JP2007327576A - Metal gasket and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal gasket with a sectionally corrugated seal portion, easy attachment to a sealed object such as a flange pipe or maintenance, easy to handle and superior in work efficiency without requiring a skilled person. <P>SOLUTION: The annular metal gasket G formed of a plate material has the seal portion 7 formed in a concentrically corrugated shape. A flat outer periphery portion 9 is continuously provided on the outer diameter side of the seal portion 7. In the outer periphery portion 9, an insertion portion S is provided through which a plurality of bolts 5 are inserted to relatively fix the sealed objects 1, 1 to each other with a gasket interposed therebetween. The insertion portion S is shaped to be cut out with part of a circular hole on the outer diameter side being opened. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a metal gasket used at a connection point between flange pipes, a connection point between a fluid device such as a valve and a pipe, and the like, and a manufacturing method thereof.

  Metal gaskets are used for extremely high pressures and temperatures. Since the minimum interface pressure is high and a large tightening force is required, usually a means for tightening and fixing with multiple bolts is used. It is done. Various types such as a flat shape, a corrugated shape, and a sawtooth shape are known from the sectional shape of the seal portion. Among them, as for corrugated metal gaskets used in fluid piping systems for liquids and the like, as one having a small number of waves, for example, as disclosed in Patent Document 1, it is provided between a cylinder and a cylinder head in an engine. What is intervened is known.

  A metal gasket with a corrugated cross section (also called “corrugated gasket”) can process a metal thin plate into a concentric corrugated shape to increase the contact pressure and improve the sealing performance by adding the metal spring effect. It can be made to. It has the characteristics that it is made of metal and has a sufficient sealing function at a relatively low tightening pressure, and also has heat resistance, and is widely used as a metal gasket that is often used in fluid equipment such as valves. Recognized.

  And as a thing with many waves, as shown in FIG. 6, the metal gasket g interposed between flange piping is mentioned, for example for the purpose of fluid leakage prevention. The metal gasket g shown in FIG. 6 has an annular shape having a center hole 38 having an inner diameter equivalent to the diameter of the internal flow path w of the flange pipes 31 and 31, and an outer diameter that does not interfere with the mounting bolt 35. And the cross section is made of a steel plate press having a seal portion 37 formed in a corrugated shape (see FIG. 2) having a concentric (or substantially concentric) shape.

When assembling the metal gasket, the flanges 32 and 32 (bolt holes 32a and 32a) of the pair of flange pipes 31 and 31 arranged opposite to each other are disposed with the gasket g disposed between the flange surfaces 33. The bolt 35 is inserted and the nut 36 is tightened. In the conventional example shown in FIG. 6, the diameter n of the metal gasket g is smaller than the diameter m of the flange portion 32. Since it is difficult to match g with the center of the internal flow path w and the metal gasket g and the bolt 35 may be held at the same time, the workability is not good, and the work requires skill. It was a thing.
JP-A-2005-90699

  The object of the present invention is to make it easy and easy to assemble and maintain a metal gasket having a corrugated seal section on a sealing target such as a flange pipe. It is in providing as an excellent one.

The invention according to claim 1 is an annular metal gasket made of a plate material having a seal portion 7 formed in a concentric or substantially concentric corrugated shape,
A flat surface-shaped outer peripheral portion 9 is continuously provided on the outer diameter side of the seal portion 7, and a plurality of bolts 5 for relatively fixing the sealing objects 1, 1 in a gasket interposed state are passed through the outer peripheral portion 9. An insertion portion S is provided, and the insertion portion S is configured as a notch that has a shape in which a part of the outer diameter side of the circular hole is opened.

  The invention according to claim 2 is the metal gasket according to claim 1, wherein the outer diameter of the outer peripheral portion 9 is set to be substantially the same as or slightly smaller than the outer diameter of the seal surface 3 of the seal target 1. It is characterized by this.

  The invention according to claim 3 is the metal gasket according to claim 1 or 2, wherein at least one surface of the seal portion 7 is covered with expanded graphite 7B.

  According to a fourth aspect of the present invention, in the metal gasket according to the third aspect, the outer diameter of the expanded graphite 7B is formed to project from the notch S so as to be in contact with the bolt 5. It is what.

