Sealing structure

Abstract

The present invention is provided with: a first object (2) to be sealed having a groove portion (21); a second object (3) to be sealed having a second main surface (30); and a sealing material (1). The groove portion (21) has a first bottom surface (210), and a second side surface (212). The groove portion (21) further has, in a cross section perpendicular to a second direction (θ), a recessed portion (22) protruding from an area (Ar) surrounded by a first extension line (L1) obtained by extending a portion of the first bottom surface (210) that is in contact with the sealing material, a second extension line (L2) obtained by extending a portion of the first side surface (211) that is in contact with the sealing material (1), and a third extension line (L3) obtained by extending a portion of the second side surface (211) that is in contact with the sealing material (1). With such a configuration, it is possible to suppress an excessive reaction force of the sealing material due to a temperature rise, while appropriately maintaining the degree of sealing.

Description

Seal structure

[0001] The present invention relates to a seal structure.

[0002] Various seal structures have been proposed that increase sealing performance by sandwiching a sealing material made of an elastic material between two objects to be sealed. In the seal structure disclosed in Patent Document 1, a groove for accommodating the sealing material is formed in one of the objects to be sealed. The sealing material accommodated in the groove exhibits elastic force when pressed by the other object to be sealed. By virtue of this elastic force, the gaps between the two objects to be sealed and the sealing material are closed, and the sealing performance is improved.

[0003] Japanese Unexamined Patent Application Publication No. 2011-80607

[0004] Depending on the environment in which the seal structure is used, there may be situations where the operating temperature during use is higher than the initial temperature when the seal structure is assembled. In this case, the sealing material undergoes volume expansion due to the temperature rise. When most or all of the groove is occupied by the sealing material, a reaction force is generated due to restriction of the volume expansion of the sealing material. This reaction force gives rise to concerns about problems such as damage to any of the objects to be sealed, for example.

[0005] The present invention has been conceived under the circumstances described above, and an object thereof is to provide a seal structure that can suppress excessive reaction force of the sealing material caused by temperature rise while appropriately maintaining sealing performance.

[0006] The seal structure provided by the present invention comprises: a first object to be sealed having a first main surface facing a first side in a first direction and a groove recessed from the first main surface toward a second side in the first direction; a second object to be sealed having a second main surface facing the second side in the first direction, facing the first main surface, and closing the groove; and a seal material having a circular or elliptical cross-sectional shape, housed in the groove, and in contact with the second main surface, wherein each of the grooves is a surface that contacts the seal material, and is located toward the second side in the first direction with respect to the seal material and facing toward the first side. The groove has a first bottom surface, a first side surface located on the first side with respect to the seal material in a third direction perpendicular to the first direction and the second direction in which the seal material extends, and a second side surface located on the second side, and the groove further has a recess that protrudes from the region enclosed by a first extension line which extends the portion of the first bottom surface that abuts the seal material, a second extension line which extends the portion of the first side surface that abuts the seal material, and a third extension line which extends the portion of the second side surface that abuts the seal material, in a cross section perpendicular to the second direction.

[0007] According to a preferred embodiment of the present invention, at least one of the first side surface and the second side surface is inclined with respect to the first direction such that the distance between the first side surface and the second side surface in the third direction decreases as it moves toward the first side in the first direction, and the region is triangular.

[0008] According to a preferred embodiment of the present invention, the sealing material is annular when viewed in the first direction, the third direction is the radial direction of the sealing material, the first side in the third direction is the outer diameter side, and the second side in the third direction is the inner diameter side.

[0009] According to a preferred embodiment of the present invention, the recess is located on the first side in the third direction with respect to the sealing material.

[0010] According to a preferred embodiment of the present invention, the recess is recessed from the first bottom surface toward the second side in the first direction.

[0011] According to a preferred embodiment of the present invention, the recess is recessed in the third direction from the first or second side surface.

[0012] According to a preferred embodiment of the present invention, the first object to be sealed includes a first member having the first bottom surface and a second member having at least one of the first side surface and the second side surface.

[0013] According to a preferred embodiment of the present invention, at the initial temperature when the sealing material, the first object to be sealed, and the second object to be sealed are combined, the sealing material is in contact with the first main surface, the first side surface, and the second side surface, and is away from the recess. There is an operating temperature higher than the initial temperature at which the sealing material is in contact with the first main surface, the first side surface, and the second side surface, and a portion of the sealing material enters the recess.

