Gaskets and sealing structures

Abstract

The present invention provides a gasket and sealing structure that suppresses damage to the main body when compressed by the first and second members, and that can properly seal the space between the first and second members. [Solution] A gasket 4 is inserted into a mounting groove 2 provided in a first member 1 and compressed by the groove bottom 2a of the mounting groove and the opposing surface 3c of a second member 3 facing it to seal the two members, comprising a main body 5 formed such that a gap is provided between it and the groove wall 2b when compressed in the mounting groove, and a pair of protrusions 7, 7 projecting in the width direction from each of the widthwise side surfaces 5c, 5c of the main body, wherein the main body has a flat first contact surface 5a that abuts against the groove bottom and a flat second contact surface 5b that abuts against the opposing surface, and the protrusions are formed such that when the main body is compressed, at least one of the flat end faces 7a of the protrusions abuts against the groove wall.

Description

Technical Field

[0001] The present invention relates to an annular gasket and a sealing structure for sealing between a first member and a second member.

Background Art

[0002] Conventionally, there is known a gasket that is inserted into an annular mounting groove provided in a first member, and the main body portion is compressed between the groove bottom of the mounting groove and the opposing surface of a second member facing the groove bottom to seal so that fluids and the like do not flow between the first member and the second member. For example, Patent Document 1 below discloses a gasket having corrugated ribs formed to project from each of two side surfaces of an annular main body portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when the gasket is compressed so that the entire surface of the main body portion contacts the mounting groove or the like with pressure, there is a concern that excessive strain is applied to the main body portion, causing cracks in the gasket and resulting in breakage. When the width dimension of the gasket is reduced to avoid such a situation, there is a concern that the volume of the gasket becomes small and the reaction force is insufficient, and the members cannot be properly sealed.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a gasket and a sealing structure that can suppress breakage of the main body portion when compressed by the first member and the second member and can properly seal between the first member and the second member.

Means for Solving the Problems

[0006] To achieve the above objective, the present invention provides an annular gasket that is inserted into an annular mounting groove provided in a first member and compressed by the groove bottom of the mounting groove and the opposing surface of a second member to seal the space between the first member and the second member, comprising: a main body portion formed such that a gap is provided between it and the groove wall when compressed in the mounting groove; and a pair of protrusions projecting in the width direction from each of the widthwise side surfaces of the main body portion, wherein the main body portion has a flat first contact surface that abuts against the groove bottom and a flat second contact surface that abuts against the opposing surface, and the protrusions are formed such that, when the main body portion is compressed, at least one of the flat end faces of the protrusions abuts against the groove wall.

[0007] To achieve the above objective, the present invention provides a sealing structure for an annular gasket that is inserted into an annular mounting groove provided in a first member and compressed by the groove bottom of the mounting groove and the opposing surface of a second member to seal the space between the first member and the second member, wherein the gasket comprises a main body formed such that a gap is provided between it and the groove wall when compressed in the mounting groove, and a pair of protrusions projecting in the width direction from each of the widthwise side surfaces of the main body, the main body having a flat first contact surface that abuts the groove bottom and a flat second contact surface that abuts the opposing surface, the protrusions are formed such that, when the main body is compressed, at least one of the flat end faces of the protrusions abuts the groove wall, and the filling rate of the gasket into the mounting groove is 95% or less. [Effects of the Invention]

[0008] Because the gasket and sealing structure of the present invention have the above-described configuration, damage to the main body is suppressed when compressed by the first and second members, and the space between the first and second members can be properly sealed. [Brief explanation of the drawing]

[0009] [Figure 1]This is a schematic plan view illustrating a gasket according to one embodiment of the present invention. [Figure 2] This is a schematic longitudinal section of the gasket before compression, and is a cross-sectional view taken along line XX in Figure 1. [Figure 3] This is a schematic longitudinal cross-sectional view of the gasket after compression. [Figure 4] (a) and (b) are schematic longitudinal cross-sectional views of the gasket according to the comparative example. (a) is a schematic longitudinal cross-sectional view of the gasket before compression, and (b) is a schematic longitudinal cross-sectional view of the gasket after compression. (c) is a graph schematically showing comparative test data between the gasket according to one embodiment and the gasket according to the comparative example. [Figure 5] (a) to (d) are schematic longitudinal cross-sectional views of gaskets relating to modified examples. [Modes for carrying out the invention]

[0010] Hereinafter, an example of a gasket and sealing structure according to the embodiment, and its modified form, will be described with reference to the drawings. Note that in some of the drawings, some of the detailed reference numerals used in other drawings have been omitted.

