JP4125905B2 - Sealing structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to tight sealed structure.
[0002]
[Prior Art and Problems to be Solved by the Invention]
There are various types of seals. When the sealed sliding part is rotating, a rotating seal is used, and when the sliding part is reciprocating, a reciprocating seal is used.
In the conventional seal, only one of the sliding sliding and the reciprocating sliding is considered, and an O-ring or an oil seal is used depending on the sliding condition.
[0003]
On the other hand, an object of the present invention is to enable appropriate sealing even under new sliding conditions that have not been achieved in the past in which rotation is added to reciprocation.
That is, when rotation is applied to the reciprocating motion, sliding acts in an oblique direction, so that the follow-up performance of the sealing material is deteriorated. Moreover, since a large resistance is generated on the sliding surface, the seal ring rotates together, and the sliding surface wears abnormally. As described above, when rotation is added to the reciprocating motion, there arises a problem that the sealing performance is not stabilized and the life of the seal is shortened.
[0004]
BACKGROUND OF THE INVENTION
The present invention takes into account the above-mentioned problems that occur under new sliding conditions in which rotation is added to reciprocation, and even if rotation is added to reciprocation, the seal ring does not rotate together, and stable sealing performance is achieved. providing tight sealing structure that obtained.
[0005]
[Means for Solving the Problems]
The sealing structure according to the present invention includes a mounted member having a circumferential groove in which a seal ring is mounted, and another member that is reciprocated and rotated relative to the mounted member. wherein between said other member and the attached member, a sealing structure for the compressed fluid in the axial direction on both sides of the seal ring is prevented from leaking into the seal ring axial direction while the object mounting member, the mounting A first flange portion and a second flange portion provided on both axial sides of the member main body portion, and the circumferential groove is formed between both flange portions, The flange portion is formed separately from the mounted member main body portion, and is configured to be clamped and mounted to the mounted member main body portion by a fastener, and the seal ring has an elastic force with respect to the other member. Axial lip that can generate sealing force due to A first annular body that has sliding at the opposite ends and slides in an oblique direction in which the relative rotation is added to the relative reciprocation, and the first annular body. A second annular body that is concentrically provided and held in the circumferential groove of the mounted member, and a connection base that connects and integrates the first and second annular bodies. And both end surfaces in the axial direction of the second torus are positioned so as to protrude in the axial direction with respect to the first torus, and the first flange portion is fastened to the mounted member main body portion. The clamping surface is clamped by the first flange portion and the second flange portion from both sides in the axial direction by the tightening force of the fastener for mounting, and the seal ring is relatively reciprocated. In addition to the relative rotation, if the relative rotation occurs in the first torus, it will not co-rotate Is the first flange portion which said fixed to the circumferential groove of the mating attachment member by force the tightening by the fasteners for mounting the fastening onto the mounting member body.
[0006]
Since the lip portions are at both axial ends of the first annular body, fluid from one axial direction is sealed by the lip portion at one axial end, and fluid from the other axial end is sealed by the lip portion at the other axial end. The Accordingly, seal followability in both axial directions can be obtained, and sufficient sealability can be obtained with respect to reciprocation. In addition, since the second annular body is sandwiched and held by the member to which the seal ring is attached, the rotation of the seal ring is prevented even if rotation occurs. For this reason, even if rotation is added to the reciprocating motion, the seal ring does not rotate together, and a stable sealing performance can be obtained.
[0007]
It is preferable that the second annular body is provided with a sub-seal member that performs a seal between the attached member to which the seal ring is attached and the second annular body. The sub-sealing member improves the sealing performance of the second annular body, and sufficient sealing performance can be obtained even for a low-viscosity fluid such as gas.
[0008]
In addition, it is preferable that the second torus is formed to have a greater radial thickness than the first torus. By increasing the thickness of the second torus, the clamping surfaces at both ends in the axial direction are increased, and the holding strength and the sealing performance at the clamping surfaces are improved.
[0009]
Furthermore, it is preferable that the first annular body is provided on the radially outer side and the second annular body is provided on the radially inner side. In this case, sealing can be performed on the outer surface side of the member to which the seal ring is attached. In addition, if the arrangement of the first and second toruses is reversed inside and outside, sealing on the inner surface side of the member to which the seal ring is attached can be performed.
