JPH086856B2 - Exhaust pipe spherical joint - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a spherical joint for an exhaust pipe.

[0002]

2. Description of the Related Art In automobiles, a spherical joint is mounted between the exhaust pipes to suppress vibrations in order to suppress vibrations in the exhaust pipes caused by engine vibrations and reduce resonance.

In FIG. 4, the spherical joints 1 and 2 are connected to the exhaust pipes 3 and 4,
The exhaust system connected between 5 is shown. 6 and 7 are mufflers. The structure of this type of spherical joint is shown in FIG. Reference numeral 8 denotes a bellows tube provided inside for maintaining airtightness, and has a ridge portion 8a having a wavy cross section, and cylindrical connecting portions 8b and 8c integrally formed on the right and left sides of the ridge portion 8a. Valleys 8d are formed between the mountain portions 8a.

Reference numeral 9 denotes a spherical inner tube, the left end of which is formed into a cylindrical shape which is fitted and welded to the connecting portion 8b of the bellows tube 8. Further, the right end spherical surface portion of the spherical surface inner tube 9 is formed in a spherical shape, and is fitted slidably with the left end spherical surface portion of the spherical surface outer tube 10. The right end of the spherical outer tube 10 is formed into a cylindrical shape that is fitted and welded to the connecting portion 8c of the bellows tube 8.

The bellows pipe 8 has left and right connecting portions 8b and 8c.
The inner diameter of is the inner diameter of the raw material tube before forming the bellows, that is, the diameter D of the general portion of the tube, and the inner diameter D ′ of the valley 8d is formed to have the same dimension as the diameter D of the general portion. The height of the mountain portion 8a was formed to be the same for all mountain portions. or,
Border parts 8e, 8 between the bellows part and the connecting parts 8b, 8c
f was formed with R having a small radius of curvature as shown in the sectional shape of the figure.

[0006]

SUMMARY OF THE INVENTION In the above conventional technique,
If you try to downsize the spherical part in order to reduce the sliding resistance of the spherical part and improve the vehicle mountability, the internal space will decrease due to the downsizing, and it will not be possible to secure the peak height and number of peaks of the bellows. Bellows rigidity is increased. Therefore, there has been a problem that the smooth flexibility required for the joint is impaired.

Therefore, an object of the present invention is to provide a spherical joint for an exhaust pipe which can solve such problems.

[0008]

In order to achieve the above object, the present invention relates to a spherical joint for an exhaust pipe having a bellows pipe (11) inside, and a valley portion diameter (D ') of the bellows is defined as a pipe general diameter ( D) and the radius of curvature (R _h ) of the vertical section of the valleys (11h) (11m) at both ends of the bellows
(R _m ) is set to be larger than the radius of curvature (R _{i to} R ₁ ) of the vertical cross section of the other valleys (11 _{i to 11 l} ).

It is effective to determine the height of each peak portion (11c to 11g) of the bellows along the inner surface shape of the spherical surface portion (9a).

[0010]

By reducing the diameter of the valley portion of the bellows, the height of the peak portion is substantially increased and the bending rigidity of the bellows is lowered. Therefore, both miniaturization and flexibility of the spherical portion are compatible. Also, the sliding resistance is reduced by making the spherical surface smaller. By making the radius of curvature of the valleys at both ends of the bellows larger than the radius of curvature of the other valleys, the stress concentration on the ends of the bellows during bending is relaxed,
The durable life until cracking is extended.

Furthermore, by defining the height of each crest along the inner surface of the spherical surface, the height of the crest located particularly in the central part of the bellows can be increased, and the bending rigidity is further reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention in which 9 is an inner tube of a spherical surface portion, 10 is an outer tube of a spherical surface portion, and respective spherical surface portions 9a and 10a are provided.
a is slidably fitted to each other. The left end of the spherical inner tube 9 forms a cylindrical connecting portion 9b, and the right end of the spherical outer tube 10 forms a cylindrical connecting portion 10b.

Reference numeral 11 is a bellows pipe, and left and right end portions are connecting portions 11a and 11b having a cylindrical pipe general portion diameter D, and central portions are peak portions 11c, 11d and 11e and valley portions 11h and 11.
i, 11j, and 11m are formed. Tanibe 11h-1
The diameter (inner diameter) D'of 1 m is set to be smaller than the diameter D of the general pipe portion of the connecting portions 11a and 11b.

