Gasket and assembly method of the same

Abstract

To provide a gasket which enables improvement of workability during assembly despite having a structure capable of inhibiting misalignment, and to provide an assembly method of the gasket.SOLUTION: A gasket includes: an annular body 11 which is compressed between a first surface 2a of a first member 2 and a second surface 3a of a second member 3 which are formed in planar shapes; and a plurality of collar holding parts 15 which is provided spaced apart from each other in a circumferential direction of the body so as to be connected to at least one side part 14 of the body and each of which holds a collar member 6 provided with a through hole 6a into which a fastener 4a for fastening the first member to the second member is fitted. An interval L1 of the adjacent collar holding parts is smaller than an interval L2 between the adjacent fasteners in a natural state of the body before assembly so that the fastener is fitted through the through hole of the collar member in a state that the body is extended longer than the natural state of the body.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gasket that seals between a first surface of a first member and a second surface of a second member, and to a method for assembling the same. [Background technology]

[0002] Conventionally, gaskets that seal between a first member and a second member that are joined together have been known. When such a gasket is accommodated in an attachment groove provided in one of the first member and the second member, the groove wall of the attachment groove restricts misalignment of the gasket in the width direction (groove width direction). On the other hand, when the mounting surfaces of the gasket of the first member and the second member are both flat, there is a concern that the gasket may be misaligned in the width direction. For example, Patent Document 1 listed below discloses a gasket in which a collar retaining portion provided on a main body portion sandwiched between a planar first surface of a first member and a planar second surface of a second member is provided with a positioning protrusion that is inserted into a hole formed on the first surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7141041 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the gasket described in Patent Document 1 above, when assembling the gasket, it is necessary to insert a positioning protrusion into a hole formed in the first surface to position the gasket, which raises concerns that workability may be reduced when assembling the gasket.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a gasket and an assembly method thereof that can improve the workability during assembly while suppressing misalignment. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the gasket of the present invention comprises an annular main body portion that is compressed between a first surface of a first member and a second surface of a second member that are mutually planar, and a plurality of collar retaining portions that are spaced circumferentially of the main body portion and connected to at least one side of the main body portion, and that hold a collar member having a through hole through which a fastener that fastens the first member and the second member is inserted, and is characterized in that the spacing between adjacent collar retaining portions in the natural state of the main body portion is smaller than the spacing between adjacent fasteners so that the fasteners can insert into the through holes of the collar members when the main body portion is stretched more than in its natural state before assembly.

[0007] In the above gasket, the main body portion may include a bent portion that is bent to fit along an outer periphery of the collar member, which is tubular in shape. In addition, in the above gasket, the main body portion may have a straight portion arranged in a straight line between adjacent collar retaining portions, and the straight portion and the collar member held by the collar retaining portion may be arranged to overlap when viewed in the circumferential direction. In addition, in the above gasket, the main body portion may be configured so that a widthwise center thereof, which is a direction perpendicular to the opposing direction between the first surface and the second surface in the straight portion and the circumferential direction of the main body portion, coincides with a hole center of the collar member held in the collar holding portion in the width direction. In addition, in the above gasket, the width dimension, which is the dimension in the opposing direction between the first surface and the second surface at the bent portion and in a direction perpendicular to the circumferential direction of the main body portion, may be smaller than the width dimension of other parts of the main body portion. In addition, in the above gasket, a collapse prevention protrusion may be provided between adjacent collar retaining portions, protruding in a width direction that is perpendicular to the opposing direction between the first surface and the second surface and the circumferential direction of the main body portion.

[0008] In addition, in order to achieve the above-mentioned object, the gasket assembling method of the present invention is a method of assembling the gasket, which is characterized in that the main body portion is extended when each of the fasteners protruding from one of the first surface and the second surface is inserted into a through hole of the collar member held by each of the plurality of collar holding portions. Effect of the Invention

