body 27 are in contact with each other so that they can slide relative to each other.

Further, the outward flange 26 and the annular taper body 2
7 is partially connected via a connecting bolt 28 and a spring 29, and both pipes 21 and 22 are connected to each other. However, due to the partial spherical contact between the support ring 25 and the annular taper body 27, the inner ring is formed. The pipe 21 is freely tiltable relative to the connecting pipe 22 as shown by an arrow C in the figure.

FIG. 5 shows another structure of the conventional joint. In the joint 31 of FIG. 5, it may be interposed between the connecting pipe 21 and the inner pipe 22, and since it is substantially symmetrical, only the right side portion is shown. The joint 31 includes a flexible tube 32,
A connecting pipe 33 connected to the axial end of the flexible tube 32 and extending outward in the axial direction, and an outward flange portion 3 provided at the extended free end of the connecting pipe 33.
4 and.

The inner pipe 22 is integrally flange-connected to the outward flange portion 34, and the connecting pipe 21 is integrally flange-connected to the outward flange portion (not shown) on the other end side. Since both pipes 21 and 22 are connected to each other via the flexible tube 32, the inner pipe 22 can freely swing relative to the connecting pipe 21 as shown by an arrow C in the figure.

In each of the conventional joints 24 and 31, when the pipes 21 and 22 affected by the exhaust heat are thermally expanded and contracted and a large displacement is generated in the axial direction, which is the longitudinal direction of the pipes, the structure is reduced. In addition, the axial displacement of the pipe cannot be absorbed, and the outer shell is hung on the vehicle body via the elastic member to absorb the axial displacement due to thermal expansion and contraction of the pipe. Therefore, the exhaust pipe structure that can absorb the swinging motion of the connecting portion between the pipes due to engine vibration or the like is complicated.

[0011]

In view of the above problems of the prior art, the main object of the present invention is to improve the relative swinging motion which can be generated in the connecting portion of both pipes due to vibration or the like. It is to provide an exhaust pipe structure.

[0012]

According to the invention, such an object is achieved by forming one end of both pipes connected to each other so as to be coaxially received in the other end, A plurality of rolling element support grooves extending in the axial direction on the outer peripheral surface of one end portion and the inner peripheral surface of the other end portion are provided at point symmetrical positions in the circumferential direction, respectively, and face each other, and each of the pair of This is achieved by providing an exhaust pipe structure characterized in that rolling elements are received between rolling element support grooves so as to be displaceable in the grooves. In particular, it is suitable when one of the two pipes is connected to the engine and the other of the two pipes is connected to an exhaust silencer made of synthetic resin directly attached to the vehicle body.

[0013]

According to this structure, when a swinging motion is relatively generated between the pipes due to the vibration of the engine or the like, the rolling element support grooves arranged in point symmetrical positions in the circumferential direction are respectively provided in the rolling element support grooves. Since both pipes are freely swingable relative to each other as in the case of the universal joint, when the pipes are thermally expanded and contracted in the axial direction which is the longitudinal direction due to the influence of exhaust heat, Since the rolling element can move while rolling in the rolling element support groove, both pipes can be relatively displaced in the axial direction.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is an exploded perspective view of an essential part of an automobile exhaust pipe to which the present invention is applied. The entire structure of the exhaust pipe is the same as that shown in FIG. Arrow
FIG. 4 is a fragmentary cutaway view of the joint 1, which may be used for the portion indicated by IV. In FIG. 1, the rear end of the connecting pipe 2 corresponding to the conventional connecting pipe 21 and the front end of the inner pipe 3 corresponding to the conventional inner pipe 22 are coaxially connected to each other.

The outer peripheral surface of the rear end of the connecting pipe 2 is shown in FIG.
And, as shown in FIG. 2 showing an exploded perspective view, at each position of 90 ° pitch as a point-symmetrical position in the circumferential direction,
Two pairs of diametrically paired inner ball support grooves 4a and 4b are provided as rolling element support grooves that are recessed along the axial direction so as to extend parallel to each other. One pair of inner ball support grooves 4a is formed longer than the other pair of inner ball support grooves 4b in the axial direction, and these inner ball support grooves 4a and 4b are made of steel balls as rolling elements. Part of 5 is accepted.

The front end in the axial direction of the inner pipe 3 is formed to have a large diameter so that it can be fitted into the rear end of the connecting pipe 2, and the connecting pipe 2 is assembled in the assembled state shown in FIG. The front end of the inner pipe 3 surrounds the rear end of the inner pipe 3, and the inner peripheral surface of the front end of the inner pipe 3 can be assembled to the inner ball support grooves 4a and 4b. Two pairs of outer ball support grooves 6a and 6b as rolling element support grooves are provided at positions of 90 ° pitch in the circumferential direction. Each of these outer ball support grooves 6a and 6b also includes the ball 5
A pair of outer ball support grooves 6a corresponding to the pair of inner ball support grooves 4a of a longer side are shorter and a pair of inner ball support grooves 4b of a shorter side are formed.
The pair of outer ball support grooves 6b corresponding to 1 are formed long.

In the assembled state as shown in FIG. 1, the balls 5 are interposed so that the ball supporting grooves 4a, 4b, 6a, 6b face each other, but the balls 5 are interposed between them. The respective ends of the connecting pipe 2 and the inner pipe 3 shown by the arrow A in FIG. 1 are rollably received in the ball support grooves 4a, 4b, 6a, 6b when they are displaced in the axial direction. A flexible tube cover 7 is coaxially fitted between the pipes 1 and 2 to prevent the exhaust gas from leaking out from the gap between the connecting portions of the pipes 1 and 2. Both ends of the flexible tube cover 7 in the axial direction are fitted into the pipes 1 and 2.

