JPH0260489B2 - - 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. It is installed in a joint part provided in the middle of an 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 engine's exhaust port, which vibrates when the engine rotates, but if these vibrations were to be transmitted to the entire exhaust pipe, the exhaust purifiers and mufflers, which are relatively heavy, would become bulky. This is undesirable because the vibration may damage the connection between the exhaust pipe and these devices, or cause abnormal noise under the floor.

For this reason, a vibration-proof joint 1 as shown in Fig. 3 has traditionally been installed 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 one in which a band-shaped refractory material 15 made of graphite or the like and a wire mesh 16 are aligned as shown in FIG. 4. The seal member 7 is wound into a cylindrical shape as shown in FIG. 6, 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 the conventional sealing member manufactured by winding a sheet-shaped refractory material and press-forming it as described above, the refractory material is not completely integrated even after press-forming. Sheet-like refractory material tends 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 made of stockinette knitted wire mesh. It is made by press-molding expanded graphite powder as a core material.

When manufacturing the sealing material according to the earlier invention as described above, as shown in FIG. The expanded graphite particles 19, 19 and the wire mesh 20 are inserted into the molding space 1 by the male mold 21 that tightly fits into the molding space 18.
8 to bring the expanded graphite particles into close contact with each other and crush the individual particles to form an annular sealing member 7 integrally. At this time, in order to cover the surface of the sealing member 7 after molding with graphite and to prevent the wire mesh from being exposed on the surface of the sealing member 7 as much as possible, it is necessary to small amount of expanded graphite particles 19,
19, and then a wire mesh 20 wound into a cylindrical shape is inserted into the space 18. After inserting the wire mesh 20 into the space 18 in this way, the wire mesh 2
It is preferable to fill the molding space 18 with expanded graphite particles 19 until the 0 is completely hidden.
A sufficient amount of expanded graphite particles 19 in the molding space 18,
19 is filled, the male mold 21 is then inserted into the molding space 18 and the wire mesh 20 described above is filled.
and expanded graphite particles 19, 19 are pressed toward the bottom of the molding space 18.

(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, if the wire mesh 16 wound into a cylindrical shape is simply put into the molding space 18 of the female mold 17 as shown in FIG.
Not only will the density of the expanded graphite particles filled in the wire mesh 16 become non-uniform, but also when the expanded graphite particles filled in the female mold 17 are press-molded together with the wire mesh 16, parts of the wire mesh 16 will become uneven. As shown in Figure 8, the wire mesh deforms so that it sticks closely to each other, resulting in poor adhesion in this area, which not only makes peeling more likely, but also makes the density of the wire mesh as a core material uneven. As a result, a portion of the wire mesh 16 is exposed on the surface of the sealing material, deteriorating the sealing performance, or the portions of the wire mesh with low density are insufficiently reinforced.

In the specification of the earlier invention, as shown in FIGS. 9 and 10, a wire mesh 16 is formed into a wave shape in a direction perpendicular to the winding direction thereof, and this wire mesh is placed in a molding space 18 of a male die 17. A method is also shown in which when the wire mesh 16 is inserted, the molding space 18 located on the outer and inner sides of the wire mesh 16 is evenly filled with expanded graphite particles. Even when a wire mesh formed in a corrugated shape in the right angle direction is press-molded together with expanded graphite particles, the wire mesh deforms so that parts of the wire mesh 16 are in close contact with each other, as shown in FIG. 11, and may peel off. However, there are still disadvantages such as the tendency to cause problems.

The method for manufacturing a sealing member for an exhaust pipe joint of the present invention involves forming a waveform on a wire mesh placed in a female mold together with expanded graphite particles, which is inclined with respect to the moving direction of a male mold that presses the wire mesh during press molding. This solves the above-mentioned inconvenience.

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 similar to the method for manufacturing a sealing member for an exhaust pipe joint according to the earlier invention. Similarly, expanded graphite particles and a cylindrical wire mesh are inserted into a molding space with an annular cross section in the upper opening formed in the female mold, and then a male mold with a circular cross section is pushed into the molding space.
A sealing member is produced by press-molding expanded graphite particles and a wire mesh between the lower surface of the male mold and the inner surface of the molding space of the female mold.