[0009] The gasket and the method for assembling the gasket of the present invention are capable of suppressing misalignment, while improving the workability during assembling. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2(a) is a plan view illustrating a schematic example of a gasket according to an embodiment, and FIG. 2(b) is a schematic plan view of a first member. [Diagram 2] 1(a) is a cross-sectional view taken along line X1-X1 in FIG. 1(a), (b) is a cross-sectional view taken along line X2-X2 in FIG. 1(a), and (c) is a cross-sectional view taken along line X3-X3 in FIG. 1(a). [Diagram 3] 2(a) to (c) show an example of a method for assembling the gasket, where (a) and (b) are plan views showing a schematic view of a portion of the gasket, and (c) is a vertical cross-sectional view corresponding to FIG. 2(a). [Figure 4] FIG. 11 is a plan view showing a schematic diagram of a modified example of the gasket. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the gasket according to the present embodiment will be described with reference to the drawings. Note that in some drawings, some of the detailed reference numerals attached to other drawings are omitted. In addition, in the following description of the gasket, the direction along the opposing direction between the first surface of the first member and the second surface of the second member is defined as the height direction, and the direction perpendicular to this height direction and the circumferential direction of the main body is defined as the width direction.

[0012] 1 to 3, the gasket 10 according to this embodiment includes an annular main body 11 that is compressed between a first surface 2a of a first member 2 and a second surface 3a of a second member 3, which are planar to each other. With this configuration, the main body 11 can seal between the first member 2 and the second member 3. This gasket 10 is provided with a plurality of collar holding portions 15 spaced apart in the circumferential direction of the main body portion 11 and connected to at least one side portion 14 of the main body portion 11, and holds a collar member 6 having a through hole 6a through which a shaft portion 4a constituting a fastener that fastens the first member 2 and the second member 3 is inserted. With this configuration, the collar member 6 held by the collar holding portions 15 can regulate the fastening dimension between the first member 2 and the second member 3. The details are explained below.

[0013] 1 to 3 show an example in which a gasket 10 is assembled to a case 1 that houses an automobile battery pack (not shown). The case 1 includes a box-shaped case body having an opening, and a lid that covers the opening of the case body. In the following description, the case body of the case 1 is referred to as the first member 2, and the lid of the case 1 is referred to as the second member 3. An annular flange portion is formed on each of the peripheral portions of the first member 2 and the second member 3. The opposing surfaces of these flange portions constitute the first surface 2a of the first member 2 and the second surface 3a of the second member 3, which are planar in shape. In the illustrated example, the first surface 2a and the second surface 3a are planar in a substantially rectangular annular shape. The first member 2 and the second member 3 are provided with a plurality of through holes 2b, 3b, through which the shaft portion 4a is inserted, at intervals along the circumferential direction of the flange portion, so as to open on the first surface 2a and the second surface 3a. The through holes 2b, 3b of the first member 2 and the second member 3 are provided at approximately the same circumferential position of each flange portion of the first member 2 and the second member 3 so that they communicate with each other via the through hole 6a of the collar member 6 when the first member 2 and the second member 3 are combined with each other.

[0014] The shaft portion 4a is the shaft portion of the bolt 4 inserted through the through hole 2b of the first member 2, the through hole 6a of the collar member 6, and the through hole 3b of the second member 3. The shaft portion 4a is formed with a male thread to which a nut 5 is fastened. FIG. 2(a) shows an example in which the first member 2 and the second member 3 are joined together by fastening the nut 5 to the shaft portion 4a inserted through the through hole 2b of the first member 2, the through hole 6a of the collar member 6, and the through hole 3b of the second member 3 with a gasket 10 interposed between the first surface 2a and the second surface 3a. The first member 2 and the second member 3 are not limited to the two members constituting the case 1, and may be other two members. In addition, instead of the embodiment in which the nut 5 to which the shaft portion 4a provided on one of the first member 2 and the second member 3 is screwed is provided on the other side, a configuration in which a female screw hole to which the shaft portion 4a is screwed may be provided on the other member on the other side. 2(a), the shaft portion 4a is a bolt 4 having a head portion 4b, but it may be a stud bolt or the like that does not have a head portion 4b. The shaft portion 4a may be fixed (implanted) to one of the first member 2 and the second member 3 by welding or the like.

