JP2020020358A - Seal ring - Google Patents

Abstract

To provide a seal ring that is excellent in hermetically sealing performance in a use condition where use temperature varies between high temperature and room temperature.SOLUTION: A seal ring includes: an annular resin seal ring body (1) having an abutment part (5) in one part of the circumference; and a C-shaped metal spring (11) laid at an inner peripheral surface (2) of the seal ring body (1). The metal spring (11) comes into contact with the seal ring body (1) over 285° or more out of 360° of the whole inner circumference.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a seal ring.

Conventionally, a seal ring composed of a resin seal ring main body and a metal spring that urges the seal ring main body in the radial direction has a structure as shown in FIG. At low temperatures, the metal spring 43 maintained stable sealing performance as long as the seal ring main body 41 was urged in the radial direction. Incidentally, as shown in FIG. 12, the metal spring 43, a straight spring wire material 43A having a predetermined length, elastically while applying an external force as indicated by an arrow M _43, M ₄₃ shown in FIG. 12 (B) curve Then, as shown in FIG. 12A, it was fitted so as to be in contact with the inner peripheral surface 42 of the resin seal ring main body 41.
Further, as a prior art, there is Patent Document 1, for example.

Japanese Utility Model Publication No. Hei 2-18964

However, for the purpose of reducing the weight of the seal ring itself having the structure shown in FIG. 12 and the weight of a product incorporating the seal ring, a temperature higher than the glass transition temperature of the resin of the resin seal ring body 41, Even under a temperature environment that changes between low temperatures, use of a seal ring in which the seal ring main body 41 is made of resin has increased.
Under the use environment where such a temperature change occurs, the following problems occur.
This is because when the resin seal ring main body 41 is at a temperature higher than the glass transition temperature, creep occurs and the metal spring 43 is contacted (biased) with the metal spring 43, and the glass spring 43 is not contacted (biased). When the temperature became lower than the transition temperature, the degree of thermal shrinkage of the seal ring main body 41 was different, and a gap was formed between the surface to be sealed and the seal ring.

  As described above, the present invention suppresses the amount of fluid leakage even when the use environment temperature changes between a high temperature exceeding the glass transition temperature of the resin of the seal ring main body and a temperature lower than the glass transition temperature. It is an object of the present invention to provide a seal ring that can be used.

Therefore, according to the present invention, a resin-made seal ring main body having an abutment portion at one circumferential position is fitted to the inner peripheral surface of the seal ring main body so as to radially outwardly come into contact with an elastic biasing force. A seal ring having a C-shaped metal spring; used in a temperature environment that undergoes a temperature change between a high temperature equal to or higher than the glass transition temperature of the resin of the seal ring body and a temperature lower than the glass transition temperature. The seal ring body has a true circular shape when the abutment is closed; and the metal spring has at least 285 ° of the entire 360 ° inner circumference of the seal ring body when the abutment of the seal ring body is closed. Contact at a contact center angle of.
The cross-sectional shape of the metal spring is rectangular.

  According to the present invention, between a high temperature exceeding the glass transition temperature of the resin of the seal ring main body and a temperature lower than the glass transition temperature, in an operating temperature environment in which the temperature changes, the amount of leakage of the fluid to be sealed Can be sufficiently suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows one Embodiment of this invention, (A) is a front view of a free state, (B) is a top view, (C) is a schematic structure explanatory drawing. It is a figure which shows the use condition which reduced the whole diameter to the outer diameter dimension corresponding to the inner diameter dimension of the circular inner peripheral surface for sealing, (A) is a front view, (B) is a top view. It is the figure which showed the whole shape of the single article in a free state, (A) is a front view of a seal ring main body, (B) is a front view of a metal spring. 3A and 3B are diagrams illustrating the entire shape of a single product in the use state of FIG. 2, wherein FIG. 3A is a front view of a seal ring main body, and FIG. 3B is a front view of a metal spring. It is explanatory drawing, (A) is a principal part enlarged sectional explanatory view in a use state, (B) is a simplified front explanatory view of a metal spring, and (C) is a principal part enlarged sectional explanatory view in a use state of another embodiment. It is. (Aa), (bb), (cc), (dd), (ee), (ff), (gg), (hh), (jj), (k) in FIG. It is each enlarged sectional view of -k). FIG. 7 is an enlarged cross-sectional view corresponding to each part shown in FIGS. 2 and 6 in another embodiment shown in FIG. 5C. FIG. 4 is a graph illustrating that the contact surface pressure P at which the outer peripheral surface of the seal ring of the present invention presses against the circular inner peripheral surface to be sealed changes with the use time N. It is the figure which showed the whole shape in the free state of other embodiment, (A) is a front view of a seal ring, (B) is a front view of a metal spring. It is a figure which shows a leak test apparatus, (A) is a partial cross-section front view, (B) is an enlarged explanatory view which shows the dimension of the principal part. FIG. 4 is a graph showing the length of a metal spring on the horizontal axis and the amount of increase in leakage on the vertical axis. It is a figure which shows a prior art example, (A) is a front view of the seal ring of a free state, (B) is a front view which shows the state before assembling of a spring wire.