  The invention according to claim 5 is the method of manufacturing a metal gasket according to any one of claims 1 to 4, wherein the notch forming step in which the notch S is formed by pressing is performed by pressing. A corrugation forming process in which the seal portion 7 is formed is performed.

  According to the invention of claim 1, although described in detail in the section of the embodiment, it is possible to operate the outer peripheral portion with a finger or the like by forming a flat outer peripheral portion on the outer diameter side of the seal portion. It becomes possible. In other words, the operation of inserting between the seal targets by pinching the outer periphery or sandwiching two places on the outer periphery, and the operation of passing the bolt from the seal target through the insertion portion in the inserted state are the conventional metal Compared to the gasket, it is easier to perform, and the operation of placing the metal gasket at a predetermined position to be sealed is facilitated. In addition, when the insertion portion is a simple hole, it is not useful because it is deformed so that the radially narrow portion on the outer peripheral side of the hole is undulated by press processing for forming the hole. By using an open notch, it is possible to remove internal stress and maintain a flat state, and it is possible to use a press process that is inexpensive and excellent in productivity without problems.

  As a result, it is easy and easy to assemble and maintain a metal gasket having a seal section with a corrugated cross-section on a sealing target such as flange piping, while avoiding processing restrictions and inconveniences. Even if it is not an expert, it can be provided as an easy-to-handle and excellent workability.

  According to the invention of claim 2, since the outer diameter of the metal gasket is substantially the same as or slightly smaller than the outer diameter of the seal surface to be sealed, the gasket is smaller than the object to be sealed even if compression deformation occurs due to tightening. It does not fly out in the outer diameter direction. And since the outer periphery of the outer peripheral portion can be visually observed between the objects to be sealed, the operation of positioning the metal gasket at a predetermined location such as the center of the flange surface is further facilitated, and it is easy by pushing or pulling the outer peripheral portion. Has the advantage of being able to be removed.

  According to the invention of claim 3, since at least one surface of the seal portion is covered with expanded graphite, the sealability and heat resistance are further improved, and a rational metal gasket that can easily improve the basic performance as a gasket. Can provide.

  According to the invention of claim 4, the details will be described in the section of the embodiment. However, if the notch is enlarged for the ease of the bolt insertion operation and the absorption of the dimensional error of the insertion portion, the bolt is passed through. The bolt deforms the outer peripheral portion of the expanded graphite and enters a state where it comes into contact, and it is possible to reinforce the adjustment of the metal gasket to a predetermined position with respect to the seal target, and the inner peripheral portion of the gasket There is an advantage that it is possible to avoid the generation of abnormal noise due to the direct contact between the bolt and the bolt.

  According to the invention of claim 5, this will also be described in detail in the section of the embodiment, but by performing the notch forming process before the corrugated forming process, the gasket having a corrugated cross section is press-molded. An adverse effect that the outer peripheral side tends to be distorted can be avoided, and a manufacturing method can be obtained in which a metal gasket can be produced in a state of excellent productivity by press working while achieving high processing accuracy.

  Embodiments of a metal gasket and a method for manufacturing the same according to the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a metal gasket, FIG. 2 is a side view of the metal gasket, FIG. 3 is an exploded perspective view showing an assembled state to a sealing object, and FIGS. 4 and 5 are operation views showing a method for manufacturing the metal gasket. . FIG. 6 is a perspective view showing a conventional metal gasket.

[Example 1]
2 and 3 show a connection structure portion A between the flange pipes 1 and 1. The connection structure portion A includes a pair of flange portions 2 and 2 that are end portions of the flange pipes 1, a metal gasket G that is interposed between seal surfaces 3 and 3 that are end surfaces thereof, and a plurality of bolts. 5 and a nut 6. Each of the flange pipes 1 is formed with a circular internal flow path w, and the internal flow paths w do not leak through the hole 8 that is the inner diameter side portion of the seal portion 7 in the metal gasket G. Communication connection is made. FIG. 2 shows a state before tightening. When each bolt 5 is tightened with a specified torque, the illustration is omitted, but the seal portion 7 is compressed and flattened to become a flange portion. Two and two are closer together.