[0012]
It is preferable that a space between both lip portions of the first torus is a bearing surface that contacts the other member and supports the mounted member. By having the bearing surface, it is possible to prevent the mounted member provided with the seal ring from being tilted and to smoothly slide.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration diagram of a rotary piston pump 1. The rotary piston pump 1 is used for compressing and supplying a fluid such as city gas, natural gas, methanol, kerosene, and hydrogen gas to a micro gas turbine or a fuel cell. It can also be used for supplying liquid foods such as soups and filling high viscosity foods.
[0014]
The rotary piston pump 1 includes a pump body 3 having a hollow cylindrical space therein, a cylinder 5 rotatably disposed in the hollow cylindrical space of the pump body 3, and a reciprocating motion in the axial direction within the cylinder 5. And a provided piston 7.
The pump body 3 is provided with fluid inlet ports 9a and 9a. The fluid inlet ports 9 a and 9 b are for supplying fluid into the pump 1 and are formed so as to penetrate inside and outside the pump body 3. As the fluid inlet port, there are a first fluid inlet port 9a provided on one axial side and a second fluid inlet port 9b provided on the other axial side.
[0015]
The pump body 3 is provided with fluid outlet ports 10a and 10b. The fluid outlet ports 10a and 10b are for discharging compressed fluid to the outside of the pump, and are formed so as to penetrate inside and outside the pump body 3. The fluid outlet port includes a first fluid outlet port 10a provided on one axial side and a second fluid outlet port 10b provided on the other axial side.
[0016]
The fluid outlet ports 10a and 10b are formed at positions facing the fluid inlet ports 9a and 9b. That is, in FIG. 1, the fluid inlet ports 9 a and 9 b are formed on the upper side of the pump body 3, whereas the fluid outlet ports 10 a and 10 b are formed on the lower side of the pump body 3.
[0017]
The cylinder 5 is rotatably provided around the axis of the piston 7 in the pump body 3 and is driven to rotate by a rotation mechanism (not shown). The cylinder 5 has a first cylinder port 12 formed on one side in the axial direction. The first cylinder port 12 is positioned and communicated with the first fluid inlet port 9a by rotation of the cylinder 5, or is positioned and communicated with the first fluid outlet port 10a, or both the ports 9a and 10a. And the three states of the non-communication state can be taken. A second cylinder port 13 is formed on the other axial side of the cylinder 5. The second cylinder port 13 is also positioned and communicated with the second fluid inlet port 9b by rotation of the cylinder 5, or is located and communicated with the second fluid outlet port 10b, or both ports 9b and 10b. And the three states of the non-communication state can be taken. The second cylinder port 13 is arranged 180 degrees out of phase with respect to the first cylinder port 12 in the circumferential direction of the cylinder 5.
[0018]
The piston 7 includes a piston main body portion 17 and flange portions 18 and 19 provided on both axial sides of the piston main body portion 17, and a circumferential groove 22 in which a seal ring 21 is disposed between both flange portions 18 and 19. Is formed. Of the flange portions 18 and 19, the first flange portion 18 on one axial side is formed separately from the piston main body portion 17, and is fastened and fixed to the piston main body portion 17 by a fastener such as a bolt. The second flange portion 19 on the other side in the axial direction is formed integrally with the piston main body portion 17.
[0019]
The piston 7 includes piston rods 20 and 20 extending in the axial direction from flanges 18 and 19 at both ends in the axial direction. The piston rods 20 and 20 are slidably supported by the cylinder 5. ing. The piston 7 reciprocates in the cylinder 5 when the piston rod 20 is reciprocated by a linear drive mechanism (not shown). That is, the cylinder 5 and the piston 7 relatively reciprocate and rotate. The rotation of the cylinder 5 and the reciprocation of the piston 7 are synchronized, and the piston 7 reciprocates once while the cylinder 5 rotates once.
[0020]
The internal space of the cylinder 5 is divided into two by the piston 7 in the axial direction. In the following, among the divided spaces, the space on the one side in the axial direction of the piston 7 (the space on the left side in FIG. 1) is referred to as the first fluid chamber 23, and the space on the other side in the axial direction (the space on the right side in FIG. 2). ) Is referred to as a second fluid chamber 24. Sealing is performed between the first fluid chamber 23 and the second fluid chamber 24 by a seal ring 21 attached to the circumferential groove 22 of the piston 7.
