JP7474632B2 - Sealing material - Google Patents

Description

The present invention relates to a sealing member.

Seal members are used in various machine elements to achieve desired functions such as airtightness or liquid tightness. As an example of such a seal member, a seal member used in a rotary valve is known. For example, a seal member disclosed in Patent Document 1 is shown in FIG. 8. The seal member 177 shown in FIG. 8 is provided so as to extend toward the rotor 101 housed in the rotor housing space formed by the casing 102. More specifically, the seal member 177 is disposed in the opening 125a that opens toward the rotor housing space. The seal member 177 has a cylindrical portion that abuts against the inner peripheral surface of the opening 125a, and a tip abutment portion 180 that protrudes from one end of the cylindrical portion and abuts against the rotor 101. The tip abutment portion 180 has an inner curved portion 181 that narrows inward toward the tip side and is curved so as to be folded back. In this way, the seal member 177 abuts against the rotating rotor 101 at the tip abutment portion 180, sealing the gap between the sliding rotor 101 and the opening 125a. The cylindrical portion of the seal member 177 serves as a path for cooling water to the rotor 101, for example.

JP 2013-245737 A

The portion of the sealing member that is pressed against the rotor as described above needs to be able to slide as well as seal against the rotor. It can be said that sealing and sliding are contradictory properties. For example, the aforementioned Patent Document 1 describes forming the sealing member 177 from a resin member with a relatively low coefficient of friction. If the sealing member 177 is formed from a resin member with a relatively low coefficient of friction, there is a risk that the sliding properties will be sufficient but the sealing properties will be insufficient.

Therefore, one aspect of the present invention aims to realize a sealing member that combines sealing properties and sliding properties.

In order to solve the above problem, the sealing member according to one embodiment of the present invention has a first ridge portion that is elastic and has a ring-shaped planar shape, a second ridge portion that is elastic and has a ring-shaped planar shape and is adjacent to the first ridge portion, a recess that has a ring-shaped planar shape formed between the first ridge portion and the second ridge portion, and a slippery protrusion that is made of a slippery material that has a lower friction coefficient than the first ridge portion and the second ridge portion, is supported by the recess, and is arranged in a ring shape when viewed in a plane.

According to one aspect of the present invention, it is possible to provide a sealing member that combines sealing properties and sliding properties.

FIG. 2 is a partial cross-sectional view of a seal member according to the first embodiment of the present invention. 1 is a perspective view showing an external appearance of a sealing member according to a first embodiment of the present invention. FIG. 2 is a partial cross-sectional view showing a state in which the sealing member according to the first embodiment of the present invention is sealing. FIG. 2 is a plan view of the seal member according to the first embodiment of the present invention. FIG. 6 is a partial cross-sectional view of a seal member according to a second embodiment of the present invention. FIG. 11 is a partial cross-sectional view showing a state in which a sealing member according to a second embodiment of the present invention is sealing FIG. 11 is a plan view of a seal member according to a third embodiment of the present invention. FIG. 1 illustrates the prior art.

[Embodiment 1]
Hereinafter, one embodiment of a seal member according to the present invention will be described with reference to FIGS.

(Configuration of sealing member)
First, the appearance of the seal member of the present embodiment 1 will be described. Fig. 2 is a perspective view showing the appearance of the seal member 1A of the present embodiment 1. The seal member 1A can be made of an elastic material, and by bringing a part of the seal member into contact with the object to be sealed, the sealability is realized in the contact area.

As shown in FIG. 2, the sealing member 1A has a main body 10 having an overall cylindrical structure. The upper surface 10a of the main body 10 is annular in plan view, and has a curved surface that corresponds to a part of a sphere that is deeply recessed at the position of the central axis C of the main body 10 shown in FIG. 2. Note that the shape of the main body 10 is not limited to this, and it is sufficient if it matches the three-dimensional shape of the surface so as to generally follow the surface of the object to be sealed. Therefore, the annular upper surface 10a may have a flat surface.

The sealing member 1A has, on the upper surface 10a, a first protrusion 11 that is elastic and has a ring-shaped planar shape, a second protrusion 12 that is elastic and has a ring-shaped planar shape and is adjacent to the first protrusion 11, and a slippery protrusion 30 that is formed between the first protrusion 11 and the second protrusion 12 and is arranged in a ring shape when viewed in a plane.

