JPH0514522U - Exhaust pipe fitting - Google Patents

Abstract

(57) [Abstract] [Purpose] Exhaust pipe joints that connect exhaust pipes of automobiles, motorcycles, etc. that can prevent leakage of exhaust gas from the joints when assembled to the exhaust pipes. Provide a pipe joint. [Structure] A pair of slit grooves are formed in an enlarged cylindrical portion formed at a pipe end portion of an outer pipe, and a pair of nuts are fixed on an extension of the slit groove. A cylindrical gasket is press-fitted on the inner surface and an inner tube is fitted on the inner surface of the gasket, and a pressing ring having a cylindrical portion and a pair of ears opposed to the outer peripheral surface of the cylindrical portion is provided. The cylindrical portion is brought into contact with the end surface of the cylindrical gasket, the ear portion is inserted into the slit groove, and is fitted and inserted into the outer surface of the inner pipe. The cylindrical gasket is inserted through the ear portion of the pressing ring and screwed into the nut. Is pressed in the axial direction by tightening the bolt to compress the space between the inner surface of the enlarged cylindrical portion and the outer surface of the inner pipe,
The space is tightly closed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an exhaust pipe joint used in automobiles, motorcycles and the like, and more particularly to an exhaust pipe joint that prevents leakage of exhaust gas from the exhaust pipe joint at the initial stage of assembly.

[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 wound in a cylindrical shape. Then, fit a cylindrical gasket formed by applying a solid lubricant such as graphite powder to prevent slippage and sticking to the outer peripheral surface of the inner pipe, 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.

Conventionally known plug-in type fittings of this type have the advantages that they require less space and are easier to assemble than other types, such as the flange type. On the other hand, there was a problem that it was disadvantageous to vibration and heat generated by the internal combustion engine.

In view of the above problems, the present applicant has previously proposed an exhaust gas that solves the above problems in Japanese Patent Application No. 2-244941 (Japanese Patent Application Laid-Open No. 2-125907: hereinafter referred to as “prior art”). Proposed a pipe joint.

An exhaust pipe joint according to this prior art will be described with reference to FIG.

[0006] The inner pipe 1, the outer pipe 2 fitted to the outer peripheral surface of the inner pipe 1 by a certain length from the opening portion 1a, and inside of these, the annular gap formed in the fitting 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 tube 2 is divided into a radially enlarged portion 2a at the end of the tube and a radially stepped portion in the circumferential direction and in the axial direction. 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 the enlarged diameter portion 2a of the outer pipe 2, and a pipe end portion 1b of the inner pipe 1 is fitted into this fitting portion. And an annular gap is formed between 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 has one end abutting against one end face of the annular flange 1c, and the other end thereof has a thermal expansion coefficient of the cylindrical gasket 3. The exhaust pipe joint is arranged so that the space portion G closed by is left.

The exhaust pipe joint according to the prior art described above 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. ..

[0008]

[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 it was found that exhaust gas leaks from the joint when the joint is assembled.

The present invention has been made in view of the above problems, and an object of the present invention is to obtain an exhaust pipe joint capable of preventing leakage of exhaust gas from the joint part when the exhaust pipe joint is assembled. To do.

[0011]

[Means for solving problems]

 In order to achieve the above-mentioned object, the present invention has the following configurations. That is, according to the first configuration of the present invention, the outer tube has an outer tube body and an enlarged cylindrical portion that expands in diameter with a shoulder portion at the tube end portion. To the shoulder direction, and a pair of slit grooves are formed at positions facing each other across the axis of the outer tube body, and a pair of nuts are provided on the outer peripheral surface near the shoulder portion on the extension of the slit grooves. Is fixed, a cylindrical gasket is press-fitted on the inner surface of the enlarged cylindrical portion, and an inner pipe is inserted in the inner surface of the cylindrical gasket, and the cylindrical portion and the outer peripheral surface of the cylindrical portion face each other. A pressing ring having a pair of ears makes the end surface of the cylindrical portion contact the end surface of the cylindrical gasket, and inserts the pair of ears into the slits of the enlarged cylindrical portion to form the outer peripheral surface of the inner tube. Bolts are inserted into the ears of the pressing ring, respectively. At the same time, the bolt is screwed into a nut fixed to the enlarged cylindrical portion, and by tightening the bolt, the cylindrical gasket is pressed in the axial direction so that a space between the inner surface of the enlarged cylindrical portion and the outer surface of the inner tube is formed. It provides an exhaust pipe joint that is compressed into a closed space to close the space.

