JPH0532718U - Exhaust pipe fitting - Google Patents

Abstract

(57) [Abstract] [Purpose] In an exhaust pipe joint used for automobiles, motorcycles, etc., it prevents leakage of exhaust gas from the exhaust pipe joint at the initial stage of assembly, and seals due to minute vibration applied to the exhaust pipe. Prevents damage to the cylindrical gasket that forms the. [Structure] An outer tube is formed with an enlarged cylindrical portion whose diameter is increased by a shoulder portion at an end portion of the outer tube, and the enlarged cylindrical portion has a pair of slits and a pair of opposed slits sandwiching the slit. Is formed with a slit groove and a pair of nuts are fixed on the extension of the slit groove, a cylindrical gasket is press-fitted on the inner surface of the enlarged cylindrical portion, and the inner surface of the gasket is An inner tube is inserted, and the gasket is compressed and deformed by a pair of pressing pieces through which bolts screwed into the nut are inserted to seal the space between the inner surface of the enlarged cylindrical portion and the outer surface of the inner tube. The pressing pieces are fastened to each other to strongly hold the inner tube and rigidly connect the inner and outer tubes.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is an exhaust pipe joint used in automobiles, motorcycles, etc., more specifically, an exhaust pipe that prevents leakage of exhaust gas from the exhaust pipe joint at the initial stage of assembly and prevents damage to the cylindrical gasket due to minute vibration applied to the exhaust pipe. It concerns a joint.

[0002]

[Prior Art]

 Conventionally, exhaust pipe joints used for exhaust pipes of automobiles, motorcycles, etc., have a metal plate or a metal plate and asbestos laid on top of each other, and then wound into a cylindrical shape. Then, fit a cylindrical gasket formed by coating a solid lubricant such as graphite powder on the outer peripheral surface of the inner pipe to prevent slipping and sticking, and after fitting the outer pipe on the outer peripheral surface of this gasket, In order to enhance the sealing performance between the outer peripheral surface of the inner pipe and the inner peripheral surface of the outer pipe, a so-called plug-in type is known in which the outer peripheral surface of the outer pipe is tightened by a tightening tool such as a band.

The conventionally known plug-in type exhaust pipe joint of this type has advantages that it requires less space and is easier to assemble than 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.

In view of the above problems, the present applicant proposes an exhaust pipe joint that solves the above problems in Japanese Patent Application No. 2-244941 (JP-A-2-125907: hereinafter referred to as “prior art”). did. The exhaust pipe joint according to this prior art will be described with reference to FIG.

The inner pipe 1, the outer pipe 2 fitted to the outer peripheral surface of the inner pipe 1 from the opening 1 a by a certain length, and the inside and the annular gap formed in the fitted portion of the outer pipes 1 and 2. In an exhaust pipe joint consisting of a cylindrical gasket 3 inserted into the outer pipe 2 and a tightening band 4 that is fastened and fixed to the outer peripheral surface of the outer pipe 2, the inner pipe 1 has a pipe end portion near the opening 1a. An annular flange 1c protruding outward in the radial direction is fixed, leaving 1b, and the outer pipe 2 is divided into a radially enlarged portion 2a at the pipe end portion and a radially enlarged portion in the circumferential direction, and axially. A slit 2b is provided along the inner pipe 1, and a pipe end portion 1b including an annular flange 1c of the inner pipe 1 is fitted into a diameter-enlarged portion 2a of the outer pipe 2 and a pipe end portion 1b of the inner pipe 1 An annular gap is formed by one end surface of the annular flange 1c and the inner peripheral surface of the enlarged diameter portion 2a of the outer tube 2. In this annular gap, a cylindrical gasket 3 made of a reinforcing material and expanded graphite is brought into contact with one end of the annular flange 1c at one end and thermal expansion of the cylindrical gasket 3 at the other end. The exhaust pipe joint is arranged so as to leave the space G closed.

The exhaust pipe joint according to the above-described prior art has an annular gap formed by the pipe end portion 1b of the inner pipe 1, one end surface of the annular flange 1c, and the inner peripheral surface of the enlarged diameter portion 2a of the outer pipe 2. The cylindrical gasket 3 composed of a reinforcing material and expanded graphite arranged in the inner tube 1 expands in volume by the heat of the high-temperature exhaust gas flowing in the inner tube 1, and due to this volume expansion, the pipe end portion 1a of the inner tube 1 is assembled. The space G formed by the end surface of the gasket 3 and the shoulder of the enlarged diameter portion 2a of the outer tube 2 is tightly closed, and the sealing performance of the joint can be improved. ..