[0014] According to the present invention, it is possible to suppress excessive reaction force of the sealing material due to temperature rise while appropriately maintaining the degree of airtightness.

[0015] Other features and advantages of the present invention will become more apparent from the detailed description below with reference to the accompanying drawings.

[0016] The following are examples of sealing materials used in the sealing structure according to the present invention, where (a) is a plan view and (b) to (d) are partial cross-sectional views. The following are examples of sealing structures according to the first embodiment of the present invention, where (a) is a partial cross-sectional view at the initial temperature and (b) is a partial cross-sectional view at the operating temperature. The following are examples of sealing structures according to the first embodiment of the present invention, where (a) is a partial cross-sectional view at the initial temperature and (b) is a partial cross-sectional view at the operating temperature. The following are examples of sealing structures according to the first embodiment of the present invention, where (a) is a partial cross-sectional view at the initial temperature and (b) is a partial cross-sectional view at the operating temperature. The following are examples of sealing structures according to the second (a) is a graph showing the relationship between the reaction force of the sealing material and temperature in the sealing structures of the embodiments and reference examples of the present invention, and (b) is the reduction rate of the reaction force. The following are partial cross-sectional views showing a sealing structure according to the third embodiment of the present invention. (a) to (c) are partial cross-sectional views showing an example of a method for manufacturing a seal structure according to the third embodiment of the present invention. These are partial cross-sectional views showing a first modified example of the seal structure according to the third embodiment of the present invention. (a) to (d) are partial cross-sectional views showing a seal structure according to the fourth embodiment of the present invention and first to third modified seal structures. (a) to (h) are partial cross-sectional views showing modified examples of recesses in the seal structure of the present invention.

[0017] Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

[0018] The terms "first," "second," "third," etc., used in this invention are used solely for identification purposes and are not intended to assign a sequence to the objects.

[0019] First Embodiment: Figures 1 and 2 show a seal structure according to the first embodiment of the present invention. The seal structure A1 of this embodiment comprises a seal material 1, a first object to be sealed 2, and a second object to be sealed 3. The apparatus in which the seal structure A1 is used is not limited in any way, and may be used, for example, in manufacturing equipment used in semiconductor manufacturing processes.

[0020] The sealing material 1 is a component made of an elastic material that exhibits elastic force when compressed. The material of the sealing material 1 is not limited in any way, and examples include FFKM (perfluoroelastomer), FKM (fluororubber), FVMQ (fluorosilicone rubber), silicone rubber (VMQ), nitrile rubber (NBR), acrylic rubber (ACM), and ethylene propylene rubber (EPDM).

[0021] The overall shape (plan view shape) of the sealing material 1 is not limited in any way. The plan view shape of the sealing material 1 may be, for example, an annular shape which is a closed shape, or it may be an open shape which is linear, curved, bent, etc., and various shapes may be adopted. In the example shown in Figure 1(a), the plan view shape of the sealing material 1 is an annular shape, for example, a ring shape. When the plan view shape of the sealing material 1 is an annular shape, it may be an elliptical annular shape, a rectangular annular shape, a polygonal annular shape, etc.

[0022] The sealant 1 has a circular or elliptical cross-sectional shape. Figures (b) to (d) are cross-sectional views along the line B-B in Figure (a). In the example shown in Figure (b), the cross-sectional shape of the sealant 1 is circular. In the examples shown in Figures (c) and (d), the cross-sectional shape of the sealant 1 is elliptical, with the major axis in Figure (c) being aligned with the axial direction (thickness direction) of the sealant 1, and the major axis in Figure (d) being aligned with the radial direction of the sealant 1.

[0023] The size of the sealant 1 is not limited in any way. The inner diameter R1 of the sealant 1 is, for example, 0.5 mm or more and 1500 mm or less, and is, for example, about 50 mm. The diameter D1 of the sealant 1 is, for example, 0.5 mm or more and 10 mm or less, and is, for example, about 6 mm.

[0024] In the following explanation, we will describe the case where the plan view shape of the seal material 1 is annular and the cross-section is circular. However, even if the shape is one of the other shapes described above, the matters described below can be applied as appropriate to the extent that they do not cause technical inconsistencies. Also, in the figure, the first direction z corresponds to the axial direction, the second direction θ corresponds to the circumferential direction, and the third direction r corresponds to the radial direction. The first side r1 of the third direction r corresponds to the outer diameter side, and the second side r2 corresponds to the inner diameter side. However, the relationship between these first to third directions is just one embodiment, and as will be described later, the first to third directions may have other relationships.

