Seal Structure

Abstract

To inhibit deterioration of seal performance even if a gasket is used under a low-temperature environment or has low reaction force.SOLUTION: A gasket 1 includes: a body part 10; a high pressure side projection part 20 protruding from the body part 10 so as to contact with a side surface which is the high pressure side of a groove; and a low pressure side projection part 30 protruding from the body part 10 toward a side surface which is the low pressure side of the groove. The body part 10 has an upper side contact surface 11 and a lower side contact surface 12. The high pressure side projection part 20 extends along an extending direction of the body part 10. Further, the low pressure side projection part 30 extends along the extending direction of the body part 10 and is formed so as not to generate a reaction force applied to the side surface which is the low pressure side of the groove in an attachment state of the gasket 1.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a gasket. [Background technology]

[0002] Gaskets have been used as sealing devices to seal gaps between multiple components that are fixed to each other so that they cannot move relative to each other, such as a housing and a cover or a pipe and a pipe, to form a sealed space. For example, gaskets are used to seal the space inside the battery case of fuel cell vehicles, electric vehicles, hybrid vehicles, etc. Some of these conventional gaskets are attached to annular grooves formed in one or both of the fixed components, and are intended to close the gap between these components.

[0003] Some such gaskets have a pair of protrusions formed on both sides of the gasket to stabilize the position of the gasket when it is attached to the groove. When the gasket is attached to the groove, the pair of protrusions press against the side surfaces of the groove, thereby stabilizing the position of the gasket in the groove (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-281110 Summary of the Invention [Problem to be solved by the invention]

[0005] Furthermore, some conventional gaskets are used in low-temperature environments, and others are used to seal gaps between components made of low-rigidity materials such as resin or aluminum. For gaskets used between low-rigidity components, there is a demand for gaskets with low reaction force (low load) to prevent the components from being deformed by the reaction force (load) of the gasket applied to the sealing surface with which the gasket comes into contact.

[0006] Furthermore, in low-temperature environments, the rubber hardens and loses its elasticity, which means that when the gasket receives pressure from the object being sealed during use and moves or deforms in the groove, the reduced elasticity of the rubber reduces the contact pressure of the gasket with the sealing surface, potentially resulting in a loss of sealing performance.

[0007] Furthermore, gaskets made of low-hardness rubber materials in order to reduce the reaction force of the gasket or to prevent the hardness from becoming too high even in low-temperature environments have a low reaction force, and when the gasket receives pressure from the object to be sealed during use and moves or deforms in the groove, the contact pressure of the gasket on the sealing surface decreases, which can result in a decrease in sealing performance.

[0008] As mentioned above, some conventional gaskets have a structure for stabilizing the position of the gasket in the groove, but as mentioned above, the sealing performance may decrease in low-temperature environments, and the sealing performance may also decrease in low-reaction gaskets. For this reason, there is a need for a structure that can prevent the sealing performance of conventional gaskets from decreasing even when used in low-temperature environments and even in low-reaction gaskets.

[0009] The present invention has been made in consideration of the above-mentioned problems, and provides a gasket that can suppress deterioration of sealing performance even when used in a low-temperature environment or even when the gasket has a low reaction force. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the gasket of the present invention is a gasket that is attached to a groove that opens into a gap between components and aims to close the gap, and comprises: a main body portion formed to contact opposing surfaces across the gap; a high-pressure side protrusion portion that protrudes from the main body portion to contact the high-pressure side of the opposing side surfaces of the groove; and a low-pressure side protrusion portion that protrudes from the main body portion toward the low-pressure side of the opposing side surfaces of the groove, and the main body portion has a one-side contact surface that is formed to contact one of the opposing surfaces across the gap, and an other-side contact surface that is formed to contact the other of the opposing surfaces across the gap, and the high-pressure side protrusion portion extends along the extension direction of the main body portion, and the low-pressure side protrusion portion extends along the extension direction of the main body portion, and is formed so as not to generate a reaction force against the low-pressure side of the groove when the gasket is in an attached state.

[0011] In a gasket according to one aspect of the present invention, the low-pressure-side protrusion is formed so as not to come into contact with the other of the opposing side surfaces of the groove when the gasket is in an attached state.

[0012] In one embodiment of the gasket of the present invention, the high-pressure side protrusion is formed so that, when the gasket is installed, the center of the main body is located in the center or near the center between the opposing side surfaces of the groove.

[0013] In one embodiment of the gasket of the present invention, the high-pressure side protrusion is formed so that, when the gasket is installed, the center of the main body is located closer to the side of the groove that is on the low-pressure side than the center between the opposing side surfaces of the groove.

[0014] In a gasket according to one aspect of the present invention, the high-pressure-side protrusion has a tip end that is smaller in cross section along the depth direction of the groove than the base end when the gasket is attached.

[0015] In a gasket according to one aspect of the present invention, the low-pressure-side protrusion has a tip end that is smaller in cross section along the depth direction of the groove than the base end when the gasket is attached.

[0016] In a gasket according to one aspect of the present invention, the high-pressure side protrusion and the low-pressure side protrusion are provided so as to face each other across the main body portion. [Effects of the Invention]

[0017] According to the gasket of the present invention, even when used in a low temperature environment or even when the gasket has a low reaction force, it is possible to prevent a decrease in sealing performance. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a plan view of a gasket according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view showing a cross section of the gasket shown in FIG. 1 taken along line AA. [Figure 3] FIG. 10 is a view showing the gasket installed in the groove of the case. [Figure 4] FIG. 10 is a diagram showing the gasket in use, with the cover attached to the case to close the gap between the case and the cover. [Figure 5] FIG. 3 is a cross-sectional view showing a cross section taken along line AA of a modified example of the gasket according to the embodiment of the present invention. [Figure 6] FIG. 10 is a view showing the gasket installed in the groove of the case. [Figure 7] FIG. 10 is a diagram showing the gasket in use, with the cover attached to the case to close the gap between the case and the cover. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0020] FIG. 1 is a plan view of a gasket 1 according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the gasket 1 taken along line AA in FIG. 1. That is, FIG. 2 shows a cross-section perpendicular to the extension direction of the gasket 1. Hereinafter, for convenience of explanation, the side (one side) in the direction of arrow a (see FIG. 2) will be referred to as the upper side, and the side (the other side) in the direction of arrow b (see FIG. 2) will be referred to as the lower side. Arrows a and b each extend parallel to a straight line and extend in the direction in which the space S surrounded by the gasket 1 opens in a plan view. FIG. 1 shows the gasket 1 as seen from above. Furthermore, the side of the space S surrounded by the gasket 1 (the side indicated by arrow c in FIGS. 1 and 2) that is perpendicular to the upper and lower sides is referred to as the inner circumferential side, and the side opposite the inner circumferential side (the side indicated by arrow d in FIGS. 1 and 2) is referred to as the outer circumferential side. Note that the above-mentioned upper and lower sides do not limit the orientation of the gasket 1 in space; the gasket 1 can assume any orientation in space.