[0021]
The suction process and compression stroke by the rotary piston pump 1 configured as described above will be described. First, the piston 7 moves to the left side (first fluid chamber 23 side) in FIG. 1 and the cylinder 5 rotates, and the second cylinder port 13 is in communication with the second fluid inlet port 9b of the pump body 3 so that the fluid flows. It is sucked into the second fluid chamber 24 of the cylinder 5 (start of the suction process). When the piston 7 moves to the left end, the positions of the second cylinder port 13 and the second fluid inlet port are displaced, and the fluid suction step into the second fluid chamber 24 is completed.
[0022]
Subsequently, the piston 7 moves to the right side, the cylinder 5 rotates, and the fluid is compressed by the second fluid chamber 24 being in an airtight state (start of the compression process). Immediately before the piston 7 reaches the right end position, the second cylinder port 13 and the second fluid outlet port 10b are in communication with each other, and the compressed fluid is discharged from the second fluid outlet port 10b.
[0023]
Since the pump 1 is a double-action type, the fluid compression process is performed in the first fluid chamber 23 during the fluid suction process into the second fluid chamber 24, and the fluid compression process in the second fluid chamber 24 is performed during the fluid compression process. In the first fluid chamber 23, a fluid suction process is performed. Further, since the cylinder 5 rotates to play the role of a valve, the valve is omitted.
[0024]
2 to 4 show the seal ring 21 that is mounted in the circumferential groove 22 of the piston (attached member) 7 and that is in sliding contact with the cylinder (other member) 5. The seal ring 21 includes an annular ring body 28 having a first annular groove 26 and a second annular groove 27 that are laterally open on both end faces in the axial direction, and spring members 30 loaded in the annular grooves 26 and 27, respectively. And an O-ring 32 as a sub-seal member provided on the inner peripheral surface of the ring main body 28.
[0025]
The ring body 28 is integrally formed of an elastic material such as a synthetic resin. Specifically, a self-lubricating and low-friction fluororesin such as polytetrafluoroethylene (PTFE), glass fiber, The elastic composite material is formed by blending one or more special fillers such as carbon fiber and molybdenum disulfide. The ring body 28 includes a first annular body 34 that is located radially outside and is in sliding contact with the cylinder 5, and a second annular body 36 that is located radially inside and is held by the piston 7. The central portions in the axial direction of both annular bodies 35, 36 are connected and integrated by a connecting base 38, and the cross section is formed in a horizontal H shape.
[0026]
The seal ring 21 is fitted and attached to the outer periphery of the piston body 17 in a state where the first flange portion 18 of the piston 7 is not attached to the piston body 17. The second annular body 36 is firmly sandwiched between the first flange portion 18 and the second flange portion 19 by fastening the first flange portion 18 to the piston body portion 17 with a bolt or the like. That is, the flat axial end surfaces 36a and 36b of the second torus 36 are sandwiching surfaces. Here, since both end surfaces 36a and 36b in the axial direction of the second annular body 36 are wider in the axial direction than the first annular body 34 and project in the axial direction, the second annular ring 36 Only the body 36 is sandwiched between the flange portions 18 and 19. On the other hand, the first annular body 34 is not sandwiched between the flange portions 18 and 19, and a gap is formed between both axial ends of the first annular body 34 and the flange portions 18 and 19. This gap allows free elastic deformation of both ends (lip portions 40 and 41 described later) of the first annular body 34 in the axial direction.
[0027]
Further, since the second annular body 36 is formed to have a larger radial thickness than the first annular body 34, the sandwiching surfaces 36a and 36b are increased, so that the two annular portions 18 and 19 are sandwiched and sealed. The strength is strong.
[0028]
The annular grooves 26, 27 having a U-shaped cross section are formed between the first annular body 34 and the second annular body 36, and these annular grooves 26, 27 are left and right as viewed in the axial direction. It is formed symmetrically. The spring member 30 mounted in the annular grooves 26 and 27 is formed by annularly forming a leaf spring bent in a U shape along the shape of the annular grooves 26 and 27, and is mounted in the annular grooves 26 and 27. In this state, the first annular body 34 and the second annular body 36 are urged in the direction of increasing the radial interval.
