JP2017101690A - piston ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piston ring excellent in sealing property.SOLUTION: The piston ring includes: an annular resin piston ring body 1 having one cut part 5 in the circumference thereof; and a metal elastic C-shaped ring 11 disposed at an inner peripheral surface 2 of the piston ring body 1. The piston ring has a non-circular shape while being set free, and has a circular shape while the cut part is closed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a piston ring.

  Conventionally, as shown in FIG. 13 or FIG. 14, an annular resin piston ring body 41 having a cut (joint) 40 at one place on the circumference, and an inner peripheral surface 42 of the piston ring body 41 is elastically impacted. There has been proposed a piston ring 44 composed of a steel expander ring (elastic ring) 43 that is pressed with force (see Patent Document 1).

Japanese Utility Model Publication No. 2-18964

As shown in FIGS. 13 and 14, the piston ring 44 is mounted in a seal groove 47 formed on the outer peripheral surface 46 of the piston 45, and the outer peripheral surface 48 of the piston ring main body 41 is pressed against the peripheral surface 49 of the cylindrical body. However, it is slid as the piston 45 reciprocates.
However, in the conventional piston ring 44 shown in FIGS. 13 and 14, the following problems remain unsolved.

Problem (i): As clearly shown in FIGS. 13 and 14, the expander ring 43 is always arranged in correspondence with the cut 40 (joint) 40 of the piston ring main body 41, and the expander ring 43 having a single letter cross section. In this structure, the gap 50 of the joint 40 is closed (from the inner periphery side) to reduce fluid leakage. However, the amount of fluid leakage of the piston ring 44 is determined by the total amount of leakage of the piston ring 44 from the entire 360 ° circumference, and it is not sufficient to consider only the joint 40. In particular, measures for the piston ring outer peripheral surface 48 to be in close contact with the cylindrical inner peripheral surface 49 over the entire circumference were insufficient.
Problem (ii): The piston ring body 41 has a structure in which the expander ring 43 is strongly pressed from the inner peripheral surface 42 side of the joint (cut) of the piston ring body 41. The elastic minute diameter expansion / reduction operation is hindered, and a moment in which the cylinder body peripheral surface 49 cannot be pressed tightly occurs, resulting in fluid leakage.

Problem (iii): As shown by the arrow 39 in FIG. 14, the expander ring 43 is likely to be displaced, and the inner surface of the seal groove 47 is scratched (see * 1, * 2 in FIG. 14). ) And the sealing performance may deteriorate.
Problems (iv): As indicated by arrows 39 in FIG. 14, if the expander ring 43 relative to the piston ring main body 41 is misaligned, the piston ring main body 41 resiliently as an arrow M ₄₁ An urging force is applied, and the outer peripheral surface 48 of the piston ring main body 41 is not pressed against the cylindrical inner peripheral surface 49 with a uniform contact surface pressure, but is slidably contacted locally to generate uneven wear. That is, the corner portion 38 indicated by * 3 in FIG.
Problem (v): When the piston ring 44 is attached to the cylinder inner peripheral surface 49, the axial direction position (position in the direction of arrow 39) of the piston ring main body 41 and the expander ring 43 is difficult to determine. There is.

Accordingly, the present invention provides an annular resin piston ring main body having a cut at one place on the circumference, and a metal elastic C disposed so as to contact the inner peripheral surface of the ring main body with an elastic biasing force. In the piston ring having the shape ring, the overall shape of the piston ring in the free state includes a portion having a maximum radius of curvature within a range of 180 ° ± 30 ° with respect to the center point of the cut. The radius of curvature is set so as to decrease from the maximum dimension portion toward the cut in the circumferential direction, and the entire shape is configured to be a perfect circle when the cut is closed.
In addition, a circumferential groove is formed on the inner peripheral surface of the ring body, and the C-shaped ring is fitted into the groove to prevent positional displacement of the C-shaped ring in the axial direction. .
In addition, a first convex portion and a second convex portion are projected in the circumferential direction at the first end portion and the second end portion that form the cut of the ring body, and a first cut portion of the C-shaped ring is formed. The 1 endmost part and the 2nd endmost part are arranged at positions in the circumferential direction with respect to the roots of the first and second convex parts in the ring body.