[0021] As shown in FIGS. 1 and 2 , a gasket 1 according to an embodiment of the present invention is attached to a groove that opens into a gap between components to seal the gap. The gasket 1 includes a main body 10 formed to contact opposing surfaces across the gap between the components, a high-pressure-side protrusion 20 that protrudes from the main body 10 to contact the high-pressure side of the opposing side of the groove that opens into the gap between the components, and a low-pressure-side protrusion 30 that protrudes from the main body 10 toward the low-pressure side of the opposing side of the groove that opens into the gap between the components. The main body 10 includes an upper contact surface 11 that serves as a one-side contact surface and is formed to contact one side (upper surface) of the opposing surfaces across the gap between the components, and a lower contact surface 12 that serves as a other-side contact surface and is formed to contact the other side (lower surface) of the opposing surfaces across the gap between the components. As shown in FIG. 1 , the high-pressure-side protrusion 20 extends along the extension direction of the main body 10. 1, the low-pressure-side protrusion 30 extends in the extension direction of the main body 10 and is formed so as not to generate a reaction force against the low-pressure side of the groove that opens into the gap between the members when the gasket 1 is installed. The gasket 1 will be described in detail below.

[0022] As shown in FIG. 1, the gasket 1 extends in an annular shape, and the main body 10, high-pressure side protrusion 20, and low-pressure side protrusion 30 also extend in an annular shape. The gasket 1 is made integrally from a rubber-like elastic material, and the main body 10, high-pressure side protrusion 20, and low-pressure side protrusion 30 are parts of the integrated gasket 1 formed from the same material. The shape (hereinafter simply referred to as the cross-section) of the gasket 1 perpendicular to the extension direction (hereinafter simply referred to as the cross-sectional shape) is uniform or approximately uniform throughout the extension direction (over the entire circumference). The rubber-like elastic material of the gasket 1 is a low-hardness rubber-like elastic material. Note that the rubber-like elastic material of the gasket 1 does not have to be a low-hardness rubber-like elastic material.

[0023] Specifically, the cross-sectional shape of the gasket 1 is as shown in FIG. 2. The main body 10 extends along an imaginary line x in the cross section, for example, extending parallel or approximately parallel to the imaginary line x, and has a rectangular or approximately rectangular shape. The main body 10 is shaped so that the imaginary line x is the center line or approximately the center line in the cross section. For example, as shown in FIG. 2, the cross-sectional shape of the main body 10 is tapered from the center or near the center of the main body 10 toward the upper contact surface 11, and from the center or near the center of the main body 10 toward the lower contact surface 12. The cross-sectional shape of the main body 10 is not limited thereto, and may be formed, for example, so that the contour from the center or near the center of the main body 10 toward the upper contact surface 11 or the lower contact surface 12 has an R-shape (arc-like shape).

[0024] Furthermore, when the gasket 1 is installed in a groove and sandwiched between components in a use state described below, the upper contact surface 11 is formed to contact the upper surface of the opposing surfaces across the gap between the components. On the other hand, when the gasket 1 is in use, the lower contact surface 12 is formed to contact the lower surface of the opposing surfaces across the gap between the components. The upper contact surface 11 is formed in an annular shape around the entire circumference of the main body 10, and as shown in FIG. 2, for example, the cross-sectional outline is shaped to be perpendicular or approximately perpendicular to the imaginary line x, and as shown in FIG. 1, the upper contact surface 11 is formed to be flat or approximately flat. The lower contact surface 12 is also formed in an annular shape around the entire circumference of the main body 10, and as shown in FIG. 2, for example, the cross-sectional outline is shaped to be perpendicular or approximately perpendicular to the imaginary line x, and as shown in FIG. 1, the lower contact surface 12 is formed to be flat or approximately flat.

[0025] The high-pressure-side protrusion 20 is formed, for example, on the inner edge (inner circumferential side) of the gasket 1, in a ring shape along the entire circumference of the main body 10. When the gasket 1 is installed as described below, the high-pressure-side protrusion 20 protrudes from the main body 10 toward one of the opposing side surfaces of the groove to which the gasket 1 is attached, which is the high-pressure side due to the pressure of the sealed object, such as a sealed gas or hydraulic oil, acting thereon. As shown in FIG. 2 , the high-pressure-side protrusion 20 protrudes from the center or approximately the center of the main body 10 in the direction of the imaginary line x. Furthermore, as described above, the high-pressure-side protrusion 20 is configured to contact the high-pressure-side side surface of the groove when the gasket 1 is installed. Specifically, the tip surface 21 of the high-pressure-side protrusion 20 is configured to contact the high-pressure-side side surface of the groove when the gasket 1 is installed. When an object to be sealed is present outside the gasket 1, the high-pressure-side protrusion 20 is formed on the outer edge (outer periphery) of the gasket 1.

[0026] The high-pressure side projection 20 tapers toward the tip surface 21, and as shown in FIG. 2, the cross-sectional shape of the high-pressure side projection 20 narrows toward the tip surface 21. The width of the high-pressure side projection 20 is the distance between the upper surface 22 and the lower surface 23 in the direction of the imaginary line x. The upper surface 22 is the surface facing upward of the high-pressure side projection 20, and the lower surface 23 is the surface facing downward of the high-pressure side projection 20. The high-pressure side projection 20 may be formed so that, when the gasket 1 is installed, the tip end (tip surface 21) has a smaller cross section along the depth direction of the groove 51 (see FIG. 3) than the base end, and in addition to a tapered shape, the contour of the tip end may be formed to have an R-shape (arcuate).

[0027] 2, in cross section, the upper surface 22 of the high-pressure-side protrusion 20 is formed to have an outline that slopes downward with respect to the imaginary line x, and the outline of the upper surface 22 in cross section is straight or approximately straight. The upper surface 22 may have other shapes, such as a shape that has a curved outline in cross section, a shape that has an outline formed by a combination of straight lines in cross section, or a shape that has an outline formed by a combination of curves and straight lines in cross section.

[0028] 2, in cross section, the lower surface 23 of the high-pressure-side protrusion 20 is formed to have an outline that slopes upward with respect to the imaginary line x, and the outline of the lower surface 23 in cross section is straight or approximately straight. The lower surface 23 may have other shapes, such as a shape that has a curved outline in cross section, a shape that has an outline formed by a combination of straight lines in cross section, or a shape that has an outline formed by a combination of curves and straight lines in cross section.

[0029] 2, in cross section, tip surface 21 of high-pressure-side protrusion 20 is formed to describe an outline along imaginary straight line x, and the outline of tip surface 21 in cross section is a straight line or an approximately straight line parallel or approximately parallel to imaginary line x. Tip surface 21 may have other shapes, such as a shape that presents a curved outline in cross section, a shape that presents an outline formed by a combination of straight lines in cross section, or a shape that presents an outline formed by a combination of curves and straight lines in cross section.

[0030] High-pressure-side protrusion 20 is formed so that, in an attached state of gasket 1 described below, the center of main body 10 is located at or near the center between the opposing side surfaces of the groove to which gasket 1 is attached. Specifically, the length of high-pressure-side protrusion 20 in the direction perpendicular to imaginary line x is set so that, in an attached state of gasket 1, the center line (imaginary line x) of main body 10 is located at or near the center between the side surface on the high-pressure side of the groove and the side surface on the low-pressure side of the groove.

