JP5340400B2 - Muffler gasket and muffler joint - Google Patents

Abstract

Provided are a gasket for a muffler, having mechanical strength and sealing ability which do not degrade even if the gasket is used for a long period of time in a use environment subjected to a frequent occurrence of vibration, and a muffler joint. A gasket (1) for a muffler is provided with a metallic mesh material (3) expanded in a flat plane, and also with a band-like seal material (5) layered on the metallic mesh material (3) so as to overlap with the metallic mesh material (3) in a part of the range of the metallic mesh material in the longitudinal direction (Y) thereof. The metallic mesh material (3) and the seal material (5) are compressed in the axis direction (G) in a state in which the metallic mesh material (3) and the seal material (5) are rolled in the width direction (X). By this, the gasket (1) is formed in a state in which the gasket (1) is split in the axis direction (G) into a hard layer (7) consisting only of the metallic mesh material (3) and a soft layer (9) consisting of the metallic mesh material (3) and the seal material (5). A metallic mesh material (3A) applied to a superposed section (11) at which the metallic mesh material (3) overlaps with the seal material (5) is formed so as to have a lower density than a metallic mesh material (3B) not included in the superposed section (11).

Description

  The present invention relates to a muffler joint used in a muffler of a vehicle such as a motorcycle, a four-wheel buggy, and a snowmobile, and a muffler gasket mounted on the muffler joint, and in particular, a seal performance and traveling that prevent leakage of exhaust gas. The present invention relates to a muffler gasket excellent in fastening strength that can withstand vibrations at the time, and a muffler joint including the muffler gasket.

  As this type of muffler joint, a structure like an exhaust pipe joint shown in Patent Document 1 below has been developed and is already used. The exhaust pipe joint has an inner pipe and an outer pipe having an inner diameter slightly larger than the outer diameter of the inner pipe, and a diameter-expanded portion is formed at the pipe end of the outer pipe. Further, a gasket is loaded in the annular space between the inner tube and the expanded diameter portion of the outer tube, and the inner tube and the outer tube are connected by tightening the outer peripheral surface of the outer tube with a tightening band, Leakage of exhaust gas from the connecting portion is prevented.

  Further, the gasket is a cylindrical member, provided on the inner peripheral surface side of the gasket, and formed of a stainless steel mesh, and expanded graphite provided on the outer peripheral surface side so as to cover the reinforcing material. It is configured. This expanded graphite has heat resistance, chemical resistance, and a low coefficient of friction, and can be easily molded by applying pressure without using a binder, and is flexible and can be deformed flexibly. doing.

  The gasket expands in volume by the heat of the exhaust gas flowing in the inner pipe, and has the flexibility and flexibility described above, so that the annular space between the inner pipe and the enlarged diameter portion of the outer pipe. It has a feature that it can improve the sealing performance at the connection portion between the inner tube and the outer tube because it adapts and adapts well to the shape of the tube.

JP-A-2-125907 JP 2004-3604 A

  However, in recent years, mufflers have become larger as noise countermeasures, and catalyst devices have come to be installed as exhaust gas countermeasures, which places an excessive load on the fastening parts of muffler joints and the places where muffler gaskets are loaded. It has become like this. In particular, off-road motorcycles and other mufflers travel on rough roads with a lot of ups and downs, so that impacts due to bouncing are applied, and the connection between the inner pipe and the outer pipe is repeatedly subjected to twisting and bending torque.

  In such a state, the muffler gasket is plastically deformed, or the gap at the joint between the inner tube and the outer tube is enlarged, so that the sealing performance of the muffler joint is lowered. In addition, there is a possibility that a problem that the tightening force for connecting the inner tube and the outer tube is lowered due to the tightening screw tightening the tightening band being loosened by the repeated impact is reduced. Therefore, the present applicant has already reached the patent application related to the above-mentioned Patent Document 2, and provides an exhaust pipe gasket that uses a highly rigid metal mesh material as a base and minimizes the formation range of the inorganic material. The occurrence of the problem is prevented.

However, when the ratio of the metal mesh material is increased, the mechanical strength is improved and the impact resistance is improved, but it is difficult to be deformed. Accordingly, there arises a problem that a gap is formed between the inner pipe and the outer pipe constituted by the welded parts that inevitably vary in dimensional accuracy and roundness, and the sealing performance is deteriorated.
On the contrary, if the amount of the expanded graphite is increased, it is easy to be deformed and the sealing performance is improved. However, the mechanical strength is lowered, so that the impact resistance is lowered, and the problem of the reduction of the tightening force is again caused. Will arise.