[0007]

[Problems to be solved by the device]

 However, in the exhaust pipe joint in the above-mentioned prior art, the cylindrical gasket 3 expands in volume by the heat of the high-temperature exhaust gas flowing in the inner pipe 1, and due to this volume expansion, the pipe end portion 1a of the inner pipe 1 and the gasket 3 are assembled. The space G formed by the end face and the shoulder of the enlarged diameter portion 2a of the outer pipe 2 is tightly closed, and is present at the time of assembling the exhaust pipe joint, in other words, when assembling to the exhaust pipe, In particular, no measures have been taken against the leakage of exhaust gas from the annular gap between the inner surface of the cylindrical gasket and the outer peripheral surface of the inner pipe.

Since the volume expansion of the cylindrical gasket 3 due to the heat of the high temperature exhaust gas is a factor of time, it is said that the volume expansion is immediately caused by the heat of the high temperature exhaust gas and the space G is immediately closed. It is difficult to expect the effect, and a problem was found that exhaust gas leaks from the joint when the joint is assembled.

In the exhaust pipe joint described above, 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 outer pipe 2 has a dimensional tolerance in the longitudinal direction that cannot be prevented due to its manufacturing, the cumulative exhaustion of these dimensional tolerances causes the exhaust pipe joint to become a cylinder when assembled to the engine-side exhaust pipe and the muffler-side exhaust pipe. An axial gap may be created between one end of the gasket 3 and the annular flange 1c of the inner pipe 1. If an exhaust pipe joint is used with a gap formed between one end of the cylindrical gasket 3 and the annular flange 1c of the inner pipe 1, it is transmitted from the engine side to the inner and outer pipes 1 and 2. The minute vibrations are directly transmitted to the cylindrical gasket 3. Due to this minute vibration, the cylindrical gasket 3 is beaten between the inner and outer pipes, and as a result, the gasket is settled or damaged, which causes the cause of exhaust gas leakage.

The present invention has been made in view of the above problems, and effectively utilizes the advantage of improving the sealing performance due to the volume expansion of the gasket in the prior art, and the joint portion at the time of assembling the exhaust pipe joint. The purpose of the present invention is to obtain an exhaust pipe joint that can prevent leakage of exhaust gas from the cylinder and also prevent damage to the gasket due to vibration of the outer pipe in the cylindrical gasket. ..

[0011]

[Means for Solving the Problems]

 According to the present invention, the above-mentioned object is that the outer tube is formed with an enlarged cylindrical portion for expanding the diameter at the tube end portion with a shoulder portion, and the enlarged cylindrical portion extends from the tube end portion toward the shoulder portion. In addition, a pair of slit grooves are formed at positions facing each other across the axis of the outer pipe, and a pair of slit recess grooves are formed at positions facing each other across the slit groove. A pair of nuts are fixed to face each other in the vicinity of the shoulder portion of the cylinder, a cylindrical gasket is press-fitted on the inner surface of the expanded cylindrical portion, and an inner pipe is attached to the inner surface of the cylindrical gasket. Is inserted so as to extend to the inner surface of the outer tube, and the outer peripheral surface of the inner tube has a semi-cylindrical portion, a protrusion integrally formed on the apex of the outer peripheral surface of the semi-cylindrical portion, and the projection portion being sandwiched. A pair of pushers, each of which has a flange portion formed at the end of the semi-cylindrical portion and extending outward in the radial direction. A piece surrounds the inner surface of the semi-cylindrical portion with the outer peripheral surface of the inner tube, and is integrally fastened to the flange portion and is screwed into a nut fixed to the enlarged cylindrical portion through the protruding portion. By tightening a pair of bolts, the protruding portion is engaged with the slit groove of the enlarged cylindrical portion, and the combined flange portion is engaged with the slit groove, so that the protruding portion is movable in the axial direction of the outer tube. 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 space between the inner surface of the enlarged cylindrical portion and the outer surface of the inner tube. Part is compressed and deformed to tightly close the space part, and the pressing piece further tightens the combined brim part to firmly hold the inner pipe on the inner surface of the semi-cylindrical part, and the inner pipe and the outer pipe. Achieved by an exhaust pipe joint made by rigidly connecting and That.