[0015] The collar member 6 is interposed between the first surface 2a and the second surface 3a, and suppresses excessive compression of the main body 11 due to excessive fastening of fasteners (bolts 4 and nuts 5 in FIG. 2(a)), and regulates the fastening dimension between the first surface 2a and the second surface 3a (the separation dimension in the height direction between the first surface 2a and the second surface 3a). The collar member 6 is configured so as to be able to be held by the collar holding portion 15 of the gasket 10. In FIG. 2(a), the collar member 6 is substantially cylindrical in shape with its axial dimension (height dimension) smaller than its radial dimension (width dimension). The diameter of the through hole 6a of the collar member 6 may be slightly larger than the outer diameter of the shaft portion 4a so that the shaft portion 4a can be inserted therethrough. The collar member 6 may be made of, for example, metal or resin. The collar member 6 is formed with an annular flange 6c that protrudes radially outward from an edge portion on the second surface 3a side, which is one side in the height direction, and has an outer diameter larger than the inner diameter of a through hole 15a of a collar holding portion 15, which will be described later. A plurality of collar members 6 are held by the gasket 10 at appropriate intervals along the circumferential direction of the main body 11.

[0016] The gasket 10 is integrally formed from an elastically deformable rubber material. Examples of such rubber materials include EPDM, NBR, H-NBR, ACM, AEM, and FKM. In FIG. 1(a), the gasket 10 is configured in a substantially rectangular ring shape. Collar holding portions 15 that hold the collar members 6 are provided at the four corners and at the circumferential center portions of the two long side portions of the gasket 10. That is, the gasket 10 in the illustrated example has six collar holding portions 15. These six collar holding portions 15 are provided at appropriate intervals in the circumferential direction of the gasket 10.

[0017] In this gasket 10, the interval L1 between adjacent collar holding parts 15, 15 in the natural state of the main body part 11 is smaller than the interval L2 between adjacent shaft parts 4a so that the through hole 6a of the collar member 6 fits into the shaft part 4a in a state in which the main body part 11 is stretched more than in the natural state before assembly (see FIG. 3(a)). With this configuration, the gasket 10 can be assembled by holding the collar member 6 in the collar holding part 15 and fitting the shaft part 4a into the through hole 6a. In addition, in the assembled state, the main body part 11 is stretched more than in the natural state before assembly and tension is applied, so that the main body part 11 is less likely to meander or tilt, and positional deviation can be effectively suppressed (see FIG. 3(b)). As a result, it is not necessary to increase the installation space, such as the flange width that serves as the mounting surface of the gasket 10, in consideration of positional deviation. In addition, it is not necessary to insert a positioning protrusion to position the gasket, and workability during assembly can be improved.

[0018] The interval L1 between adjacent collar holding parts 15, 15 in the natural state before assembly (the dimension between the hole centers of the through holes 15a, 15a of the collar holding parts 15, 15 adjacent in the circumferential direction) is preferably 0.5% to 5% smaller than the interval L2 between adjacent shaft parts 4a, 4a (the dimension between the shaft centers of the shaft parts 4a, 4a adjacent in the circumferential direction), and more preferably about 2% smaller. In other words, the interval L1 between adjacent collar holding parts 15, 15 in the natural state is preferably 99.5% to 95% of the interval L2 between adjacent shaft parts 4a, 4a, and more preferably 98% of the interval L2 between adjacent shaft parts 4a, 4a. With this configuration, it is easy to stretch the main body 11 until the straight portion 17 between the circumferentially adjacent collar holding portions 15, 15 matches the interval L2 between the adjacent shaft portions 4a, 4a, and an appropriate tension can be applied to the stretched main body 11. Also, as shown in Figures 3(a) and 3(b), the width dimension of the main body 11 when stretched (width dimension w3 of the stretched straight portion 17 and width dimension w4 of the curved portion 16) is slightly smaller than the width dimension of the main body 11 in its natural state (width dimension w1 of the straight portion 17 and width dimension w2 of the curved portion 16 in its natural state).