  The present invention has been made on the basis of these points, and the purpose of the present invention is to provide mechanical strength that can withstand a use environment in which large impacts and vibrations are repeatedly applied, as well as variations in dimensional accuracy and roundness of joined parts. It is an object to provide a muffler gasket having a simple structure with excellent deformability that can cope with the above, and an excellent sealability, and a muffler joint including the muffler gasket.

  In order to achieve the above object, a muffler gasket according to claim 1 of the present invention is mounted in an annular space at a joint portion between an inner pipe and an outer pipe of a muffler joint, and tightens a tightening band mounted on an outer peripheral surface of the outer pipe. In a cylindrical muffler gasket that exhibits sealing performance by force, a metal mesh material stretched in a planar shape and a belt-like shape overlapped with the metal mesh material in a part of the length direction. The metal mesh material and the sealing material are compressed in the axial direction in a state of being rolled in the width direction, thereby comprising a hard layer made of only the metal mesh material, and the metal mesh material and the sealing material. A metal layer that is formed in a state of being axially divided into a soft layer and is applied to the overlapping portion that overlaps with the sealing material. Shoe material, and is characterized in that it is formed in the lower density than the metal mesh material other than the overlap portion.

  Further, the muffler gasket according to claim 2 is the muffler gasket according to claim 1, wherein the metal mesh material applied to the overlapping portion skips one stitch or a plurality of stitches when knit knitting the stainless wire. It is characterized by being formed at a low density by knitting.

  Further, the muffler gasket according to claim 3 is the muffler gasket according to claim 1 or 2, wherein the sealing material applied to the overlapping portion appears on the outer peripheral surface of the muffler gasket when rounded into a cylindrical shape. It is provided at least on the surface of the metal mesh material.

  Further, the muffler gasket according to claim 4 is the muffler gasket according to any one of claims 1 to 3, wherein the inner circumferential surface of the soft layer has the sealing material having the same width as the outer circumferential surface of the soft layer. It is characterized by being exposed.

  A muffler gasket according to claim 5 is the muffler gasket according to any one of claims 1 to 4, wherein the sealing material is formed of an inorganic material containing expanded graphite. .

  Further, the muffler gasket according to claim 6 is the muffler gasket according to any one of claims 1 to 5, wherein the sealing material has a thin film layer coated with a liquid inorganic material mainly composed of zirconia on the surface. It is characterized by that.

  A muffler gasket according to claim 7 is the muffler gasket according to any one of claims 1 to 6, wherein a thermally expandable inorganic material is provided between the layers of the metal mesh material provided in the soft layer. It exists over the range of the said sealing material currently formed in the outer peripheral side at least.

  The muffler gasket according to claim 8 is the muffler gasket according to any one of claims 1 to 4, wherein the seal material is formed of a thermally expandable inorganic material containing unexpanded graphite, heat resistant fibers, and a heat resistant binder. It is characterized by being.

  According to a ninth aspect of the present invention, there is provided a muffler joint comprising: an outer pipe provided with a slit arranged in the joint portion in the axial direction from the end face; an inner pipe connected to the outer pipe; and the outer pipe and the inner pipe. A muffler gasket to be loaded in the annular space of the joint portion and a tightening band attached to the outer peripheral surface of the joint portion of the outer pipe, wherein the muffler gasket is any one of claims 1 to 8. It is a muffler gasket as described above.

  Further, the muffler joint according to claim 10 is the muffler joint according to claim 9, wherein the muffler gasket is loaded at a position where the soft layer provided with the sealing material is applied to the slit formed in the outer pipe. It is characterized by that.

  The muffler joint according to claim 11 is characterized in that, in the muffler joint according to claim 9 or 10, the tightening band is attached at a position where it covers both the hard layer and the soft layer.

  The following actions are obtained by the above means. First, since the hard layer made of only the metal mesh material is formed at a high density, it has excellent mechanical strength and exhibits high impact resistance. Therefore, even if twisting and excessive bending torque occur repeatedly between the inner pipe and the outer pipe due to vibrations on rough roads, etc., the high impact resistance of the hard layer prevents plastic deformation of the muffler gasket. Thus, it is difficult to cause loosening of a fastener such as a fastening screw that fastens the fastening band.

