JPH0258503B2 - - Google Patents

Description

[Detailed Description of the Invention] a. Purpose of the Invention (Industrial Application Field) The sealing member for an exhaust pipe joint produced by the manufacturing method of the present invention dissipates exhaust gas emitted from an automobile engine into the atmosphere. A joint part is installed in the middle of the exhaust pipe for the purpose of preventing exhaust gas from leaking from this joint part.

(Prior Art) Exhaust gas discharged from an automobile engine is released into the atmosphere through a long exhaust pipe provided along the underfloor. An exhaust purifier and a muffler are installed in the middle of the exhaust pipe to detoxify harmful components contained in the exhaust gas and attenuate noise components.

Engine vibrations are transmitted to the exhaust pipe, which has one end connected to the exhaust port of the engine that vibrates during operation, but if these vibrations are transmitted to the entire exhaust pipe, the comparatively heavy exhaust purifiers and mufflers will vibrate greatly. This is undesirable because the connection between the exhaust pipe and these devices may be damaged, or abnormal noise may be generated under the floor.

For this reason, a vibration-proof joint 1 as shown in Fig. 4 has been conventionally provided in the middle of the exhaust pipe near the engine.
This prevents engine vibrations from being transmitted directly to the entire exhaust pipe. This anti-vibration joint 1 has a flange-like shape at the end of one of the two exhaust pipe elements 2 and 3 to be connected, and a spherical receiving surface on the opposite side from the exhaust pipe element 2. 4, and an annular sealing member 7 having a sliding surface 6 in close contact with the receiving surface 4 of the above-mentioned exhaust pipe element 3 at the end of the other exhaust pipe element 3.
and flange piece 8 are fixed. Bolts 10, 1 are inserted from the side opposite to the flange piece 8 into through holes 9, 9 drilled in a portion closer to the outer periphery than the receiving surface 4 of the receiver 5.
0 is screwed into the screw holes 11, 11 provided near the outer periphery of the flange piece 8, and lock nuts 12, 1 are screwed together.
2, and compression springs 14, 1 are installed between the heads 13, 13 of each bolt 10, 10 and the receiver.
4 is provided to press the sliding surface 6 of the sealing member 7 against the receiving surface 4 of the receiver 5.

The exhaust pipe elements 2 and 3 connected to each other by such an anti-vibration joint 1 can be freely displaced in the direction in which the connecting portion is bent by sliding the receiving surface 4 and the sliding surface 6 against each other, so that the vibration of the engine Even if the vibration is transmitted to one exhaust pipe element 2, this vibration will not be directly transmitted to the other exhaust pipe element 3.

By the way, in order to effectively prevent vibrations from being transmitted from one exhaust pipe element 2 to the other exhaust pipe element 3 with the vibration-proof joint 1 configured and operated in this way, it is necessary to adjust the sliding surface of the sealing member 7. 6 is the receiving surface 4 of the receiver 5
It must be possible to slide with light force.
For this reason, conventional sealing members 7 made of various materials have been used.
are used or proposed.

Among these, the sealing member disclosed in Japanese Patent Publication No. 58-21144 is a sealing member in which a band-shaped refractory material 15 made of graphite or the like is aligned with a wire mesh 15 as shown in FIG. 5. The seal member 7 is wound into a cylindrical shape as shown in FIG. 7, and then press-molded in a mold to form a sealing member 7 as shown in FIG. During this press molding, the refractory material is evenly filled into the inside of the mesh of the wire mesh that is the core material.

However, in conventional sealing members such as Joju, which are made by winding a sheet of refractory material and press-forming it, the refractory material is not completely integrated even after press-forming. , the sheet-like refractory material is likely to peel off.

A sealing member for an exhaust pipe joint and a manufacturing method thereof that eliminates such inconveniences are disclosed in the patent application filed in 1983.
There is one disclosed in No. 204077. The sealing member for the exhaust pipe joint according to the present invention is entirely annular and has a sliding surface that makes close sliding contact with the spherical receiving surface of the vibration-proof exhaust pipe joint, and is wound or It is made by press-molding expanded graphite powder using a cylindrical knitted wire mesh as the core material.

