JPH0546476B2 - - Google Patents

Description

[Detailed Description of the Invention] a. Purpose of the Invention (Field of Industrial Application) The exhaust pipe joint sealing member that is the subject of this invention is an exhaust pipe joint sealing member for dispersing exhaust gas emitted from an automobile engine into the atmosphere. It is installed in a joint part provided in the middle of a pipe to prevent 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 are transmitted to the entire exhaust pipe, the exhaust purifiers and mufflers, which are relatively heavy, will be required. This is undesirable because the large vibrations may damage the joints 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. 6 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 connects one of the two exhaust pipe elements 2 and 3 to be connected.
A receiver 5, which is entirely flange-shaped and has a spherical receiving surface 4 on the opposite side of the exhaust pipe element 2, is fixed to the end of the exhaust pipe element 3. An annular sealing member 7 having a sliding surface 6 in close contact with the surface 4 and a flange piece 8 are fixed. Bolts 10 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.
Numeral 10 is a lock nut 12, which is screwed into screw holes 11, 11 provided in a portion near the outer periphery of the flange piece 8.
12, and a compression spring 14 is installed between the head 13 of each bolt 10, 10 and the receiver.
14 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 a vibration-proof joint 1 can be freely displaced in the bending direction in which the connection part is bent by sliding the receiving surface 4 and the sliding surface 6 against each other. Even if vibrations are 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 is aligned with a wire mesh 16 as shown in FIG. 7. The seal member 7 is wound into a cylindrical shape as shown in FIG. 9, 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.

(Problems to be Solved by the Invention) However, in the conventional sealing member manufactured by winding a sheet-shaped fireproof material and press-forming it as described above, the fireproofing is not achieved even after press-forming. The materials are not completely integrated, and the sheet-like refractory material is likely to peel off.

In addition, since the wire mesh core material has low rigidity, the rigidity of the completed sealing member is not that high, and if it is assembled into an exhaust pipe joint and used for a long time, the sealing member may deform and cause the above-mentioned problems. The sealing properties of the joint are likely to be poor.

An object of the present invention is to provide a sealing member for an exhaust pipe joint and a method for manufacturing the same, which is free from such inconveniences.

b Structure of the Invention The sealing member of the exhaust pipe joint of the present invention is entirely annular and has a vibration-proof type exhaust pipe joint with a sliding surface that makes close sliding contact with a spherical receiving surface, and has both front and back surfaces. It is manufactured by press-forming expanded graphite particles using a core material made of a band-shaped metal plate with a hook formed by punching it out and wound several times in a spiral shape. Expanded graphite particles are obtained by expanding graphite particles in the absence of an adhesive, and are disclosed, for example, in Japanese Patent Publication No. 32966/1983. These expanded graphite particles have a small bulk density (for example, 0.008 to 0.40 g/
cm ³ ), when press-molded, the volume decreases significantly and the individual particles interlock with each other, solidifying into one piece. For this reason, in the case of the sealing member of the present invention, which is made by press-molding expanded graphite particles using a band-shaped metal plate with a hook as a core material, the expanded graphite particles are integrally bonded to each other through the inside of the hook, and You can obtain strong strength.

Furthermore, Teflon powder can be added to the above-mentioned expanded graphite particles as a friction reducing agent. The greater the amount of Teflon powder added, the greater the friction reduction effect, but it can be added up to a maximum of 50% by weight as long as it does not prevent the solidification of expanded graphite particles by pressing.

Next, a method of manufacturing such a sealing member for an exhaust pipe joint will be described.

When manufacturing a sealing member for an exhaust pipe joint by the method of the present invention, as shown in FIG.
9 and a core material 20 formed into a cylindrical shape by spirally winding a metal plate with a hook, and the expanded graphite particles 19 and the core material 20 are molded by a male mold 21 that tightly fits into the molding space 18. is pressed toward the bottom of the molding space 18 to bring the expanded graphite particles into close contact with each other and crush the individual particles to integrally mold the annular sealing member 7. At this time, in order to ensure that the surface of the sealing member 7 after molding is covered with graphite and the core material 20 is not exposed to the surface of the sealing member 7 as much as possible, the inside of the molding space 18 of the female mold is initially Add a small amount of expanded graphite particles 19,
Thereafter, the spirally wound core material 20 is placed in the space 1.
Insert into 8. In this way, the core material 20 is
After the molding space 18 is inserted, expanded graphite particles 19 are filled into the molding space 18 until the core material 20 is completely hidden. Once the molding space 18 is filled with a sufficient amount of expanded graphite particles 19, the male mold 21 is then inserted into the molding space 18, and the core material 20 and the expanded graphite particles 19 are molded into the molding space 18. Press toward the bottom of the space 18. In order to efficiently fill the expanded graphite particles 19 before pressing with the male die 21, it is effective to apply fine vibrations to the female die 17 during the filling operation.

The expanded graphite particles 19 filled in the molding space 18 of the female mold 17 and molded into one piece by pressing are as follows:
Commercially available expanded graphite particles may be used as they are, or a sheet of expanded graphite commercially available as Nika Film (trade name of Nippon Carbon Co., Ltd.) may be pulverized into particles.

Although it is preferable for the appearance that the core material 20 is not exposed at all on the surface of the sealing member 7, some exposure is not a problem in terms of the sealing effect. In particular, exposing the core material to surfaces other than the sliding contact surface 6 does not affect the sealing performance at all.