Hereinafter, the present invention will be described in detail based on the illustrated embodiments.
As shown in FIGS. 1 to 4, a seal ring S according to the present invention includes a seal ring main body 1 made of an annular resin having an abutment (cut) 5 at one circumferential position, and an annular shape. A metal spring 11 having a C shape in a plan view is fitted so as to contact (contact) the inner peripheral surface 2 of the seal ring main body 1 with a radially outward urging force.

The cross-sectional shape of the metal spring 11 is circular.
As shown in FIGS. 1 and 2, when the metal spring 11 is fitted (attached) to the seal ring main body 1, the metal spring 11 also has a cut 15 at one circumferential position, and the overall shape is C. Shape.

  As shown in FIG. 5A, a groove 10 having a triangular cross section is formed on the inner peripheral surface 2 of the seal ring main body 1. A metal spring 11 is fitted in the concave groove 10. The cross-sectional shape of the concave groove 10 is free, such as rectangular, trapezoidal, or arc-shaped (not shown). Reference numeral 20 denotes a fixing member such as a cylinder barrel (cylinder tube) or a casing of various fluid machines (such as a pump and a valve). The fixing member 20 has a circular hole 21. It is slidably pressed against the inner peripheral surface 21A of the slab 21.

The sealed fluid is a gas such as air or various gases, or a liquid such as hydraulic oil. In the present invention, in particular, in the present invention, the temperature of the resin of the seal ring main body 1 is determined based on the glass transition temperature of the resin. This is suitable when the temperature changes between a high temperature and a temperature lower than the glass transition temperature of the resin of the seal ring main body 1. More preferably, in a temperature environment in which the temperature changes between a temperature higher than the glass transition temperature of the resin of the seal ring main body 1 and around room temperature (20 ° C.) which is a temperature lower than the glass transition temperature of the resin of the seal ring main body 1. More preferably, a temperature that changes between a temperature higher than the glass transition temperature of the resin of the seal ring main body 1 and a low temperature (−60 ° C.) which is lower than the glass transition temperature of the resin of the seal ring main body. Environment.
The glass transition temperature of the resin is measured using a differential scanning calorimeter (DSC).
It was measured in.

In FIG. 5A, a seal groove 22 having a rectangular cross section is formed in a reciprocating member such as a piston 23, and a seal ring S according to the present invention is mounted in the seal groove 22. ing.
As shown in a simplified diagram in FIG. 1 (C), in the seal ring S of the present invention, the abutment portion 5 of the seal ring main body 1 and the cut 15 of the metal spring 11 have the same circumferential position.

As shown in FIG. 1 (A), the seal ring S according to the present invention has a seal ring main body 1 in a free state of a completed product in which a metal spring 11 is mounted on the inner peripheral surface 2 of the seal ring main body 1. the central point of the first abutment portion 5 (the center point) P _5, a range of 180 ° ± 30 °, the radius of curvature R ₁₃ is present site 13 of maximum dimension.
That is, the angle θ that shown in FIG. 1 (A) is ± 30 °, the portion 13 of maximum dimension R ₁₃ in the range of 2 [Theta] = 60 °, are provided. The largest portion 13 of the dimension R _13, the center angle of the central point O ₁ around may be selected in the range of 1 ° to 60 °. In FIG. 1A, L ₀ is a line (diameter line) indicating the diameter including the center point P ₅ .

More specifically, the radii of curvature R ₁ , R ₂ gradually decrease from the portion 13 having the largest dimension toward each of the first end 6 and the second end 7 in the circumferential direction M ₁ , M _2. Thus, the radii of curvature R ₆ and R _{7 of} the first end 6 and the second end ₇ are set to the minimum dimensions.
In FIGS. 1 to 4 and 6, the first end portion 6 and the second end portion 7 of the seal ring main body 1 have a first convex portion 8 and a second convex portion whose cross sections change in a plurality of steps. 9 illustrates a case where the protrusion 9 is provided in the circumferential direction.

Therefore, in the present invention, in order to clearly define the boundaries between the end portions 6 and 7 and the convex portions 8 and 9, the cross-sectional area of the substantially rectangular cross-section (having the concave groove 10) shown in FIG. Portions having a cross-sectional area of less than 60% are referred to as convex portions 8 and 9. That is, in FIG. 6 and (FIG. 2A described later), the first end 6 extends to the (dd) cross section, and becomes the first convex portion 8 in the (ee) cross section. Is between (dd) and (ee). In addition, the boundary between the second end 7 and the second convex portion 9 exists between the (hh) cross section and the (gg) cross section.
Note that the fitting of the first convex portion 8 and the second convex portion 9 that changes in a plurality of stages does not generate a radially penetrating gap, thereby preventing (reducing) fluid leakage in the radial direction. There is.