The first ridge portion 11 has an annular planar shape centered on the central axis C. The second ridge portion 12 also has an annular planar shape centered on the central axis C, and is formed outside the first ridge portion 11. The slippery protrusion 30 also has an annular planar shape centered on the central axis C, and is disposed outside the first ridge portion 11 and inside the second ridge portion 12.

The sealing member 1A will be described in further detail with reference to FIG. 1. FIG. 1 is a cross-sectional view showing the sealing member 1A cut along the cutting line A-A' shown in FIG. 2.

As shown in FIG. 1, the sealing member 1A has a first protrusion 11 and a second protrusion 12 protruding upward on the upper surface 10a of the main body 10. Here, "upward" refers to the positive direction of the Z axis in a three-dimensional coordinate system consisting of XYZ coordinates in which the Z axis is perpendicular to the XY plane when the upper surface 10a is considered to be a plane and the plane is assumed to be the XY plane. The Z axis is generally parallel to the central axis C. The first protrusion 11 and the second protrusion 12 may protrude generally straight upward, or may form a V-shape by expanding in a direction away from each other toward the protruding end. There is no particular limit to the protruding length H (FIG. 1) of the first protrusion 11 and the second protrusion 12 from the upper surface 10a, but in this embodiment 1, the protruding ends of the first protrusion 11 and the second protrusion 12 protrude upward from the upper end of the slippery convex portion 30. In other words, there is a difference Δd between the height of the protruding ends of the first ridge portion 11 and the second ridge portion 12 and the height of the upper end of the smooth convex portion 30.

Between the first ridge 11 and the second ridge 12, a recess 13 having a ring-shaped planar shape is provided. The recess 13 has a shape that is recessed below the upper surface 10a, and the slippery protrusion 30 is fitted into the recess 13. This allows the slippery protrusion 30 to be reliably supported by the main body 10. However, this is not limited to this form, and the bottom of the recess 13 may be located in the same plane as the upper surface 10a.

The main body 10, including the first ridge 11 and the second ridge 12, can be made of a material that has elasticity and a higher coefficient of friction than the smooth convex portion 30. For example, the material of the main body 10 can be a normal rubber material. The elasticity of the main body 10 can be determined appropriately depending on the application of the sealing member 1A.

The "friction coefficient" is defined as JIS K7125. The friction coefficient of the main body 10, including the first ridge 11 and the second ridge 12, can be appropriately determined within a range in which the main body 10 exhibits sufficient relative slipperiness according to the application of the seal member 1A. For example, when used to seal a sliding surface, it may be appropriately determined within a range of 0.04 to 0.5.

Specific examples of the main body 10 that satisfy these conditions include general rubber materials and various resin materials. These materials can be selected appropriately depending on the intended use.

The slippery protrusion 30 is a separate member from the main body 10 and is supported by the recess 13. Specifically, the slippery protrusion 30 is disposed between the annular first protrusion 11 and second protrusion 12 by fitting into the recess 13. In addition to fitting the slippery protrusion 30 into the recess 13, the slippery protrusion 30 may also be fixed to the surface of the recess 13 using an appropriate adhesive.

As shown in FIG. 1, the smooth protrusion 30 has a circular cross-sectional shape. The diameter of the cross section is slightly larger than the width of the recess 13 when the smooth protrusion 30 is not engaged, i.e., the distance between the first protrusion 11 and the second protrusion 12. Therefore, the smooth protrusion 30 engages with the recess 13 by slightly expanding the recess 13. Here, in the embodiment in which the first protrusion 11 and the second protrusion 12 form a V-shape as described above, the first protrusion 11 and the second protrusion 12 may protrude upward in parallel before the smooth protrusion 30 engages with the recess 13. Then, the first protrusion 11 and the second protrusion 12 may form a V-shape by expanding the recess 13 due to the engagement.

Figure 3 is a plan view of the sealing member 1A as viewed from the upper surface 10a side. As shown in Figure 3, the slippery protrusion 30 is an annular member that is overlaid on the recess 13. However, it does not have to be an annular member, and may be another form as shown in embodiment 3 described later. In addition, in this embodiment 1, the cross-sectional shape of the slippery protrusion 30 is circular as shown in Figure 1, but is not limited to this shape. For example, the cross-sectional shape may be rectangular, such as a square or hexagon including a trapezoid, or the cross section may be elliptical. In addition, the slippery protrusion 30 may be hollow.