[0031] The low-pressure-side protrusion 30 is formed, for example, on the outer edge (outer periphery) of the gasket 1, in a ring shape along the entire circumference of the main body 10. When the gasket 1 is installed, as described below, the low-pressure-side protrusion 30 protrudes from the main body 10 toward one of the opposing side surfaces of the groove to which the gasket 1 is attached, which is the low-pressure side opposite the high-pressure side due to the pressure of the sealed object, such as a sealed gas or hydraulic oil. The low-pressure-side protrusion 30 is disposed opposite the high-pressure-side protrusion 20 across the main body 10, and protrudes from the center or approximately the center of the main body 10 in the direction of the imaginary line x, as shown in FIG. 2 . Furthermore, as described above, the low-pressure-side protrusion 30 is configured not to generate a reaction force against the low-pressure side of the groove when the gasket 1 is installed. Specifically, the tip surface 31 of the low-pressure-side protrusion 30 is configured not to come into contact with the low-pressure side of the groove when the gasket 1 is installed. 3, the tip end surface 31 of the low-pressure side protrusion 30 is in contact with the low-pressure side of the groove when the gasket 1 is installed, but the tip end surface 31 of the pressure side protrusion 30 is not pressed against the low-pressure side of the groove and does not generate a reaction force against the low-pressure side of the groove. If an object to be sealed is present on the outside of the gasket 1, the low-pressure side protrusion 30 is formed on the inner edge side (inner circumferential side) of the gasket 1.

[0032] The low-pressure side protrusion 30 tapers toward the tip surface 31, and as shown in FIG. 2, the cross-sectional shape of the low-pressure side protrusion 30 narrows toward the tip surface 31. The width of the low-pressure side protrusion 30 is the distance between the upper surface 32 and the lower surface 33 in the direction of the imaginary line x. The upper surface 32 is the surface facing upward of the low-pressure side protrusion 30, and the lower surface 33 is the surface facing downward of the low-pressure side protrusion 30. The low-pressure side protrusion 30 may be formed so that, when the gasket 1 is installed, its tip end (tip surface 31) has a smaller cross section along the depth direction of the groove 51 (see FIG. 3) than its base end, and in addition to a tapered shape, the contour of the tip end may be formed to have an R-shape (arcuate).

[0033] 2, in cross section, the upper surface 32 of the low-pressure-side protrusion 30 is formed to have an outline that slopes downward with respect to the imaginary line x, and the outline of the upper surface 32 in cross section is straight or approximately straight. The upper surface 32 may have other shapes, such as a shape that has a curved outline in cross section, a shape that has an outline formed by a combination of straight lines in cross section, or a shape that has an outline formed by a combination of curves and straight lines in cross section.

[0034] 2, in cross section, the lower surface 33 of the low-pressure-side protrusion 30 is formed to have an outline that slopes upward with respect to the imaginary line x, and the outline of the lower surface 33 in cross section is straight or approximately straight. The lower surface 33 may have other shapes, such as a shape that has a curved outline in cross section, a shape that has an outline formed by a combination of straight lines in cross section, or a shape that has an outline formed by a combination of curves and straight lines in cross section.

[0035] 2, in cross section, the tip surface 31 of the low-pressure side protrusion 30 is formed to describe an outline along the imaginary straight line x, and the outline of the tip surface 31 in cross section is a straight line or an approximately straight line parallel or approximately parallel to the imaginary straight line x. The tip surface 31 may have other shapes, such as a shape that presents a curved outline in cross section, a shape that presents an outline formed by a combination of straight lines in cross section, or a shape that presents an outline formed by a combination of curves and straight lines in cross section.

[0036] As described above, when the gasket 1 is installed, the low-pressure-side protrusion 30 is configured so that the tip surface 31 does not come into contact with the low-pressure side of the groove, or alternatively, the tip surface 31 comes into contact with the low-pressure side of the groove but is not pressed against the low-pressure side of the groove, so that the low-pressure-side protrusion 30 does not generate a reaction force against the low-pressure side of the groove. For this reason, the length of the low-pressure-side protrusion 30 in a direction perpendicular to the imaginary line x is shorter than the length of the high-pressure-side protrusion 20 in a direction perpendicular to the imaginary line x. When the low-pressure-side protrusion 30 is configured so that the tip surface 31 does not come into contact with the low-pressure side of the groove and so that the low-pressure-side protrusion 30 does not generate a reaction force against the low-pressure side of the groove, the length of the low-pressure-side protrusion 30 in a direction perpendicular to the imaginary line x is slightly shorter than the length of the high-pressure-side protrusion 20 in a direction perpendicular to the imaginary line x.

[0037] As shown in FIG. 2, in the cross section of the gasket 1, the main body 10 is symmetrical or approximately symmetrical with respect to the center line (imaginary line x). The main body 10 is also symmetrical or approximately symmetrical with respect to a line perpendicular to the imaginary line x at the center of the main body 10 in the direction of the imaginary line x. The high-pressure-side protrusions 20 are also symmetrical or approximately symmetrical with respect to a line (center line) extending through the center in the direction of the imaginary line x. The low-pressure-side protrusions 30 are also symmetrical or approximately symmetrical with respect to a line (center line) extending through the center in the direction of the imaginary line x. The gasket 1 is also symmetrical or approximately symmetrical with respect to the center line (imaginary line x) in the cross section. The gasket 1 is also symmetrical or approximately symmetrical with respect to a line perpendicular to the center of the width of the gasket 1 in the direction of the imaginary line x. The gasket 1 or each part of the gasket 1 does not have to be symmetrical as described above in the cross section of the gasket 1.

[0038] Next, the operation of the gasket 1 having the above-described configuration will be described.

[0039] As described above, the gasket 1 is attached to a groove that opens into a gap between components and is used to close the gap between the components. For example, as shown in Figures 3 and 4, the gasket 1 is used between a pair of components, a case 50 and a cover 60, to seal the internal space between the components. Note that Figure 3 shows the gasket 1 attached to the groove 51 of the case 50, and Figure 4 shows the gasket 1 in use, with the cover 60 attached and fixed to the case 50 to close the gap between the case 50 and the cover 60.

[0040] The case 50 and cover 60 are components that form a housing for a battery, such as a fuel cell or a lithium-ion battery, and the fuel cell or the like is housed inside the case 50. Note that the attachment target of the gasket 1 is not limited to a battery housing. Furthermore, the attachment target of the gasket 1 is not limited to a pair of members, and the gasket 1 can also be used to close gaps between three or more members.

[0041] As shown in FIG. 3 , for example, an annular groove 51 is formed in the outer edge 52 of the case 50, and the gasket 1 is attached to this groove 51. The groove 51 is recessed from the upper surface 52a of the outer edge 52 of the case 50 and opens into the gap between the case 50 and the cover 60 as shown in FIG. 4 . As shown in FIG. 3 , the groove 51 has a rectangular or approximately rectangular cross section, a pair of opposing side surfaces 51a and 51b, and a bottom surface 51c extending between the side surfaces 51a and 51b. The side surface 51a is located on the inside of the case 50 and, in the operating state shown in FIG. 4 , serves as the high-pressure side that receives pressure from the sealed object inside and becomes high pressure. The side surface 51b is located on the outside of the case 50 and serves as the low-pressure side opposite the high-pressure side surface. Hereinafter, the high-pressure side surface 51a will be referred to as the high-pressure side side surface 51a, and the low-pressure side surface 51b will be referred to as the low-pressure side side surface 51b. The groove 51 may be formed in the cover 60 instead of the case 50. Alternatively, the groove may be formed in both the case 50 and the cover 60. The cross-sectional shape of the groove 51 is not limited to a rectangular or approximately rectangular shape.