  According to the present invention, the problems (i) to (v) are solved, and the piston ring is uniformly pressed against the inner peripheral surface of a cylindrical body such as a cylinder barrel (cylinder tube) over the entire 360 ° circumference. However, it will slide while exhibiting excellent sealing performance (sealability).

It is a top view of the free state (cut open state) of one embodiment of the present invention. It is a top view of a break closed state. It is a top view which shows a free state, Comprising: (A) is a top view of a piston ring main body, (B) is a top view of an elastic C-shaped ring. It is a top view which shows a break closed state, Comprising: (A) is a top view of a piston ring main body, (B) is a top view of an elastic C-shaped ring. It is a principal part expanded sectional view of a use condition. It is a principal part expanded sectional view which shows other embodiment. It is a principal part expanded sectional view which shows another embodiment. It is a principal part enlarged view, Comprising: (A) is a plane principal part enlarged view, (B) is a front principal part enlarged view. It is a principal part enlarged view which shows other embodiment, Comprising: (A) is a plane principal part enlarged view, (B) is a front principal part enlarged view. It is a principal part perspective view which shows another embodiment, Comprising: (A) is a principal part perspective view of a free state, (B) is a principal part perspective view of a break closed state. It is a figure explaining the shape of a 2nd convex part, Comprising: (A) is a perspective view, (B) is bb sectional drawing of (A), (C) is cc sectional drawing of (A). . It is a figure explaining the shape of a 1st convex part, Comprising: (A) is a perspective view, (B) is bb sectional drawing of (A), (C) is cc sectional drawing of (A). . It is a principal part perspective view which shows a prior art example. It is principal part sectional drawing for demonstrating a prior art example.

Hereinafter, the present invention will be described in detail based on the illustrated embodiment.
As shown in FIGS. 1 to 4, a piston ring S according to the present invention includes a resin-made piston ring body 1 having an annular shape as a whole and having a notch 5 at one circumference, and an inner portion of the piston ring body 1. And a metal elastic C-shaped ring 11 disposed so as to come into contact (pressure contact) with a resilient urging force. This C-shaped ring 11 also has a cut 15 at one place on the circumference, and the entire shape is annular (C-shaped).

As illustrated in FIGS. 5 to 7, a circumferential groove 3 is formed in the inner peripheral surface 2 of the ring main body 1 on the inner peripheral surface 2 of the ring main body 1.
5 has a triangular shape in FIG. 5, a trapezoidal shape in FIG. 6, and a dovetail shape in FIG. 7, both of which are on the inner peripheral surface 2 of the ring body 1, A concave groove 3 is provided at the center position in the axial direction (vertical direction in FIGS. 5 to 7).
The cross-sectional shape of the elastic C-shaped ring 11 is circular. 5 to 7, 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), has a circular hole 21, and has an outer peripheral surface of the ring body 1. 4 is slidably pressed against the inner peripheral surface 21A of the circular hole 21.
The sealed fluid is a gas such as air or various gases, or a liquid such as hydraulic oil. 5 to 7, a seal groove 22 having a rectangular cross section is formed in a reciprocating body such as a piston 23, and the piston ring S according to the present invention is mounted in the seal groove 22. Yes.

The C-shaped ring 11 is fitted in the circumferential groove 3 of the ring body 1, thereby preventing the C-shaped ring 11 from being displaced in the axial direction K. That is, the C-shaped ring 11 is held at the center position in the axial direction K on the inner peripheral surface 2 of the ring body 1.
And the 1st convex parts 8 and 9 are protrudingly provided by the 1st edge part 6 and the 2nd edge part 7 which form the cut | interruption 5 of the ring main body 1 in the circumferential direction.
The first outermost end 16 and the second outermost end 17 that form the cut 15 of the C-shaped ring 11 are located on the inner periphery of the ring body 1 more than the roots 8A and 9A of the first convex portion 8 and the second convex portion 9. It is arranged at the position of the direction-the circumferential direction opposite to the cut line 5-. As shown in FIG. 8 or FIG. 9, with respect to the concave groove 3 of the ring main body 1, both end surfaces 3A, 3A are arranged in the inner circumferential direction with respect to the root portions 8A, 9A without reaching the cut line 5. And the extent to which the first and second final ends 16 and 17 of the C-shaped ring 11 do not touch--only a small dimension --- the end face 3A is arranged in the direction of the cut 5 It is desirable.