  In addition, the soft layer made of low-density metal mesh material and sealing material also has flexibility, so even if the dimensional accuracy and roundness of the inner pipe and outer pipe vary, the inner pipe and outer pipe Since it deforms freely in conformity with the shape of the annular space of the joint portion of the pipe, generation of a gap between them is prevented, and high sealing performance is exhibited. In addition, since the hard layer and the soft layer are provided in a state of being divided in the axial direction, the action and effect of each of the hard layer and the soft layer are effectively reduced without being reduced by the mutual action and effect. Comes to work.

In order to reduce the density of the metal mesh material, when using knitting stitches for knitting stainless wire, it is easy to use an existing knitting machine and pull out the needle at the part where the stitches are to be skipped. By the simple operation, it becomes possible to efficiently produce a low-density metal mesh material at a low cost.
Further, when the sealing material is overlapped with the metal mesh material, if the sealing material is provided on the surface of the metal mesh material on the side where the sealing material appears on the outer peripheral surface of the molded muffler gasket, The sealing performance between the pipes can be improved. In addition, when a seal material is also provided on the surface of the metal mesh material on the side where the seal material appears on the inner peripheral surface of the muffler gasket, the sealing performance between the muffler gasket and the outer pipe and the gap between the muffler gasket and the inner pipe Both of the sealing performance can be improved.

  Also, when the sealing material is formed in the same width on the outer peripheral side and the inner peripheral side of the soft layer, the inner pipe and the outer pipe have the same sealing performance on the inner pipe side as the outer pipe side. Further improvement of the sealing performance at the joint portion is achieved.

  Further, when the sealing material is formed of an inorganic material containing expanded graphite, it is possible to provide a muffler gasket having improved durability by improving the heat resistance and low friction properties of the sealing material.

  Further, when the sealing material is formed by forming a thin film layer coated with a liquid inorganic material mainly composed of zirconia on the surface, the elasticity of the sealing material surface side is increased by the thin film layer. The performance is improved and the effect of suppressing the twisting and bending torque at the joint between the inner pipe and the outer pipe caused by the vibration is added, and the plastic deformation of the muffler gasket is further suppressed, so that it is stably desired over a long period of time. The seal performance can be demonstrated.

  In addition, when a heat-expandable inorganic material is interposed between the wound layers of the metal mesh material provided on the soft layer over the formation range of the sealing material, the muffler gasket is forcibly tightened with a tightening band or the like. Even if it is not, the muffler gasket is heated by the heat of the exhaust gas flowing through the muffler and thermally expands, and the thermally expandable inorganic material itself does not return to its original shape. The degree of adhesion with the outer pipe is increased and the sealing performance is further improved. In addition, assembling of the muffler gasket is facilitated because excessive tightening of a tightening band or the like is unnecessary.

  In addition, when the sealing material is formed of a thermally expandable inorganic material containing unexpanded graphite, heat resistant fibers, and a heat resistant binder, the temperature of the periphery of the muffler gasket is increased by the heat of exhaust gas flowing in the muffler. As a result, the unexpanded graphite rapidly expands and the sealing performance of the muffler gasket can be improved. In addition, even if unexpanded graphite is about to scatter during expansion, there can be obtained an action and effect of suppressing rapid expansion that causes scattering of unexpanded graphite by heat-resistant fibers made of aramid fibers or the like that are well entangled with a heat-resistant binder such as rubber.

In addition, when the muffler gasket is applied to a muffler joint, the various effects and effects of the muffler gasket can improve the shock resistance and seal performance of the muffler joint, resulting in many vibrations. The durability of the muffler used in the usage environment can be improved.
Further, when assembling the muffler joint, when the muffler gasket is arranged so that the soft part provided with the sealing material is put on the slit formed in the outer pipe, the exhaust gas leaks from the slit. This can improve the sealing performance of the muffler joint.

  In addition, when assembling the muffler joint, when the fastening band is attached to a position that hangs over both the hard layer and the soft layer, the above-described functions and effects of the hard layer and the soft layer are exhibited synergistically. As a result, the impact resistance and sealing performance of the muffler joint are further improved.