Incidentally, as described above, the curvature radii R ₆ and R _{7 of} the first end portion 6 and the second end portion 7 are set to the minimum dimensions. 8. The radius of curvature of the outer peripheral surface of the second convex portion 9 is the same as the radius of curvature R ₆ · R ₇ .
Then, as shown in FIG. 2, the metal spring 11 is assembled so as to be in contact with (the concave groove 10 of) the inner peripheral surface 2 of the seal ring main body 1, and the seal ring S is attached (as shown in FIG. 5). a) When diameter to the inner diameter dimension D ₂₁ corresponding to (equal to each other) outside diameter D ₀ of the sealing circular inner peripheral surface 21A, a perfect circle having the same radius R ₀ from the center point O _1. That is, as shown in FIG. 5, the circular inner peripheral surface 21A comes into close contact with the circular inner peripheral surface 21A over 360 °.

As described above, when the seal ring S is elastically deformed from the free state in FIG. 1A to the seal use state in FIG. 2A, the portion 13 having the largest dimension is the largest and the radius of curvature is reduced. The first and second end portions 6 and 7 and the first and second convex portions 8 and 9 are hardly deformed, and the radius of curvature R ₀ shown in FIG. The curvature radii R ₆ and R ₇ of the ends ₆ and ₇ are equal to each other.

The seal ring body 1 is, in a single pre-assembled, the free state of FIG. 3 (A), when to shrink deformation (see FIG. 4 (A)) to the outer diameter D ₀ of the aforementioned corresponding to FIG. 2, It exerts a resilient biasing force in the expanding direction.
In addition, as shown by the two-dot chain line in FIGS. 3 (B) and 4 (B), the metal spring 11 alone has a first cut in which the cut 15 is largely opened in a free state as shown in FIGS. 3 (B) and 4 (B). If the cut 15 shown in the solid line in FIG. 4B (corresponding to FIG. 2) is changed to the smaller open second cut from the open state, the metal spring 11 made of metal can move in the radially expanding direction. Demonstrate the repulsive force.

As described above, when the two parts, that is, the ring main body 1 and the metal spring 11 are assembled into a completed seal ring S as shown in FIGS. There, as shown in FIG. 5 (a), when mounting using the circular inner peripheral surface 21A is an example of a specific means for the outer diameter D ₀ and the true circle will be described below.

As shown in FIG. 3 (A), the shape of the ring body 1 in the unassembled state is a non-circular shape in a free state, and as shown in FIGS. 5 and 4, the inner diameter of the circular inner peripheral surface 21A in the state in which the same outer diameter D ₀ and D _21, a true circle with a radius R ₀ '. Note that R ₀ ′ = D _0/2 .
Further, the cross-sectional shape of the metal spring 11 is, for example, a circular wire spring as shown in FIG. 5 (A), and the entire shape of the single unit in the free state is, as shown in FIG. radius of curvature in the direction central region M ₁₁ are present site 13B of the largest dimension r _1, the radius of curvature r as the distance from the central region M ₁₁ each tip 16 is sequentially reduced as r _2, r _3, r ₄ Set as follows.

Further, as shown in FIG. 3B, the overall shape of the metal spring 11 in the free state is represented by two straight lines L ₁₆ , connecting the center point Pm of the circumferential central region M ₁₁ and each of the tips ₁₆ . The angle β ₁₆ formed by L ₁₆ is set to be not less than 60 ° and not more than 100 °, and the both ends 16, 16 are C-shaped with open legs.
As described above, as shown in FIG. 3B, the radius of curvature increases from r ₁ to r ₂ , r ₃ as approaching each of the tips 16, 16 from the central region M _{11 where} the portion 13 B having the maximum dimension r ₁ exists. , with successively decreasing with r _4, the curvature center point G ₁ of the largest dimension r ₁ is present on the symmetrical center line Lm, the curvature radius r ₂ for sequentially reduced, r _3, r curvature center point G ₂ of _4, G ₃ and G ₄ move away from the left-right symmetric center line Lm.

In such a free state, the open leg C-shaped metal spring 11 is assembled so as to be in contact with the inner peripheral surface 2 of the seal ring main body 1, and the inner diameter of the circular inner peripheral surface 21A for sealing is sealed. When diameter to the outer diameter D ₀ corresponding to the size D ₂₁ (see FIG. 5 (a)), as shown in FIG. 2, the overall shape of the metal spring 11 is a perfect circle.

