JP2562096Y2 - Exhaust pipe fitting - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust pipe joint used for automobiles, motorcycles, etc., and more particularly, to a cylindrical gasket which prevents leakage of exhaust gas from an exhaust pipe joint at an initial stage of assembly and which is caused by minute vibration applied to the exhaust pipe. The present invention relates to an exhaust pipe joint that prevents damage to the exhaust pipe.

[0002]

2. Description of the Related Art Conventionally, exhaust pipe joints used for exhaust pipes of automobiles, motorcycles, etc. are made by laminating a metal plate or a metal plate and asbestos, and winding the resultant into a cylindrical shape. On the surface, a cylindrical gasket formed by applying a solid lubricant such as graphite powder to prevent slippage and sticking is fitted on the outer peripheral surface of the inner tube, and after fitting the outer tube on the outer peripheral surface of this gasket, In order to enhance the sealing between the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube, there is known a type in which the outer peripheral surface of the outer tube is fastened by a fastener such as a band, a so-called plug-in type.

Conventionally known plug-in type exhaust pipe joints of this type have the advantages of requiring less space and being easy to assemble as compared with other types, for example, flange type. On the other hand, there is a problem that it is disadvantageous to vibration and heat generated by the internal combustion engine.

[0004] In view of the above problems, the present applicant has filed Japanese Patent Application No. 2-44941 (Japanese Patent Application Laid-Open No. 2-125907: hereinafter referred to as "prior art").
Proposed an exhaust pipe joint that solved the above problems. An exhaust pipe joint according to this prior art will be described with reference to FIG.

[0005] An inner tube 1 and an opening 1a in the outer peripheral surface of the inner tube 1 are provided.
An outer tube 2 having a certain length inserted therein, a cylindrical gasket 3 inserted into an annular gap formed in a fitting portion of the outer tube 1 and the inner tube 2, and an outer peripheral surface of the outer tube 2. In the exhaust pipe joint comprising the tightening band 4 to be formed, the inner pipe 1 is fixed with an annular flange 1c protruding radially outward, leaving a pipe end 1b near the opening 1a, The outer pipe 2 is provided at its end with an enlarged diameter portion 2a and at the enlarged diameter portion a slit 2b which is equally divided in the circumferential direction and extends along the axial direction, and the inner tube 1 has a tube end including its annular flange 1c. The portion 1b is fitted into the enlarged diameter portion 2a of the outer tube 2, and the fitted portion includes the tube end portion 1b of the inner tube 1, one end surface of the annular flange 1c, and the inner peripheral surface of the enlarged diameter portion 2a of the outer tube 2. An annular gap is formed in the annular gap, and a cylindrical gas comprising a reinforcing material and expanded graphite is formed in the annular gap. An exhaust pipe joint in which the end portion of the gasket 3 is in contact with one end surface of the annular flange 1c, and the other end portion is arranged to leave a space G closed by thermal expansion of the cylindrical gasket 3. is there.

[0006] The exhaust pipe joints of the prior art described above are:
A cylindrical shape made of a reinforcing material and expanded graphite disposed in an annular gap formed by a tube end portion 1b of the inner tube 1, one end surface of the annular flange 1c, and an inner peripheral surface of the enlarged diameter portion 2a of the outer tube 2. The gasket 3 expands in volume due to the heat of the high-temperature exhaust gas flowing through the inner tube 1. Due to the volume expansion, the assembling of the tube end portion 1 a of the inner tube 1, the end face of the gasket 3, and the shoulder of the enlarged diameter portion 2 a of the outer tube 2. This has the advantage that the space G formed by the joints can be closed tightly and the sealing performance of the joint can be improved.

[0007]

However, in the exhaust pipe joint of the prior art, the volumetric expansion of the cylindrical gasket 3 due to the heat of the high-temperature exhaust gas flowing through the inner pipe 1 causes the volume expansion of the inner pipe 1 during assembly. The space G formed by the pipe end portion 1a, the end face of the gasket 3, and the shoulder of the enlarged diameter portion 2a of the outer tube 2 is tightly closed. When assembling the exhaust pipe joint, in other words, the exhaust pipe No measures have been taken against leakage of exhaust gas, which is present at the time of assembling, particularly from an annular gap between the inner surface of the cylindrical gasket and the outer surface of the inner tube.