[0025] The first object to be sealed 2 and the second object to be sealed 3 are objects whose airtightness between them is enhanced by sandwiching the sealing material 1 between them. The materials of the first object to be sealed 2 and the second object to be sealed 3 are not limited in any way and include metals, resins, quartz, etc. Examples of metals that make up the first object to be sealed 2 and the second object to be sealed 3 include stainless steel, iron, copper, aluminum, nickel, molybdenum, chromium, etc., or alloys of any of these. The materials of the first object to be sealed 2 and the second object to be sealed 3 may be the same or different.

[0026] Figure 2(a) shows a cross-sectional view of the seal structure A1 at its initial temperature when it is constructed, and Figure 2(b) shows a cross-sectional view of the seal structure A1 at its operating temperature, which is higher than the initial temperature, when it is in use. In this invention, "initial temperature" refers to the temperature at which the seal structure A1 is constructed when the seal material 1, the first object to be sealed 2, and the second object to be sealed 3 are combined, and is typically room temperature, for example, 21°C to 25°C. In this invention, "operating temperature" refers to the ambient temperature that is higher than the initial temperature when the seal structure A1 is used in a device, etc., due to the operation of the device, etc., and is the temperature at which the seal material 1 still exhibits elastic force, for example, when the seal material 1 is made of FFKM, it may be 50°C to 330°C. However, it is not necessary for the ambient temperature to be maintained at the operating temperature in this invention for the entire period during which the seal structure A1 is used, and it may include cases in which the ambient temperature temporarily reaches the operating temperature under certain conditions. The initial temperature and operating temperature at which the behavior of the sealing material 1 described below is realized are temperatures that may vary depending on the material, shape, and size of the sealing material 1, as well as the shape and size of the groove 21 and recess 22.

[0027] The first object to be sealed 2 has a first main surface 20 and a groove 21. The first main surface 20 is a surface facing the first side z1 in the first direction z, and in the illustrated example, it is a flat surface.

[0028] The groove 21 is recessed from the first main surface 20 toward the second side z2 in the first direction z. The groove 21 accommodates the sealing material 1. The groove 21 has a first bottom surface 210, a first side surface 211, and a second side surface 212. The first bottom surface 210, the first side surface 211, and the second side surface 212 are in contact with the sealing material 1 at the initial temperature shown in Figure 2(a). In Figure 2(a), for ease of understanding, hatching consisting of multiple discrete points is appropriately applied to the parts of the first bottom surface 210, the first side surface 211, and the second side surface 212 that are in contact with the sealing material 1, and the same applies to subsequent figures. The size of the groove 21 is not limited in any way; for example, if the diameter D1 of the sealing material 1 is about 6 mm, the opening width W1 may be about 4.8 mm and the depth H1 may be about 5 mm.

[0029] The first bottom surface 210 is located on the second side z2 in the first direction z with respect to the sealant 1 and faces the first side z1. The first side surface 211 is located on the first side r1 in the third direction r with respect to the sealant 1. Because the cross-sectional shape of the sealant 1 is circular or elliptical, the center of the cross-section of the sealant 1 is positioned between the portion of the first bottom surface 210 that abuts the sealant 1 and the portion of the second main surface 30 that abuts the sealant 1. The second side surface 212 is located on the second side r2 in the third direction r with respect to the sealant 1. The specific shapes of the first bottom surface 210, the first side surface 211 and the second side surface 212 are not limited in any way. In the illustrated example, the first bottom surface 210 is a flat surface perpendicular to the first direction z. The first side surface 211 and the second side surface 212 are flat surfaces inclined with respect to the first direction z such that the distance in the third direction r decreases as it approaches the first side z1 in the first direction z. In the illustrated example, the angle α1 that the first side surface 211 makes with the first direction z and the angle α2 that the second side surface 212 makes with the first direction z may each be about 24°.

[0030] At the points where the first main surface 20, the first bottom surface 210, the first side surface 211, and the second side surface 212 intersect, a curved surface may be formed by so-called curved surface processing, an inclined plane may be formed by so-called chamfer processing, or it may be an acute corner where no curved surface, inclined plane, etc., are formed. In the illustrated example, the case in which a curved surface is formed by curved surface processing is shown as an example.