[0042] As shown in Figure 3, when the gasket 1 is attached to the groove 51 of the case 50, the tip end surface 21 of the high-pressure side protrusion 20 is in contact with the high-pressure side surface 51a of the groove 51. This contact of the tip end surface 21 of the high-pressure side protrusion 20 holds the gasket 1 in the groove 51 of the case 50 with a predetermined force, thereby preventing the gasket 1 from falling off from the groove 51. When the gasket 1 is attached to the groove 51, the high-pressure side protrusion 20 comes into contact with the upper surface 52a of the case 50 or the high-pressure side surface 51a of the groove 51, but because the high-pressure side protrusion 20 has a tapered shape, the resistance caused by this contact can be reduced, and the attachment load of the gasket 1 to the groove 51 can be reduced.

[0043] As described above, the length of the high-pressure-side protrusion 20 in the direction perpendicular to the imaginary line x is set so that the center line (imaginary line x) of the main body 10 of the gasket 1 attached to the groove 51 is located at or near the center in the width direction between the high-pressure-side side surface 51a and the low-pressure-side side surface 51b of the groove 51. Therefore, in the gasket 1 attached to the groove 51, the center line (imaginary line x) of the main body 10 is located at or near the center in the width direction of the groove 51.

[0044] Furthermore, as described above, when the gasket 1 is attached to the groove 51 of the case 50, the low-pressure-side protrusion 30 does not generate a reaction force against the low-pressure-side side surface 51b of the groove 51. In other words, the tip surface 31 of the low-pressure-side protrusion 30 does not contact the low-pressure-side side surface 51b of the groove 51, or, as shown in Figure 3, the tip surface 31 contacts the low-pressure-side side surface 51b of the groove 51, but the low-pressure-side protrusion 30 does not generate a reaction force against the low-pressure-side side surface 51b.

[0045] As described above, when the gasket 1 is attached to the groove 51, the high-pressure-side protrusion 20 contacts the high-pressure-side side surface 51a of the groove 51. Therefore, the length of the main body 10 in the direction of the imaginary line x (vertical direction) or the position of the high-pressure-side protrusion 20 on the gasket 1 in the direction of the imaginary line x is set to a length or position such that the high-pressure-side protrusion 20 contacts the high-pressure-side side surface 51a of the groove 51 when the lower contact surface 12 or the upper contact surface 11 of the main body 10 is in contact with the bottom surface 51c of the groove 51. Note that, in the in-use state of the gasket 1 shown in FIG. 4 , the portion of the main body 10 on the side of the lower contact surface 12 is accommodated in the groove 51, but in the in-use state of the gasket 1, the portion of the main body 10 on the side of the upper contact surface 11 may also be accommodated in the groove 51.

[0046] 4, when the cover 60 is fixed by bolts or the like to the case 50 with the gasket 1 attached to the groove 51, the gasket 1 is compressed between the case 50 and the cover 60, bringing the gasket 1 into a usable state. With the cover 60 attached to the case 50, a gap G is formed between the top surface 52a of the case 50 and the inner surface 60a of the cover 60 facing the top surface 52a, but this gap G is closed at the position of the gasket 1. In a usable state, the lower contact surface 12 of the main body 10 contacts the bottom surface 51c of the groove 51, and the upper contact surface 11 of the main body 10 contacts the portion of the inner surface 60a of the cover 60 facing the bottom surface 51c of the groove 51.

[0047] When the cover 60 is fixed to the case 50, the main body 10 is compressed between the inner surface 60a of the cover 60 and the bottom surface 51c of the groove 51. At this time, as shown in FIG. 4, the main body 10 expands in the width direction perpendicular to the imaginary line x, and the tip surface 31 of the low-pressure-side protrusion 30 moves toward the low-pressure-side side surface 51b of the groove 51. Then, when the cover 60 is fixed to the case 50, the tip surface 31 of the low-pressure-side protrusion 30 contacts the low-pressure-side side surface 51b of the groove 51, as shown in FIG. 4. In this way, the low-pressure-side protrusion 30 is shaped so that the tip surface 31 of the low-pressure-side protrusion 30 contacts the low-pressure-side side surface 51b of the groove 51 when the gasket 1 is in use with the cover 60 fixed to the case 50. Specifically, the length of the low-pressure side protrusion 30 in a direction perpendicular to the imaginary line x is set to a length such that the tip surface 31 of the low-pressure side protrusion 30 comes into contact with the low-pressure side surface 51b of the groove 51 when the gasket 1 is in use with the cover 60 fixed to the case 50.

[0048] In this way, when in use, the upper contact surface 11 of the main body 10 is pressed against the inner surface 60a of the cover 60, and the lower contact surface 12 of the main body 10 is pressed against the bottom surface 51c of the groove 51, and the gasket 1 closes the gap G between the case 50 and the cover 60 and seals the space formed by the case 50 and the cover 60.

[0049] When the gasket 1 is attached in the opposite manner to the illustrated example, the upper contact surface 11 of the main body 10 contacts the bottom surface 51c of the groove 51 in the same manner as the lower contact surface 12 shown in Figure 4, and the lower contact surface 12 of the main body 10 contacts the inner surface 60a of the cover 60 in the same manner as the upper contact surface 11 shown in Figure 4, and the gasket 1 closes the gap G between the case 50 and the cover 60.

[0050] Furthermore, as described above, when the cover 60 is fixed to the case 50, the tip surface 31 of the low-pressure-side protrusion 30 moves toward the low-pressure-side side surface 51b of the groove 51, and when the gasket 1 is in use with the cover 60 fixed to the case 50, the tip surface 31 of the low-pressure-side protrusion 30 contacts the low-pressure-side side surface 51b of the groove 51. Therefore, when pressure is applied from the object to be sealed and the gasket 1 receives pressure from the high-pressure side, the main body 10 is pushed toward the low-pressure side, i.e., toward the low-pressure-side side surface 51b of the groove 51, and the tip surface 31 of the low-pressure-side protrusion 30 is pressed against the low-pressure-side side surface 51b of the groove 51. As a result, the reaction force of the low-pressure-side protrusion 30 based on contact with the low-pressure-side side surface 51b and the pressure from the high-pressure side compress the main body 10 in the width direction, causing the main body 10 to expand in the direction of the imaginary line x, and the upper contact surface 11 and the lower contact surface 12 of the main body 10 to move away from each other. As a result, the upper contact surface 11 is pressed toward the inner surface 60a of the cover 60, and the lower contact surface 12 is pressed toward the bottom surface 51c of the groove 51, so that the upper contact surface 11 is further pressed against the inner surface 60a of the cover 60, and the lower contact surface 12 is further pressed against the bottom surface 51c of the groove 51. In this way, the self-sealing action of the gasket 1 is obtained.