[0019] In this embodiment, the main body 11 has a curved portion 16 that curves along the outer periphery (outer periphery surface 6b) of the cylindrical collar member 6. Compared to a configuration in which the collar holding portion 15 protrudes from the side portion 14 of the main body 11 that is linear, this configuration makes it easier to position the main body 11 between adjacent collar holding portions 15, 15 on the side where the shaft portion 4a is provided in the width direction of the mounting surface of the first surface 2a and the second surface 3a, for example, on the center side in the flange width direction. This makes it possible to effectively reduce the width dimension (flange width dimension) of the mounting surface of the first surface 2a and the second surface 3a. Furthermore, the main body 11 has a straight portion 17 provided in a straight line between adjacent collar holding portions 15, 15. The main body 11 is provided such that the straight portion 17 and the collar member 6 held by the collar holding portion 15 overlap when viewed in the circumferential direction. With this configuration, the collar holding portion 15 is less likely to tilt when the straight portion 17 is extended while holding the collar holding portion 15, compared to a configuration in which the collar holding portion 15 protrudes from the straight side portion 14 of the main body 11. This can further improve the ease of operation when fitting the shaft portion 4a into the through hole 6a of the collar member 6. Furthermore, the main body 11 is provided such that the widthwise center of the straight line portion 17 coincides with the hole center of the collar member 6 held by the collar holding portion 15 (the hole center of the through hole 6a of the collar member 6) in the width direction. With this configuration, the straight line portion 17 between adjacent collar holding portions 15, 15 can be more easily positioned on the side of the mounting surfaces of the first surface 2a and the second surface 3a where the shaft portion 4a is provided, for example, on the center side in the width direction. This makes it possible to more effectively reduce the width dimension of the mounting surfaces of the first surface 2a and the second surface 3a.

[0020] Specifically, as shown in FIG. 1(a), the main body 11 is formed in a substantially rectangular ring shape that can correspond to the shapes of the first surface 2a and the second surface 3a. As shown in Figs. 2(a) to (c), the cross section of the main body 11 cut along the width direction is elongated in the height direction. The height dimension of the main body 11 is greater than the height dimension of the collar member 6. One side surface of the main body 11 in the height direction constitutes a first seal surface 12 that abuts against the first surface 2a, and the other side surface of the main body 11 in the height direction constitutes a second seal surface 13 that abuts against the second surface 3a. When the main body 11 assembled between the first member 2 and the second member 3 is compressed, the first seal surface 12 and the second seal surface 13 abut against the first surface 2a and the second surface 3a, and foreign matter, fluid, etc. are prevented from passing between the gasket 10 and each flange portion of the first member 2 and the second member 3. In the illustrated example, both sides of the first seal surface 12 and the second seal surface 13 in the width direction are chamfered. The width dimension of the second seal surface 13 is smaller than the width dimension of the first seal surface 12. Grooves 12a and 13a are formed around the entire circumference of the main body 11, extending along the circumferential direction so as to open at the widthwise center of the first seal surface 12 and the second seal surface 13. The grooves 12a and 13a divide the first seal surface 12 and the second seal surface 13 into two strips. The grooves 12a and 13a are defined by a groove bottom that is a flat surface substantially parallel to the first surface 2a and the second surface 3a, and a groove wall that is inclined toward the widthwise center from the opening toward the groove bottom. In the illustrated example, the width dimension of the opening of the groove 12a of the first seal surface 12 is larger than the width dimension of the opening of the groove 13a of the second seal surface 13. In the illustrated example, the groove depth dimension of the groove 12a of the first seal surface 12 is larger than the groove depth dimension of the groove 13a of the second seal surface 13.

[0021] The straight line portion 17 is provided so as to extend between the collar holding portions 15, 15 provided at the corners on both sides of the short side portion of the main body portion 11. The straight line portion 17 is also provided so as to extend between the collar holding portions 15, 15 provided at the corners and the midway portion of the long side portion of the main body portion 11. The collar holding portions 15 at the corners are provided so that the center of the hole of the collar member 6 is located at the position where a virtual line that is a virtual extension of the straight line portion 17 at the short side portion intersects with a virtual line that is a virtual extension of the straight line portion 17 at the long side portion. The collar holding portion 15 at the midway portion of the long side portion of the main body portion 11 is provided so that a virtual line that is a virtual extension of the straight line portions 17 connected to both sides thereof passes through the center of the hole of the collar member 6. In a cross section cut along the width direction, the straight portion 17 is symmetrical with respect to the width center line as the axis of symmetry. The straight portion 17 has a width dimension smaller at the second seal surface 13 side than at the first seal surface 12 side. Steps 14a, 14a are formed at intermediate positions in the height direction of both widthwise sides 14, 14 of the straight portion 17 due to the difference in width between the second seal surface 13 side and the first seal surface 12 side (see FIG. 2(b)). The width w1 of the straight portion 17 in its natural state is preferably 40% to 90% of the height, and more preferably 45% to 85%, from the viewpoints of improving sealing performance, reducing costs, and preventing tilting of the main body 11.