When manufacturing the sealing material according to the earlier invention as described above, as shown in FIG.
Then, a wire mesh 20 made of a wire mesh wound into a cylindrical shape or a wire mesh 20 made of a filament of stainless steel or the like braided into a cylindrical shape as shown in FIG. 9 is inserted into the molding space 18.
The expanded graphite particles 19, 19 and the wire mesh 20 are pressed toward the bottom of the molding space 18 by the male die 21 which is tightly fitted with the expanded graphite particles, and the expanded graphite particles are brought into close contact with each other, and the individual particles are pressed. The annular sealing member 7 is integrally molded.

First, the expanded graphite particles are spread evenly on the inner and outer circumferential sides of the wire mesh 20 formed in a cylindrical shape.
As shown in FIGS. 0 to 11, the wire mesh 16 was formed into a wave shape in a direction perpendicular to the winding direction or in a direction inclined thereto, and this wire mesh was inserted into the molding space 18 of the female mold 17. In this case, a method has also been considered in which the molding space 18 located on the outer circumferential side and the inner circumferential side of the wire mesh 16 is evenly filled with expanded graphite particles.

(Problems to be Solved by the Invention) However, when a sealing member is manufactured by the method according to the previous invention as described above, the following disadvantages occur.

That is, as shown in FIG. 8, the wire mesh 16 wound into a cylindrical shape is simply put into the molding space 18 of the female mold 17, and the wire mesh 16 and the expanded graphite particles 19 are directed toward the bottom of the molding space 18. Just by pressing, the strength of the portion of the sliding surface 6 that makes sliding contact with the receiving surface 4 (Fig. 4) of the receiver 5 is not necessarily sufficient, and if the usage conditions are severe, this portion of the sliding surface 6 may not be strong enough. In this case, the sealing member is crushed or deformed.

The method of manufacturing a sealing member for an exhaust pipe joint of the present invention solves the above-mentioned disadvantages by performing press molding of expanded graphite particles and a wire mesh in two stages.

b. Structure of the invention (means for solving problems) The method for manufacturing a sealing member for an exhaust pipe joint according to the present invention is characterized in that press forming of expanded graphite particles and a wire mesh is carried out in two stages. However, the expanded graphite particles used are the same as those used in the sealing member for the exhaust pipe joint according to the previous invention described above.

That is, expanded graphite particles are obtained by expanding graphite particles in the absence of an adhesive.
No. 44-23966.

These expanded graphite particles have a small bulk density (e.g.
0.008 to 0.40 g/cm ³ ), and when press-molded, the volume decreases significantly and the individual particles interlock with each other and solidify into one piece. Therefore, in the case of a sealing member made by press-molding expanded graphite particles using a wire mesh as a core material, the expanded graphite particles are integrally bonded to each other through the holes of the wire mesh, and sufficient strength can be obtained.

In the method for manufacturing a sealing member for an exhaust pipe joint according to the present invention, in which a sealing member is manufactured by press-molding such expanded graphite particles and a wire mesh, first, the expanded graphite particles and the wire mesh are compared with each other. By preliminary press forming with a light force, a thick cylindrical material 22 as shown in FIG. 1 is formed.

As shown in the second figure, a first female mold 23 for producing such a material 22 has a first molding space 24 in the shape of a thick cylinder that is open at the top.

When manufacturing the material 22, as shown in FIG. 2, expanded graphite particles 19 and a wire mesh 16 wound or braided into a cylindrical shape are placed in the first molding space 24. , the wire mesh 16 is filled with the upper part exposed above the expanded graphite particles 19, and then a first male mold 25 having an annular cross section is pushed into the first molding space 24. 25 and the first molding space 2 formed in the first female mold 23
4 between the expanded graphite particles 19 and the wire mesh 16
and are preliminarily press-molded.

When performing preliminary press molding, the first male mold 2
The force for lowering 5 is relatively small, and the density of the material 22 obtained by this preliminary press forming is
The density shall be sufficiently lower than the density of the completed sealing member 7.

The density of the wire mesh 16 in the material 22 obtained by this preforming is higher on the upper side and higher on the lower side because the upper part of the wire mesh 16 was exposed above the expanded graphite particles 19 before preforming. becomes smaller.

Thick cylindrical material 22 made in this way
is taken out from the inside of the first molding space 24 and then turned upside down so that the part of the wire mesh 16 with a higher density is placed on the bottom and, conversely, the part of the wire mesh 16 with a lower density is placed on top.

In this way, the thick cylindrical material 22 with the high-density part of the wire mesh 16 facing down and, conversely, the low-density part of the wire mesh 16 facing up, is then transferred to the second female mold 2.
6 into the second molding space 27 formed at 6.