In this embodiment, as shown in the conventional example, the front end of the connecting pipe 2 is connected to the engine, and the rear end of the inner pipe 3 is made of synthetic resin, so that the surface temperature It is connected to an outer shell 23 that is directly fixed to the vehicle body in order to suppress the rise. Therefore, due to the vibration of the engine or the like, the connecting pipe 2 is
Vibrates relative to each other, a relative swinging motion occurs between the pipes. In this embodiment, each ball support groove 4a
4b, 6a, and 6b are arranged at 90 pitches which are point-symmetrical positions, and like the universal joint, are shown around the axis connecting the pair of balls 5 on one side, for example, as shown by an arrow B in FIG. As described above, the pipes 1 and 2 can freely swing around each other. Therefore, as described above, by structuring the outer shell of the silencer directly on the vehicle body, even if a swinging motion occurs in the connecting portion of the exhaust pipe due to engine vibration or the like, the displacement can be absorbed. Advantages of using the outer shell made of synthetic resin can be suitably secured.

Further, the connecting pipe 2 and the inner pipe 3
However, when it expands and contracts in the direction shown by arrow A in FIG. 1 due to the effect of exhaust heat, the rear end portion of the connecting pipe 2 and the inner pipe 3
Relative displacement occurs between the front end and the front end. According to the present embodiment, both pipes 1 and 2 are relatively supported via the balls 5 as described above, and the displacement generated between the pipes 1 and 2 is adjusted by the ball support grooves 4a, 4b, 6a and 6b. It can be absorbed by the movement of the balls 5 rolling in the opposing ones. Furthermore, the resistance between the two pipes 1 and 2 at the time of relative displacement can be suitably reduced by rolling the balls 5.

The structure of the present invention can be applied to various places in the portion where the displacement of the exhaust pipe occurs, but, for example, it can be applied to only one place shown in the embodiment, and various displacements of the exhaust system can be made to one place. Can be absorbed. In the present embodiment, the ball support grooves are arranged at a pitch of 90 degrees in the circumferential direction, but they may be located at point symmetrical positions. Also, although ball support grooves are provided on both pipes, it is sufficient if balls can roll,
The ball support groove may be provided on only one of the outer sides. Alternatively, two parallel ridges may be provided to form a groove so that the ball is received between the ridges.

[0022]

As described above, according to the present invention, even if a swinging motion occurs in a connecting portion between exhausts due to engine vibration or the like,
As with the universal joint, the displacement due to its swinging motion can be absorbed, and when the pipe thermally expands and contracts under the influence of exhaust heat, the rolling element can move while rolling in the axial direction of the pipe end. Therefore, the relative displacement between both pipes can be absorbed, and the pipes can be displaceably supported by a simple structure, so that the durability can be improved and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a fragmentary sectional view of a connecting portion of an automobile exhaust pipe to which the present invention is applied.

FIG. 2 is an exploded perspective view of an essential part of the connecting portion of FIG.

FIG. 3 is an external view of a conventional automobile exhaust pipe structure.

FIG. 4 is an enlarged side sectional view of an essential part showing a conventional exhaust pipe structure.

[Explanation of symbols]

 1 joint 2 connection pipe 3 inner pipe 4a, 4b inner ball support groove 5 ball 6a, 6b outer ball support groove 7 flexible tube cover 21 connection pipe 22 inner pipe 23 outer shell 24 joint 25 support ring 26 outward flange 27 annular taper body 28 connection Bolt 29 Spring 31 Joint 32 Flexible tube 33 Connection pipe 34 Outward flange

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[Procedure amendment]

[Submission date] October 12, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a fragmentary sectional view of a connecting portion of an automobile exhaust pipe to which the present invention is applied.

FIG. 2 is an exploded perspective view of an essential part of the connecting portion of FIG.

FIG. 3 is an external view of a conventional automobile exhaust pipe structure.

FIG. 4 is an enlarged side sectional view of an essential part showing a conventional exhaust pipe structure.

FIG. 5 is an enlarged main part showing another embodiment of a conventional exhaust pipe structure.
Large side sectional view.

[Explanation of symbols] 1 joint 2 connecting pipe 3 inner pipe 4a, 4b inner ball supporting groove 5 ball 6a, 6b outer ball supporting groove 7 flexible tube cover 21 connecting pipe 22 inner pipe 23 outer shell 24 joint 25 supporting ring 26 outward flange 27 Annular taper body 28 Connection bolt 29 Spring 31 Joint 32 Flexible tube 33 Connection pipe 34 Outward flange part

Claims (2)

[Claims] 1. An outer peripheral surface of the one end portion and an inner peripheral surface of the other end portion are formed so that one end portions of both pipes connected to each other are coaxially received in the other end portion. A plurality of rolling element support grooves extending in the axial direction with respect to the surface are provided at circumferentially point-symmetrical positions and opposed to each other so that the rolling elements can be displaced between the pair of rolling element support grooves. Exhaust pipe structure characterized by being accepted by. 2. One of the two pipes is connected to an engine, and the other of the two pipes is connected to an exhaust silencer made of synthetic resin directly attached to a vehicle body. Exhaust pipe structure described.