  According to the muffler gasket and the muffler joint according to the present invention, it is possible to obtain a mechanical strength that can withstand a use environment in which a large impact or vibration is repeatedly applied. Further, the sealability is improved by the easy deformability that can cope with the variation in the dimensional accuracy and roundness of the muffler joined parts. Moreover, the said effect is exhibited by the simple structure which only makes a metal mesh material low-density.

It is a figure which shows embodiment of this invention, and is a perspective view which shows the metal mesh material knit-knitted in the hoop state. It is a figure which shows embodiment of this invention, and is a top view which shows the state which crushed the metal mesh material knit-knitted in the hoop state, and was extended in planar shape. The figure which shows embodiment of this invention, and is a top view which shows the state which piled up the sealing material in the partial range of the length direction from the 1st surface of the metal mesh material extended | stretched planarly to the 2nd surface It is. It is a figure which shows embodiment of this invention, and is a top view which shows the state which piled up the sealing material in the partial range of the length direction in the 1st surface of the metal mesh material extended | stretched planarly. It is a figure which shows embodiment of this invention, and is a perspective view which shows the state which rounded what overlapped the sealing material on the metal mesh material. It is a figure which shows embodiment of this invention, and is a perspective view which shows the state which rolled what overlapped the sealing material on the metal mesh material in multiple. It is a figure which shows embodiment of this invention, and is a perspective view which shows a mode that the metal mesh material and sealing material which were round-rolled are compression-molded to a predetermined shape with a press molding machine. It is a figure which shows embodiment of this invention, and is the top view (a) which shows the molded gasket for mufflers, and (A) AA sectional drawing (b) in a figure. It is a figure which shows embodiment of this invention, and is a perspective view which shows the decomposition | disassembly state of a muffler joint. It is a figure which shows embodiment of this invention, and is a sectional side view which shows the state which fractured | ruptured the junction part of the muffler joint. It is a figure which shows embodiment of this invention, and is a perspective view which shows the assembly state of a muffler joint. It is a figure which shows embodiment of this invention, and is a perspective view which shows three types of gaskets for mufflers which made the formation range of a soft layer different. It is explanatory drawing which represented the result of the vibration test of this invention product and two types of conventional products.

Hereinafter, an embodiment for carrying out the present invention will be described taking the embodiment shown in FIGS. 1 to 12 as an example.
The illustrated muffler gasket 1 includes a metal mesh material 3 extended in a planar shape, and a band-shaped sealing material 5 that is overlapped with the metal mesh material 3 so as to overlap in a part of the length direction Y. As a starting material 27. Then, the starting material 27 is compression-molded in the axial direction G in a state where the starting material 27 is rounded in the width direction X, thereby forming the muffler gasket 1 having a predetermined cylindrical shape.

In the muffler gasket 1 thus formed, the hard layer 7 made of only the metal mesh material 3 and the soft material 9 made of the metal mesh material 3 and the sealing material 5 were divided in the axial direction G. It is formed in a state.
Further, the metal mesh material 3 </ b> A applied to the overlapping portion 11 that overlaps with the sealing material 5 is formed at a lower density than the metal mesh material 3 </ b> B other than the overlapping portion 11.

The metal mesh material 3 is knitted into a hoop shape as shown in FIG. 1 by using a knitting machine (not shown) to form a stainless steel wire 13 such as SUS304, and is crushed as shown in FIG. I am using something. The knitted metal mesh material 3 improves durability and rigidity by entanglement of the stainless wire 13 and realizes high mechanical strength that is not influenced by the direction.
Further, in the present embodiment, as shown in FIG. 2, the metal mesh material 3A applied to the overlapping portion 11 on which the seal material 5 is overlapped, the stitches 15 when the stainless wire 13 is knit knitted are skipped one by one. The metal mesh material 3 is reduced in density by forming the knitted flying eyes 17.

The band-shaped sealing material 5 is applied to the first surface 19 of the metal mesh material 3 </ b> A applied to the overlapping portion 11 in the width direction X with respect to the metal mesh material 3 extended in the planar shape thus configured. A starting material 27 as shown in FIG. 3 is obtained by superimposing all the ranges over a range of about half of the width direction X from the one end 23 to the central portion 25 on the second surface 21.
The starting material 29 is used in which the sealing material 5 is overlapped only in the entire range in the width direction X on the first surface 19 of the metal mesh material 3A applied to the overlapping portion 11 as shown in FIG. Is also possible.