As the material of the metal plate with a hook used in the sealing member of the present invention, stainless steel plate, galvanized steel plate, etc. can be used. The thickness T (Fig. 2) of the metal plate is 0.05 to 0.25 mm, preferably 0.1 to 0.15 mm, and the diameter R of the hooks 22 formed on both the front and back sides of this metal plate is preferably 0.8 to 2.0 mm.
mm, the pitch P and height H of each hook 22, 22 are:
Preferably each is 2.0 to 3.0 mm. Furthermore,
The diameter of the expanded graphite particles constituting the sealing member together with the core material made of a metal plate formed on both the front and back surfaces of the hook 22 is such that the expanded graphite particles can freely enter between the spirally wound metal plates. However, it is preferable that the thickness be 1 mm or less.

Furthermore, the cross-sectional shape of the hook 22 with a rounded base as shown in FIG. 3 is better than the angular shape as shown in FIG. This is preferable because it makes it easier to fill.

c. Effects of the Invention The sealing member for the exhaust pipe joint of the present invention is configured and manufactured as described above, but since the expanded graphite particles stick together and become integral after press molding, the sealing member for the exhaust pipe joint part of the present invention is manufactured as described above. Unlike when a graphite sheet is press-molded, peeling of graphite does not occur.

Furthermore, since the surface of the sealing member covered with graphite becomes homogeneous, the sealing performance between the sliding surface of this sealing member and the receiving surface 4 of the receiver 5 (FIG. 6) is improved. The present inventor has developed sample 1 in which mica was solidified using metal as the core material, sample 2 in which sheet-shaped graphite was solidified with metal as the core material as shown in Figures 7 to 9, and hook as shown in Figure 1. A sealing test was conducted with Sample 3 (product of the present invention) in which expanded graphite particles were hardened using a metal plate as a core material, and the results shown in Fig. 4 were obtained, indicating that the exhaust pipe according to the present invention It was found that the joint not only has good strength but also good sheet performance.

Furthermore, by making the sliding surface uniform, there is an effect that no large noise is generated when the sliding surface and the receiving surface slide against each other due to engine vibration. That is, when the present inventor measured the level of noise generated when the sliding surface and the receiving surface were rubbed together using the above samples 1 to 3, the results shown in FIG. 5 were obtained. . On the vertical axis of the same figure, A is a noise level that feels continuous and noisy, B is a noise level that sometimes feels slightly noisy, C is a noise level that can be heard if you pay attention, and D is almost audible. It shows that there is no condition. In this way, the noise level is lowered by the sliding surface 6 of the sealing member 7.
This is because the sealing member is smooth and has a small coefficient of friction with the receiving surface 4. However, if the expanded graphite particles constituting the sealing member are mixed with Teflon powder as a friction reducing agent, the noise level can be reduced even better. be able to.

[Brief explanation of the drawing]

Fig. 1 is a half longitudinal sectional view showing the manufacturing state of the sealing member of the present invention, Fig. 2 is a first example of a metal plate with a hook used as a core material, and Fig. 3 is a second example of the same. FIG. 4 is a diagram comparing the sealing performance of the sealing member of the present invention with that of a conventional product, and FIG.
Figure 6 is a diagram for comparing noise levels, Figure 6 is a sectional view of an exhaust pipe joint incorporating a sealing member, Figures 7 to 9 show an example of a conventional sealing member, and Figure 6 is a cross-sectional view of an exhaust pipe joint incorporating a sealing member. Figure 7 is a perspective view showing the core material and refractory material before forming, Figure 8 is a plan view showing the state in which they are rolled into a cylindrical shape prior to forming, and Figure 9 is a partially cutaway perspective view showing the state after forming. It is a diagram. 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: Core material, 21: Male mold, 22: Hook.

Claims (1)

[Scope of Claims] 1. A sealing member for an exhaust pipe joint, which has an annular shape as a whole and has a sliding surface that comes into close contact with a spherical receiving surface of a receiver constituting a vibration-proof exhaust pipe joint. Then, the core material is a band-shaped metal plate with hooks formed by punching out hooks on both the front and back sides, wound several times in a spiral shape, and expanded graphite particles are press-molded, and the expanded graphite particles are used as the core material. A sealing member for an exhaust pipe joint, which is made by entering the inside of a hook and integrally solidifying the expanded graphite particles present on both the front and back surfaces of a metal plate forming a core material. 2. A sealing member for an exhaust pipe joint that has an annular shape as a whole and has a sliding surface that comes into close contact with the spherical receiving surface of the receiver that constitutes a vibration-proof exhaust pipe joint, and has hooks on both the front and back sides. The core material is a belt-shaped metal plate with a hook formed by punching and wound multiple times in a spiral shape, and the core material is a mixture of expanded graphite particles of 50% by weight or more and Teflon powder particles of 50% by weight or less. by press molding the mixture of expanded graphite particles and Teflon powder to enter the inside of the hook of the core material,
A sealing member for an exhaust pipe joint that is made by integrally solidifying a mixture of expanded graphite particles and Teflon that are present on both the front and back sides of a metal plate that forms a core material. 3. After putting a small amount of expanded graphite particles into the molding space with an annular cross section in the upper opening formed in the female mold,
A core material made by spirally winding a metal plate with hooks formed by punching out hooks on both the front and back sides is inserted into this molding space, and then expanded graphite particles are inserted into the molding space until the core material is completely hidden. After filling the molding space up to 100%, a male mold with an annular cross section is pushed into the molding space, and the expanded graphite particles and core material are press-molded between the lower surface of the male mold and the inner surface of the female molding space. A method for manufacturing a sealing member for a pipe joint.