As shown in FIG. 1, the piston ring S according to the present invention has an overall shape in a piston ring free state as a finished product in which a C-shaped ring 11 is assembled on the inner peripheral side of the ring body 1 (finished product). also the central point (the center point) P ₅ cuts fifth formation to) the ring body 1, in the range of 180 ° ± 30 °, the radius of curvature R ₁₃ is present site 13 of the largest dimension of the cut.
That is, the angle θ shown in FIG. 1 is 30 °, and the portion 13 having the maximum dimension is disposed in the range of 2θ = 60 °. The central angle of the maximum dimension portion 13 around the central point O ₁ may be selected in the range of 1 ° to 60 °. In FIG. 1, L ₀ is a line (diameter line) indicating the diameter including the central point P ₅ .

If additional explanation, a portion 13 of maximum dimension toward each of the first end portion 6, the second end portion 7, toward the circumferential direction M _1, M _2, the radius of curvature R _1, R ₂ is gradually reduced Then, the curvature radii R ₆ and R 7 of the first end portions 6 and ₇ are set to the minimum dimension, and further, the curvature radii of the outer peripheral surfaces of the first convex portion 8 and the second convex portion 9 (of small projecting dimensions) are set. Is the same as the curvature radii R ₆ and R ₇ .
As shown in FIG. 2, in the closed state where the first convex portion 8 and the second convex portion 9 overlap each other, a perfect circle having the same radius R ₀ from the center point O ₁ is obtained. Alternatively, the inner surface 21A shown in FIG. When elastically deforming from the open state of the cut (FIG. 1) to the closed state of the cut (FIG. 2), the portion 13 having the largest dimension is deformed so that the radius of curvature is the largest and the first end 6 and the second end The portion 7 is hardly deformed, and the curvature radius R ₀ shown in FIG. 2 is equal to the curvature radii R ₆ and R ₇ of the end portions 6 and 7.
The curvature radii R ₁ , R ₂ , R ₁₃ , R ₆ and R ₇ are from the center point O ₁ to the outer peripheral surface of the piston ring S (that is, the outer peripheral surface of the ring body 1) as shown in FIG. Dimension.

If the ring main body 1 is a single unit before assembling, from the cut open state (free state) shown in FIG. 3 (A) to the cut closed state shown in FIG. 4 (A) (corresponding to FIG. 2). , Exerts an impact force in the direction of diameter expansion. Furthermore, C-shaped ring 11, in a single pre-assembled, from FIG. 3 (B) to the large-open cut first opened state cut 15 with a large central angle beta ₁ shown (free state), (2 4B), if the slit 15 shown in FIG. 4B is in the second open state where the slit 15 has a small central angle β ₀ and is opened to a small size, the metallic C-shaped ring 11 has a resilient urging force in the expanding direction. Demonstrate.
When these two parts--ring body 1 and C-shaped ring 11--are assembled into the finished product shown in FIGS. 1 and 2, it is non-circular in a free state and is closed An example of specific means for obtaining a true circle in the state will be described below.

As the specific means, as shown in FIGS. 3 (A) and 4 (A), the shape of the ring body 1 in the non-assembled state is a non-circular shape in a free state and a perfect circle in a closed state. As shown in FIGS. 3 (B) and 4 (B), the C-shaped ring 11 in the non-assembled state is non-circular in the free state and corresponds to FIG. It is set so that it becomes a true circle in the second closed state reduced to β ₀ .
More specifically, as shown in FIG. 3A, when the ring body 1 is in a free state, the radius of curvature R ₁₃ ′ is maximum within a range of 180 ° ± 30 ° with respect to the center point P ₅ of the cut 5. There is a dimension 13A. That is, the angle θ ′ shown in FIG. 3A is 30 °, and the portion 13A having the maximum dimension is disposed in the range of 2θ ′ = 60 °. The central angle around the central point O ₁ of the maximum dimension portion 13A is selected in the range of 1 ° to 60 °. If additional explanation, a portion 13A of the largest dimension toward each of the first end portion 6, the second end portion 7, toward the circumferential direction M _1, M _2, the radius of curvature R ₁ ', R _2' is private university The curvature radii R ₆ ′ and R ₇ ′ of the first and second end portions 6 and ₇ are minimized. Furthermore, the curvature radii of the outer peripheral surfaces of the first convex portion 8 and the second convex portion 9 are the same as the curvature radii R ₆ and R ₇ (as described above).