As shown in FIG. 4B, since extremely large elastic deformation is possible from a two-dot chain line (free state) to a solid circle (with a radius R ₀ ″), the use state shown in FIG. 2 and FIG. Below, the entire outer peripheral surface of the seal ring main body 1 is uniformly and flexibly pressed against the circular inner peripheral surface 21A to always provide a good sealing action.
In addition, even if the outer peripheral surface of the resin seal ring main body 1 is worn out or its thickness is reduced due to heat or the like, it is possible to maintain a constant contact surface pressure against the circular inner peripheral surface 21A. Possible (excellent followability).

In the state of the outer diameter dimension D ₀ shown in FIG. 2B, the seal ring main body 1 is a perfect circle, and the inner circumferential surface 2 of the seal ring main body 1 The outer peripheral surface can be reliably and uniformly contacted (pressed) without any gap at each position in the circumferential direction.
In the seal ring of the present invention, the metal spring 11 has a contact center angle θ ₂₀ of 285 ° or more of the entire inner circumference 360 ° of the seal ring main body 1 when the abutment 5 of the seal ring main body 1 is in a closed state. Touch with.
In FIGS. 5A and 2, the range in which the outer peripheral surface of the metal spring 11 contacts (presses) the inner peripheral surface 2 (the concave groove 10) of the seal ring main body 1 will be described. When the center angle θ ₂₀ of the inner peripheral surface 2 is displayed, 285 ° ≦ θ ₂₀ ≦ 330 °. More preferably, 300 ° ≦ θ ₂₀ ≦ 330 °.

  In FIG. 4 (A), reference numerals 10E and 10E denote end faces of the groove 10, and each end face in the circumferential direction of the groove 10 is closed to thereby prevent the metal spring 11 from being displaced in the circumferential direction. Acts as a stopper.

However, ambient temperature is, the application --- that is exposed to the glass transition temperature T _G above ambient temperature --- when used with a glass transition temperature T _G above high temperature of the resin of the seal ring main body 1, the The seal ring S according to the invention is adaptable.
That is, when the seal ring main body 1 is in the above-described high-temperature use condition, the decrease in the elastic modulus of the seal ring main body 1 is determined by the radially outward urging force F (see FIG. 5B) by the metal spring 11. , Can assist.

As already described that the seal ring main body 1 is a true circle in the closed state, the radius of (the inner peripheral surface 2 of) the seal ring main body 1 in the closed state is R ₁₁ (see FIG. 4A). 9 (A)). The (average) in the circumferential center region M ₁₁ shown in FIG. 9 (B) mounting the metal spring 11 as shown in the previous 135 ° of (free state) (4:30) ~ 225 ° (7 pm) curvature Assuming that the radius is r ₁ , it is desirable to set the following equation 1 to be satisfied.
0.5 ≦ (R ₁₁ / r ₁ ) ≦ 0.85 [Formula 1]
The following equation 2 is derived from the equation 1.
1.18 · R ₁₁ ≦ r ₁ ≦ 2 × R ₁₁ ...... [Equation 2]

By the way, in the embodiments shown in FIGS. 1, 2, 5 (A) and 6, the metal spring 11 has a circular cross section, but this is shown in FIGS. 5 (C), 7 and 9. As shown, it is also preferable that the cross-sectional shape of the metal spring 11 be rectangular. In the following description of Tables 1 to 6, etc., the former (circular in cross section) may be referred to as “wire spring”, and the latter (rectangular in cross section) may be referred to as “plate spring”. .
Specifically, as shown in FIG. 5 (C), the cross-section is an elongated rectangle (one character type) whose wall thickness t is sufficiently smaller than the width W.

  The rectangular cross section of the metal spring 11 has the following advantages: (i) the contact with the inner peripheral surface 2 of the seal ring main body 1 is in surface contact and is stable; and (ii) the metal spring 11 is fixed. Therefore, there is no need to form the concave groove 10 on the inner peripheral surface of the seal ring main body 1, so that the design of the mold for molding the seal ring main body 1 is not complicated, and (iii) the abutment portion 5 of the seal ring main body 1 The metal spring 11 can also be arranged on the inner peripheral surface, and the joint portion 5 of the seal ring main body 1 is elastically urged radially outward to further prevent fluid leakage from near the joint portion 5 and improve sealing performance. There is an advantage, that can be.

  FIG. 10 shows a test apparatus 60 for actually measuring (increase) the amount of leakage of a fluid (air) described below, and shows a test object (seal ring) 61 such as an example of the present invention and a comparative example. A piston-type holding body 63 having a seal groove 62 for fitting is provided in a (sealed) casing 64, and the casing 64 (although not shown) has a structure in which a ceiling wall 64A can be freely opened and closed and sealed. I do.