[0022] The bent portion 16 is provided in correspondence with the location of the main body 11 where the collar member 6 is attached, that is, the location where the collar holding portion 15 is provided. That is, in FIG. 1(a), the bent portion 16 is provided at each of the four corners and the circumferential center of the two long side portions of the gasket 10. In this embodiment, the collar holding portion 15 is provided on the outer periphery side of the main body 11. The bent portion 16 is provided so as to bend the main body 11 at the location where the collar holding portion 15 is provided to the inner periphery side. The bent portion 16 is formed in a convex arc shape curved toward the inner periphery side of the main body 11 when viewed in the height direction. Note that the bent portion 16 is not limited to a configuration that is arc-shaped when viewed in the height direction, and may be formed in a bent shape that constitutes a part of the outer periphery side of the polygonal shape in correspondence with the collar member 6 that is polygonal when viewed in the height direction.

[0023] The curved portion 16 is provided on both circumferential sides via a concavely curved portion on the inner circumferential side of the main body portion 11 when viewed in the height direction. The arc length of the curved portion 16 that is convexly curved on the inner circumferential side of the main body portion 11 so as to follow the outer periphery of the collar member 6 is set according to the position where the curved portion 16 is provided and the position of the collar member 6 relative to the width direction of the straight portion 17. For example, the curved portion 16 provided in the middle of the portion on the long side of the main body portion 11 may have an arc length corresponding to approximately 1 / 3 to 2 / 3 of the outer periphery of the collar member 6. In addition, the curved portion 16 provided in the corner of the main body portion 11 may have an arc length corresponding to approximately 1 / 12 to 1 / 2 of the outer periphery of the collar member 6.

[0024] The height dimension of this curved portion 16 is approximately the same as the height dimension of the straight portion 17 . The width dimension w2 of the curved portion 16 (the dimension along the radial direction of the collar member 6) may be smaller than the width dimension w1 of the other portion (the straight portion 17) of the main body portion 11 (see FIG. 3(a)). With this configuration, the width dimension of the first surface 2a and the second surface 3a at the mounting surface can be more effectively reduced. Since the curved portion 16 is adjacent to the collar member 6, it is difficult for the curved portion 16 to fall over, and the width dimension can be reduced. The width dimension w2 of the curved portion 16 in the natural state may be 40% to 95% of the width dimension w1 of the straight portion 17 in the natural state from the viewpoint of improving the sealing property and from the viewpoint of reducing the width dimension w2 of the curved portion 16. In addition, the width dimension w2 of the curved portion 16 in the natural state is preferably 40% to 60% of the height dimension of the main body portion 11 including the curved portion 16 in the natural state, and more preferably 45% to 55%.

[0025] The cross-sectional shape of the curved portion 16 taken along the width direction is different from that of the straight portion 17 (see FIG. 2(a)). A step 14a is formed on the side portion 14 on the inner periphery of the curved portion 16, which is substantially the same as that of the straight portion 17. A protrusion 14b protruding toward the collar member 6 is provided on the outer periphery of the curved portion 16, i.e., on the side portion 14 on the collar member 6 side. The surface of the protrusion 14b on the collar member 6 side constitutes a part of the inner periphery of the through hole 15a of the collar holding portion 15. In other words, the curved portion 16 may constitute a part of the collar holding portion 15. The protrusion 14b may come into contact with the collar member 6 with elastic deformation. The height dimension of the protrusion 14b is smaller than the height dimension of the collar member 6. The cross-sectional shape of the bent portion 16 excluding the protrusion 14b is generally similar to the cross-sectional shape of the straight portion 17, and is a shape obtained by narrowing the straight portion 17 in the width direction.