This second molding space 27 is completely similar to the molding space 18 of the female mold 17 shown in FIG.
It has an inner shape that matches the outer shape of the completed sealing member 7, such as by curving the bottom part into an arcuate cross section.

In this way, the material 22 is transferred to the second molding space 27.
Then, a second male mold 28 having an annular cross section is pushed into the second molding space 27, so that the lower surface of the second male mold 28 and the second molding space 27 are inserted into the second molding space 27. The material 22 is press-molded between the inner surface of the holder and the inner surface of the holder.

The press forming in this second stage is performed with a sufficiently large force to compress the relatively low-density material 22 and complete the sealing member 7.
In this completed sealing member, the density of the wire mesh 16 is highest at the sliding surface 6 which is curved in an arc shape and slides into contact with the receiving surface 4 of the receiver 5 during use.

It should be noted that powder particles of a synthetic resin with good lubricity such as Teflon or polyimide resin can be added to the expanded graphite particles as a friction reducing agent in an amount of up to 50% by weight, and that the pressing by the first male mold 23 First, in order to efficiently fill the expanded graphite particles 19, 19, it is effective to apply fine vibrations to the first female mold 23 during the filling operation, and the expanded graphite particles 19, 19 are commercially available. Expanded graphite particles can be used as they are, or a sheet of expanded graphite commercially available as Nika Film (trade name of Nippon Carbon Co., Ltd.) can be crushed into particles. The ability to crush and utilize the expanded graphite adhering to the punching residue produced in the process is exactly the same as in the case of the previous invention.

c. Effects of the Invention The method for manufacturing a sealing member for an exhaust pipe joint of the present invention is configured as described above, and the sealing member manufactured by the manufacturing method of the present invention has a sliding surface portion Since the density of the wire mesh is high, the strength of the sliding surface area is high, and the sliding surface area will not be crushed or deformed during use.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a material that is an intermediate product when manufacturing a sealing member by the manufacturing method of the present invention;
The figure is a vertical cross-sectional view showing the state of preforming to make this material, Figure 3 is a vertical cross-sectional view showing the state of press-forming the material into a sealing member, and Figure 4 is an exhaust gas with the sealing member incorporated. 5 to 7, which are cross-sectional views of the pipe joint, show an example of a conventional sealing member.
The figure is a perspective view showing the wire mesh and refractory material before forming.
The figure is a plan view showing the state in which it is rolled into a cylindrical shape prior to molding, FIG. 7 is a partially cutaway perspective view showing the state after molding, and FIG. 8 is a state in which the sealing member according to the earlier invention is manufactured. 9 is a perspective view of a wire mesh knitted into a cylindrical shape, FIG. 10 is a perspective view of a wire mesh formed into a corrugated shape, and FIG. 11 is a half of a female mold with this wire mesh inserted into the molding space. FIG. 1: Anti-vibration joint, 2, 3: Exhaust pipe element, 4: Reception surface,
5: Receiver, 6: Sliding surface, 7: Seal member, 8:
Flange piece, 9: Through hole, 10: Bolt, 11: Screw hole, 12: Lock nut, 13: Head, 14:
Compression spring, 15: Fireproof material, 16: Wire mesh, 17: Female mold, 18: Molding space, 19: Expanded graphite particles, 2
0: wire mesh, 21: male mold, 22: material, 23: first female mold, 24: first molding space, 25: first male mold, 26: second female mold, 27: second molding space, 28: second male mold.

Claims (1)

[Claims] 1. Expanded graphite particles and a wire mesh wound in a cylindrical shape are placed in a thick-walled cylindrical first molding space with an upper opening formed in the first female mold, and the upper part of the wire mesh is placed above the expanded graphite particles. The first male mold having an annular cross section is then pushed into the first molding space, and the lower surface of the first male mold and the first molding space of the first female mold are filled. Expanded graphite particles and a wire mesh are preliminarily press-molded between the inner surface of the first molding space to form a thick cylindrical material with a lower density than the completed sealing member, and the inner surface of the first molding space is The above-mentioned material taken out from the mold is turned upside down, and then inserted into a second molding space formed in a second female mold, which has an inner shape that matches the outer shape of the completed sealing member. A second male mold having an annular cross section is pushed into the second molding space, and expanded graphite particles and a wire mesh are inserted between the lower surface of the second male mold and the inner surface of the second molding space. A method for manufacturing a sealing member for an exhaust pipe joint that is press-molded.