The casing 64 has an air inflow hole 65 and an air discharge hole 66, and air at a constant pressure (for example, air pressure of 0.1 MPa) is injected through the inflow hole 65, and is passed through a test object (seal ring) 61. In FIG. 10, the leaked air (from the upper direction to the lower direction in the direction of arrow 67) passes through the air discharge holes 66, and the flow rate is measured by a flow rate measuring device (not shown).
The casing 64 has a short cylindrical space chamber 68 having a circular inner peripheral surface 68A therein. The inner diameter dimension c of the circular inner peripheral surface 68A of the space chamber 68 is 32.01 mm. The gap dimension b (on one side) between the outer peripheral surface 63A of the piston type holding body 63 and the inner peripheral surface 68A is 0.65 mm (actual dimension).
Regarding the seal concave groove 62 of the piston type holding body 63, the groove bottom diameter d is set to 25.55 mm (actual dimension), and the groove width dimension a is set to 2.15 mm (actual dimension).
Using such a test apparatus 60, the leakage amount in Tables 1 to 6 described later is measured.

  Table 1 below shows the increase in the amount of leakage due to creep deformation of each of the examples of the flat spring and the wire spring measured by the test apparatus 60 in FIG. The test conditions were as follows: after 4 cycles between a high temperature (110 ° C.) higher than the glass transition temperature (90 ° C.) and a temperature (20 ° C.) lower than the glass transition temperature (90 ° C.), The amount of increase in the amount of leakage at 0 ° C. (increased amount from the amount of leakage four cycles before) is measured. The same test conditions are used for “increase (amount) of leakage amount” in Tables 2 to 6 described below.

In the above Table 1, the (flat plate spring) refers to the metal spring 11 having a rectangular cross section shown in FIG. 5C (to be described repeatedly), and the “wire spring” refers to the metal spring 11 shown in FIG. The metal spring 11 has a circular cross section shown in FIG.
In Table 1, for example, “0.20 t × 1.6 w × 315 °” means that the thickness t of the rectangular cross section of the metal spring 11 shown in FIG. 1.6 mm, indicating that the contact center angle θ ₂₀ illustrated in FIG. 2 is 315 °. Further, in Table 1, "shape processing" means that a metal spring 11 previously processed into a C-shape (described above) as shown in FIGS. 9B and 3B is used. Is shown. The Young's modulus of all the metal springs 11 is 200,000 N / mm ² .

From Table 1 above, it is understood that the section modulus of the metal spring 11 is desirably 0.0010 to 0.0035 N / mm ⁴ . That is, the increase in leakage amount (average value: Ave.) of the one having a section modulus of 0.0036 N / mm ⁴ (exceeding the upper limit value) suddenly increased to 8.1 liter / min.
Further, if the [section modulus x Young's modulus] of each of the metal spring 11 and the resin seal ring main body 1 is A and B, A is 200 to 700 and B is 6780. (The resin seal ring main body 1 has a section modulus of 2.33 N / mm ⁴ and a Young's modulus of 2910 N / mm ^2. )

In other words, in the seal ring according to the present invention, from Table 1 above, it is preferable that the seal ring main body 1 and the metal spring 11 have the following relationship.
A: Sectional modulus of metal spring 11 × Young's modulus of metal spring 11 B: Assuming that section diameter of resin seal ring main body 1 × Young's modulus of resin seal ring main body 1, the following equation is established.
0.03 ≦ A / B ≦ 0.10 ... [Equation 3]
If it is less than 0.03, it loses the contraction force of the resin, there is a gap in the outer periphery and there is a tendency for leakage to deteriorate, and if it is more than 0.10, the metal spring is hard, so the reaction force inside the spring can be weak and weak. There is a gap at the location and leakage occurs, and the sealing performance tends to decrease.

In addition, as a material of the seal ring main body 1, a material excellent in heat resistance is particularly desirable, but PPS, PES, PEEK and the like can be mentioned. Specifically, as the resin used for the seal ring main body, the glass transition temperature of PPS: 90 ° C. to 95 ° C., the glass transition temperature of PES: 190 ° C. to 225 ° C., and the glass transition temperature of PEEK: 140 ° C. to 145 ° C. Yes, when these resins are used for the seal ring main body, the service temperature (upper limit temperature) of the seal ring is 200 ° C. to 260 ° C.
Further, as a material of the metal spring, for example, SUS304 is preferable, and as can be seen from Table 1, the section modulus of the metal spring is 1 × 10 ⁻³ N / mm ⁴ or more and 3.5 × 10 ⁻³ N / mm. ^{A value of 4} or less is preferred.