[0011] The gasket 4 according to this embodiment is an annular member that is inserted into an annular mounting groove 2 provided in the first member 1 and is compressed by the groove bottom 2a of the mounting groove 2 and the opposing surface 3c of the second member 3 to seal the space between the first member 1 and the second member 3. The gasket 4 comprises a main body portion 5 formed such that a gap 8 (see Figure 3) is provided between it and the groove wall 2b when compressed in the mounting groove 2, and a pair of protrusions 7, 7 that protrude in the width direction from each of the widthwise sides 5c, 5c of the main body portion 5. The main body portion 5 has a flat first contact surface 5a that abuts against the groove bottom 2a and a flat second contact surface 5b that abuts against the opposing surface 3c. The protrusions 7, 7 are formed such that when the main body portion 5 is compressed, at least one of the protrusions 7 has a flat end surface 7a that abuts against the groove wall 2b. Furthermore, the sealing structure according to this embodiment has a filling rate of 95% or less of the gasket 4 into the mounting groove 2. The following is an example of a specific configuration.

[0012] In the following, the directions of the gasket 4 will be described as follows: the direction along the length of the mounting groove 2 will be referred to as the circumferential direction, the direction along the depth of the mounting groove 2 will be referred to as the height direction, and the direction along the width of the mounting groove 2 will be referred to as the width direction. Furthermore, the following description will focus on the gasket 4 that seals the space between the first member 1 of the plate-shaped lid body equipped with the mounting groove 2 and the box-shaped second member 3 with an upper opening. In addition, in Figure 1, the first member 1 is shown by a dashed line (imaginary line).

[0013] First, the gasket 4 and the sealing structure will be explained with reference to Figures 1 to 3. The first member 1 is a lid that is positioned to cover the box-shaped second member 3 from above. The first member 1 has a flat first surface 1a that is rectangular (approximately rectangular) in plan view, and an annular mounting groove 2 that opens to the first surface 1a side and runs along the circumferential direction of the outer edge of the first member 1. The mounting groove 2 has a groove bottom 2a formed approximately parallel to the first surface 1a, and groove walls 2b, 2b provided on both sides of the groove bottom 2a in the width direction, and a gasket 4 is assembled inside this mounting groove 2. The second member 3 is a box-shaped body with an open central portion in plan view, and has a bottomed storage section 3a with a space inside capable of accommodating contents. An annular flange section 3b is provided around this storage section 3a, running along the circumferential direction of the first member 1. This flange section 3b is formed on a flat opposing surface 3c that faces the groove bottom 2a of the mounting groove 2 when the second member 3 is assembled with the first member 1. The housing portion 3a of the second member 3 is provided so as to be surrounded by the mounting groove 2 of the first member 1 when viewed from above, and the inside of the housing portion 3a is a space sealed by a gasket 4.

[0014] The first member 1 and the second member 3 are each provided with multiple through holes (not shown) on their peripheral edges through which fasteners such as bolts are inserted. When the first member 1 and the second member 3 are assembled, these through holes communicate with each other, fastening the first member 1 and the second member 3 together as a single unit. The material of the first member 1 and the second member 3 is not particularly limited, but may be a metal material such as iron or aluminum. Although the diagram shows a simplified example of its application, for example, one may be a heat exchanger cover for an internal combustion engine, the other a heat exchanger, one a cylinder block, and the other an oil pan, oil cooler, or intake manifold.

[0015] Gasket 4 is formed using an elastic material such as EPDM, NBR, H-NBR, ACM, AEM, or FKM, and is an endless annular gasket without a core. By being interposed in a compressed state between the first member 1 and the second member 3, it seals the space between the external space and the housing 3a (internal space) to prevent the flow of fluids and foreign matter. As shown in Figure 2, in its uncompressed state, gasket 4 is formed with a height dimension greater than the depth dimension of the mounting groove 2, and a width dimension smaller than the groove width dimension of the mounting groove 2. In cross-sectional view, gasket 4 is formed in an elongated shape with a height dimension greater than its width dimension, and is formed symmetrically with respect to the center line in the width direction as the axis of symmetry.