[0029]
Lip portions 40 and 41 that form a seal surface for the cylinder 5 are formed at both axial ends of the outer circumferential surface of the first annular body 34. Since the spring member 30 urges the lip portions 40 and 41 in the radially outward direction, the lip portions 40 and 41 are pressed against the cylinder 5 by the elastic force of the spring member 30 to ensure a sealing force. The portions near the center in the axial direction of the lip portions 40, 41 are thin portions 40a, 41a, and the lip portions 40, 41 are easily elastically deformed in the radial direction.
[0030]
The O-ring 32 is mounted in an annular seal groove 43 formed in a concave shape on the inner peripheral surface of the second annular body 36. As described above, since the radial thickness of the second torus 36 is large, even if the seal groove 43 is formed and the portion is thinner than other portions, the strength of the second torus is somewhat increased. It can be secured. Here, in order to ensure the strength of the second annular body 36, if the depth of the seal groove 43 is h and the radial thickness of the second annular body 36 is H, then H> 2h. preferable. Further, the seal groove 43 is formed at the center in the axial direction of the second annular body 36, and the connection base portion 38 exists behind (in the radial direction) of the second annular body 36. In this case, even if the second annular body 36 is thin, it is reinforced by the connecting base 38, and the strength of the seal ring 21 as a whole is ensured.
[0031]
Here, for example, when the piston 7 moves toward the first fluid chamber 23, the fluid in the first fluid chamber 23 is compressed to a high pressure, and the compressed fluid tends to leak into the low-pressure second fluid chamber 24. At this time, there are an outer peripheral side and an inner peripheral side of the seal ring 21 as a leakage path of the compressed fluid. Leakage on the outer peripheral side is prevented by the lip portion 40. That is, when the compressed fluid in the first fluid chamber 23 enters the first annular groove 26, the compressed fluid deforms the lip portion 40 in the radially outward direction to generate a pressing pressure against the cylinder 5, and the sealing by the lip portion 40. And the leakage from the outer peripheral side of the seal ring 21 is prevented.
[0032]
Conversely, when the piston 7 moves to the second fluid chamber 24 side and the second fluid chamber 24 side becomes high pressure, leakage from the outer peripheral side of the seal ring 21 to the first fluid chamber 24 is prevented by the lip portion 41. Therefore, even if the piston 7 reciprocates, the sealing performance is maintained by both the lip portions 40 and 41, and it is in charge of rotational sliding. In addition, the seal ring 21 is firmly fixed to the piston 7 by the tightening force of the first flange portion 18, and the seal ring 21 does not rotate together even when the cylinder 5 rotates.
[0033]
Leakage from the inner peripheral side of the seal ring 21 is mainly sealed by an O-ring 32 as a sub seal member. Further, leakage from the inner peripheral side of the seal ring 21 is also sealed by the sandwiching surfaces 36 a and 36 b of the second torus 36. That is, the flat clamping surfaces 36a and 36b are pressed against and closely contact the flange portions 18 and 19 to prevent leakage of the compressed fluid. In particular, when the viscosity of the fluid is large, the O-ring 32 can be eliminated, and the sealing performance can be sufficiently secured only by the surface sealing by the clamping surfaces 36a and 36b.
[0034]
A bearing surface 45 is formed in an annular shape at the axially central portion of the outer circumferential surface of the first annular body 34 so as to protrude radially outward from the thin portions 40a and 41b. As shown in FIG. 3, in a state where the seal ring 21 is not attached to the piston 7, the bearing surface 45 has a protruding amount in the radially outward direction from a protruding amount in the radially outward direction of both the lip portions 40 and 41. Suppressed and formed. On the other hand, as shown in the sealing structure of FIG. 4, when the seal ring 21 is mounted on the piston 7 and is in sliding contact with the cylinder 5, the lip portions 40 and 41 are elastically deformed radially inward by the cylinder 5, and the bearing The surface 45 also contacts the cylinder 5. Since the coupling base 38 is located behind the bearing surface 45 (inside in the radial direction), the bearing surface 45 has higher rigidity than the lip portions 40 and 41. The piston 7 is supported by the cylinder 5 via the bearing surface 45, prevents the piston 7 from being tilted, and allows the piston 7 to slide smoothly.