  As shown in FIGS. 1 to 3, the metal gasket G is integrated with an inner circumferential portion 7 </ b> A formed in a concentric (or substantially concentric) corrugated shape, and pasted (adhered) on both sides thereof. It is an annular gasket made of a metal plate material such as a stainless steel plate having a seal portion 7 composed of expanded graphite sheets 7B and 7B. On the outer diameter side of the seal portion 7, a flat outer peripheral portion 9 for loading and unloading operation is continuously provided, and flange piping (an example of a seal target) 1, 1 is connected to the outer peripheral portion 9 via a gasket. An insertion portion S through which the four bolts 5 for relative fixing in the mounted state are passed. The insertion part S is a notch having a shape in which a part of the outer diameter side of the circular hole is opened. Specifically, the insertion part S includes the circular hole part 10 and the communication part 11 and relates to the radiation X at the center P of the hole 8. It is formed in the shape used as a contrast.

The outer diameter D of the outer peripheral portion 9 is set to be substantially the same as or slightly smaller than the outer diameter d of the seal surface 3 of the flange portion 2. By this, the operation of inserting between the flange portions 2 and 2 arranged opposite to each other by grasping the front and back surfaces of the outer peripheral portion 9 with fingers or supporting the two outer peripheral portions of the outer peripheral portion 9 with fingers or the like. In addition, the operation of passing the bolt 5 from the bolt hole 2a of any of the flange portions 2 through the insertion portion S in the inserted state is much easier than the conventional metal gasket shown in FIG. . And since the outer peripheral part 9 between the flange parts 2 and 2 becomes visible, the operation of arranging the metal gasket at the center position of the flange surface 3 is facilitated, and the outer peripheral part 9 is pushed or pulled. There is also an advantage that it can be easily removed.

  The expanded graphite sheet 7B is formed in a corrugated and annular shape in cross section along the surface shape of the corrugated inner peripheral portion 7A, and its outer diameter L is passed through the bolt hole 2a of the flange portion 2 The bolt 5 is set to a value that projects from the notch S so as to be able to contact the bolt 5 (specifically, the thread portion or the outer peripheral portion of the main body bar). That is, as shown in FIG. 1, the outer periphery of the expanded graphite sheet 7 </ b> B is formed so as to protrude into the circular hole portion 10 of the notch S.

  In this way, by setting the diameter of the expanded graphite sheet 7B to a slightly larger diameter, the bolt 5 can be easily inserted into the bolt 5 and the diameter of the circular hole 10 can be increased to absorb dimensional errors. If 5 is passed through the insertion portion S, the bolt 5 deforms the outer peripheral portion of the expanded graphite sheet 7B and comes into contact with it, so that it is possible to reinforce the adjustment of the metal gasket G to a predetermined position. At the same time, the direct contact between the inner peripheral portion 7A and the bolt 5 is restricted, and the advantage that it is possible to avoid the generation of abnormal noise due to the contact between the metal materials is obtained.

  By the way, the reason why the common insertion portion S along the bolt is not a closed loop like a circular hole but a notch is as follows. That is, in order to clear the above-mentioned problem of the conventional corrugated metal gasket, it is conceivable to increase the outer diameter of the metal gasket shown in FIG. 6 so that it is easy to hold and visible from the outside between the flange portions. It was. In this case, since it interferes with the bolt, means for forming a bolt insertion hole (a general closed loop-shaped circular hole) in the increased outer peripheral portion has been tried.

  In order to perform the shape processing of the metal plate, press processing that is excellent in productivity is generally adopted, and the processing order includes corrugated processing that forms a corrugated seal portion and bolts that form a plurality of bolt insertion holes. Forming means in which drilling is performed at the same time, and forming means in which these corrugated processing and bolt hole processing are performed separately while shifting the time from each other are adopted. It has been found that the outer peripheral side portion of the insertion hole, that is, the connecting portion having a narrow radial width (the portion corresponding to the communicating portion 11 in FIG. 1) is deformed so as to be undulated and cannot be used. The cause seems to be that the metal plate is pulled in the direction along the surface by forming the corrugation of the seal portion in addition to the narrow width of the connecting portion and poor rigidity.

  In order to solve the above inconvenience, it is necessary for the metal to further increase the outer diameter of the sket so that the width of the connecting portion can be made sufficiently wide to increase the rigidity. Since the diameter is increased, it is still difficult to realize. Therefore, as shown in FIG. 1 and the like, the outer diameter side portion of the bolt insertion hole is deleted to be in an externally penetrating state, that is, a notch S composed of the circular hole portion 10 and the communication portion 11 is formed. I was reminded. With this means, it has been found that by removing the connecting portion, the internal stress to be undulated due to press working is released, and a flat shape is maintained. According to this, since it is not necessary to increase the outer diameter, a corrugated metal gasket that has no practical problem is realized by pressing with normal accuracy.