[0051] Although the length of low-pressure-side protrusion 30 in the direction perpendicular to imaginary line x is set to a length such that tip surface 31 of low-pressure-side protrusion 30 contacts low-pressure-side side surface 51b of groove 51 when gasket 1 is in use with cover 60 fixed to case 50, the length of low-pressure-side protrusion 30 in the direction perpendicular to imaginary line x may be set to a length such that tip surface 31 of low-pressure-side protrusion 30 does not contact low-pressure-side side surface 51b of groove 51 when gasket 1 is in use with cover 60 fixed to case 50. In this case, too, when main body 10 is pressed from the high-pressure side, tip surface 31 of low-pressure-side protrusion 30 contacts low-pressure-side side surface 51b of groove 51, and the self-sealing action of gasket 1 is obtained as in the above-mentioned case. In order to obtain a self-sealing effect, when the gasket 1 is in use with the cover 60 fixed to the case 50, if the tip surface 31 of the low-pressure side protrusion 30 does not come into contact with the low-pressure side surface 51b of the groove 51, it is preferable that the gap between this tip surface 31 and the low-pressure side surface 51b be narrow.

[0052] As described above, when the main body 10 of the gasket 1 is pressed from the high-pressure side, the main body 10 or the gasket 1 does not move or deform in the groove 51, or the main body 10 or the gasket 1 moves or deforms slightly in the groove 51, thereby achieving the self-sealing effect of the gasket 1. In this way, the self-sealing effect of the gasket 1 is more reliably achieved.

[0053] Furthermore, as described above, when the main body 10 is pressed from the high-pressure side, the main body 10 or the gasket 1 does not move or deform in the groove 51, or the main body 10 or the gasket 1 moves or deforms slightly in the groove 51, thereby achieving a self-sealing effect of the gasket 1. For this reason, when the gasket 1 is used in a low-temperature environment, the rubber hardness of the gasket 1 increases and the elasticity of the gasket 1 decreases, making it difficult for the gasket 1 to move or deform. However, even in this case, the gasket 1 still achieves a self-sealing effect.

[0054] Furthermore, even when the rubber-like elastic body of the gasket 1 is made low in hardness and low in reaction force, the self-sealing action of the gasket 1 can be achieved without the main body 10 or the gasket 1 moving or deforming in the groove 51, or by the main body 10 or the gasket 1 moving or deforming slightly in the groove 51. Therefore, in order for the gasket 1 to exhibit its self-sealing action, it is not necessary to significantly deform or move the gasket 1, and it is possible to prevent loss of contact of the sealing surface of the main body 10 due to deformation or movement of the gasket 1, which has low hardness.

[0055] Furthermore, the main body 10 is compressed in the width direction by the reaction force of the low-pressure-side protrusion 30 due to contact with the low-pressure-side side surface 51b and the pressure from the high-pressure side, thereby achieving a self-sealing effect, and therefore the surface pressure applied to the main body 10 by the reaction force due to contact with the low-pressure-side side surface 51b can be made larger than when the low-pressure-side side surface of the main body 10 contacts the low-pressure-side side surface 51b. This makes it possible to improve the sealing performance of the gasket 1 due to its self-sealing effect.

[0056] Furthermore, when the gasket 1 is in use, the upper contact surface 11 of the main body 10, the lower contact surface 12 of the main body 10, the tip surface 21 of the high-pressure side protrusion 20, and the tip surface 31 of the low-pressure side protrusion 30 are in contact with the cover 60 and the groove 51, respectively. Alternatively, when the gasket 1 is in use, the upper contact surface 11 of the main body 10, the lower contact surface 12 of the main body 10, and the tip surface 21 of the high-pressure side protrusion 20 are in contact with the cover 60 and the groove 51, respectively, and the tip surface 31 of the low-pressure side protrusion 30 faces the low-pressure side surface 51b of the groove 51 with a small gap between them. Therefore, the posture of the gasket 1 is stable when in use. Furthermore, because the high-pressure side protrusion 20 and the low-pressure side protrusion 30 face each other across the main body 10, the posture of the gasket 1 can be stabilized when in use. Therefore, even if a force is applied to the gasket 1 from the high-pressure side, the gasket 1 is prevented from deforming or moving, and deterioration of the sealing performance due to the gasket 1 being warped or collapsed is prevented.

[0057] Thus, the gasket 1 according to the first embodiment of the present invention can prevent a decrease in sealing performance even when used in a low-temperature environment or when formed from a low-reaction rubber-like elastic material.

[0058] Next, a gasket 2 according to a second embodiment of the present invention will be described.

[0059] Fig. 5 is a cross-sectional view showing a cross section perpendicular to the extension direction of a gasket 2 according to a second embodiment of the present invention. Gasket 2 has the same shape in a plan view as gasket 1 shown in Fig. 1, and the cross-section shown in Fig. 5 corresponds to the cross-section of gasket 1 shown in Fig. 2. Gasket 2 differs from the above-described gasket 1 in the shapes of the high-pressure side protrusions and low-pressure side protrusions, and is provided with high-pressure side protrusions 25 and low-pressure side protrusions 35 that are different from high-pressure side protrusions 20 and low-pressure side protrusions 30, respectively. Hereinafter, for gasket 2, components that are the same as or have similar functions to those of the above-described gasket 1 will be assigned the same reference numerals and their description will be omitted, and only different components will be described.

[0060] The high-pressure-side protrusion 25 is formed, for example, on the inner edge side (inner circumferential side) of the gasket 2, in an annular shape along the entire circumference of the main body 10. When the gasket 2 is in an installed state, the high-pressure-side protrusion 25 protrudes from the main body 10 toward the high-pressure-side side surface 51a of the groove 51 to which the gasket 2 is attached. As shown in FIG. 5, for example, the high-pressure-side protrusion 25 protrudes from the center or approximately the center of the main body 10 in the direction of the imaginary line x. When the gasket 2 is in an installed state, the high-pressure-side protrusion 25 contacts the high-pressure-side side surface 51a of the groove 51. Specifically, a tip surface 26, which is the surface at the tip of the high-pressure-side protrusion 25, contacts the high-pressure-side side surface 51a of the groove 51. When an object to be sealed exists outside the gasket 2, the high-pressure-side protrusion 25 is formed on the outer edge side (outer periphery) of the gasket 2.

[0061] High-pressure side protrusion 25 tapers toward tip surface 26, and as shown in FIG. 5, the cross-sectional shape of high-pressure side protrusion 25 narrows toward tip surface 26. The width of high-pressure side protrusion 25 is the distance between upper surface 27 and lower surface 28 in the direction of imaginary line x. Upper surface 27 is the surface facing upward of high-pressure side protrusion 25, and lower surface 28 is the surface facing downward of high-pressure side protrusion 25. High-pressure side protrusion 25 may be formed so that its tip end (tip surface 26) has a smaller cross section along the depth direction of groove 51 (see FIG. 6) than its base end when gasket 1 is installed. In addition to a tapered shape, the contour of the tip end may be formed to have an R-shape (arcuate shape).

[0062] 5, in cross section, upper surface 27 of high-pressure-side protrusion 25 is formed to describe an outline that slopes downward with respect to imaginary line x, and the outline of upper surface 27 in cross section is straight or approximately straight. Upper surface 27 may have other shapes, such as a shape that presents a curved outline in cross section, a shape that presents an outline formed by a combination of straight lines in cross section, or a shape that presents an outline formed by a combination of curves and straight lines in cross section.