[0035]
FIG. 5 shows a seal ring 51 according to the second embodiment. This seal ring 51 has a configuration similar to that of the seal ring 21 by combining a first divided body 53 obtained by dividing the seal ring 21 in the axial direction and a second divided body 55 back to back. However, the O-ring 32 is provided in each of the first divided body 53 and the second divided body 54. Other points are the same as the seal ring 21 in FIGS.
[0036]
In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible within the range of the matter described in the claim. In particular, the sealing structure of the present invention is not limited to a rotary piston pump, and can be applied to various devices that cause sliding in which reciprocation is added.
[0037]
【The invention's effect】
According to the present invention, seal followability in both axial directions is obtained by the lip portions at both axial ends of the first annular body, and sufficient sealability is obtained against reciprocating motion. In addition, since the second annular body is sandwiched and held by the member to which the seal ring is attached, the seal ring is prevented from rotating even if rotation occurs, and the seal ring rotates even if rotation is added to the reciprocating motion. Therefore, stable sealing performance can be obtained.
[0038]
In addition, in the case where a sub seal member is provided that seals between a member on which the seal ring is attached to the second torus and the second torus, the sealing performance in the second torus is also provided. And a sufficient sealing property can be obtained even for a low-viscosity fluid such as a gas.
In addition, when the second torus is formed with a larger radial thickness than the first torus, the holding surfaces at both ends in the axial direction are increased, and the holding strength and the sealing performance at the holding surfaces are increased. improves.
[0039]
Further, when the space between the two lip portions of the first annular body is a bearing surface, the mounted member provided with the seal ring is prevented from being inclined and smooth sliding is obtained. .
[Brief description of the drawings]
FIG. 1 is a sectional view of a rotary piston pump having a sealing structure with a seal ring of the present invention. FIG. 2 is a side view of the seal ring of the present invention.
FIG. 3 is a plan view of the seal ring of the present invention.
4 is an enlarged view of the sealing structure of FIG. 1. FIG.
FIG. 5 is a cross-sectional view of a sealing structure using a seal ring according to a second embodiment.
[Explanation of symbols]
1 Rotary piston pump 5 Cylinder (other members)
7 Piston (member to be mounted)
21 Seal ring 30 Spring member 32 O-ring (sub seal member)
34 1st ring body 36 2nd ring body 40 Lip part 41 Lip part 45 Bearing surface 51 Seal ring

Claims (5)

A mounted member having a circumferential groove on which a seal ring is mounted, and another member that is reciprocated and rotated relative to the mounted member, and the mounted member and the other member A sealing structure that prevents the compressed fluid on both axial sides of the seal ring from leaking to the other axial direction of the seal ring,
The mounted member includes a mounted member main body portion, and a first flange portion and a second flange portion provided on both sides in the axial direction of the mounted member main body portion. Directional grooves are formed,
The first flange portion is formed separately from the mounted member main body portion, and is configured to be fastened and mounted to the mounted member main body portion by a fastener.
The seal ring is
The lip portion that can generate a sealing force by elastic force with respect to the other member is provided at both ends in the axial direction, and the relative rotation is added to the relative reciprocation by slidingly contacting the other member. A first torus in which direction sliding occurs;
A second torus provided concentrically with respect to the first torus and held in the circumferential groove of the mounted member;
A coupling base for coupling and integrating the first and second toric bodies,
Both end surfaces in the axial direction of the second torus are positioned so as to protrude in the axial direction with respect to the first torus, and the first flange portion is fastened and attached to the mounting member main body portion. Due to the tightening force by the fastener , the first flange portion and the second flange portion are sandwiched from both sides in the axial direction,
The seal ring clamps the first flange portion to the mounting member main body portion so that the seal ring does not rotate even if the relative rotation occurs in the first torus in addition to the relative reciprocation. A sealing structure characterized by being fixed in the circumferential groove of the mounted member by the tightening force by the fastener for attaching .   The sub-sealing member that seals between the attached member to which the seal ring is attached and the second torus is provided in the second torus. Sealing structure.   3. The sealing structure according to claim 1, wherein the second annular body has a larger radial thickness than the first annular body.   The sealing structure according to any one of claims 1 to 3, wherein the first torus is provided radially outward and the second torus is provided radially inward.   The space between both lip portions of the first torus is a bearing surface that abuts on the other member and supports the mounted member. Sealing structure.

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