  Next, an example of a method for manufacturing the metal gasket G according to the first embodiment will be described. First, as shown in FIG. 4A, a circular material 22 is obtained from a flat plate material 21 such as a stainless steel plate or a rolled steel plate by punching or the like. The circular hole 21a is a hole that has already been punched. Next, as shown in FIG. 4B, the material 22 is subjected to press working to produce an intermediate material 23 in which a single center hole 8 and four notches (insertion portions) S are punched and formed. The 1st process process (an example of a notch formation process) to perform is performed.

  And as shown to Fig.5 (a), the corrugation formation process which performs the press work to the internal-diameter side part of the intermediate material 23, and produces the internal peripheral part 7A with a corrugated cross section is performed. When the inner peripheral portion 7A is created, as shown in FIG. 5 (b), an annular expanded graphite sheet 7B is bonded to both the front and back surfaces of the inner peripheral portion 7A to form a seal portion 7. A metal gasket G is created. As a method for manufacturing the metal gasket G, for example, a means for simultaneously creating the center hole 8 when the material 22 is punched, or a means for simultaneously pressing the notch (insertion portion) S and the inner peripheral portion 7A is possible. Yes, it is not limited to the creation procedure described above. In addition, a means for forming the sealing portion 7 having a corrugated cross section by pressing after the expanded graphite sheet 7B is adhered to the flat inner peripheral portion 7A is also possible.

[Another Example]
The shape of the insertion portion S is not particularly limited as long as the circumferential position (angular position) with respect to the center P of the metal gasket G is determined when the bolt 5 is passed. A letter-shaped notch may be used. However, if the condition for preventing the removal due to the relative lateral movement with the bolt 5 is added as in the first embodiment, the width of the communication portion 11 may be made smaller than the diameter of the bolt 5, and the insertion portion S The shape is not limited to that shown in FIG.

  The expanded graphite sheet 8 may be integrated with the inner peripheral portion 7A only on one side, and the outer diameter of the expanded graphite sheet 8 is large enough to match the outer diameter of the outer peripheral portion 9, or the size of the outer periphery passing through the insertion portion S. Or a small diameter that does not reach the insertion portion S. The insertion part S may be a plurality of places other than four places, such as three places and five places. The shape of the outer peripheral portion 9 may be other than a circle such as a regular polygon or a star.

Front view of a gasket for piping according to Example 1 1 is a cross-sectional view of the gasket of FIG. Exploded perspective view showing mounting status to flange piping 1 shows the gasket manufacturing method of FIG. 1, (a) is a first punching step, (b) is a second punching step. 1 shows the gasket manufacturing method of FIG. 1, (a) is a gasket part forming step, (b) is a finishing step. A perspective view showing a conventional gasket and mounting condition

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seal object 3 Seal surface 5 Bolt 7 Seal part 7B Expanded graphite 9 Outer peripheral part S Insertion part, Notch

Claims (5)

An annular metal gasket made of a plate material having a seal portion formed in a concentric or substantially concentric corrugated shape,
A flat outer peripheral portion is continuously provided on the outer diameter side of the seal portion, and an insertion portion through which a plurality of bolts for relatively fixing the objects to be sealed with gaskets interposed is provided on the outer peripheral portion, and the insertion The part is a metal gasket configured as a notch having a shape in which a part of the outer diameter side of the circular hole is opened.   2. The metal gasket according to claim 1, wherein an outer diameter of the outer peripheral portion is set to be substantially the same as or slightly smaller than an outer diameter of the seal surface to be sealed.   The metal gasket according to claim 1 or 2, wherein at least one surface of the seal portion is covered with expanded graphite.   4. The metal gasket according to claim 3, wherein an outer diameter of the expanded graphite is formed to project from the notch so as to be in contact with the bolt. It is a manufacturing method of the metal gasket as described in any one of Claims 1-4, Comprising: The corrugate by which the said seal part is formed by press work after the notch formation process in which the said notch is formed by press work A method for producing a metal gasket for performing a forming step.

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