  The starting material 27 to the starting material 29 are wound in a cylindrical shape as shown in FIG. 5, and are further wound twice as shown in FIG. 6 and then applied to a press molding machine 31 as shown in FIG. Then, by compression molding into the shape of the cavity 37 formed by the upper die 33 and the lower die 35, the short cylindrical muffler gasket 1 as shown in FIGS. 7 to 8 is formed.

  The first surface 19 is a surface that appears on the outer peripheral side of the muffler gasket 1 after molding shown in FIGS. 7 and 8, and the second surface 21 is on the inner peripheral side of the muffler gasket 1 after molding. It is a surface that appears. Therefore, when the starting material 27 shown in FIG. 3 is used, the sealing material 5 is exposed on both the outer peripheral side and the inner peripheral side of the muffler gasket 1 after molding, and further, by the multiple winding shown in FIG. The metal mesh material 3 is also molded between the layers around which the metal mesh material 3 is wound with the seal material 5 interposed.

  On the other hand, when the starting material 29 shown in FIG. 4 is used, the sealing material 5 is exposed only on the outer peripheral surface of the muffler gasket 1 after molding, and the inner peripheral side of the muffler gasket 1 after molding is exposed. The seal material 5 is not exposed on the surface. Further, the metal mesh material 3 is also formed between the layers around which the metal mesh material 3 is wound by multiple winding shown in FIG.

Further, the formation range of the soft layer 9 is set to a longer range beyond the central portion 41 from the one end face 39 of the muffler gasket 1 as shown in FIG. 12A, or as shown in FIG. In addition, it can be set in a range extending from one end surface 39 of the muffler gasket 1 to the central portion 41, and the formation range of the soft layer 9 is appropriately adjusted according to the type of the muffler to be loaded.
In addition, as shown in FIG. 12 (c), it is also possible to form the hard layers 7 and 7 at both ends of the muffler gasket 1 and the soft layer 9 at the central portion. Incorrect mounting of the muffler gasket 1 is prevented.

The sealing material 5 can be formed of an inorganic material containing expanded graphite. The expanded graphite has heat resistance, chemical resistance, and low frictional properties equivalent to those of graphite, and can be easily molded into a predetermined shape by pressing with the press molding machine 31 described above without using a binder or the like. It is easy to mold. In addition, expanded graphite is a suitable material for the sealing material 5 because it is flexible and has good flexibility.
In addition, as the inorganic material, mica sheet, ceramic fiber, molybdenum disulfide, or the like can be used.

Further, the sealing material 5 may be configured to have a thin film layer coated with a liquid inorganic material mainly composed of zirconia on the surface.
The liquid inorganic material has heat resistance capable of withstanding temperatures exceeding 1000 ° C., and polymerization is accelerated by moisture in the air during natural drying, so that a strong thin film layer can be formed. Examples of the coating portion of the liquid inorganic material include the inner peripheral surface 43, the outer peripheral surface 45, and the one end surface 39 of the insertion side end portion where the soft layer 9 of the muffler gasket 1 is formed.

In forming the thin film layer, the muffler gasket 1 with the inorganic material exposed is formed into a desired shape and size, and then the coating portion is immersed in a solution of the liquid inorganic material, and then naturally dried. Therefore, the manufacturing cost can be greatly reduced because the manufacturing can be performed by a simple process.
The sealing material 5 having such a structure is improved in elasticity by the thin film layer provided on the surface thereof to improve the sealing performance, and has the effect of suppressing the plastic deformation of the muffler gasket 1 for a long time. A stable sealing property is exhibited over the entire range.

Further, it is also possible to interpose a thermally expandable inorganic material over at least the range of the sealing material 5 formed on the outer peripheral side between the wound layers of the metal mesh material 3 provided on the soft layer 9.
This heat-expandable inorganic material is obtained by adding heat-resistant fibers to unexpanded graphite before heat treatment that expands by heating, and forming it into a sheet shape with a heat-resistant binder.