  As a method of forming a metal spring into a C shape in a plan view, a straight flat plate, a strip, and a wire are placed in a mold having a diameter smaller than a desired inner diameter (assuming springback) and pressed. Can be made. In the present invention, the term “resin” is defined to include a resin composition mixed with a low-wear powder, a low-friction powder, and the like. The manufacturing method is injection molding or machining such as cutting and grinding.

  Next, Table 2 below shows the results of actual measurement (using the test device 60 in FIG. 10) of how the increase in the amount of leakage due to the creep deformation of the flat spring changes depending on the contact ratio of the flat spring. is there.

In Table 2 above, “0.25t × 1.6w × 315 °” is the same plate spring as in Table 1 described above. The “shape processing” in the left half of Table 2 is the metal spring 11 previously processed into a C shape as shown in FIGS. 9B and 3B.
On the other hand, “as is” in the right half of Table 2 refers to a straight shape as shown in FIG. 12B fitted into the seal ring body 1 while being elastically deformed into a C shape. is there.
From Table 2 above, it can be said that the contact ratio of the flat spring is preferably 45% or more.

  Next, Table 3 below shows how the increase in the amount of leakage due to creep deformation of the wire spring changes depending on the contact ratio of the wire spring (using the test device 60 in FIG. 10). Is shown.

In Table 3 above, “cut 315 ° from the ring” refers to a C-shaped metal spring obtained by cutting the closed annular ring from 360 ° to 45 °. The reason why the contact ratio is higher when the outer diameter of the original closed annular ring is 32 mm than 34 mm is that the diameter c of the inner peripheral surface 68A of the space chamber 68 of the test device 60 (see FIG. 10) is 32.01. This is because the diameter is relatively easy to fit on the inner peripheral surface 68A.
The “shape processing” in Table 3 is processing as described in Table 2 (Table 1).
From Table 3 above, it is desirable that the contact ratio of the wire spring be 45% or more, as in Table 3. In addition, it can be seen that the wire spring having been subjected to the “shaping” shown in FIG. 3B has a better contact ratio than the wire spring obtained by cutting off 45 ° from the closed annular ring. That is, the former had a contact rate of 61%, and the latter had a contact rate of 48%.

Next, Table 4 below shows how the increase in the amount of leakage of the flat spring depends on the contact center angle θ ₂₀ (see FIG. 2A)-corresponding to the length of the flat spring. Is a test result measured.
In addition, Table 4 is described by dividing into upper and lower two columns, but the upper and lower two columns are one continuous table in the horizontal direction.

In addition, Table 5 below shows that for the wire spring, the contact center angle θ ₂₀ (see FIG. 2 (A))-corresponding to the length dimension of the wire spring-- It shows the test results of the actual measurement as to whether it changes.

  The above Tables 4 and 5 will be described in further detail. As shown in FIGS. 9A and 9B, each position in the circumferential direction is specified with the metal spring 11 attached to the seal ring main body 1. For the sake of simplicity, they are referred to as 0:00, 1:30, 3:00, and 4:30 (like the time display on a clock). Each time (circumferential position) in the assembled state of FIG. 9A is the same as the time (circumferential position) of the metal spring 11--plate spring, wire spring--before assembly (free state). ).

Table 6 below shows the dimensional specifications of the flat springs (0.25 t × 1.6 w) used in the measurement test for the increase in the amount of leakage shown in Table 4 (radius of curvature r ₁ , r ₂ , r ₃ , r). See FIG. 9 for ₄ ).

The results of measuring the radius of curvature r of the actually manufactured flat spring (0.25 t × 1.6 w) according to the dimensional specifications shown in Table 6 above are shown in Table 7 below (curvature radii r ₁ , r ₂ , r). see FIG. 9 for _3, r _4).

Here, the seal ring main body 1 to which the metal springs 11 described in Tables 4 to 7 are assembled will be described. (I) The inner diameter (diameter) 2 × R ₁₁ when the abutment 5 is closed is 26.9 mm (see Fig. 9). (ii) The material of the seal ring main body 1 is a PPS resin composition, specifically, a material obtained by mixing PTFE powder and carbon black (powder) with PPS resin and injection molding.
On the other hand, the material of the metal spring 11 is SUS304. When the metal spring 11 is a flat spring (having a rectangular cross section), the thickness t is 0.25 mm, the width w is 1.6 mm, and each of the test products 1 to 9 has a thickness of 135 ° to 225 mm. °, that is, press working so that the average radius of curvature r ₁ from 4:30 to 7:30 (see FIG. 9) is 22.5 mm. That is, the radius of curvature r ₁ in Table 6 according to a 20Mm～25mm, is obtained by pressing so that the average value (22.5 mm).