[0026] The collar holding portion 15 is provided between the straight portions 17, 17 adjacent to each other in the circumferential direction. The collar holding portion 15 is molded integrally with the main body portion 11 so as to be continuous with the side portion 14 on the outer circumferential side of the main body portion 11. The collar holding portion 15 is configured to be able to hold the collar member 6. The collar holding portion 15 is provided with a circular through hole 15a through which the collar member 6 is inserted. The collar holding portion 15 is provided with an outer circumferential portion 15b that is arc-shaped when viewed in the height direction so as to define the through hole 15a. The outer circumferential portion 15b is provided so as to be convexly curved from the side portion 14 on the outer circumferential side of the main body portion 11 toward the outer circumferential side. In other words, the through hole 15a is defined by the outer circumferential portion 15b and the above-mentioned bent portion 16. The inner diameter of the through hole 15a before the collar member 6 is inserted may be smaller than the outer diameter of the collar member 6. With this configuration, the collar member 6 is inserted into the through hole 15a with the elastic deformation of the collar holding portion 15, so that the collar member 6 can be prevented from falling off. The collar holding portion 15 may be provided with a protrusion or the like that protrudes toward the hole center side on the inner circumferential surface of the through hole 15a and is compressed when the collar member 6 is inserted.

[0027] The arc length of the outer circumferential portion 15b is set to an appropriate length so that the outer circumferential portion 15b can surround the entire outer periphery of the collar member 6 together with the above-mentioned bent portion 16. For example, the outer circumferential portion 15b of the collar holding portion 15 provided in the middle of the portion on the long side of the main body portion 11 may have an arc length corresponding to approximately 1 / 3 to 2 / 3 of the outer periphery of the collar member 6. The outer circumferential portion 15b of the collar holding portion 15 provided in the corner of the main body portion 11 may have an arc length corresponding to approximately 1 / 2 to 11 / 12 of the outer periphery of the collar member 6. The cross section of the outer circumferential portion 15b cut in the width direction is substantially rectangular. The portions on both sides of the outer circumferential portion 15b are formed wide so as to close the recessed corners between the portions of the bent portion 16 on both sides of the circumferential direction that are concavely curved toward the inner circumferential side and the collar member 6. The portion between the portions on both sides of the outer circumferential portion 15b has a width dimension (the dimension along the radial direction of the collar member 6) smaller than the width dimension of the bent portion 16 (see FIG. 2(a)).

[0028] The height dimension of the outer circumferential portion 15b is smaller than the height dimension of the collar member 6. The outer circumferential portion 15b and the protrusion 14b of the bent portion 16 described above are not in contact with the first surface 2a and the second surface 3a when the gasket 10 is assembled to the first member 2 and the second member 3. A recessed step 15c is formed in a portion of the collar holding portion 15 facing the second surface 3a, to which the flange 6c of the collar member 6 is engaged. This step 15c is provided around the entire periphery of the through hole 15a on the second surface 3a side. The protrusion 14b of the bent portion 16 and the portion of the outer circumferential portion 15b facing the second surface 3a form the step 15c.

[0029] Between adjacent collar holding portions 15, 15, anti-tilt protrusions 18 protruding in the width direction are provided. With this configuration, tilting, twisting, etc. of main body portion 11 between collar holding portions 15, 15 can be effectively suppressed by the anti-tilt protrusions 18. The anti-tilt protrusion 18 protrudes in the width direction from the side portion 14 of the straight portion 17. When viewed in the height direction, the anti-tilt protrusion 18 has an outer wall surface 18c formed in an arc shape that is convexly curved outward in the width direction. As shown in Fig. 2(c) , the height dimension of this anti-tilt protrusion 18 in its natural state is smaller than the height dimension of the straight portion 17, and the anti-tilt protrusion 18 is formed to protrude in the width direction from approximately the center of the straight portion 17 in the height direction.