[0031] The groove 21 further has a recess 22. The recess 22 protrudes from region Ar in a cross-section (Figure 2) perpendicular to the second direction θ, which is the direction in which the sealing material 1 extends. Region Ar is the area enclosed by the first extension line L1, the second extension line L2, and the third extension line L3. Also, at the initial temperature (Figure 2(a)), the recess 22 is away from the sealing material 1. Furthermore, at the initial temperature, the recess 22 is away from the portions of the first bottom surface 210, the first side surface 211, and the second side surface 212 that are in contact with the sealing material 1.

[0032] The first extension line L1 is the extension of the portion of the first bottom surface 210 that comes into contact with the sealant 1 at the initial temperature in the cross-section. In the illustrated example, the first extension line L1 is a straight line along the third direction r. The second extension line L2 is the extension of the portion of the first side surface 211 that comes into contact with the sealant 1 at the initial temperature in the cross-section. In the illustrated example, the second extension line L2 is a straight line inclined at an angle α1 with respect to the first direction z. The third extension line L3 is the extension of the portion of the second side surface 212 that comes into contact with the sealant 1 at the initial temperature in the cross-section. In the illustrated example, the third extension line L3 is a straight line inclined at an angle α2 with respect to the first direction z. The region Ar enclosed by these first extension lines L1, second extension line L2, and third extension line L3 is a triangle, more specifically an isosceles triangle, in the illustrated example.

[0033] The specific location, shape, size, etc., of the recess 22 are not limited in any way. In the illustrated example, the recess 22 is recessed from the first bottom surface 210 toward the second side z2 in the first direction z, and extends beyond the first extension line L1 from region Ar. The recess 22 is separated from the portion of the first bottom surface 210 that contacts the sealing material 1 at the initial temperature toward the first side r1 in the third direction r. The recess 22 may have a shape that includes, for example, a second bottom surface 220, a third side surface 221, and a fourth side surface 222. The second bottom surface 220 is located toward the second side z2 in the first direction z with respect to the first bottom surface 210, and is a flat surface along the third direction r. The third side surface 221 is located toward the first side r1 in the third direction r with respect to the second bottom surface 220, and is flush with the first side surface 211. The fourth side surface 222 is located on the second side r2 in the third direction r with respect to the second bottom surface 220, and is parallel to the first side surface 211 and the third side surface 221. In the illustrated example, the opening width W2 of the recess 22 is, for example, about 2 mm. The depth H2 of the recess 22 is, for example, about 0.5 mm.

[0034] At the points where the multiple surfaces included in the recess 22 and the multiple surfaces included in the groove 21 intersect, a curved surface may be formed by so-called curved surface processing, an inclined plane may be formed by so-called chamfer processing, or it may be an acute corner where no curved surface, inclined plane, etc., are formed. In the illustrated example, the case in which a curved surface is formed by curved surface processing is shown as an example.

[0035] Figure 2(b) shows the seal structure A1 at the operating temperature. As the temperature rises from the initial temperature to the operating temperature, the volume of the seal material 1 expands. As a result, the proportion of the groove 21 occupied by the seal material 1 increases. Almost all or all of the first main surface 20, the first side surface 211, and the second side surface 212 are in contact with the seal material 1. In addition, a portion of the seal material 1 has entered the recess 22.

[0036] Figures 3 and subsequent figures show modified examples and other embodiments of the present invention. In these figures, elements identical or similar to those in the above embodiments are denoted by the same reference numerals. Furthermore, the configurations of each part in each modified example and each embodiment can be appropriately combined with each other to the extent that no technical inconsistencies arise.

[0037] First Embodiment, First Modification: Figure 3 shows a first modification of the seal structure A1. In this modified seal structure A11, the size of the opening width W2 of the recess 22 is different from that of the seal structure A1. In the seal structure A11, the opening width W2 is, for example, about 2.7 mm. That is, at the initial temperature shown in Figure (a), the recess 22 is separated from the portion of the first bottom surface 210 that contacts the seal material 1, but the distance from that portion is smaller than the distance in the seal structure A1. As shown in Figure (b), at the operating temperature, the size of the seal material 1 that enters the recess 22 is larger than the size in the seal structure A1.

[0038] Second Modification of the First Embodiment: Figure 4 shows a second modification of the seal structure A1. In this modified seal structure A12, the recess 22 is located on the second side r2 in the third direction r with respect to the portion of the first bottom surface 210 that contacts the seal material 1 at the initial temperature. That is, the groove 21 of this modified form may be symmetric to the groove 21 of the seal structure A1 with respect to the axis of symmetry extending in the first direction z.