In addition, in addition to the above-described first configuration, a second configuration is a head and an ear of a bolt screwed into a nut fixed to the enlarged cylindrical portion by inserting the ear of the pressing ring. And a coil spring is provided between the coil spring and the valve, and the spring provides the exhaust pipe joint in which the cylindrical gasket is constantly pressed toward the shoulder of the enlarged cylindrical portion.

In the above first and second configurations, a metal gasket and an expanded graphite sheet are stacked as a cylindrical gasket, which is wound into a cylindrical shape and then compression molded in the axial direction. When the gasket described above is used, the gasket is expanded in volume by the action of heat of the high-temperature exhaust gas flowing in the exhaust pipe, as in the above-described prior art, and thus a further sealing action can be performed.

[0014]

[Action]

 The exhaust pipe joint of the present invention having the above-described structure operates as follows. A cylindrical gasket is press-fitted in the space between the inner surface of the enlarged cylindrical portion of the outer pipe and the outer surface of the inner pipe, and is compressed by the pressing ring to close the space, so that the gap existing during joint assembly is filled. As a result, there is no leakage of exhaust gas from the joint part when the joint is attached to the exhaust pipe.

[0015]

【Example】

 Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 4 of the accompanying drawings.

1 and 2 are exhaust pipe joints showing a first embodiment of the present invention. In the figure, 10 is an outer pipe connected to the muffler side, and the outer pipe 10 has an outer cylinder body and a shoulder 11 at the end of the outer cylinder, and an enlarged cylindrical portion 12 and an enlarged cylindrical portion 12 that expand in diameter. A pair of slit grooves 13, 13 are formed at positions facing the shoulder portion direction 11 from the tube end portion of the cylindrical portion 12 and facing each other with the axis of the outer tube body interposed therebetween.

Reference numerals 20 and 20 denote a pair of nuts fixed to the outer peripheral surface near the shoulder portion 11 of the enlarged cylindrical portion 12 so as to face each other. The nuts 20 and 20 have internal thread portions on the inner surface thereof and the enlarged cylindrical portion. It is positioned on the extension of the pair of slit grooves 13, 13 formed in the portion 12.

Reference numeral 30 denotes a cylindrical gasket, and the gasket 30 is press-fitted on the inner surface of the enlarged cylindrical portion 12. The gasket 30 is not particularly limited as long as it is a material that can be deformed when compressed and has heat resistance. For example, a reinforcing material composed of a wire mesh obtained by weaving or knitting thin metal wires and expanded graphite, It is preferable to use a product obtained by stacking a heat-resistant sheet such as mica and winding this into a cylindrical shape to form a preform, and then compressing the preform in the axial direction. In particular, when a gasket made of expanded graphite and a reinforcement made of wire mesh is used, the gasket causes volume expansion due to the heat of the high-temperature exhaust gas flowing in the exhaust pipe, and the sealing effect is further enhanced. It

Reference numeral 40 denotes an inner pipe connected to the engine side, and a pipe end portion of the inner pipe 40 is inserted through the inner surface of the cylindrical gasket 30 so as to project to the inner surface side of the outer pipe body. ..

Reference numeral 50 denotes a pressing ring, and the pressing ring 50 has a cylindrical portion 51, a pair of ears 52 projecting oppositely from the outer peripheral surface of the cylindrical portion 51, and a through hole 53 formed in the ears 52. Is equipped with. The pressing ring 50 is fitted into the outer peripheral surface of the inner pipe 40, the end surface of the cylindrical portion 51 is brought into contact with the end surface of the cylindrical gasket 30, and the ear portions 52, 52 are formed in the enlarged cylindrical portion 12. Are arranged in engagement with the slit grooves 13 ,.

Reference numeral 60 denotes a tightening bolt, and the bolt 60 is inserted through a through hole 53 formed in the ear portion 52 of the pressing ring 50, and nuts 20, 20 having a male screw portion fixed to the enlarged cylindrical portion 12 are provided. It is arranged so as to be screwed into the internal thread portion of the inner surface.