[0016] The main body portion 5 of the gasket 4 is formed in a roughly rectangular shape with an elongated vertical shape in cross-section. The surface of the main body portion 5 on the groove bottom 2a side is formed as a flat first contact surface 5a that abuts against the groove bottom 2a, and the surface of the main body portion 5 on the opposing surface 3c side is formed as a flat second contact surface 5b that abuts against the opposing surface 3c.

[0017] The main body portion 5 has a tapered chamfer portion 6 provided at the corner portion 5d. In the illustrated example, the main body portion 5 is formed in a vertically long shape with the dimension in the height direction being larger than the dimension in the width direction in a cross-sectional view, and chamfer portions 6 are provided at the four corner portions 5d, respectively, and are provided on both sides in the width direction of the first contact surface 5a and the second contact surface 5b. Further, as shown in FIG. 1, the chamfer portion 6 is formed over the entire circumference of the gasket 4. With such a configuration, compared with a configuration in which the chamfer portion 6 is not provided, the volume of the main body portion 5 becomes smaller, and the ratio occupied by the gasket 4 with respect to the mounting groove 2 when the main body portion 5 is compressed can be reduced. The dimension w1 in the width direction of the main body portion 5 of the gasket 4 is not particularly limited, but as shown in FIG. 2, the dimension w1 in the width direction of the main body portion 5 is set to be approximately half of the groove width dimension w2 of the mounting groove 2, and it preferably has appropriate dimensions in the width direction and the height direction such that the filling rate of the gasket 4 into the mounting groove 2 in the compressed state is 95% or less.

[0018] The first contact surface 5a is formed in a flat shape as described above and is formed so as to be substantially parallel to the groove bottom 2a. Further, the second contact surface 5b is formed in a flat shape as described above and is formed so as to be substantially parallel to the opposing surface 3c. The first contact surface 5a and the second contact surface 5b are provided at the central portion in the width direction of the main body portion 5.

[0019] A pair of protruding portions 7, ⑦ are provided on the side surface 5c in the width direction of the main body portion 5, protruding in the width direction. As shown in FIG. 1, the protruding portion 7 is continuously formed along the circumferential direction of the main body portion 5. Further, as shown in FIG. 2, the protruding portion 7 is provided at the central portion in the height direction on both side surfaces 5c, 5c of the main body portion 5. The protruding portion 7 is formed such that the tip end portion in the protruding direction is smaller than the base end portion in the protruding direction, and is formed in a substantially trapezoidal shape in a cross-sectional view. The end surface 7a of the protruding portion 7 is provided in a flat shape at the tip end portion in the protruding direction of the protruding portion 7 and is formed substantially parallel to the groove wall 2b.

[0020] FIG. 3 is a view showing a state in which the gasket 4 shown in FIG. 2 is compressed and sealed in the mounting groove 2. The gasket 4 is formed so that, when compressed between the first member 1 and the second member 3, the filling rate into the mounting groove 2 is not 100% but 95% or less. Thus, as shown here, when the gasket 4 is compressed, the left and right end faces 7a, 7a of the protruding portion 7 actively abut against the groove walls 2b, 2b, while a gap 8 is formed between the side faces 5c, 5c in the width direction of the main body portion 5 and the groove walls 2b, 2b. In the example of FIG. 3, the "gap 8" is formed at four locations, upper, lower, left, and right, sandwiching the pair of protruding portions 7, 7. However, the first contact surface 5a and the second contact surface 5b are in firm elastic contact with the groove bottom 2a and the opposing surface 3c, respectively, without a gap.

[0021] According to the above, since the first contact surface 5a and the second contact surface 5b of the gasket 4 are formed in a flat surface shape, when compressed, the portion contacting the groove bottom 2a or the opposing surface 3c contacts the groove bottom 2a and the opposing surface 3c in a state where the posture of the main body portion 5 is stable, compared to an arcuate shape. Therefore, it is possible to prevent the gasket 4 from falling sideways or obliquely. Further, the protruding portion 7 provided on the gasket 4 functions as a rib and actively abuts against the groove wall 2b when compressed as shown in FIG. 3. Thus, the reaction force of the gasket 4 can be compensated, and a higher surface pressure (linear pressure) can be applied even with a small compression amount. Furthermore, since the filling rate of the gasket 4 into the mounting groove 2 is 95% or less, a gap is generated between the gasket 4 and the groove wall 2b in the compressed state in the mounting groove 2, suppressing excessive strain from being applied to the main body portion 5 and preventing damage such as cracks from occurring in the gasket 4.