Since the volume expansion of the cylindrical gasket 3 due to the heat of the high-temperature exhaust gas is a factor of time,
The effect of immediately expanding the volume due to the heat of the high-temperature exhaust gas and immediately closing the space G cannot be expected, and there is a problem that the exhaust gas leaks from the joint when the joint is assembled. Was issued.

In the above-described exhaust pipe joint, the outer pipe 2 is usually connected and fixed to the muffler side, and then the inner pipe 1 is connected and fixed to the engine side. Since the pipe 2 has dimensional tolerances in the longitudinal direction in its manufacture, the accumulation of these dimensional tolerances causes the exhaust pipe joint to have a cylindrical shape when assembled to the engine-side exhaust pipe and the muffler-side exhaust pipe. There may be an axial gap between one end of the gasket 3 and the annular flange 1c of the inner tube 1. One end of the cylindrical gasket 3 and the inner tube 1
When the exhaust pipe joint is used in a state where a gap is formed between the outer pipe 1 and the annular flange 1c, the minute vibration transmitted from the engine side to the inner and outer pipes 1 and 2 is directly transmitted to the cylindrical gasket 3. Due to this minute vibration, the cylindrical gasket 3
There is also a problem that the gasket is hit or damaged as a result of being hit between the outer tubes, which causes a leak of exhaust gas.

The present invention has been made in view of the above-mentioned problems, and effectively utilizes the advantage of the improvement in the sealing performance caused by the volume expansion of the gasket in the prior art. It is an object of the present invention to provide an exhaust pipe joint which can prevent the exhaust gas from leaking and prevent the gasket from being damaged due to the vibration of the outer pipe among the cylindrical gaskets.

[0011]

According to the present invention, an object of the present invention is to provide an outer tube in which an enlarged cylindrical portion having a shoulder portion is formed at the end of the outer tube, and the enlarged cylindrical portion is provided on the enlarged cylindrical portion. A pair of slit grooves are formed at a position facing the shoulder from the end and facing the axis of the outer tube, and a pair of slit grooves are formed at positions facing each other across the groove. A pair of nuts are fixed facing each other in the vicinity of a shoulder on the extension of the slit groove, a cylindrical gasket is press-fitted on the inner surface of the enlarged cylindrical portion, and an inner surface of the cylindrical gasket is fixed on the inner surface of the cylindrical gasket. The inner pipe has a pipe end extending to the inner surface of the outer pipe and is inserted into the outer pipe. A semi-cylindrical part is formed integrally with the outer peripheral surface of the inner pipe at the top of the outer peripheral surface of the semi-cylindrical part. Projecting portions and extending radially outwardly formed at the ends of the semi-cylindrical portion with the projecting portions interposed therebetween. And a pair of pressing pieces surrounding the inner surface of the semi-cylindrical portion with the outer peripheral surface of the inner tube, and are integrally fastened at the flange portion and inserted through the protruding portion to the enlarged cylindrical portion. By tightening a pair of bolts screwed to the fixed nut, the protruding portion is engaged with the notch groove of the enlarged cylindrical portion, and the combined flange portion is engaged with the notch groove, respectively. The cylindrical gasket is pressed by the end surface of the semi-cylindrical portion of the pressing piece by the movement of the pressing piece by tightening the bolt, and the inner surface and the inner surface of the enlarged cylindrical portion are moved. The space between the outer surface of the tube and the outer surface of the tube is compressed and deformed, and the space is tightly closed.The pressing piece further holds the inner tube on the inner surface of the semi-cylindrical portion by further tightening the combined flange. Exhaust pipe joints the inner and outer pipes rigidly It is achieved by.

In the above-described configuration, when a gasket obtained by laminating a metal wire mesh and an expanded graphite sheet, winding this in a cylindrical shape, and then compression-molding in the axial direction is used as the cylindrical gasket, As in the prior art, the gasket expands its volume by the action of the heat of the high-temperature exhaust gas flowing through the exhaust pipe, so that a further sealing action can be performed.