Note that the materials and dimensions of the test products 10 to 15 (circular cross-section wire springs) shown in Table 5 are the same as those of the above-described flat springs, and thus the details are omitted.
For the seal ring main body 1 used in Tables 4 and 5, the following formula is satisfied (see Table 1 and the description thereof).
Section modulus x Young's modulus = 6780
The section modulus x Young's modulus of the metal spring 11 is 200 to 700.

Then, the seal ring of each test product (1 to 15) is attached to the test device 60 shown in FIG. 10, and the amount of leakage when an air pressure of 0.1 MPa is applied is measured. , As follows.
That is, after four cycles between a temperature (110 ° C.) higher than the glass transition temperature (90 ° C.) of the resin of the seal ring main body 1 (90 ° C.) and a temperature lower than the glass transition temperature (90 ° C.) by 20 ° C. Measure the increase in leakage at room temperature (20 ° C.) (increased flow from leakage 4 cycles before).
In Tables 4 and 5, the numerical value (liter / min) of the increase in the amount of leakage is displayed in the lower half part.
Table 8 below is a table in which only the “increase in the amount of leakage” displayed in Tables 4 and 5 is extracted and displayed.

FIG. 11 shows the test results of Table 8 (and Tables 4 and 5). The measured value of the flat spring is indicated by x, the measured value of the wire spring is indicated by ●, and the ○ indicates the calculated value of the polynomial.
From FIG. 11 and Table 8 (Tables 4 and 5), it is clear that the increase in leakage is significantly reduced when the contact center angle θ ₂₀ is 285 ° or more. That is, the increase in the amount of leakage suddenly becomes smaller than 4.0 liter / min.
Due to the self-sealing property, the leak can be increased to 5 to 6 liters / min up to just before 280 °, but to further reduce the leak, the entire inner circumference of the seal ring body 1 must be reduced to 360 °. ° with the contact center angle theta ₂₀ of 285 ° or more of the metal spring 11, it is necessary to contact with the inner peripheral surface 2 of the seal ring main body 1, it was demonstrated.

Next, FIG. 8 shows that the horizontal axis of the seal ring S composed of the resin seal ring main body 1 and the metal spring 11 is equal to or higher than the glass transition temperature T _{G of the} resin (described above) and (T _G + 50 ° C.). ) Taking the use time N when used in the following high temperature atmosphere, taking the contact surface pressure P at which the outer peripheral surface of the seal ring S is pressed against the sealed circular inner peripheral surface 21A on the vertical axis, It is the graph which showed the state which P changes.

The following can be seen from the graph of FIG. That, (i) horizontally graph line 26 (hatched portion 26Z) is to maintain a constant contact surface pressure P ₁₁ regardless metal spring 11 is used time. (ii) The elasticity of the resin seal ring main body 1 decreases as the use time N elapses (loses the resilient urging force) and becomes zero at the point R, as indicated by a gradient line 28 (dotted area 28Z). Is to maintain the contact surface pressure of the entire seal ring S only by the elastic biasing force of the metal spring 11. (iii) The elasticity may decrease with each use as shown by the step-shaped broken line 29, or the contact surface pressure P may decrease rapidly in a short time as shown by the steep slope line 30. (iv) a contact surface pressure P of the entire seal ring S is able to maintain the contact surface pressure P ₁₁ of at least a metal spring 11. We can see the above. Then, even if the resin seal ring main body 1 loses its elasticity, the frictional resistance with the inner peripheral surface 21A is reduced by continuing to contact the circular inner peripheral surface 21A as shown in FIG. In addition, it is possible to prevent the inner peripheral surface 21A from being damaged.

In the present invention, when the seal ring main body 1 thermally contracts as it descends from a predetermined high temperature to room temperature (low temperature), the metal spring 11 extends from the inside over 285 ° of the entire inner circumference 360 °. By supporting, the whole seal ring main body 1 can be maintained in a perfect circular shape.
In other words, when the seal ring main body 1 thermally shrinks, the seal ring S according to the present invention has a circular inner peripheral surface 21A to be sealed (see FIG. 5A) and an outer peripheral surface 4 of the seal ring main body 1. The generation of a minute gap (gap) therebetween is suppressed by the radially outwardly biasing force F by the metal spring 11 to maintain the sealing performance.

  The present invention is not limited to the above-described embodiment, and can be freely changed in design. The shape of the abutment 5 is not a complicated shape as shown in FIGS. It is free even if it has a simple shape.