As heat-resistant fibers, inorganic fibers and aramid fibers can be used as examples. Moreover, as said inorganic fiber, although artificial fibers, such as glass fiber, rock wool, and a ceramic fiber, are suitable, natural mineral fiber etc. can also be used.
As the unexpanded graphite, a flake graphite having crystallinity obtained in nature and acid-treated to give thermal expansion performance can be used as an example. As the heat-resistant binder, NBR, SBR, acrylic rubber, silicon rubber, or the like can be used.

And since the said heat-expandable inorganic material is generally used in many cases as a fire spreader of a ventilation unit installed in a filler or an attic of a fire door, it is strong against heat and the surroundings are heated to a predetermined When the temperature reaches a high temperature, the volume expands in the range of 30 to 50 times.
Further, even if the unexpanded graphite is about to expand rapidly due to a rapid temperature rise, the expansion of the unexpanded graphite is suppressed by the heat-resistant fibers that are well entangled with the heat-resistant binder.

  Further, the sealing material 5 itself may be formed of a band-like thermally expandable inorganic material having the above composition instead of the inorganic material. Even when the sealing material 5 having such a configuration is used, the same operations and effects as those of the above-described embodiments using the inorganic material are exhibited. In particular, the muffler gasket 1 and the outer pipe 53 in the muffler joint 51 described below are used. Further, it is possible to further improve the sealing property by improving the adhesion with the inner pipe 55 and preventing the leakage of the exhaust gas.

  The muffler joint 51 of the present invention is connected to an exhaust pipe as an example, and is connected to a silencer as an example, and an outer pipe 53 provided with a slit 61 arranged at the joint 57 in a circumferential direction extending from the end surface 59 in the axial direction G. On the outer peripheral surface of the muffler gasket 1 loaded in the annular space 65 formed in the joint portions 57 and 63 of the outer pipe 53 and the inner pipe 55, and the joint portion 57 of the outer pipe 53. And a tightening band 67 to be loaded.

As shown in FIGS. 9 to 11, the outer pipe 53 welds a cylindrical joint portion 57 having a smaller diameter than the large-diameter cylinder body 69 whose both end surfaces are open to one end face 71 of the cylindrical large-diameter cylinder body 69. It is formed by connecting by etc.
Further, the joint portion 57 is provided with a neck portion 73 on the connection portion side with the large-diameter cylindrical body 69, and has a large diameter on the distal end portion 75 side with respect to the neck portion 73, and on the large-diameter cylindrical body 69 side. As an example, the neck 73 is formed in a shape that is reduced in a stepwise manner so that the diameter is reduced.
In addition, six slits 61 extending from the end face 59 in parallel to the axial direction G as an example are provided at the distal end portion of the joint portion 57 having a large diameter, equally arranged in the circumferential direction.

As shown in FIGS. 9 to 11, the inner pipe 55 includes a cylindrical large-diameter tube portion 77, a cylindrical joint portion 63 having a smaller diameter than the large-diameter tube portion 77, and the large-diameter tube portion 77 and the joint portion. As an example of connecting the connecting portion 63 and the connecting portion 63, the shoulder portion 79 has a gentle slope.
Further, on the outer peripheral surface of the joint portion 63 on the shoulder 79 side, a positioning ring-shaped projection 81 for setting an overlapping state at the joint portions 57 and 63 of the outer pipe 53 and the inner pipe 55 is formed.

  The tightening band 67 includes a ring-shaped band portion 83 having a cut-off end having an inner diameter larger than the outer diameter of the joint portion 57 that is directed to the outer peripheral surface of the joint portion 57 of the outer pipe 53, and the ring-shaped band portion 83. A mounting part 85 formed by bending the cut ends of the two ends outward, and a tightening screw 87 which is attached using the mounting part 85 and reduces the inner diameter of the ring-shaped band part 83. And comprising.

As shown in FIG. 10, the mounting position of the muffler gasket 1 is positioned at a position where one end surface 93 of the hard layer 7 contacts the ring-shaped protrusion 81 on the inner pipe 55 side, and on the outer pipe 53 side. The soft layer 9 is positioned within a range of positions where the soft layer 9 is applied to the slit 61 formed in the outer pipe 53.
Further, the fastening band 67 is attached to a position where it covers both the hard layer 7 and the soft layer 9 of the muffler gasket 1 as shown in FIG. Incidentally, when the muffler gasket 1 and the tightening band 67 are attached at such positions, leakage of exhaust gas from the slit 61 is prevented, and the mechanical strength of the hard layer 7 and the sealing property of the soft layer 9 are obtained. Is effectively exhibited, and the muffler joint 51 that can be used with confidence over a long period of time can be provided.