[0022] Next, a comparative test will be described while referring to FIG. 4. Figures 4(a) and 4(b) show gasket 100 used as a comparative example. Figure 4(a) shows gasket 100 of the comparative example in its uncompressed state, and Figure 4(b) shows gasket 100 of the comparative example in its compressed state. This gasket 100 is formed such that the width dimension w3 of the main body portion 101 is approximately 60% to 70% of the groove width dimension w2 of the mounting groove 2. In this gasket 100, the contact surfaces 102 and 103 that abut the groove bottom 2a and the opposing surface 3c are formed in an arc shape in cross-sectional view. In addition, the tips of the protruding portions 104, 104 that protrude in the width direction from both sides of the gasket 100 are formed in an arc shape in cross-sectional view. When this gasket 100 is compressed, as shown in Figure 4(b), almost the entire surface of the main body portion 101 abuts against the mounting groove 2 and the opposing surface 3c. The filling rate of gasket 100 into the mounting groove 2 was set to 99%.

[0023] As a comparative example, gasket 100 was used, while gasket 4, shown in Figures 1 to 3, was used as an example. This gasket 4 was formed such that the width dimension w1 of the main body 5 was approximately 45% to 55% of the groove width dimension w2 of the mounting groove 2, and the filling rate of gasket 4 into the mounting groove 2 was 91%.

[0024] Figure 4(c) is a graph showing the results of a comparative test between gasket 4 according to the embodiment and gasket 100 according to the comparative example. As shown in this graph, both the embodiment and the comparative example share the characteristic that the reaction force increases as the amount of compression increases, but the reaction force of the embodiment is greater than that of the comparative example. Therefore, from this comparative test, it was found that gasket 4 according to the embodiment can seal more firmly because, compared to gasket 100 according to the comparative example, in which almost the entire surface of the main body 101 abuts against the mounting groove 2 and the opposing surface 3c, the main body 5 and the protruding part 7 actively abut against the groove bottom 2a, the opposing surface 3c, and the groove wall 2b with a slight gap, thereby increasing the reaction force. Furthermore, it was found that the filling rate of gasket 4 into the mounting groove 2 can be reduced while maintaining sealing performance by increasing the surface pressure between the upper and lower parts, as in gasket 4, rather than filling it to nearly 100% without any gaps.

[0025] Next, the gaskets related to the modified examples will be explained with reference to Figures 5(a) to (d). In each of the following modified examples, the differences from the previously described examples will be mainly explained, and the common parts and their effects will be omitted or briefly explained.

[0026] The shape of the gasket 4 is not limited to the shapes shown in Figures 1 to 3, and may be as shown in Figures 5(a) to 5(d), as long as it has a flat first contact surface 5a and a second contact surface 5b. The gasket 4A shown in Figure 5(a) differs mainly in the configuration of the main body 5 from the example described earlier. The main body 5 of the gasket 4A has a change in width in the middle of the height direction between the chamfered portions 6, 6, and this difference in dimensions forms a stepped portion 5ca on the side surface 5c. In the illustrated example, the width direction of the main body 5 on both ends is smaller than the height direction of the central portion. This makes it possible to reduce the filling rate of the gasket 4A into the mounting groove 2 when it is compressed.

[0027] The gasket 4B shown in Figure 5(b) differs from the previously described example mainly in the configuration of the main body 5. At the widthwise center of both ends of the main body 5 in the height direction, grooves 5e and 5f are formed along the circumferential direction of the main body 5, opening in the height direction and extending along the entire length of the main body 5. This configuration allows for a more effective reduction in the filling rate of the gasket 4B into the mounting groove 2. In the illustrated example, first contact surfaces 5a are provided on both sides of the widthwise side of groove 5e, and second contact surfaces 5b are provided on both sides of the widthwise side of groove 5f. In other words, these grooves 5e and 5f divide the first contact surface 5a and the second contact surface 5b into two sections each. Also in the illustrated example, grooves 5e and 5f are divided into a groove bottom having a flat surface substantially parallel to the first contact surface 5a, and a groove wall that slopes towards the widthwise center as it moves from the opening towards the groove bottom.

[0028] The gasket 4C shown in Figure 5(c) differs from the previously described example in the configuration of both ends of the main body 5 in the height direction. In the gasket 4C, notches 5g are formed in the shape of notches on the height-direction ends of each of the four corners 5d. In the illustrated example, the notches 5g are provided so as to form inclined surfaces, which makes the widthwise dimensions of the first contact surface 5a and the second contact surface 5b smaller than in the previously described example. The formation of the notches 5g allows for a reduction in the filling rate of the gasket 4C into the mounting groove 2 when compressed.