In this state, by tightening the tightening bolts 60, 60, the pressing ring 50 moves in the axial direction while pressing the end surface of the cylindrical gasket 30 on the end surface of the cylindrical portion 51, and the cylindrical gasket 30 moves in the axial direction. The exhaust pipe joint is assembled by compressing the space and tightly closing the space formed by the inner surface of the enlarged cylindrical portion 12 and the outer surface of the inner pipe 40.

3 to 4 are exhaust pipe joints showing a second embodiment of the present invention. The difference from the exhaust pipe joint according to the first embodiment is that the coil springs 70, 70 are interposed between the ear portion 52 of the pressing ring 50 and the head portion of the tightening bolt 60. In the exhaust pipe joint of the example, the coil springs 70, 70 constantly press the cylindrical gasket 30 in the axial direction.

Thus, by constantly compressing the cylindrical gasket 30 in the axial direction by the coil springs 70, 70, even when the cylindrical gasket 30 is consumed by oxidation due to high temperature exhaust gas, the springs 70, 70 Due to the spring force, the cylindrical gasket 30 is compressed in the axial direction to tightly close the space defined by the inner surface of the enlarged cylindrical portion 12 and the outer surface of the inner tube 40.

[0025]

[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 compressed in the axial direction by the pressing ring during assembly and fills the space formed by the inner surface of the enlarged cylindrical portion where the cylindrical gasket is arranged and the outer surface of the inner tube to close the space tightly. It is possible to prevent the exhaust gas from leaking from the joint at the initial stage of assembly. In an exhaust pipe joint in which a coil spring is interposed between the ear of the pressure ring and the head of the tightening bolt, the cylindrical gasket is always compressed in the axial direction by the spring force of the coil spring. Even when oxidative consumption is caused by the high-temperature exhaust gas, the space formed by the inner surface of the enlarged cylindrical part and the outer surface of the inner tube is tightly closed, and the exhaust gas from the joint part even during initial assembly and use Leakage is prevented.

[Brief description of drawings]

1 is a longitudinal sectional view showing a first embodiment of 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 longitudinal sectional view showing a second embodiment of the exhaust pipe joint of the present invention.

FIG. 4 is a cross-sectional view taken along the line Loro of FIG.

FIG. 5 is a vertical sectional view showing a conventional exhaust pipe joint.

[Explanation of symbols]

 10 Outer tube 12 Enlarged cylindrical portion 13 Notch groove 20 Nut 30 Inner tube 40 Cylindrical gasket 50 Press ring 60 Tightening bolt

Claims (2)

[Scope of utility model registration request] 1. An outer tube is provided with an outer tube main body and an enlarged cylindrical portion having a shoulder portion at an end portion of the outer tube, the enlarged cylindrical portion having an enlarged diameter, and the enlarged cylindrical portion extends from the tube end portion toward a shoulder portion. Further, a pair of slit grooves are formed at positions opposite to each other with the axis of the outer tube body interposed therebetween, and a pair of nuts are fixed to the outer peripheral surface near the shoulder portion on the extension of the slit groove, A cylindrical gasket is press-fitted on the inner surface of the enlarged cylindrical portion, an inner pipe is inserted in the inner surface of the cylindrical gasket, and a pressing member having a pair of ears facing the cylindrical portion and the outer peripheral surface of the cylindrical portion is provided. A ring is inserted into the outer peripheral surface of the inner pipe by abutting the end surface of the cylindrical portion with the end surface of the cylindrical gasket, and inserting the pair of ears into the slit grooves of the enlarged cylindrical portion, respectively, and pressing the ring. Bolts are inserted into the ears of each and the bolts are expanded as described above. It is screwed into a nut fixed to the cylindrical portion, and by tightening the bolt, the cylindrical gasket is pressed in the axial direction and compressed into the space portion between the inner surface of the enlarged cylindrical portion and the outer surface of the inner pipe, An exhaust pipe joint characterized by tightly closing the portion. 2. A coil spring is provided between the head and the ear of the bolt screwed into the nut fixed to the enlarged cylindrical portion by inserting the ear of the pressing ring and the spring. The exhaust pipe joint according to claim 1, wherein the cylindrical gasket is constantly pressed toward the shoulder of the enlarged cylindrical portion.