Then, as shown in FIG. 4A, in the closed state where the first convex portion 8 and the second convex portion 9 overlap each other, a perfect circle having the same radius R ₀ ′ from the center point O ₁ is obtained. The curvature radii R ₆ ′ and R ₇ ′ of the first end 6 and the second end 7 are hardly deformed when elastically deforming from FIG. 3 (A) to FIG. 4 (A), as shown in FIG. 4 (A). Equal to the radius of curvature _R0 .
On the other hand, when the C-shaped ring 11 is in a free state, as shown in FIG. 3 (B), the radius of curvature R ₁₃ ″ is within the range of 180 ° ± 30 ° with respect to the center point P ₅ of the cut 15 3B exists, that is, the angle θ ″ shown in FIG. 3B is 30 °, and the portion 13B having the maximum dimension is disposed in the range of 2θ ″ = 60 °. The center angle around the center point O ₁ is selected in the range of 1 ° to 60 °.

In additional explanation, the radius of curvature R ₁ ″, R ₂ ″ approaches the circumferential direction M ₁ , M ₂ from the maximum dimension portion 13 B toward the first end portion 16 and the second end portion 17. Gradually, the radius of curvature R ₁₆ and R ₁₇ is minimized in the vicinity of the first end 16 and the second end 17.
Then, if the (center point O ₁ around) the center angle of the cut 15 of the C-shaped ring 11 break the closed state in the assembled state shown in FIG. 2 and beta _0, with respect to only the C-shaped ring 11, FIG. 4 ( As shown in B), when the diameter is elastically reduced to the same center angle β ₀ , a perfect circle with the same radius R ₀ ″ is obtained from the center point O ₁ .

3 and 4, the ring body 1 and the C-shaped ring 11 described above are assembled to each other, so that the outer periphery of the piston ring S that is a perfect circle from the non-true circle in FIG. A surface shape is obtained, and it slides (mainly) in the axial direction while in close contact with the inner circumferential surface 21A of the perfect circle (circular hole 21).
When comparing the free state in which the ring body 1 and the C-shaped ring 11 shown in FIG. 1 are assembled with the free state of the ring body 1 and the C-shaped ring 11 shown in FIG. 1) is slightly larger than the outer diameter of the ring body 1 of FIG. 1 and is larger than the outer diameter of the C-shaped ring 11 of FIG. 3 (B). The outer diameter of 11 is assembled so as to be slightly smaller. By being assembled in this way, the resin-made piston ring main body 1 is always subjected to the elastic outward biasing force by the metal elastic C-shaped ring 11, and FIG. 2, FIG. 5, FIG. 7, the inner surface 21 </ b> A of the circular hole 21 is brought into contact with a strong elastic pressure contact force.

The material and manufacturing method will be described. First, the ring body 1 can use a wide variety of resins, such as PTFE, PEEK, PPS, and PES. In the present invention, “resin” is defined to include a resin composition mixed with low wear powder, low friction powder, or the like. And it manufactures by injection molding or machining, such as cutting and grinding. Examples of the elastic C-shaped ring 11 include steels such as carbon steel (spring steel) and malleable cast iron, titanium, aluminum, various alloys, and the like. Plastic processing such as press working of wire rods, forging, casting, die Cast molding and the like can be mentioned, and further, these two or more types can be combined.
Further, the cut 5 of the piston ring main body 1 and the cut 15 of the elastic C-shaped ring 11 may be at a position of about 180 ° (opposite positions) or at a position of about 90 °. Further, the elastic C-shaped ring 11 may be in the shape of a coil wound twice (a plurality of turns).