[0029] The gasket 4D shown in Figure 5(d) is an example in which the filling rate into the mounting groove 2 is even smaller than that of the gasket 4 shown in Figures 1 to 3. In the example shown, the filling rate into the mounting groove 2 is formed to be approximately 50% to 80%. Therefore, in the example of Figure 5(d), after the gasket 4D is compressed vertically, internal pressure is applied from the right side, pushing the gasket 4D to the left side, causing it to bend into an L-shape. Then, two "gaps 8" are formed on the left groove wall 2b side, with the protrusions 7 in between, and one gap is formed on the right groove wall 2b side. As a result, the end face 7a of one of the pair of protrusions 7, 7 abuts against the groove wall 2b, while the end face 7a of the other protrusion 7 does not abut against the groove wall 2b. However, the first contact surface 5a and the second contact surface 5b are in firm elastic contact with the groove bottom 2a and the opposing surface 3c respectively, without any gaps. Even when the filling ratio is set to the above value, a stable compression state can be achieved because the first contact surface 5a and the second contact surface 5b are formed in a flat surface shape, thereby ensuring a reaction force and properly sealing the space between the first member 1 and the second member 3.

[0030] The different configurations described in the above embodiments and their respective modifications may be modified, rearranged, and applied as appropriate and necessary. Furthermore, the components are not limited to the configurations described above. For example, the housing portion 3a may be provided at least on the first component 1 side. Also, the plan view shape of the mounting groove 2 may be an appropriate shape corresponding to the shapes of the first component 1 and the second component 3. The gasket 4 is not limited to a configuration in which the first contact surface and the protruding portion 7 are continuously formed along the circumferential direction of the main body portion 5, but may be formed intermittently. Furthermore, the gaskets 4, 4A to 4D are not limited to being formed symmetrically with respect to the center line in the width direction or the center line in the height direction as the axis of symmetry in cross-sectional view. Also, the dimensions of the gaskets 4, 4A to 4D are not limited to the embodiments described above. Furthermore, while the above description and illustrations illustrate an example in which gaskets 4, 4A to 4D are provided in a portion where the first member 1 and the second member 3 are fastened together without gaps by fasteners, gaskets 4, 4A to 4D can also be applied to portions where there is a gap between the first surface 1a and the flange portion 3b. [Explanation of Symbols]

[0031] 1. First member 2 Mounting groove 2a groove bottom 2b Groove wall 3. Second Member 3c Opposite surface 4,4A~4D Gasket 5 Main body 5a 1st contact surface 5b Second contact surface 6 Chamfer 7 Protrusion 7a End face 8 gaps

Claims

1. An annular gasket that is inserted into an annular mounting groove provided in a first member and compressed by the bottom of the mounting groove and the opposing surface of a second member to seal the space between the first member and the second member, The device comprises a main body formed such that a gap is provided between it and the groove wall when compressed within the mounting groove, and a pair of protrusions projecting in the width direction from each of the two sides of the main body in the width direction. The main body portion has a flat first contact surface that abuts against the bottom of the groove and a flat second contact surface that abuts against the opposing surface. The gasket is characterized in that, when the main body is compressed, the flat end face of the protrusion, provided on at least one side, contacts the groove wall.

2. In claim 1, The gasket is characterized in that the protrusion is provided at the central part in the height direction on the side surface of the main body.

3. In claim 1 or claim 2, The gasket is characterized in that the main body is formed in a substantially rectangular shape in cross-section, and tapered chamfered portions are provided at its corners.

4. An annular gasket sealing structure in which an annular gasket is inserted into an annular mounting groove provided in a first member and compressed by the groove bottom of the mounting groove and the opposing surface of a second member facing it to seal the space between the first member and the second member, The gasket comprises a main body formed such that a gap is provided between it and the groove wall when compressed within the mounting groove, and a pair of protrusions projecting in the width direction from each of the widthwise side surfaces of the main body. The main body portion has a flat first contact surface that abuts against the bottom of the groove and a flat second contact surface that abuts against the opposing surface. The aforementioned protrusion is formed such that, when the main body is compressed, at least one of the flat end faces of the protrusion abuts against the groove wall. A sealing structure characterized in that the filling rate of the gasket into the mounting groove is 95% or less.

Images