[0063] 5, in cross section, the lower surface 28 of the high-pressure-side protrusion 25 is formed to have an outline that slopes upward with respect to the imaginary line x, and the outline of the lower surface 28 in cross section is straight or approximately straight. The lower surface 28 may have other shapes, such as a shape that has a curved outline in cross section, a shape that has an outline formed by a combination of straight lines in cross section, or a shape that has an outline formed by a combination of curves and straight lines in cross section.

[0064] 5, in cross section, tip surface 26 of high-pressure-side protrusion 25 is formed to describe an outline along imaginary straight line x, and the outline of tip surface 26 in cross section is a straight line or an approximately straight line parallel or approximately parallel to imaginary line x. Tip surface 26 may have other shapes, such as a shape that presents a curved outline in cross section, a shape that presents an outline formed by a combination of straight lines in cross section, or a shape that presents an outline formed by a combination of curves and straight lines in cross section.

[0065] High-pressure-side protrusion 25 is formed so that, when gasket 2 is attached, the center of main body 10 is located closer to low-pressure-side side 51b than the center between high-pressure-side side 51a and low-pressure-side side 51b of groove 51. Specifically, the length of high-pressure-side protrusion 25 in a direction perpendicular to imaginary line x is set so that, when gasket 2 is attached, the center line (imaginary line x) of main body 10 is located closer to low-pressure-side side 51b than the center between high-pressure-side side 51a and low-pressure-side side 51b of groove 51. In other words, the length of high-pressure-side protrusion 25 in a direction perpendicular to imaginary line x is longer than the length of high-pressure-side protrusion 20 described above in a direction perpendicular to imaginary line x.

[0066] The low-pressure-side protrusion 35 is formed, for example, on the outer edge side (outer periphery) of the gasket 2, in an annular shape along the entire circumference of the main body 10, and protrudes from the main body 10 toward the low-pressure-side side surface 51b of the groove 51 when the gasket 2 is installed. The low-pressure-side protrusion 35 is provided to face the high-pressure-side protrusion 25 across the main body 10, and protrudes from the center or approximately the center of the main body 10 in the direction of the imaginary line x, as shown in FIG. 5, for example. As described above, the low-pressure-side protrusion 35 is configured not to generate a reaction force against the low-pressure-side side surface 51b of the groove 51 when the gasket 2 is installed. Specifically, the tip surface 36 of the low-pressure-side protrusion 35 is configured not to come into contact with the low-pressure-side side surface 51b of the groove 51 when the gasket 2 is installed. Alternatively, when the gasket 2 is attached, the tip surface 36 of the low-pressure side protrusion 35 is in contact with the low-pressure side surface 51b of the groove 51, but the tip surface 36 of the pressure side protrusion 35 is not pressed against the low-pressure side surface 51b of the groove 51 and does not generate a reaction force against the low-pressure side surface 51b of the groove 51. If an object to be sealed is present on the outside of the gasket 2, the low-pressure side protrusion 35 is formed on the inner edge side (inner circumferential side) of the gasket 2.

[0067] The low-pressure side protrusion 35 tapers toward the tip surface 36, and as shown in FIG. 5, the cross-sectional shape of the low-pressure side protrusion 35 narrows toward the tip surface 36. The width of the low-pressure side protrusion 35 is the distance between the upper surface 37 and the lower surface 38 in the direction of the imaginary line x. The upper surface 37 is the surface facing upward of the low-pressure side protrusion 35, and the lower surface 38 is the surface facing downward of the low-pressure side protrusion 35. The low-pressure side protrusion 35 may be formed so that, when the gasket 1 is installed, its tip end (tip surface 36) has a smaller cross section along the depth direction of the groove 51 (see FIG. 6) than its base end, and in addition to a tapered shape, the contour of the tip end may be formed to have an R-shape (arcuate).

[0068] 5, in cross section, the upper surface 37 of the low-pressure-side protrusion 35 is formed to have an outline that slopes downward with respect to the imaginary line x, and the outline of the upper surface 37 in cross section is straight or approximately straight. The upper surface 37 may have other shapes, such as a shape that has a curved outline in cross section, a shape that has an outline formed by a combination of straight lines in cross section, or a shape that has an outline formed by a combination of curves and straight lines in cross section.

[0069] 5, in cross section, the lower surface 38 of the low-pressure-side protrusion 35 is formed to have an outline that slopes upward with respect to the imaginary line x, and the outline of the lower surface 38 in cross section is straight or approximately straight. The lower surface 38 may have other shapes, such as a shape that has a curved outline in cross section, a shape that has an outline formed by a combination of straight lines in cross section, or a shape that has an outline formed by a combination of curves and straight lines in cross section.

[0070] 5, in cross section, the tip surface 36 of the low-pressure-side protrusion 35 is formed to describe an outline along the imaginary straight line x, and the outline of the tip surface 36 in cross section is a straight line or an approximately straight line parallel or approximately parallel to the imaginary straight line x. The tip surface 36 may have other shapes, such as a shape that presents a curved outline in cross section, a shape that presents an outline formed by a combination of straight lines in cross section, or a shape that presents an outline formed by a combination of curves and straight lines in cross section.

[0071] As described above, when the gasket 2 is installed, the low-pressure side protrusion 35 is configured so that the tip surface 36 does not come into contact with the low-pressure side surface 51b of the groove 51, or, although the tip surface 36 comes into contact with the low-pressure side surface 51b of the groove 51, the tip surface 36 is not pressed against the low-pressure side surface 51b of the groove 51, and the low-pressure side protrusion 36 does not generate a reaction force against the low-pressure side surface 51b of the groove 51.

[0072] As described above, in the attached state of the gasket 2, the length of the high-pressure-side protrusion 25 in a direction perpendicular to the imaginary line x is longer than the length of the high-pressure-side protrusion 20 in a direction perpendicular to the imaginary line x so that the center line (imaginary line x) of the main body 10 is located closer to the low-pressure-side side surface 51b than the center between the high-pressure-side side surface 51a and the low-pressure-side side surface 51b of the groove 51. Therefore, the length of the low-pressure-side protrusion 35 in a direction perpendicular to the imaginary line x is shorter than the length of the low-pressure-side protrusion 30 of the gasket 1 in a direction perpendicular to the imaginary line x.

[0073] As shown in Figure 5, in the cross section of the gasket 2, the high-pressure-side protrusions 25 are symmetrical or approximately symmetrical with respect to a line (center line) extending through the center in the imaginary line x direction. Also, in the cross section of the gasket 2, the low-pressure-side protrusions 35 are symmetrical or approximately symmetrical with respect to a line (center line) extending through the center in the imaginary line x direction. Also, in the cross section of the gasket 2, the gasket 2 is symmetrical or approximately symmetrical with respect to a line perpendicular to the center of the width of the gasket 2 in the imaginary line x direction. Note that in the cross section of the gasket 2, the gasket 2 or each part does not have to be symmetrical as described above.

[0074] Next, the operation of the gasket 2 having the above-described structure will be described.