Next, the contents and results of a vibration test conducted to test the effect of the muffler joint 51 of the present invention loaded with the muffler gasket 1 of the present invention constructed as described above will be described.
In this vibration test, a conventional product 1 according to Patent Document 1 and a conventional product 2 according to Patent Document 2 using a vibration test apparatus having an excitation force of 8 KN (sine wave) and product number i220 / SA2 manufactured by IMV Corporation. And a vibration test was performed in a form comparing the product of the present invention.

The vibration test conditions were: tightening torque of the tightening band was 23 N · m, vertical acceleration of the muffler joint was 49 m / s ² , frequency was 16 to 335 Hz (Log sweep), cycle number was 1 million cycles (vibration time approx. 2.5 hours), the conventional product 1, the conventional product 2, and the product of the present invention having the same dimensions were tested three times under the same conditions, and the average was obtained. The measurement items include the amount of air leak before and after the vibration test under the two conditions of air pressure 5 kPa and 25 kPa, the residual torque after the vibration test, the maximum in the axial direction of the muffler gasket after the vibration test. The amount of deformation was adopted.

As shown in FIG. 13, the test results show that the product of the present invention and the conventional product 2 have much less air leakage before and after the vibration test than the conventional product 1, the residual torque after the vibration test is high, and after the vibration test. The test result that the maximum deformation amount of the muffler gasket was reduced was obtained.
Also, when the product of the present invention and the conventional product 2 are compared, the difference between the two is smaller than that of the conventional product 1, but the product of the present invention has an air leak amount before and after the vibration test compared to the conventional product 2. The test result was obtained that the residual torque after the vibration test was increased and the maximum deformation amount of the muffler gasket after the vibration test was decreased.

  Therefore, when the product of the present invention is used, the followability of the seal portion to the mating surface is improved, so that a stable seal performance can be obtained even when used for a long period of time, and the tightening screw 87 is loosened. The test results revealed that the mechanical strength was extremely high because the amount of deformation of the muffler gasket 1 was small.

  The muffler gasket 1 and the muffler joint 51 of the present invention are not limited to those of the above-described embodiment, and can be changed in design within the gist of the present invention. For example, the end sides in the width direction X of the starting materials 27 and 29 in the muffler gasket 1 may have a shape cut off obliquely in addition to a shape cut off vertically as shown in FIGS. Incidentally, in the case of such a configuration, even when the position of the end side of the sealing material 5 is in phase with the position of the slit 61 formed in the connecting portion 57 of the outer pipe 53, it matches over the entire length of the end side. Therefore, stable sealing performance can be maintained. Further, the assembly of the muffler joint 51 is improved by preventing the displacement in the circumferential direction when the muffler gasket 1 having the above structure is loaded into the annular space 65 between the joint portions 57 and 63 of the outer pipe 53 and the inner pipe 55. To do.

Further, taper portions 89 and 91 can be formed on the outer periphery of the end portion on the insertion side of the outer pipe 53 and the inner periphery of the end portion on the insertion side of the inner pipe 55 as shown in FIGS. is there. Incidentally, when such tapered portions 89 and 91 are formed, the insertion of the muffler gasket 1 into the outer pipe 53 and the inner pipe 55 is facilitated, and the assembly efficiency of the muffler joint 51 is improved.
Moreover, in the said embodiment, although the gasket 1 for mufflers was shape | molded using the sealing material 5 previously shape | molded by the strip | belt shape, it is a powdery sealing material 5 with respect to the metal mesh material 3 extended | stretched planarly. In the case where the muffler gasket 1 is molded using these as starting materials 27 and 29, or the metal mesh material 3 is molded by a molding form other than knit knitting, such as punching press processing, etc., the metal mesh before molding It is also possible to add the sealing material 5 to the material of the material 3 in advance and integrally mold it together with the sealing material 5 in the process of forming the metal mesh material 3.