[0039] Second Embodiment: Figure 5 shows a seal structure according to a second embodiment of the present invention. In the seal structure A2 of this embodiment, the recess 22 is recessed in the third direction r. In the illustrated example, the recess 22 is recessed from the first side surface 211 toward the first side r1 in the third direction r, and extends beyond the second extension line L2 from region Ar. That is, the recess 22 is located toward the first side r1 in the third direction r with respect to the seal material 1.

[0040] The recess 22 in this modified example may include a second bottom surface 220, a third side surface 221, and a fourth side surface 222. The second bottom surface 220 is located on the first side r1 in the third direction r relative to the first side surface 211 and is parallel to the first side surface 211. The third side surface 221 is interposed between the second bottom surface 220 and the first side surface 211 and is aligned with the third direction r. The fourth side surface 222 is interposed between the first bottom surface 210 and the second bottom surface 220, is aligned with the third direction r and is flush with the first bottom surface 210.

[0041] Second Embodiment, First Modification: Figure 6 shows a first modification of the seal structure A2. In this modified seal structure A21, the recess 22 is recessed from the second side surface 212 toward the second side r2 in the third direction r, and extends beyond the third extension line L3 from region Ar. That is, the recess 22 is located toward the second side r2 in the third direction r with respect to the seal material 1. The groove 21 of this modified example may be symmetrical with the groove 21 of the seal structure A2 with respect to the axis of symmetry extending in the first direction z.

[0042] Figure 7 shows the simulation results of the reaction force generated in the sealing material 1, using sealing structures A1, A11, A12, A2, and A21 as examples. Also shown are the simulation results for a comparative example of a sealing structure having a first bottom surface 210, a first side surface 211, and a second side surface 212, as shown in Figure 2, etc., but with a groove 21 that does not have a recess 22. Figure (a) shows the relationship between temperature and reaction force. Figure (b) shows the reduction rate of the reaction force for each example, relative to the reaction force of the comparative example at the operating temperature. The material of the sealing material 1 is FFKM in all cases.

[0043] In these examples and comparative examples, the initial temperature is 21°C to 25°C, and the operating temperature is assumed to be around 300°C. In all examples, the reaction force generated in the sealing material 1 increases with increasing temperature. In the comparative example, the increase in reaction force is particularly large from around 200°C, and the increase in reaction force when the temperature rises from 200°C to 300°C is significant. This is thought to be because the sealing material 1 expanded in volume, filling the entire groove 21 in the temperature range above 200°C, and the subsequent volume expansion of the sealing material 1 was severely limited. In this simulation, the reaction force of the comparative example at 300°C exceeds 6,000 N. This reaction force is a force that pushes the second object to be sealed 3 upward toward the first side z1 in the first direction z, or pushes the first object to be sealed 2 downward toward the second side z2 in the first direction z, and depending on the material, shape, size, etc., of the first object to be sealed 2 or the second object to be sealed 3, it may be large enough to cause damage to either of them.

[0044] On the other hand, the reaction forces at 300°C of seal structures A1, A11, A12, A2, and A21 as working examples are all smaller than those of the comparative example. This is considered to result from the relaxation of restriction on volume expansion caused by a part of the volume-expanded sealing material 1 entering the recessed portion 22 at the operating temperature. Accordingly, excessive reaction force at the operating temperature can be suppressed, and damage to the first sealing target object 2 or the second sealing target object 3 can be avoided. Further, in the temperature range from the initial temperature to the operating temperature, the reaction forces of the seal structures A1, A11, A12, A2, and A21 as working examples are almost the same as the reaction force of the comparative example. This is considered to result from that the center of the cross-section of the sealing material 1 is in a positional relationship sandwiched between the portion of the first bottom surface 210 that abuts on the sealing material 1 and the portion of the second main surface 30 that abuts on the sealing material 1, and that the elastic force caused by compression of the sealing material 1 is properly exerted because the sealing material 1 has not entered the recessed portion 22 yet. Therefore, in the temperature range from the initial temperature to the operating temperature, the sealing material 1, the first sealing target object 2, and the second sealing target object 3 are in contact with each other with an appropriate pressing force, and the sealing degree of each seal structure is appropriately maintained. Therefore, according to the seal structure of the present invention, excessive reaction force of the sealing material caused by temperature rise can be suppressed while appropriately maintaining the sealing degree.