[0075] As with the above-described gasket 1, the gasket 2 is installed in the groove 51 and the cover 60 is fixed to the case 50 with bolts or the like, as shown in Figures 6 and 7. Note that Figure 6 is a diagram showing the gasket 2 installed in the groove 51 of the case 50, and Figure 7 is a diagram showing the gasket 2 in use, with the cover 60 installed and fixed to the case 50, closing the gap between the case 50 and the cover 60.

[0076] As shown in Figure 6, when the gasket 2 is attached to the groove 51 of the case 50, the tip surface 26 of the high-pressure side protrusion 25 comes into contact with the high-pressure side surface 51a of the groove 51. This contact of the tip surface 26 of the high-pressure side protrusion 25 holds the gasket 2 in the groove 51 of the case 50 with a predetermined force, thereby preventing the gasket 2 from falling off from the groove 51. When the gasket 2 is attached to the groove 51, the high-pressure side protrusion 25 comes into contact with the upper surface 52a of the case 50 or the high-pressure side surface 51a of the groove 51. However, because the high-pressure side protrusion 25 has a tapered shape, the resistance caused by this contact can be reduced, and the attachment load of the gasket 2 to the groove 51 can be reduced.

[0077] As described above, the length of high-pressure-side protrusion 25 in the direction perpendicular to imaginary line x is set so that the center line (imaginary line x) of main body 10 of gasket 2 attached to groove 51 is located closer to low-pressure-side side surface 51b than the center in the width direction between high-pressure-side side surface 51a and low-pressure-side side surface 51b of groove 51. Therefore, in gasket 2 attached to groove 51, the center line (imaginary line x) of main body 10 is located closer to low-pressure-side side surface 51b than the center in the width direction of groove 51.

[0078] Furthermore, as described above, when the gasket 2 is attached to the groove 51 of the case 50, the low-pressure-side protrusion 35 does not generate a reaction force against the low-pressure-side side surface 51b of the groove 51. In other words, the tip surface 36 of the low-pressure-side protrusion 35 is not in contact with the low-pressure-side side surface 51b of the groove 51, or the tip surface 36 is in contact with the low-pressure-side side surface 51b of the groove 51 but the low-pressure-side protrusion 35 does not generate a reaction force against the low-pressure-side side surface 51b. In Figure 6, the tip surface 36 of the low-pressure-side protrusion 35 is not in contact with the low-pressure-side side surface 51b of the groove 51, and a gap is formed between the tip surface 36 and the low-pressure-side side surface 51b.

[0079] As described above, when the gasket 2 is attached to the groove 51, the high-pressure-side protrusion 25 contacts the high-pressure-side side surface 51a of the groove 51. Therefore, the length of the main body 10 in the direction of the imaginary line x (vertical direction) or the position of the high-pressure-side protrusion 25 on the gasket 2 in the direction of the imaginary line x is set to a length or position such that the high-pressure-side protrusion 25 contacts the high-pressure-side side surface 51a of the groove 51 when the lower contact surface 12 or the upper contact surface 11 of the main body 10 is in contact with the bottom surface 51c of the groove 51. In the state in which the gasket 2 is in use shown in FIG. 7 , the portion of the main body 10 on the side of the lower contact surface 12 is accommodated in the groove 51, but in the state in which the gasket 2 is in use, the portion of the main body 10 on the side of the upper contact surface 11 may also be accommodated in the groove 51.

[0080] 7, when the cover 60 is fixed by bolts or the like to the case 50 with the gasket 2 attached to the groove 51, the gasket 2 is compressed between the case 50 and the cover 60 and enters an operating state. With the cover 60 attached to the case 50, a gap G is formed between the top surface 52a of the case 50 and the inner surface 60a of the cover 60 facing the top surface 52a, but this gap G is closed at the position of the gasket 2. In an operating state, the lower contact surface 12 of the main body 10 contacts the bottom surface 51c of the groove 51, and the upper contact surface 11 of the main body 10 contacts the portion of the inner surface 60a of the cover 60 facing the bottom surface 51c of the groove 51.

[0081] When the cover 60 is fixed to the case 50, the main body 10 is compressed between the inner surface 60a of the cover 60 and the bottom surface 51c of the groove 51. At this time, as shown in FIG. 7, the main body 10 expands in the width direction perpendicular to the imaginary line x, and the tip surface 36 of the low-pressure-side protrusion 35 moves toward the low-pressure-side side surface 51b of the groove 51. Then, when the cover 60 is fixed to the case 50, the tip surface 36 of the low-pressure-side protrusion 35 comes into contact with the low-pressure-side side surface 51b of the groove 51, as shown in FIG. 7. In this way, the low-pressure-side protrusion 35 is shaped so that the tip surface 36 of the low-pressure-side protrusion 35 comes into contact with the low-pressure-side side surface 51b of the groove 51 when the gasket 2 is in use with the cover 60 fixed to the case 50. Specifically, the length of the low-pressure side protrusion 35 in a direction perpendicular to the imaginary line x is set to a length such that the tip surface 36 of the low-pressure side protrusion 35 comes into contact with the low-pressure side surface 51b of the groove 51 when the gasket 2 is in use with the cover 60 fixed to the case 50.

[0082] Furthermore, as described above, when cover 60 is fixed to case 50, tip surface 36 of low-pressure-side protrusion 35 moves toward low-pressure-side side surface 51b of groove 51, and when gasket 2 is in use with cover 60 fixed to case 50, tip surface 36 of low-pressure-side protrusion 35 comes into contact with low-pressure-side side surface 51b of groove 51. Therefore, when pressure is applied from the object to be sealed and gasket 2 is subjected to pressure from the high-pressure side, gasket 2 acts in the same manner as gasket 1, and main body 10 is pressed toward the low-pressure side, i.e., toward low-pressure-side side surface 51b of groove 51, and tip surface 36 of low-pressure-side protrusion 35 is pressed against low-pressure-side side surface 51b of groove 51. As a result, the reaction force of the low-pressure-side protrusion 35 due to contact with the low-pressure-side side surface 51b and the pressure from the high-pressure side compress the main body 10 in the width direction, causing the main body 10 to expand in the direction of the imaginary line x, and the upper contact surface 11 and the lower contact surface 12 of the main body 10 to move away from each other. As a result, the upper contact surface 11 is pressed toward the inner surface 60a of the cover 60, and the lower contact surface 12 is pressed toward the bottom surface 51c of the groove 51, so that the upper contact surface 11 is further pressed against the inner surface 60a of the cover 60, and the lower contact surface 12 is further pressed against the bottom surface 51c of the groove 51. In this way, the self-sealing action of the gasket 2 is obtained.

[0083] Although the length of low-pressure-side protrusion 35 in the direction perpendicular to imaginary line x is set to a length such that tip surface 36 of low-pressure-side protrusion 35 comes into contact with low-pressure-side side surface 51b of groove 51 when gasket 2 is in use with cover 60 fixed to case 50, the length of low-pressure-side protrusion 35 in the direction perpendicular to imaginary line x may be set to a length such that tip surface 36 of low-pressure-side protrusion 35 does not come into contact with low-pressure-side side surface 51b of groove 51 when gasket 1 is in use with cover 60 fixed to case 50. In this case, too, when main body 10 is pressed from the high-pressure side, tip surface 36 of low-pressure-side protrusion 35 comes into contact with low-pressure-side side surface 51b of groove 51, and the self-sealing action of gasket 2 is obtained as in the above-mentioned case. In order to obtain a self-sealing effect, when the gasket 2 is in use with the cover 60 fixed to the case 50, if the tip surface 36 of the low-pressure side protrusion 35 does not come into contact with the low-pressure side surface 51b of the groove 51, it is preferable that the gap between this tip surface 36 and the low-pressure side surface 51b be narrow.