[0013]

A cylindrical gasket is press-fitted into the space between the enlarged cylindrical portion of the outer tube and the outer surface of the inner tube. The cylindrical gasket is pressed in the axial direction by a pressing piece to be compressed and deformed, thereby tightly closing the space. Because of the closing, the gap existing at the time of assembly is filled, and as a result, leakage of exhaust gas from the joint portion at the time of assembling the joint to the exhaust pipe is prevented.

Further, since the inner cylinder and the enlarged cylindrical portion of the outer pipe are rigidly connected via the pressing piece, the vibration of the inner and outer pipes does not directly act on the cylindrical gasket. There is no damage to the cylindrical gasket.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings showing an embodiment thereof.

FIG. 1 is a longitudinal sectional view showing an exhaust pipe joint of the present invention, FIG. 2 is a sectional view taken along the line II in FIG. 1, and FIG. 3 is a longitudinal sectional view showing a state before assembly is completed. In the figure, reference numeral 10 denotes an outer tube connected to the muffler side. The outer tube 10 has an enlarged cylindrical portion 12 formed at the end of the outer tube with an outer tube 10 and a shoulder portion 11 to expand the diameter.

The enlarged cylindrical portion 12 has a shoulder 11
A pair of slits 13 are formed at positions opposite to each other across the axis of the outer tube 10 and a pair of slits 14 at positions opposite to each other across the slit 13.

Numeral 20 denotes a pair of nuts which are fixed to the outer peripheral surface of the enlarged cylindrical portion near the shoulder in opposition to each other. The nut 20 has a female screw portion on the inner surface and is formed on the enlarged cylindrical portion 12. It is located on an extension of the pair of slits 13.

Reference numeral 30 denotes a cylindrical gasket.
30 is press-fitted into the inner surface of the enlarged cylindrical portion 12. The gasket 30 is not particularly limited as long as it is easily deformed when compressed and has heat resistance. For example, a reinforcing material consisting of a wire mesh obtained by weaving or knitting a thin metal wire is superimposed on a heat-resistant sheet such as expanded graphite or mica, and this is wound into a cylindrical shape to form a preform, and then the preform is formed. A body formed by compressing the body in the axial direction can be cited as a preferable one.

Reference numeral 40 denotes an inner pipe connected to the engine side,
The tube end of the inner tube 40 is inserted through the inner surface of the cylindrical gasket 30 so as to extend to the inner surface of the outer tube 10.

Reference numeral 50 denotes a pair of pressing pieces which are divided into two in the radial direction. The pressing pieces 50 include a semi-cylindrical portion 51, a projecting portion 52 integrally formed on the outer circumferential surface of the semi-cylindrical portion, and a projecting portion. And a flange portion 53 extending radially outwardly formed at each end of the semi-cylindrical portion with the interposed portion therebetween. A through hole 54 is formed in the projecting portion 51 of the pressing piece 50 along the axial direction of the outer tube, and a through hole 55 is formed in the flange 53 so as to penetrate the plate surface.

A pair of pressing pieces 50 respectively surround the inner surface of the semi-cylindrical portion 51 with the outer peripheral surface of the inner tube 40, and have a flange portion.
A pair of bolts 53 are integrally fastened by bolts and nuts 60 passing through the through holes 55 and screwed into the nuts 20 fixed to the enlarged cylindrical portion 12 through the through holes 54 of the protrusions 52. By tightening 70, the projection 52 is engaged with the slit 13 of the enlarged cylindrical portion 12, and the combined flange 53 is engaged with the slit 14 so that the outer tube 10 can be moved in the axial direction. It is arranged on the outer peripheral surface of the inner tube 40.

In this state, the bolt 70 is tightened to move the integrally joined pressing piece 50 along the inner tube 40, and the end surface of the semi-cylindrical portion 51 of the pressing piece 50 contacts the cylindrical gasket 30. At the same time, the cylindrical gasket 30 is pressed in the axial direction of the outer tube 10. The cylindrical gasket 30 pressed against the end face of the semi-cylindrical portion 51 is compressed and deformed, and
And the space G formed by the inner surface of the inner tube 40 and the outer surface of the inner tube 40.

The flange 53 of the pressing piece 50 is further tightened with a bolt / nut 60 inserted through the through hole 55 of the flange 53, so that the outer peripheral surface of the inner tube 40 becomes a semi-cylindrical portion of the pressing piece 50. The inner tube 40 and the outer tube 10 are firmly held by the inner tube 51 and are firmly connected.