In the above-mentioned configuration, when a gasket obtained by stacking a metal wire mesh and an expanded graphite sheet, winding this into a cylindrical shape, and then compression-molding in the axial direction is used as the cylindrical gasket In the same manner as in the above-mentioned prior art, the gasket causes volume expansion due to the action of the heat of the high-temperature exhaust gas flowing in the exhaust pipe, so that a further sealing action can be performed.

[0013]

[Action]

 A cylindrical gasket is press-fitted into the space between the enlarged cylindrical portion of the outer pipe and the outer surface of the inner pipe, and the cylindrical gasket is axially pressed by the pressing piece to be compressed and deformed, so that the space is tightly closed. The gap existing at the time of assembling is filled up, and as a result, the leakage of exhaust gas from the joint part at the time of assembling the joint to the exhaust pipe is prevented.

Further, since the inner tube and the enlarged cylindrical portion of the outer tube are rigidly coupled to each other via the pressing piece, the vibrations of the inner and outer tubes do not directly act on the cylindrical gasket, which results from the vibration. The cylindrical gasket is not damaged.

[0015]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the accompanying drawings showing an embodiment thereof.

FIG. 1 is a vertical cross-sectional view showing an exhaust pipe joint of the present invention, FIG. 2 is a cross-sectional view taken along the line YY in FIG. 1, and FIG. 3 is a vertical cross-sectional view showing a state before completion of assembly. In the figure, 10 is an outer tube connected to the muffler side, and the outer tube 10 is formed with an outer tube 10 and an enlarged cylindrical portion 12 whose diameter is enlarged by a shoulder portion 11 at the end portion thereof.

In the enlarged cylindrical portion 12, a pair of slit grooves 13 and the slit groove 13 are sandwiched between the pipe end portion in the direction of the shoulder portion 11 and the positions facing each other across the axis of the outer pipe 10. A pair of slit grooves 14 are formed at positions facing each other.

Reference numeral 20 denotes a pair of nuts fixed to the outer peripheral surface near the shoulder portion of the enlarged cylindrical portion so as to face each other. The nut 20 has an internal thread portion on the inner surface and is formed on the enlarged cylindrical portion 12. It is located on the extension of the pair of slit grooves 13.

Reference numeral 30 is a cylindrical gasket, and the 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 a material that easily deforms when compressed and has heat resistance. For example, a reinforcing material made of wire mesh obtained by weaving or knitting fine metal wires and heat-resistant sheets such as expanded graphite and mica are superposed and wound in a cylindrical shape to form a preform, Suitable ones include those formed by compressing the preliminary molded body in the axial direction.

Reference numeral 40 denotes an inner pipe connected to the engine side. A pipe end portion of the inner pipe 40 is inserted through the inner surface of the cylindrical gasket 30 and extends to the inner surface of the outer pipe 10. There is.

Reference numeral 50 denotes a pair of pressing pieces that are divided into two in the radial direction. The pressing piece 50 includes a semi-cylindrical portion 51, a projecting portion 52 integrally formed on the top of the outer peripheral surface of the semi-cylindrical portion, and the projecting portion. And a flange portion 53 extending outward in the radial direction, which is formed at each end of the semi-cylindrical portion so as to sandwich it. A through hole 54 extending along the axial direction of the outer tube is formed in the protruding portion 51 of the pressing piece 50, and a through hole 55 penetrating the plate surface is formed in the collar portion 53.

The pair of pressing pieces 50 surrounds the inner surface of the semi-cylindrical portion 51 with the outer peripheral surface of the inner tube 40, respectively, and is integrally fastened by bolts and nuts 60 which are inserted through the through holes 55 in the collar portion 53. In addition, the protrusion 52 is cut into the enlarged cylindrical portion 12 by tightening a pair of bolts 70 that are inserted into the through holes 54 of the protruding portion 52 and screwed into the nut 20 fixed to the enlarged cylindrical portion 12. Collar portions 53 combined with the groove 13 are engaged with the slit grooves 14 and are arranged on the outer peripheral surface of the inner pipe 40 so as to be movable in the axial direction of the outer pipe 10.

In this state, by tightening the bolt 70, the integrally pressed pressing piece 50 is moved along the inner pipe 40, and the end surface of the semi-cylindrical portion 51 of the pressing piece 50 contacts the cylindrical gasket 30. While contacting, the cylindrical gasket 30 is pressed in the axial direction of the outer tube 10. The cylindrical gasket 30 pressed against the end surface of the semi-cylindrical portion 51 is compressed and deformed to fill the space G formed by the inner surface of the expanded cylindrical portion 12 and the outer surface of the inner tube 40.