As shown in the illustrated embodiment, a resin-made seal ring main body 1 having an abutment portion 5 at one circumferential position, and a radially outwardly biasing force F on the inner peripheral surface 2 of the seal ring main body 1. Te at the metal spring 11 incorporated fitted to contact with a, the sealing ring having, single overall shape in the free state of the metal spring 11, in the circumferential center region M _11, the maximum dimension of the radius of curvature r ₁ site 13B are present, the curvature radius r toward the respective tips 16, 16 from the central region M ₁₁ are set so as to decrease the contact of the metal spring 11 on the inner peripheral surface 2 of the seal ring main body 1 so that when reducing the diameter of the seal ring body 1 with assembled to the outer diameter D ₀ which corresponds to the inner diameter D ₂₁ of the sealing circular inner peripheral surface 21A overall shape of the metal spring 11 is a perfect circle The seal ring body 1 and the And sealing a circular inner peripheral surface 21A is uniformly resiliently pressed over the entire periphery, can exhibit excellent sealing performance.

  Further, in a high-temperature use condition in which the use environment temperature is equal to or higher than the glass transition temperature of the resin of the seal ring main body 1, the decrease in the elastic modulus of the seal ring main body 1 is reduced by the metal spring 11 to the radial outward direction. Since it is configured to assist and maintain the sealing performance with the elastic urging force F, it can be used in applications where a resin seal ring could not be used conventionally. In particular, the present invention solves the problem of the seal ring made of metal only, which damages the sealed circular inner peripheral surface 21A or leaks fluid. Sliding contact also significantly reduces fluid leakage. Furthermore, even if the elasticity of the resin seal ring body 1 is lost in a high-temperature atmosphere equal to or higher than the glass transition temperature, the life (durability) is sufficiently long because the metal spring 11 supports.

  Further, in the illustrated embodiment, the abutment portion 5 of the seal ring main body 1 and the cut 15 of the metal spring 11 are aligned with each other in the circumferential direction of the seal ring. The metal spring 11 is smoothly elastically deformed in the diameter-enlarging / reducing direction so that the entire circumference is uniformly and stably and closely slid on the circular inner peripheral surface 21A to be sealed.

As described above in detail, the present invention provides a resin seal ring main body 1 having an abutment portion 5 at one circumferential position, and a radially outward biasing force against an inner peripheral surface 2 of the seal ring main body 1. In a seal ring having a C-shaped metal spring 11 fitted so as to make contact with F; a high temperature equal to or higher than the glass transition temperature of the resin of the seal ring main body 1 and a temperature lower than the glass transition temperature. The seal ring body 1 is used in a temperature environment in which the temperature changes between the above; the seal ring main body 1 becomes a true circle when the abutment 5 is closed; and the metal spring 11 is used when the abutment 5 of the seal ring main body 1 is closed. , with a contact center angle theta ₂₀ of 285 ° or more of the total internal periphery 360 ° of the seal ring body 1, since it is configured in contact against the sealing circular inner peripheral surface 21A, severe temperature Under the conditions, the perfect circular seal ring body 1 Stable in sliding contact, exhibits excellent sealing performance. Moreover, the metal spring 11 is sufficiently wide (large) contact center angle theta ₂₀ to have a seal ring main body 1 and resiliently urging the radial outside direction, in intimate contact substantially over the entire circumference to the inner peripheral surface 21A , Can exhibit higher sealing performance.

Further, since the cross-sectional shape of the metal spring 11 is rectangular, the metal spring 11 comes into surface contact with the inner peripheral surface 2 of the seal ring main body 1 and can transmit the resilient urging force in a stable posture with uniform contact surface pressure. And preferred. Further, it is not necessary to form a concave groove on the inner peripheral surface of the seal ring main body 1, so that the design of the injection mold is not complicated, and the inner peripheral surface of the abutment portion 5 of the seal ring main body 1 is also provided with a metal spring. 11 can be installed, therefore, the contact center angle theta _20, even 360 ° back and forth, can be sufficiently large (not shown).

DESCRIPTION OF SYMBOLS 1 Seal ring main body 2 Inner peripheral surface 5 Abutment
11 Metal spring D ₀ Outer diameter dimension D ₂₁ Inner diameter dimension F Elastic urging force M ₁₁ Central area in circumferential direction r Radius of curvature S Seal ring θ ₂₀ Contact center angle

Claims (2)

A resin sealing ring main body (1) having an abutment (5) at one circumferential position and a radially outwardly biasing force (F) against an inner peripheral surface (2) of the sealing ring main body (1). And a C-shaped metal spring (11) fitted so as to be in contact with
Used in a temperature environment that undergoes a temperature change between a high temperature equal to or higher than the glass transition temperature of the resin of the seal ring body (1) and a temperature lower than the glass transition temperature;
The seal ring body (1) becomes a true circle when the abutment (5) is closed,
When the abutment (5) of the seal ring main body (1) is closed, the metal spring (11) has a contact center angle (285 ° or more) of at least 285 ° of the entire inner circumference 360 ° of the seal ring main body (1). θ ₂₀ ), the seal ring being in contact with the seal ring.   The seal ring according to claim 1, wherein a cross-sectional shape of the metal spring (11) is rectangular.

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