[0030] A protrusion 18a is formed on the first surface 2a side of the anti-tilt projection 18 so as to protrude toward the first surface 2a side to form a gap between the protrusion 18 and the side portion 14 of the straight portion 17. The protrusion 18a is formed so that the surface facing the first surface 2a side is located at approximately the same height as the first seal surface 12. With this configuration, it is possible to effectively suppress the inclination and twisting of the straight portion 17 when the gasket 10 is placed on the first surface 2a and assembled. In addition, since the protrusion 18a is provided at a distance from the side portion 14 of the straight portion 17 in the width direction, when the main body portion 11 is compressed, the peripheral portion deforms so as to enter the gap between the straight portion 17 and the protrusion 18a, thereby suppressing an increase in compressive stress. On the second surface 3a side of this anti-tip protrusion 18, an opposing surface 18b is formed which faces closely to but does not contact the second surface 3a when the gasket 10 is assembled between the first member 2 and the second member 3.

[0031] In this embodiment, anti-tilt protrusions 18, 18 are provided on each of the side portions 14, 14 on both sides in the width direction of the straight portion 17. Furthermore, these anti-tilt protrusions 18, 18 on both sides in the width direction are provided at coincident positions in the circumferential direction of the straight portion 17. These anti-tilt protrusions 18, 18 on both sides in the width direction are provided at approximately the center of the circumferential direction of each straight portion 17 between the collar holding portions 15, 15. These collapse prevention protrusions 18, 18 on both sides in the width direction constitute a collapse prevention portion 19. The collapse prevention portion 19 is provided so that its widthwise center approximately coincides with the widthwise center of the adjacent straight portion 17, and its outer shape is approximately circular when viewed in the height direction.

[0032] Next, an example of a gasket assembling method according to this embodiment will be described. In the gasket assembling method of this example, the main body 11 is stretched when each of the shaft parts 4a provided to protrude from one of the first surface 2a and the second surface 3a is inserted into the through holes 6a of the collar members 6 held by each of the plurality of collar holding parts 15. This improves the workability during assembling compared to a configuration in which the gasket is positioned by inserting a positioning protrusion provided on the gasket. Also, since the main body 11 is assembled in a state in which it is stretched in the circumferential direction more than in its natural state and tension is applied, the main body 11 is less likely to meander or tilt, and the gasket 10 can be assembled while effectively suppressing misalignment.

[0033] For example, the corresponding shaft portion 4a provided on the first member 2 is inserted into the through hole 6a of one (for example, a corner) of the multiple collar members 6, 6 provided on the gasket 10. Then, the main body portion 11 is extended, and the corresponding shaft portion 4a is inserted into the through hole 6a of another collar member 6 adjacent to the collar member 6 into which the shaft portion 4a is inserted. Also, the gasket 10 may be assembled by sequentially inserting the corresponding shaft portions 4a into the through holes 6a of the other adjacent collar members 6. Instead of the embodiment in which the main body portion 11 is sequentially extended and assembled, the shaft portions 4a may be inserted into the through holes 6a of the multiple collar members 6 while the main body portion 11 is extended.

[0034] Once the shaft portions 4a of the first member 2 are fitted into the through holes 6a of all the collar members 6 provided in the gasket 10, the second member 3 is assembled by fitting these shaft portions 4a into the through holes 3b of the second member 3. Then, the nut 5 is fastened to the shaft portions 4a protruding from the through holes 3b of the second member 3. As a result, the first member 2 and the second member 3 are joined together via the gasket 10. The method of assembling the gasket is not limited to the above-mentioned method, and various methods are possible.

[0035] Next, a gasket 10A according to a modified example of this embodiment will be described with reference to Fig. 4. In the following description, differences from the above example will be mainly described, and a description of the configuration and effects of common parts will be omitted. In this modification, the configuration of a collapse prevention portion 19A provided at one of the two short side portions of the gasket 10A is different from that of the above-described example. The collapse prevention portion 19A is provided such that its widthwise center is located on the inner periphery side of the main body portion 11A with respect to the widthwise centers of the straight portions 17A adjacent to it on both circumferential sides. In other words, the collapse prevention portion 19A is provided such that it is located on the inner periphery side with respect to the collapse prevention portion 19 described above. With this configuration, it is possible to reduce the width dimension of the flange portions of the first member 2 and the second member 3 required on the outer periphery side of the collapse prevention portion 19A.