In the exhaust pipe joint assembled in this manner, the gap between the enlarged cylindrical portion 12 of the outer pipe 10 and the inner pipe 40 is closed by the cylindrical gasket 30, so that the exhaust gas There is no leakage.

Further, even when the vibration transmitted from the engine causes vibration in the inner and outer tubes 40 and 10, even if the inner and outer tubes 40 and 10 are vibrated.
Since 40 and 10 are rigidly connected by the pressing piece 50,
Since the vibration transmitted to the inner and outer tubes 40 and 10 does not directly act on the cylindrical gasket 30, the cylindrical gasket 30 does not suffer from settling, damage, etc. due to the vibration of the inner and outer tubes 40 and 10. . Therefore, leakage of exhaust gas due to damage to the cylindrical gasket or the like is prevented.

[0027]

The exhaust pipe joint of the present invention having the above-described structure has the following effects. The cylindrical gasket is pressed in the axial direction of the outer tube by the pressing piece at the time of assembly, is compressed and deformed, and is formed by the inner surface of the enlarged cylindrical portion where the cylindrical gasket is disposed, the outer surface of the inner tube, and the shoulder of the outer tube. And tightly closes the space, thereby preventing leakage of exhaust gas from the joint at the initial stage of assembly. Even if the inner and outer tubes vibrate due to the vibration transmitted from the engine, since the inner and outer tubes are rigidly connected by the pressing pieces, the minute vibration transmitted to the inner and outer tubes is transferred to the cylindrical gasket. Does not act directly, so that the cylindrical gasket does not suffer from settling, damage, etc. due to the minute vibration of the inner and outer tubes, and leakage of exhaust gas due to the damage, etc., of the cylindrical gasket is prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an exhaust pipe joint of the present invention.

FIG. 2 is a sectional view taken along the line II in FIG.

FIG. 3 is a longitudinal sectional view showing a state before assembly of the exhaust pipe joint of the present invention.

FIG. 4 is a longitudinal sectional view showing a prior art exhaust pipe joint.

[Explanation of symbols]

 10 Outer pipe 11 Shoulder 12 Enlarged cylindrical section 13 Groove 14 Groove 14 Groove 20 Nut 30 Cylindrical gasket 40 Inner pipe 50 Pressing piece 51 Semi-cylindrical section 52 Projection 53 Flange 70 Bolt

Claims (1)

(57) [Scope of request for utility model registration] 1. An outer tube is formed with an enlarged cylindrical portion having a shoulder at the end of the outer tube, the enlarged cylindrical portion extending from the end of the tube toward the shoulder and extending along the axis of the outer tube. A pair of slit grooves and a pair of notch grooves are formed at positions opposing each other across the cut groove, and near a shoulder on an extension of the cut groove. A pair of nuts are fixed to face each other, a cylindrical gasket is press-fitted on the inner surface of the enlarged cylindrical portion, and an inner tube has a tube end on the inner surface of the cylindrical tube. A semi-cylindrical part, a projection integrally formed on the top of the outer peripheral surface of the semi-cylindrical part, and the semi-cylindrical body sandwiching the projection; A pair of pressing pieces each having a radially outwardly extending flange formed at an end of the semi-cylindrical portion. The inner surface of the inner tube is surrounded by the outer peripheral surface of the inner tube, and is tightened by a pair of bolts which are integrally fastened at the flange portion and which are screwed into the nut fixed to the enlarged cylindrical portion through the protruding portion. The projection is engaged with the cut groove of the enlarged cylindrical portion, and the combined flange is engaged with the cut groove, so that the protrusion is movable in the axial direction of the outer tube. As an element, the cylindrical gasket is pressed by the end surface of the semi-cylindrical portion of the pressing piece by the movement of the pressing piece by tightening the bolt, and is compressed and deformed into the space between the inner surface of the enlarged cylindrical portion and the outer surface of the inner tube. The space is tightly closed, and the pressing piece tightly holds the inner tube on the inner surface of the semi-cylindrical portion by further tightening the combined flange, thereby rigidly connecting the inner tube and the outer tube. Exhaust pipe joint characterized by the following.