[0045] At the operating temperature (300°C), the reaction force of seal structure A1 and seal structure A12 is smaller for seal structure A1. This is thought to be because the seal material 1 has an annular shape with the first side r1 in the radial direction, and as the temperature rises, the entire seal material 1 expands so that it moves toward the first side r1 (outer diameter side) in the third direction r. In other words, in seal structure A1, the recess 22 is located on the first side r1 in the third direction r relative to the seal material 1, so a part of the seal material 1 that expands while moving toward the first side r1 can easily enter the recess 22. On the other hand, in seal structure A12, the recess 22 is located on the second side r2 in the third direction r relative to the seal material 1, so a part of the seal material 1 that expands while moving toward the first side r1 due to the temperature rise is less likely to enter the recess 22 compared to seal structure A1. The reaction force of the seal structure A2, where the recess 22 is located on the first side r1 in the third direction r relative to the seal material 1, is smaller than the reaction force of the seal structure A21, where the recess 22 is located on the second side r2 in the third direction r relative to the seal material 1, is thought to be due to the same reason.

[0046] Furthermore, whether the recess 22 is recessed in the first direction z (seal structures A1, A11, A12) or recessed in the third direction r (seal structures A2, A21), the effect of suppressing excessive reaction force of the sealing material due to temperature rise while appropriately maintaining the degree of airtightness can be obtained.

[0047] Comparing the reaction force of seal structure A11 and seal structure A11 at the operating temperature, the reaction force of seal structure A11 is clearly smaller, the smallest among all embodiments. This is thought to be because the larger opening width W2 allows a larger portion of the seal material 1 to enter the recess 22. Also, the distance between the portion of the first bottom surface 210 that contacts the seal material 1 at the initial temperature and the recess 22 is closer for seal structure A11 than for seal structure A11. Therefore, as the temperature rises, a portion of the seal material 1 begins to enter the recess 22 at a lower temperature range for seal structure A11. As a result, the reaction force of seal structure A11 is clearly smaller at, for example, 200°C before reaching 300°C.

[0048] Third Embodiment: FIG. 8 shows a seal structure according to a third embodiment of the present invention. In the seal structure A3 of the present embodiment, the first sealing object 2 includes a first member 2A and a second member 2B. The first sealing object 2 is formed by fixing the first member 2A and the second member 2B to each other. The method for fixing the first member 2A and the second member 2B is not particularly limited, and various methods such as screwing using a screw or the like, engagement using a projection or the like, bonding using a bonding agent or the like, and welding may be appropriately used.

[0049] The first member 2A is a member including a first bottom surface 210. The second member 2B is a member including at least one of a first side surface 211 and a second side surface 212. In the illustrated example, the first member 2A includes the first bottom surface 210 and the second side surface 212, and the second member 2B includes the first side surface 211. Further, the first member 2A further includes a recess 22. The recess 22 is located on the first side r1 in the third direction r with respect to the sealing material 1.

[0050] FIG. 9 shows an example of a method for manufacturing the seal structure A3. First, as shown in (a) of the same figure, a first member 2A having a first main surface 20 is prepared, and a first bottom surface 210 and a second side surface 212 are formed by cutting or the like. Next, as shown in (b) of the same figure, a recess 22 recessed from the first bottom surface 210 toward the second side z2 in the first direction z is formed by cutting or the like. Subsequently, as shown in (c) of the same figure, a second member 2B having a first side surface 211 is prepared and fixed to the first member 2A mutually. Thereafter, by combining the sealing material 1, the first sealing object 2, and the second sealing object 3, the seal structure A3 shown in FIG. 8 is obtained.

[0051] According to the present embodiment as well, excessive reaction force of the sealing material caused by temperature rise can be suppressed while appropriately maintaining the sealing performance. Further, by configuring the first sealing object 2 with a plurality of members including the first member 2A and the second member 2B, as shown in FIGS. 9(a) and 9(b), it is possible to perform processing for forming the recess 22 in a state where the second member 2B having the first side surface 211 does not yet exist, so that the processing can be performed more easily and efficiently.

[0052] Third Embodiment, First Modification: Figure 10 shows a first modification of the seal structure A3. In this modified seal structure A31, the first member 2A includes a first bottom surface 210, a second side surface 212, and a recess 22, and the second member 2B includes a second side surface 212. The recess 22 is located on the second side r2 in the third direction r with respect to the seal material 1.