[0036] The projection dimension in the width direction of the outer circumferential side anti-tip projection 18A constituting the anti-tip portion 19A from the straight portion 17A is smaller than the projection dimension in the width direction of the inner circumferential side anti-tip projection 18B constituting the anti-tip portion 19A from the straight portion 17A. The portion of the main body 11A where the anti-tip portion 19A is provided is a curved portion 16A provided to be curved from the straight portion 17A adjacent to both sides in the circumferential direction. The curved portion 16A is formed in a convexly curved arc shape toward the inner circumferential side of the main body 11A when viewed in the height direction so that the width direction center is approximately aligned with the width direction center of the anti-tip portion 19A. The anti-tip projections 18A and 18B on both sides in the width direction are formed asymmetrically when viewed in the height direction. The anti-tip projection 18A on the outer circumferential side is formed in a substantially spindle shape when viewed in the height direction, and the anti-tip projection 18B on the inner circumferential side is formed in a substantially crescent shape when viewed in the height direction.

[0037] The specific configuration of the gasket 10, 10A is not limited to the above-mentioned configuration, and various other modifications are possible. For example, if the first surface 2a and the second surface 3a are substantially annular, the main body 11, 11A may not have the straight line portion 17, 17A, and the main body 11, 11A may have a substantially annular shape as a whole. In addition, instead of or in addition to the configuration in which the collar holding portion 15 is provided so as to be continuous with the side portion 14 on the outer periphery side of the main body 11, 11A, the collar holding portion 15 may be provided so as to be continuous with the side portion 14 on the inner periphery side. In addition, the cross-sectional shape cut along the width direction of the main body 11, 11A is not limited to the above-mentioned configuration. In addition, the shape of the collapse prevention protrusions 18, 18A, 18B is not limited to the above-mentioned configuration. [Explanation of symbols]

[0038] 2 First member 2a 1st page 2b Through hole 3 Second member 3a 2nd side 3b Through hole 4 Volts 4a Shaft (fixing device) 6 Colored parts 6a Through hole 6b Outer surface (outer periphery) 10,10A Gasket 11, 11A Main body 14 Side 15 Color holder 16 Bend 17,17A Straight section 18, 18A, 18B Anti-fall protrusions L1 Distance between adjacent collar retainers in natural state L2 Distance between adjacent fasteners (bolt shafts)

Claims

1. the annular main body portion is compressed between a first surface of a first member and a second surface of a second member, the first surface and the second surface of the second member being planar relative to each other; and a plurality of collar holders are provided at intervals in the circumferential direction of the main body portion and connected to at least one side of the main body portion, the collar holder holding a collar member having a through hole through which a fastener for fastening the first member and the second member is inserted, A gasket characterized in that the spacing between adjacent collar retaining portions in the natural state of the main body portion is smaller than the spacing between adjacent fasteners so that the fastener fits into the through hole of the collar member when the main body portion is stretched more than in its natural state before assembly.

2. In claim 1, The gasket is characterized in that the main body portion has a bent portion that is bent to fit along the outer periphery of the collar member, which is tubular in shape.

3. In claim 2, The gasket is characterized in that the main body portion has a straight portion arranged in a straight line between adjacent collar retaining portions, and the straight portion and the collar member held by the collar retaining portion are arranged to overlap when viewed in the circumferential direction.

4. In claim 3, The gasket is characterized in that the main body portion is arranged so that its widthwise center, which is a direction perpendicular to the opposing direction of the first surface and the second surface in the straight portion and to the circumferential direction of the main body portion, coincides with the center of a hole of the collar member held in the collar holding portion in the width direction.

5. In any one of claims 2 to 4, A gasket characterized in that the width dimension, which is the dimension in the opposing direction between the first surface and the second surface at the bent portion and in a direction perpendicular to the circumferential direction of the main body portion, is smaller than the width dimension of other parts of the main body portion.

6. In any one of claims 1 to 4, A gasket characterized in that a collapse prevention protrusion is provided between adjacent collar retaining portions, protruding in a width direction perpendicular to the opposing direction between the first surface and the second surface and the circumferential direction of the main body portion.

7. A method for assembling the gasket according to any one of claims 1 to 4, comprising the steps of: A method for assembling a gasket, characterized in that the main body portion is extended when each of the fasteners protruding from one of the first surface and the second surface is inserted into the through holes of the collar member held by each of the plurality of collar holding portions.

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