  In addition, as another form for reducing the density of the overlapping portions 11 of the metal mesh material 3, the metal mesh material 3 formed without flying the stitches 15 is stretched in a flat shape, and then the metal mesh material is punched and pressed. It is also possible to reduce the density by punching a part of the material 3. Further, in the above-described embodiment in which the stitches 17 are formed at the time of knit knitting to reduce the density of the overlapping portion 11 of the metal mesh material 3, the stitches 15 are skipped one by one, and a plurality of stitches are skipped one by one. It is also possible.

  The muffler gasket and muffler joint of the present invention can be used in the manufacture and use fields of mufflers such as motorcycles, and is used when it is desired to maintain mechanical strength and sealability over a long period of time even in environments where vibrations are repeatedly applied. Have potential.

DESCRIPTION OF SYMBOLS 1 Gasket for muffler 3 Metal mesh material 5 Seal material 7 Hard layer 9 Soft layer 11 Superposition | polymerization part 13 Stainless steel wire 15 Knitting stitch 17 Flying eye 19 1st surface 21 2nd surface 23 One end 25 Central part 27 Starting material 29 Starting material 31 Press molding Machine 33 Upper die 35 Lower die 37 Cavity 39 One end surface 41 Central portion 43 Inner peripheral surface 45 Outer peripheral surface 51 Muffler joint 53 Outer pipe 55 Inner pipe 57 Joint portion 59 End surface 61 Slit 63 Joint portion 65 Annular space 67 Fastening band 69 Large diameter Cylindrical body 71 One end surface 73 Neck portion 77 Large diameter tubular portion 79 Shoulder portion 81 Ring-shaped protrusion 83 Ring-shaped band portion 85 Mounting portion 87 Tightening screw 89 Tapered portion 91 Tapered portion 93 One end surface X Width direction Y Length direction G Axial direction

Claims (11)

In a cylindrical muffler gasket that is loaded in the annular space of the joint between the inner pipe and the outer pipe of the muffler joint and exhibits sealing performance by the tightening force of the tightening band attached to the outer peripheral surface of the outer pipe,
A metal mesh material stretched in a plane, and a band-shaped sealing material that is overlapped with the metal mesh material so as to overlap in a part of the length direction,
The metal mesh material and the seal material are compressed in the axial direction in a state of being rounded in the width direction, thereby axially forming a hard layer made of only the metal mesh material and a soft layer made of the metal mesh material and the seal material. Molded in a state of being divided into
The muffler gasket, wherein the metal mesh material applied to the overlapping portion overlapping the sealing material is formed at a lower density than the metal mesh material other than the overlapping portion.   The metal mesh material applied to the overlapping portion is formed at a low density by knitting by knitting one stitch or a plurality of stitches at the time of knitting a stainless wire. Gummet for muffler.   The sealing material applied to the overlapping portion is provided at least on the surface of the metal mesh material that appears on the outer peripheral surface of the muffler gasket when rolled into a cylindrical shape. Gasket for muffler.   The muffler gasket according to any one of claims 1 to 3, wherein the sealing material is exposed on the inner peripheral surface of the soft layer with substantially the same width as the outer peripheral surface of the soft layer.   The muffler gasket according to any one of claims 1 to 4, wherein the sealing material is formed of an inorganic material containing expanded graphite.   The muffler gasket according to any one of claims 1 to 5, wherein the sealing material has a thin film layer coated with a liquid inorganic material mainly composed of zirconia on the surface.   The heat-expandable inorganic material is interposed over at least the range of the sealing material formed on the outer peripheral side between the wound layers of the metal mesh material provided in the soft layer. The gasket for mufflers in any one of 1-6.   The muffler gasket according to any one of claims 1 to 4, wherein the sealing material is formed of a thermally expandable inorganic material containing unexpanded graphite, heat resistant fibers, and a heat resistant binder. An outer pipe provided with slits arranged in the joint portion such as a circumference extending in the axial direction from the end face;
An inner pipe connected to the outer pipe;
A muffler gasket to be loaded into the annular space at the joint between the outer pipe and the inner pipe;
A tightening band attached to the outer peripheral surface of the joint portion of the outer pipe,
The muffler joint according to any one of claims 1 to 8, wherein the muffler gasket is the muffler gasket.   The muffler joint according to claim 9, wherein the muffler gasket is loaded with a soft layer provided with a sealing material at a position where the soft layer is engaged with a slit formed in the outer pipe.   11. The muffler joint according to claim 9, wherein the fastening band is attached to a position that spans both the hard layer and the soft layer.

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