Next, the outer peripheral surface of the inner pipe 40 is a semi-cylindrical portion of the pressing piece 50 by further tightening the bolt / nut 60 which is inserted through the through hole 55 of the flange 53 of the flange 53 of the pressing piece 50. The inner tube 40 and the outer tube 10 are firmly held by 51 and are rigidly connected to each other.

In the exhaust pipe joint assembled in this way, since the cylindrical gasket 30 closes the gap between the enlarged cylindrical portion 12 of the outer pipe 10 and the inner pipe 40, the exhaust gas from the gap is exhausted. There is no gas leakage.

Further, even when the vibration transmitted from the engine causes the inner and outer pipes 40 and 10 to vibrate, the inner and outer pipes 40 and 10 are rigidly connected by the pressing piece 50. Since the vibrations transmitted to the outer pipes 40 and 10 do not directly act on the cylindrical gasket 30, the vibrations of the inner and outer pipes 40 and 10 do not cause fatigue or damage to the cylindrical gasket 30. Therefore, leakage of exhaust gas due to damage to the cylindrical gasket is prevented.

[0027]

[Effect of the device]

 The exhaust pipe joint of the present invention having the above-mentioned configuration has the following effects. The cylindrical gasket is formed by the inner surface of the enlarged cylindrical portion where the cylindrical gasket is arranged by being pressed by the pressing piece in the axial direction of the outer tube during assembly and deformed by compression, and the outer surface of the inner tube and the shoulder portion of the outer tube. Since the space that fills the space is closed and the space is tightly closed, leakage of exhaust gas from the joint at the initial stage of assembly is prevented. Even if the vibration transmitted from the engine causes vibrations in the inner and outer pipes, the inner and outer pipes are rigidly connected by the pressing piece, so the minute vibrations transmitted to the inner and outer pipes are cylindrical gaskets. Since it does not act directly on the cylinder gasket, the cylinder gasket is not settled or damaged due to minute vibrations of the inner and outer pipes, and the exhaust gas is prevented from leaking due to damage to the cylinder gasket. ..

[Brief description of drawings]

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

FIG. 2 is a sectional view taken along the line EE of FIG.

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

FIG. 4 is a vertical sectional view showing a conventional exhaust pipe joint.

[Explanation of symbols]

 10 Outer pipe 11 Shoulder part 12 Enlarged cylindrical part 13 Notch groove 14 Notch groove 20 Nut 30 Cylindrical gasket 40 Inner tube 50 Pressing piece 51 Semi-cylindrical part 52 Projection part 53 Collar part 70 Bolt

Claims (1)

[Scope of utility model registration request] 1. An outer tube is formed with an enlarged cylindrical portion that expands its diameter at its tube end portion with a shoulder portion, and the enlarged cylindrical portion extends from the tube end portion toward the shoulder portion and the axis of the outer tube. A pair of slit grooves are formed at positions facing each other with the slit interposed therebetween, and a pair of slit grooves are formed at positions facing each other with the slit groove interposed therebetween, and in the vicinity of a shoulder portion on the extension of the slit 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 pipe has its pipe end portion on the inner surface of the outer pipe of the outer pipe. Inserted into the outer peripheral surface of the inner tube, the semi-cylindrical portion and a protruding portion integrally formed on the top of the outer peripheral surface of the semi-cylindrical portion, and the semi-cylindrical portion sandwiching the protruding portion. A pair of pressing pieces each having a flange portion extending outward in the radial direction formed at each 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 that are integrally fastened to the flange portion and that are inserted through the protruding portion and screwed into the nut fixed to the enlarged cylindrical portion. , The protruding portion is engaged with the slit groove of the enlarged cylindrical portion, and the combined brim portion is engaged with the slit recess groove so as to be movable in the axial direction of the outer tube. As a component, by the movement of the pressing piece by tightening the bolt, the cylindrical gasket is pressed by the end surface of the semi-cylindrical portion of the pressing piece, and is compressed and deformed in the space portion between the inner surface of the enlarged cylindrical portion and the outer surface of the inner pipe. The space portion is tightly closed, and the pressing piece further tightens the combined flange portion to firmly hold the inner pipe on the inner surface of the semi-cylindrical portion and rigidly connect the inner pipe and the outer pipe. Exhaust pipe joint characterized by.