Next, the shape of the cut line (joint) 5 will be described. 1 to 4 and FIG. 8, a notch 27 is formed with a stepped surface 26 radially inward from the outer peripheral surface 4 at the first end 6, and the first convex portion 8 is formed. At the same time as forming, a notch 29 is formed with a stepped surface 28 radially outward from the inner peripheral surface 2 at the second end 7 to provide the second convex portion 9. The 1st convex part 8 and the 2nd convex part 9 have opposed on the circular-arc-shaped surface.
In the example shown in FIG. 9, in the first end portion 6, a notch portion 32 is formed with a stepped surface 31 in the axial direction from one side surface 30 to form the first convex portion 8, and the second end portion. 7, a notch 35 is formed with a stepped surface 34 in the axial direction from the other side surface 33, and the second convex portion 9 is provided. The 1st convex part 8 and the 2nd convex part 9 have opposed on the plane orthogonal to an axial center.

Next, FIGS. 10 to 12 show still another configuration (shape) of the joint. That is, the 1st convex part 8 has the base end half part 51 of an L-shaped cross section, and the front-end | tip half part 52 of a rectangular cross section. A part of the second convex portion 9 is fitted into the rectangular concave portion 51A of the base end half portion 51 of the L-shaped cross section (as will be described later).
The 2nd convex part 9 has the base end half part 53 of an L-shaped cross section, and the front end half part 54 of a rectangular cross section. The tip half 52 of the first convex portion 8 is fitted in the rectangular recess 53A of the base half 53 of the L-shaped cross section.
The first projecting portion 8 is formed on the first end portion 6 with a first stepped surface 55 and a second stepped surface 56 (two step steps). The second end portion 7 has the first stepped surface 57 and the second stepped surface 58 (two step steps), and the second convex portion 9 is formed. The tip half 54 of the second convex portion 9 is fitted into the rectangular concave portion 51 </ b> A of the first convex portion 8.
The fitting shape (structure) is not limited to the above-described embodiment, and any other shape can be used. The piston ring S according to the present invention can be suitably used for air, gases such as various gases, and liquids such as hydraulic oil.

According to the illustrated embodiment, the C-shaped ring 11 is fitted in the concave groove 3 of the inner peripheral surface 2 of the ring body 1 (see FIGS. 5 to 7), and mutual displacement is unlikely to occur. The contact surface pressure with respect to the inner peripheral surface 21A of 1 can be equalized, and uneven wear can be effectively prevented. Moreover, it is possible to prevent the metal C-shaped ring 11 from coming into contact with the side inner surface 22A of the seal concave groove 22, so that the side inner surface 22A is not damaged, and the piston ring S smoothly moves inside the seal concave groove 22. It moves finely and stably exhibits good sealing performance. Moreover, since the ring body 1 and the C-shaped ring 11 are relatively assembled and held in the concave groove 3, they can be easily and quickly mounted in the circular hole 21 of the fixing member 20, Workability is also good.
Further, the C-shaped ring 11 disposed on the inner peripheral side is not disposed at the joint (the first and second projecting portions 8 and 9) of the ring body 1, and accordingly, the first and second projecting portions. 8 and 9 do not need to be excessively restrained by the highly rigid C-shaped ring 11 made of metal, and the first and second convex portions 8 and 9 (matching ports) can be used in sudden pressure fluctuations and sudden operations. ) Responds while flexibly and elastically deforming, and can prevent leakage of fluid.

As is apparent from the drawings, the piston ring S according to the present invention is provided with an elastic C-shaped ring 11 over substantially the entire circumference (excluding the joint), and the entire fluid leakage of the piston ring S is effective. Is prevented.
Further, in comparison with the conventional expander ring 43 having a single-cross-sectional shape shown in FIG. 14, in FIGS. 5 to 7, a rigid (hard) C-shaped ring 11 having a circular cross-section and a resin piston are used. Since the contact area with the ring body 1 is small, it is smoothly absorbed when expansion / contraction due to heat occurs.

As described in detail above, the present invention makes contact with the annular resin piston ring main body 1 having the cut 5 at one circumference and the inner peripheral surface 2 of the ring main body 1 with a resilient urging force. In the piston ring having the elastic C-shaped ring 11 made of metal, the overall shape of the piston ring in a free state is within a range of 180 ° ± 30 ° with respect to the center point P _{5 of the} cut 5. There is a portion ₁₃ having the maximum radius of curvature R _{13, and the} radius of curvature R ₁ , R ₂ decreases from the maximum size portion 13 toward the cut 5 toward the circumferential direction M ₁ , M _2. Since the entire shape is configured to be a perfect circle when the cut is closed, it is tightly pressed (slidably contacted) over the entire circumference of the inner circumferential surface 21A of 360 °. As a result, the overall leakage can be significantly reduced, and the sealing performance is excellent. That.