The valleys 11h and 11m at both ends of the bellows
The radii of curvature R _h , R _m of the vertical section of the other valleys 11i, 1
It is set to be larger than the radii of curvature R _i and R _j of the vertical section of 1j.

In the first embodiment, the size of each part (m
m) is D: φ45.6, D ′: φ43.8, R _h =
R _m : R5 and R _i = R _j : R1.6.
Further, the thickness of the inner pipe 9 and the outer pipe 10 is t1.2, and the bellows pipe 1
The thickness of 1 is t0.3.

2 and 3 show a second embodiment of the present invention, in which 9 is a spherical portion inner tube, 10 is a spherical portion outer tube, and 11 is a bellows tube. Reference numerals 9a and 10a denote spherical portions formed on the spherical portion inner tube 9 and the spherical portion outer tube 10, respectively, and reference numerals 9b and 10b denote cylindrical connecting portions formed on the spherical portion inner tube 9 and the spherical portion outer tube 10, respectively.

In this embodiment, the bellows of the bellows tube 11 has five crests 11c to 11g and six troughs 11h.
It consists of ~ 11m. Valleys 11h and 11m at both ends of the bellows
The radii of curvature R _h and R _m of the vertical cross section of
It is defined greater than the radius of curvature R _i to R _l in longitudinal section of 1l.

Further, the heights of the five crests 11c to 11g are larger along the inner surface shape of the spherical surface portion 9a of the spherical inner tube 9 in the central crest portion. That is, the peak 11e is the highest, the peaks 11d and 11f are the second highest, and the peaks 11c at both ends are the highest.
And 11g is the lowest.

Incidentally, the dimensions of each part (m
m) is D: φ45.6, D ′: φ43.8, R _h = R
_m : R5, R _i = R _l : R2.0, R _j = R _k : R2.
It is specified in 3. Inner and outer tubes 9, 10 and bellows tube 1
The thickness of 1 is the same as that of the first embodiment. Also, the spherical surface 9
The inner diameter A of a is φ31.5, and the envelope that is in contact with the crests 11c to 11g of the bellows in the vertical cross section of FIG.
It is a circle along a, and its diameter B is set to a value φ27.5 which is slightly smaller than the inner diameter A. That is, the height of each mountain portion is determined according to the inner surface shape of the spherical surface portion 9a,
The maximum height. By doing so, the bending rigidity of the bellows pipe 11 can be minimized. If the bending rigidity is not so desired to be reduced, the joint can be downsized accordingly.

[0020]

Since the spherical joint of the exhaust pipe according to the present invention is constructed as described above, the bellows pipe has reduced rigidity and improved flexibility. Therefore, it is possible to achieve both miniaturization of the spherical portion and flexibility. Further, since the radius of curvature of the vertical cross section at both ends of the bellows is increased, stress concentration on the end portions of the bellows at the time of bending is alleviated, cracking is prevented, and the durability life is extended.

Furthermore, since the height of the peak portion of the bellows can be maximized within the spherical surface portion, the bending rigidity is further reduced from this surface.

[Brief description of drawings]

FIG. 1 is a partially longitudinal side view of a first embodiment of the present invention.

FIG. 2 is a vertical sectional side view of a second embodiment of the present invention.

FIG. 3 is an enlarged view of a main part of FIG.

FIG. 4 is a perspective view of an exhaust system.

FIG. 5 is a partial vertical side view of a conventional technique.

[Explanation of symbols]

9a spherical portion 11 Bellows 11c~11g crest 11h~11l valley R _h to R _m radius of curvature

Claims (2)

[Claims] 1. A spherical joint for an exhaust pipe having a bellows pipe therein, wherein the diameter of the valley portion of the bellows is made smaller than the diameter of the general pipe portion, and the radius of curvature of the vertical cross section of the valley portion at both ends of the bellows portion is set to another valley portion. A spherical joint for an exhaust pipe, characterized in that it has a larger radius of curvature than the longitudinal section. 2. The spherical joint for an exhaust pipe according to claim 1, wherein the height of each peak portion of the bellows is determined along the inner surface shape of the spherical portion.