The slippery protrusions 30 are composed of a slippery material having a lower coefficient of friction than the first ridges 11 and the second ridges 12. The coefficient of friction of the slippery protrusions 30, like that of the main body 10, can be appropriately determined within a range in which the slippery protrusions 30 exhibit sufficient slipperiness with respect to at least one of the working surface and the main body 10 according to the application of the seal member 1A. For example, if the application is to seal a sliding surface, the friction coefficient of the slippery protrusions 30 may be appropriately determined within a range of 0.04 to 0.5.

The lubricant here can be defined as a material that has lubricity relative to the surface of the object to be sealed, but may also be a material that has lubricity relative to the surface of the recess 13. Specific examples of the lubricating protrusion 30 include fluororesins such as polytetrafluoroethylene, as well as resins containing self-lubricating materials such as polyacetal, polyamide, polyolefin, silicone, and elastomers. Of these, it is preferable to use fluororesins because they have sufficient lubricity and strength.

The lubricating protrusion 30 is a single member made of the material exemplified above, but this is not a limited form of the present invention. For example, the lubricating material exemplified above may be attached in the form of a film to the surface of a ring-shaped base material.

The sealing member 1A of this embodiment 1 seals the object to be sealed by abutting it against the upper surface 10a, but allows the object to slide while being sealed. For example, as shown in FIG. 1, the sealing member 1A having the curved upper surface 10a is an appropriate sealing member for objects to be sealed, such as pipes or valves having a pipe axis perpendicular to the central axis C. The sealing member 1A is provided with the first protrusion 11 and second protrusion 12 described above, as well as the slippery convex portion 30, thereby realizing the sealing ability to the object to be sealed and the sliding ability of the object to be sealed. This will be explained below with reference to FIG. 4.

(Contacting the object to be sealed)
FIG. 4 is a partial cross-sectional view showing a state where the seal member 1A is abutted against the surface 400 of the object to be sealed. When the seal member 1A is pressed against the surface 400 with the upper surface 10a of the main body 10 facing the surface 400, the protruding ends of the first protrusion 11 and the second protrusion 12 first abut against the surface 400. Accordingly, the elastic first protrusion 11 and the second protrusion 12 are deformed so that the protruding length H becomes shorter (compared to before the abutment). At this time, the protruding ends of the first protrusion 11 and the second protrusion 12 are also deformed in a direction away from each other. This is shown in FIG. 4 as the first protrusion 11' and the second protrusion 12' after deformation. In the cross-sectional view shown in FIG. 4, two seal regions S are formed between the first protrusion 11' and the second protrusion 12' after deformation and the surface 400.

As shown in FIG. 4, the first ridge 11' and the second ridge 12' are deformed, and the slippery protrusions 30, which were buried in the first ridge 11 and the second ridge 12 before contact, are exposed and come into contact with the surface 400. As described above, the slippery protrusions 30 are made of a lubricant with a low coefficient of friction, so that in this contact area, the object to be sealed tends to slide in the planar direction of the surface 400. Hereinafter, this contact area is referred to as the sliding promotion area R, where sliding is promoted. The slippery protrusions 30 may slide within the recesses 13.

In short, according to the sealing member 1A of this embodiment 1, a sliding promotion region R is formed between two sealing regions S on the surface 400 of the object to be sealed, so that it is possible to achieve both sealing properties and sliding properties while having a relatively simple configuration.

(Method of manufacturing the sealing member)
The sealing member 1A of this embodiment 1 can be manufactured by manufacturing the main body 10 by injection molding or the like, and then fitting an annular slippery convex portion 30, which has been prepared in a separate process, into the concave portion 13 of the main body 10.

(Regarding adjustments)
1, in the seal member 1A of the present embodiment 1, the first protrusion 11 and the second protrusion 12 protrude beyond the slippery convex portion 30. Therefore, the strength of the sealability can be adjusted by adjusting the degree of contact with the surface of the object to be sealed.

Specifically, when the sealing member 1A is brought into relatively light contact with the surface of the object to be sealed, the slippery convex portion 30 does not come into contact with the surface, and only the first protrusion portion 11 and the second protrusion portion 12 come into contact, resulting in the sealing member 1A having a relatively loose sealing property.