  Further, a circumferential groove 3 is formed on the inner peripheral surface 2 of the ring body 1, and the C-shaped ring 11 is fitted into the groove 3, so that the C-shaped ring 11 is displaced in the axial direction K. Therefore, it is possible to prevent the side inner surface 22A (see FIGS. 5 to 7) of the seal concave groove 22 from being damaged due to mutual metal interference, and to prevent the sealing performance from being deteriorated. Further, when the C-shaped ring 11 on the inner peripheral surface 2 side is displaced in the axial direction K, the resin piston ring main body 1 causes uneven wear on the outer peripheral surface 4 slidably contacting the inner peripheral surface 21A of the circular hole 21. Although this may occur, such uneven wear can be effectively prevented.

The first end 6 and the second end 7 that form the cut 5 of the ring body 1 are provided with a first protrusion 8 and a second protrusion 9 in the circumferential direction so as to protrude from the C-shaped ring. The first outermost portion 16 and the second outermost portion 17 forming the cut 15 of the eleventh are in the inner circumferential direction with respect to the base portions 8A and 9A of the first convex portion 8 and the second convex portion 9 in the ring body 1. Is not excessively hindered by the smooth elastic micro-expansion / reduction operation of the first convex portion 8 and the second convex portion 9, and always against the inner peripheral surface 21A. Closely and flexibly, it effectively prevents momentary fluid leakage at the joint and greatly contributes to further improvement in sealing performance.
Further, since the metallic elastic C-shaped ring 11 is not disposed in the vicinity of the joint, the first and second extreme ends 16 and 17 of the C-shaped ring 11 do not interfere with each other. Accordingly, it is possible to prevent the fluid leakage from occurring due to the entire piston ring S becoming non-circular during use.

S piston ring (seal ring)
DESCRIPTION OF SYMBOLS 1 (Piston) ring main body 2 Inner peripheral surface 3 Groove | groove 5 Cut | interruption 6 1st edge part 7 2nd edge part 8 1st convex part 9 2nd convex part 8A, 9A Base part
11 (elastic) C-shaped ring
13 Maximum dimensions
15 breaks
16 First end
17 Second end K K Axial direction M ₁ , M ₂ circumferential direction R ₁ , R ₂ radius of curvature R ₁₃ radius of curvature P ₅ center point (center point)

Claims (3)

An annular resin piston ring main body (1) having a cut (5) at one circumference and an inner peripheral surface (2) of the ring main body (1) are arranged so as to come into contact with an elastic force. A piston ring having an elastic C-shaped ring (11) made of metal,
As for the overall shape of the piston ring in the free state, there is a portion (13) having a maximum radius of curvature (R ₁₃ ) within a range of 180 ° ± 30 ° with respect to the center point (P ₅ ) of the cut (5). , The radius of curvature (R ₁ ) (R ₂ ) is set to decrease as it approaches the circumferential direction (M ₁ ) (M ₂ ) from the maximum dimension portion (13) toward the cut (5), A piston ring characterized in that the entire shape is a perfect circle when the cut is closed.   A circumferential groove (3) is formed on the inner peripheral surface (2) of the ring body (1), and the C-shaped ring (11) is fitted into the groove (3). The piston ring according to claim 1, wherein the piston ring is configured to prevent displacement in the axial direction (K) of 11).   The first end (6) and the second end (7) forming the cut (5) of the ring body (1) have a first protrusion (8) and a second protrusion (9) in the circumferential direction. ) Projecting and forming the cut (15) of the C-shaped ring (11), the first outermost portion (16) and the second outermost portion (17) are the first end of the ring body (1). 3. The piston ring according to claim 1, wherein the piston ring is disposed at a position in an inner circumferential direction with respect to a base portion (8 </ b> A) (9 </ b> A) of the convex portion (8) / second convex portion (9).

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