[0053] This modified version also makes it possible to suppress excessive reaction force of the sealing material due to temperature rise while appropriately maintaining the degree of airtightness. Furthermore, as can be seen from this modified version, there are no limitations on how the division positions of the first member 2A and the second member 2B are set. For example, the division positions of the first member 2A and the second member 2B may be determined depending on whether the side on which the recess 22 is formed in the third direction r is the first side r1 or the second side r2. Moreover, the first object to be sealed 2 may be composed of three or more members.

[0054] Fourth Embodiment: Figure 11 shows a seal structure according to a fourth embodiment of the present invention and its modified form. The seal structures A4, A41, A42, and A43 shown in Figures (a) to (d) each have two recesses 22 in their respective grooves 21.

[0055] In the seal structure A4 shown in Figure (a), there are one recess 22 on each side of the seal material 1 in the third direction r. Each recess 22 is recessed from the first bottom surface 210 toward the second side z2 in the first direction z, and extends beyond the first extension line L1 from region Ar. The groove 21 may have a shape that is symmetrical with respect to the axis of symmetry extending in the first direction z.

[0056] In the seal structure A41 shown in Figure (b), there are two recesses 22 on either side of the seal material 1 in the third direction r. One recess 22 is recessed from the first side surface 211 toward the first side r1 in the third direction r, and extends beyond the second extension line L2 from region Ar. The other recess 22 is recessed from the second side surface 212 toward the second side r2 in the third direction r, and extends beyond the third extension line L3 from region Ar. The groove 21 may have a shape that is symmetrical with respect to the axis of symmetry extending in the first direction z.

[0057] In the seal structure A42 shown in Figure (c), two recesses 22 are located on one side (first side r1) in the third direction r relative to the seal material 1. One recess 22 is recessed from the first bottom surface 210 toward the second side z2 in the first direction z, and extends beyond the first extension line L1 from region Ar. The other recess 22 is recessed from the first side surface 211 toward the first side r1 in the third direction r, and extends beyond the second extension line L2 from region Ar.

[0058] In the seal structure A43 shown in Figure (d), there are two recesses 22 on either side of the seal material 1 in the third direction r. One recess 22 is recessed from the first bottom surface 210 toward the second side z2 in the first direction z, and extends beyond the first extension line L1 from region Ar. The other recess 22 is recessed from the second side surface 212 toward the second side r2 in the third direction r, and extends beyond the third extension line L3 from region Ar.

[0059] These embodiments and modifications also make it possible to suppress excessive reaction force of the sealing material due to temperature rise while appropriately maintaining the degree of airtightness. Furthermore, as can be seen from these embodiments and modifications, the groove 21 may have a configuration having two recesses 22, and the relative positional relationship of the two recesses 22 is not limited in any way. In addition, the groove 21 may have three or more recesses 22.

[0060] Figures 12(a) to (h) show several examples of the recess 22. In the examples shown in Figures 12(a) to (d), the recess 22 is recessed from the first bottom surface 210 toward the second side z2 in the first direction z, and extends beyond the first extension line L1 from region Ar. The cross-sectional shape of the recess 22 shown in Figure 12(a) is a trapezoid in which the size in the third direction r increases as it approaches the second side z2 in the first direction z. The cross-sectional shape of the recess 22 shown in Figure 12(b) is recessed from the first bottom surface 210 substantially parallel to the first direction z. The cross-sectional shape of the recess 22 shown in Figure 12(c) is substantially semicircular. The recess 22 shown in Figure 12(d) is located away from the first side surface 211 toward the second side r2 in the third direction r.

[0061] The recesses 22 shown in Figures (e) to (g) protrude from region Ar in the third direction r. The cross-sectional shape of the recess 22 shown in Figure (e) is a recess that is substantially parallel to the third direction r from the first side surface 211. The cross-sectional shape of the recess 22 shown in Figure (f) is substantially semi-elliptical. The recess 22 shown in Figure (g) is located away from the first bottom surface 210 on the first side z1 in the first direction z.

[0062] The recess 22 shown in Figure (h) is a single recess 22 that extends beyond both the first extension line L1 and the second extension line L2 from region Ar. This recess 22 is shaped to surround the intersection of the first extension line L1 and the second extension line L2 from the outside of region Ar and is connected to the first bottom surface 210 and the first side surface 211.