Conversely, when the seal member 1A is pressed relatively firmly against the surface of the object to be sealed, the first ridge portion 11 and the second ridge portion 12, which have a large frictional resistance, deform and become more resistant to the surface. On the other hand, the lubricating protrusions 30 also come into contact with the surface, forming a sliding promotion area and promoting sliding.

The degree of contact can be adjusted, for example, by providing a screw thread on the outer surface of the main body 10 shown in FIG. 1. That is, the seal member 1A is configured as a male screw, which is screwed into a component including a female screw provided at a position facing the surface of the object to be sealed, and the degree of screwing is adjusted. This allows the desired sealing and sliding properties to be achieved.

[Modifications]
The first protrusion portion 11 and the second protrusion portion 12 may be formed from a member separate from the main body portion 10. When formed from a member separate from the main body portion 10, the first protrusion portion 11 and the second protrusion portion 12 may be formed from the materials exemplified above, in which case there are no limitations on the material forming the main body portion 10.

Furthermore, it is not necessary that the entire first ridge portion 11 and the second ridge portion 12 are made of a material having a higher coefficient of friction than the smooth convex portion 30. For example, it is sufficient that at least the protruding ends and their vicinity on the surfaces of the first ridge portion 11 and the second ridge portion 12 are made of a material having a higher coefficient of friction than the smooth convex portion 30. In other words, the elastic first ridge portion 11 and the second ridge portion 12 and their surfaces may be made of different materials, and only the protruding ends and their vicinity on the surfaces may be made of a material having a higher coefficient of friction than the smooth convex portion 30.

[Embodiment 2]
Another embodiment of the present invention will be described below with reference to Figures 5 and 6. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

Figure 5 is a partial cross-sectional view of a sealing member 1B of the second embodiment. The state shown in Figure 5 corresponds to the state shown in Figure 1 of the first embodiment.

As shown in FIG. 1, in the sealing member 1A of the above-mentioned embodiment 1, the first ridge portion 11 and the second ridge portion 12 protrude beyond the slippery protrusion portion 30. In contrast, in the sealing member 1B of the present embodiment 2, when not in contact with the object to be sealed, the slippery protrusion portion 30 protrudes beyond the first ridge portion 21 and the second ridge portion 22. Here, the first ridge portion 21 and the second ridge portion 12 differ from the first ridge portion 11 and the second ridge portion 12 of embodiment 1 only in their shape and their relative positional relationship with the slippery protrusion portion 30. In FIG. 5, the difference in the amount of protrusion between the slippery protrusion portion 30 and the first ridge portion 21 and the second ridge portion 22 is indicated by △d'.

In the sealing member 1B, the upper surface of the slippery protrusion 30 and the upper surfaces of the first protrusion 21 and second protrusion 22 are provided in a position protruding from the upper surface 10a of the main body 10. Therefore, when the sealing member 1B is brought into contact with the surface of the object to be sealed, the upper surface of the slippery protrusion 30 and the upper surfaces of the first protrusion 21 and second protrusion 22, rather than the upper surface 10a of the main body 10, come into contact with the surface. This will be explained with reference to FIG. 6.

Figure 6 is a partial cross-sectional view showing the state in which the seal member 1B is in contact with the surface 400 of the object to be sealed. The state shown in Figure 6 corresponds to the state shown in Figure 4 of the above-mentioned embodiment 1. When the seal member 1B is pressed against the surface 400 with the upper surface 10a of the main body 10 facing the surface 400, the slippery protrusions 30 first come into contact with the surface 400. When pressed further, the slippery protrusions 30 are deformed and the contact area with the surface 400 (sliding promotion area R) is expanded while being pushed toward the bottom of the recess 13, and the upper surfaces of the first protrusions 21 and the second protrusions 22 come into contact with the surface 400. The elastic first protrusions 21 and the second protrusions 22 are deformed with the contact so that the protrusion length H' becomes shorter (than before the contact) (Figure 6 shows the first protrusions 21' and the second protrusions 22' after deformation).

As a result, similar to the sealing member 1A of embodiment 1, two sealing regions S and a sliding promotion region R between them are formed on the surface 400 of the object to be sealed.

In other words, the sealing member 1B has a relatively simple structure yet is capable of providing both sealing and sliding properties.

[Embodiment 3]
Another embodiment of the present invention will be described below with reference to Fig. 7. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

Figure 7 is a plan view of the sealing member 1C of the third embodiment. The state shown in Figure 7 corresponds to the state shown in Figure 3 of the first embodiment. In the sealing member 1A of the first embodiment, the slippery protrusion 30 made of an annular member is supported by the recess 13, whereas in the third embodiment, each of the multiple balls 33 made of a slippery material is supported by the recess 13 to form the slippery protrusion 30'.