[0084] As described above, according to the gasket 2, similarly to the gasket 1, when the main body 10 is pressed from the high-pressure side, the main body 10 or the gasket 2 does not move or deform in the groove 51, or the main body 10 or the gasket 2 moves or deforms slightly in the groove 51, thereby achieving the self-sealing action of the gasket 2. In this way, the gasket 2 is designed to achieve the self-sealing action more reliably.

[0085] Furthermore, as described above, when the main body 10 is pressed from the high-pressure side, the main body 10 or the gasket 2 does not move or deform in the groove 51, or the main body 10 or the gasket 2 moves or deforms slightly in the groove 51, thereby achieving a self-sealing effect of the gasket 2. For this reason, when the gasket 2 is used in a low-temperature environment, the rubber hardness of the gasket 2 increases and the elasticity of the gasket 2 decreases, making it difficult for the gasket 2 to move or deform. However, even in this case, the gasket 2 still achieves a self-sealing effect.

[0086] Furthermore, even when the rubber-like elastic body of the gasket 2 is made low in hardness and has low reaction force, the self-sealing action of the gasket 2 can be achieved without the main body 10 or the gasket 2 moving or deforming in the groove 51, or by the main body 10 or the gasket 2 moving or deforming slightly in the groove 51. Therefore, in order for the gasket 2 to exhibit its self-sealing action, it is not necessary to significantly deform or move the gasket 2, and it is possible to prevent loss of contact of the sealing surface of the main body 10 due to deformation or movement of the gasket 2, which has low hardness.

[0087] Furthermore, the main body 10 is compressed in the width direction by the reaction force of the low-pressure-side protrusion 30 due to contact with the low-pressure-side side surface 51b and the pressure from the high-pressure side, thereby achieving a self-sealing effect, and therefore the surface pressure applied to the main body 10 by the reaction force due to contact with the low-pressure-side side surface 51b can be made larger than when the low-pressure-side side surface of the main body 10 contacts the low-pressure-side side surface 51b. This makes it possible to improve the sealing performance due to the self-sealing effect of the gasket 2.

[0088] Furthermore, the length of low-pressure-side protrusion 35 in a direction perpendicular to imaginary line x is shorter than the length of low-pressure-side protrusion 30 of gasket 1 in a direction perpendicular to imaginary line x, and low-pressure-side protrusion 35 is more rigid than low-pressure-side protrusion 30 of gasket 1. Therefore, the reaction force of low-pressure-side protrusion 35 based on contact with low-pressure-side side surface 51b is greater than the reaction force of low-pressure-side protrusion 30 based on contact with low-pressure-side side surface 51b. Therefore, the magnitude of the surface pressure applied to main body 10 by the reaction force of low-pressure-side protrusion 35 is greater than the magnitude of the surface pressure applied to main body 10 by the reaction force of low-pressure-side protrusion 30, and the sealing performance due to the self-sealing action of gasket 2 can be improved.

[0089] Furthermore, the gasket 2 can perform the same function as the gasket 1 described above, and can stabilize the posture of the gasket 2 when in use. Even if force is applied to the gasket 2 from the high-pressure side, the gasket 2 is prevented from deforming or moving, and a decrease in sealing performance due to the gasket 2 being bent or collapsed is prevented.

[0090] Thus, the gasket 2 according to the second embodiment of the present invention can prevent a decrease in sealing performance even when used in a low-temperature environment or when formed from a low-reaction rubber-like elastic material.

[0091] Although the embodiments of the present invention have been described above, the present invention is not limited to the gaskets 1 and 2 according to the above-described embodiments of the present invention, and includes all aspects encompassed by the concept and scope of the claims. Furthermore, each configuration may be appropriately and selectively combined to achieve at least some of the above-described problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above-described embodiments may be appropriately modified depending on the specific use of the present invention.

[0092] For example, in the gaskets 1 and 2 according to the above-described embodiments of the present invention, the high-pressure side protrusions 20 and 25 are provided on the inner periphery of the gaskets 1 and 2, and the low-pressure side protrusions 30 and 35 are provided on the outer periphery of the gaskets 1 and 2, but depending on the configuration of the member to which the gasket according to the present invention is attached, the high-pressure side protrusions are provided on the inner periphery of the gasket and the low-pressure side protrusions are provided on the outer periphery of the gasket.

[0093] Furthermore, the extended shape of the gaskets 1 and 2 is not limited to the annular shape forming a single rectangular ring in a plan view as shown in Fig. 1, but may take various shapes depending on the extended shape of the groove 51 to which the gaskets 1 and 2 are attached. For example, the extended shape of the gaskets 1 and 2 may be a shape that forms a series of multiple rings. [Explanation of symbols]

[0094] 1...gasket, 10...main body, 11...upper contact surface, 12...lower contact surface, 20,25...high-pressure side protrusion, 21,26...tip surface, 22,27...upper surface, 23,28...lower surface, 30,35...low-pressure side protrusion, 31,36...tip surface, 32,37...upper surface, 33,38...lower surface, 50...case, 51...groove, 51a...side surface (high-pressure side), 51b...side surface (low-pressure side), 51c...bottom surface, 52...outer edge, 52a...top surface, 60...cover, 60a...inner surface, G...gap, x...imaginary line

Claims

1. A seal structure comprising a gasket and a pair of members sandwiching the gasket, the gasket being attached to a groove that opens into a gap between the pair of members and that closes the gap, The gasket is a main body portion formed to contact the opposing surface across the gap; a high-pressure side protrusion that protrudes from the main body so as to contact a high-pressure side of the opposing side surfaces of the groove; a low-pressure-side protrusion that protrudes from the main body toward a low-pressure-side one of the opposing side surfaces of the groove, the main body portion has a one-side contact surface which is a surface formed to contact one of the surfaces opposing the gap, and a other-side contact surface which is a surface formed to contact the other of the surfaces opposing the gap, the high-pressure-side protrusion extends along the extension direction of the main body and is disposed so as to contact a side surface of the groove that becomes a high-pressure side when the gasket is attached, A sealing structure characterized in that the low-pressure side protrusion extends along the extension direction of the main body and is positioned so as not to generate a reaction force against the side that is on the low-pressure side of the groove when the gasket is installed.

2. 2. The seal structure according to claim 1, wherein the low-pressure-side protrusion is arranged so as not to come into contact with the other of the opposing side surfaces of the groove when the gasket is installed.

3. 3. The sealing structure according to claim 1, wherein, when the gasket is installed, the center of the main body is positioned at or near the center between the opposing side surfaces of the groove.

4. The sealing structure according to claim 1 or 2, characterized in that, when the gasket is installed, the center of the main body portion is positioned closer to the side surface on the low-pressure side than the center between the opposing side surfaces of the groove.

Images