[0063] As can be seen from the examples shown in Figures 12(a) to (h), the specific shape, position, size, etc. of the recess 22 are not limited in any way.

[0064] In the seal structures shown in Figures 2 to 6 and Figures 8 to 11, the example described is when the seal material 1 is annular in shape, the first direction z is the axial direction, the second direction θ is the circumferential direction, and the third direction r is the radial direction. However, the seal structure is not limited to this configuration. For example, the seal material 1 may be annular in shape, with the radial direction corresponding to the first direction, the circumferential direction corresponding to the second direction, and the axial direction corresponding to the third direction. In this case, the outer diameter side in the radial direction may correspond to the first side in the first direction, and the inner diameter side may correspond to the second side in the first direction. For example, a first object to be sealed 2, such as a cylinder, may be located on the second side (inner diameter side) in the first direction (radial direction), and a second object to be sealed 3, such as a cylindrical shape, may be located on the first side (outer diameter side) surrounding the first object to be sealed 2. The first object to be sealed 2 has a groove 21 formed in the first main surface 20, which is the outer circumferential surface, that is recessed in the second side (inner diameter side) in the first direction (radial direction), and the sealing material 1 is housed in this groove 21.

[0065] The seal structure according to the present invention is not limited to the embodiments described above. The specific configuration of each part of the seal structure according to the present invention can be modified in various ways.

[0066] A1, A11, A12, A2, A21, A3, A31, A4, A41, A42, A43: seal structure, Ar: region, 1: seal material, 2: first object to be sealed, 2A: first member, 2B: second member, 3: second object to be sealed, 20: first main surface, 21: groove, 22: recess, 30: second main surface, 210: first bottom surface, 211: first side surface, 212: second side surface, 220: second bottom surface, 221: third side surface, 222: fourth side surface, H1, H2: depth, L1: first extension line, L2: second extension line, L3: third extension line. Long line, R1: inner diameter, W1, W2: opening width, α1, α2: angle, z: first direction, θ: second direction, r: third direction, r1: first side (outer diameter side), r2: second side (inner diameter side)

Claims

1. A first object to be sealed having a first main surface facing a first side in a first direction and a groove recessed from the first main surface toward a second side in the first direction; a second object to be sealed having a second main surface facing the second side in the first direction, facing the first main surface, and closing the groove; and a sealing material having a circular or elliptical cross-sectional shape, housed in the groove, and in contact with the second main surface, wherein each groove has a surface that contacts the sealing material, a first bottom surface located toward the second side in the first direction relative to the sealing material and facing the first side, and a first side surface located toward the first side and a second side surface located toward the second side relative to the sealing material in a third direction perpendicular to the first direction and the second direction in which the sealing material extends. The groove portion further has a recess that protrudes from the region enclosed by a first extension line extending the portion of the first bottom surface that contacts the sealing material, a second extension line extending the portion of the first side surface that contacts the sealing material, and a third extension line extending the portion of the second side surface that contacts the sealing material, in a cross section perpendicular to the second direction.

2. The seal structure according to claim 1, wherein at least one of the first side surface and the second side surface is inclined with respect to the first direction such that the distance between the first side surface and the second side surface in the third direction decreases as it approaches the first side in the first direction, and the region is triangular.

3. The seal structure according to claim 2, wherein the seal material is annular when viewed in the first direction, the third direction is the radial direction of the seal material, the first side in the third direction is the outer diameter side, and the second side in the third direction is the inner diameter side.

4. The seal structure according to claim 3, wherein the recess is located on the first side in the third direction with respect to the sealing material.

5. The seal structure according to any one of claims 1 to 4, wherein the recess is recessed from the first bottom surface toward the second side in the first direction.

6. The seal structure according to any one of claims 1 to 4, wherein the recess is recessed in the third direction from the first side surface or the second side surface.

7. The sealing structure according to any one of claims 1 to 4, wherein the first object to be sealed includes a first member having a first bottom surface and a second member having at least one of the first side surface and the second side surface.

8. The sealing structure according to any one of claims 1 to 4, wherein, at the initial temperature when the sealing material, the first object to be sealed, and the second object to be sealed are combined, the sealing material is in contact with the first main surface, the first side surface, and the second side surface, and is away from the recess, and there exists a temperature higher than the initial temperature at which the sealing material is in contact with the first main surface, the first side surface, and the second side surface, and a portion of the sealing material enters the recess.

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