Each ball 33 is manufactured in a separate process from the manufacturing process of the main body 10, and is fitted into a recess 13 that is formed in a ring shape in a plan view to form a continuous ring, thereby manufacturing the lubricating protrusion 30'. In FIG. 7, the balls 33 are in contact with each other, but this is not limited thereto, and they may be spaced apart from each other. The balls 33 may also be hollow.

The diameter of each ball 33 may be configured to be equal to the diameter of the circular cross section of the lubricating protrusion 30 of embodiment 1. The balls 33 may be configured from the same material as the lubricating protrusion 30 of embodiment 1. As in embodiment 1, the balls 33 do not need to be made of a single member, and may be configured to have a core enclosed within a material having lubricity.

When the sealing member 1C of this embodiment 3 comes into contact with the surface of the object to be sealed, it is in the same state as shown in FIG. 4, and two sealing regions S and a sliding promotion region R between them are formed on the surface 400 of the object to be sealed. In this state, at least one ball 33 may rotate within the recess 13 as the object to be sealed slides. This further promotes the sliding properties of the object to be sealed.

Furthermore, the recess 13 into which the ball 33 fits is composed of an elastic main body 10. Therefore, when the pressure from the object to be sealed is strong and varies, the ball 33 is pressed against the recess 13 with high pressure. However, the strong and fluctuating pressure from the object to be sealed is absorbed by the recess 13 that receives the ball 33, and is also absorbed by the elasticity of the ball 33 itself. Therefore, in this embodiment, even when the pressure from the object to be sealed is strong and varies, it is expected to exhibit sufficient sealing and sliding properties while also exhibiting high durability.

As described above, the sealing member 1C of this embodiment 3 has a relatively simple configuration, yet is capable of providing both sealing properties and sliding properties.

〔summary〕
A seal member according to a first aspect of the present invention includes a first ridge portion that is elastic and has an annular planar shape, a second ridge portion that is elastic and has an annular planar shape and is adjacent to the first ridge portion, a recess portion that is formed between the first ridge portion and the second ridge portion and has an annular planar shape, and a slippery protrusion portion that is made of a slipping material having a lower friction coefficient than the first ridge portion and the second ridge portion, is supported by the recess portion, and is arranged in an annular shape in a plan view. The configuration of the first aspect makes it possible to provide a seal member that achieves sealing performance for an object to be sealed without impairing the sliding properties of the object to be sealed.

In the sealing member according to aspect 2 of the present invention, in the configuration of aspect 1, the lubricating convex portion may be an annular member that overlaps the concave portion when viewed in a plan view. This allows the sealing property to be exhibited by surrounding a partial area of the object to be sealed, while at the same time allowing the sliding property to be exhibited in a ring shape surrounding that area.

In the sealing member according to aspect 3 of the present invention, in the configuration of aspect 1, the lubricating protrusions may be configured by supporting each of a plurality of balls made of the lubricant in the recesses. This allows the sealing properties to be exhibited by surrounding a portion of the area of the object to be sealed, while at the same time allowing the sliding properties to be exhibited in a ring shape surrounding that area.

In the sealing member according to aspect 4 of the present invention, in the configurations of aspects 1 to 3, the lubricant may be a fluororesin. This makes it possible to provide a sealing member having a lubricating protrusion with excellent durability.

1A, 1B, 1C Seal member 10 Body portion 10a Upper surface 11, 21 First protrusion portion 12, 22 Second protrusion portion 13 Recess 30, 30' Slippery protrusion portion 33 Ball

Claims (2)

a first protrusion portion having elasticity and an annular planar shape;
a second protrusion portion having elasticity and an annular planar shape, the second protrusion portion being adjacent to the first protrusion portion;
a recess having an annular planar shape formed between the first protrusion portion and the second protrusion portion;
a lubricating protrusion formed of a lubricating material having a lower friction coefficient than the first protrusion and the second protrusion, supported by the recess, and arranged in an annular shape in a plan view;
A sealing member, wherein the lubricating convex portion is formed by a plurality of balls made of the lubricant being supported in the recesses. The seal member according to claim 1 , wherein the lubricant is a fluororesin.

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