In the method of manufacturing a sealing member for an exhaust pipe joint of the present invention, the wire mesh 16 placed in the female mold together with the expanded graphite particles is formed into a corrugated shape as shown in FIG. , is characterized by being inclined at 20 to 90 degrees, more preferably 30 to 70 degrees, with respect to the direction of movement of the male mold.

The expanded graphite particles placed in the female mold together with the wire mesh having such an inclined waveform are the same as those used in the sealing member of the previous invention described above, and the graphite particles are placed in the female mold in the absence of an adhesive. An expanded version is shown in Japanese Patent Publication No. 44-23966, for example.

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 particular, in the case of the sealing member manufactured by the manufacturing method of the present invention, since the wire mesh serving as the core material of expanded graphite is inclined with respect to the pressing direction (the direction of movement of the male mold), the male mold is As the mold 21 enters the molding space 18 of the female mold 17, the wire mesh 1
6 is crushed uniformly and a wire mesh 16 is placed inside the completed sealing member after pressing is completed, as shown in FIG.
It will appear to exist evenly.

In addition, it is possible to add up to 50% by weight of Teflon powder as a friction reducing agent to the expanded graphite particles, and in order to efficiently fill the expanded graphite particles 19, 19 before pressing with the male die 21. , It is effective to apply fine vibrations to the female mold 17 during the filling operation, and the molding space 18 of the female mold 17
For the expanded graphite particles 19, 19 that are filled into the inside and molded into one piece by pressing, commercially available expanded graphite particles may be used as they are, or commercially available expanded graphite particles may be used as they are (trade name of Nippon Carbon Co., Ltd.). In addition to being able to use the expanded graphite sheet that is used by crushing it into powder, it is also possible to use it by crushing the expanded graphite that adheres to the punching residue that is created when manufacturing gaskets. Points other than the shape of 16 are completely 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, but since the expanded graphite particles stick together and become integral after press molding, Unlike when graphite sheets are press-formed, the graphite does not peel off, and the wire mesh, which is the core material of the expanded graphite, is uniformly present inside the sealing member, so part of the wire mesh is sealed. The sealing material may be exposed on the surface of the parts used, worsening the sealing performance, or conversely, the strength may be insufficient in areas where the density of the wire mesh is low, or even the sealing material may peel off at areas where the density of the wire mesh is too high. do not have.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a seal-like member manufactured by the manufacturing method of the present invention, Fig. 2 is a perspective view showing the state before press molding of the wire mesh used as the core material of this seal member, and Fig. 3 is A sectional view of an exhaust pipe joint incorporating a sealing member, FIGS. 4 to 6 show an example of a conventional sealing member, and FIG. 4 is a perspective view showing a wire mesh and a refractory material before forming. , FIG. 5 is a plan view showing the state in which it is rolled into a cylindrical shape prior to molding, FIG. 6 is a partially cutaway perspective view showing the state after molding, and FIG. 7 is a manufacturing of the sealing member according to the earlier invention. FIG. 8 is a cross-sectional view showing a first example of a sealing member made by the method of the previous invention, and FIG. 9 is a wire mesh formed in a corrugated shape in a direction perpendicular to the winding direction. FIG. 10 is a half plan view of a female mold with this wire mesh inserted into the molding space, and FIG. 11 is a sectional view showing a sealing member made using this wire mesh as a core material. 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
1: Male type.

Claims (1)

[Claims] 1. Insert expanded graphite particles and a cylindrical wire mesh into a molding space with an annular cross section in the upper opening formed in the female mold, and then push a male mold with an annular cross section into the molding space. In a method for manufacturing a sealing member for an exhaust pipe joint in which expanded graphite particles and a wire mesh are press-molded between the lower surface of the mold and the inner surface of the molding space of the female mold, the wire mesh is A method for manufacturing a sealing member for an exhaust pipe joint, which is characterized by a wire mesh formed in a corrugated shape inclined at ~90 degrees.