Mechanical seal

Abstract

The present invention provides a mechanical seal with high sealing performance.　This mechanical seal comprises: a fixed-side sealing ring 21 attached to a housing 4; a rotating-side sealing ring 11 attached to a rotary shaft 1 via a holding member 12; and a gasket 13 disposed in a radial gap between the holding member 12 and the rotating-side sealing ring 11. The gasket 13 has a core member 15 which is of higher rigidity than an elastic ring 14, extends in an axial direction, and is inserted into and disposed within the elastic ring 14.

Description

Mechanical seal

[0001] The present invention relates to a mechanical seal, for example, a mechanical seal for sealing a rotating shaft.

[0002] A mechanical seal is used by being mounted between a housing of a fluid device and a rotating shaft disposed so as to penetrate the housing. Specifically, the mechanical seal has a function of preventing leakage of the fluid to be sealed by bringing a sliding surface of a stationary seal ring attached to the housing side into sliding contact with a sliding surface of a rotating seal ring attached to the rotating shaft side and rotating in the circumferential direction.

[0003] For example, the mechanical seal shown in Patent Document 1 includes a stationary seal ring that is attached to the housing in a non-rotating state and is axially movable, and a rotating seal ring that is fixed in a sleeve fixed to the rotating shaft via a cup gasket. The stationary seal ring is biased toward the rotating seal ring by a biasing member, and as the rotating seal ring rotates together with the rotating shaft, the sliding surfaces slide relative to each other.

[0004] International Publication No. 2019 / 163726 (page 4, FIG. 1)

[0005] In the mechanical seal of Patent Document 1, an axial portion of the cup gasket is pressed between the inner peripheral surface of the sleeve and the outer peripheral surface of the rotating seal ring, and a radial portion of the cup gasket is pressed between the end surface of the sleeve and the back surface of the rotating seal ring, so that the space between the rotating seal ring and the sleeve is sealed However, when the rotating seal ring rotates at high speed, the axial portion of the cup gasket is deformed so as to be expanded outward by centrifugal force, and a gap is formed between the axial portion of the cup gasket and the outer peripheral surface of the rotating seal ring, which may reduce the sealing performance.

[0006] The present invention has been made paying attention to such problems, and an object thereof is to provide a mechanical seal having high sealing performance.

[0007] To solve the aforementioned problems, the mechanical seal of the present invention comprises a fixed-side sealing ring attached to a housing, a rotating-side sealing ring attached to a rotating shaft via a retaining member, and a gasket disposed in the radial gap between the retaining member and the rotating-side sealing ring, wherein the gasket has a core material that is more rigid than an elastic ring, extending in the axial direction and inserted into the elastic ring. This suppresses deformation of the elastic ring disposed on the inner diameter side of the core material, thereby maintaining a sealed state between the retaining member and the rotating-side sealing ring.

[0008] The tip of the core material may be embedded in the elastic ring. In this case, the inner and outer diameters of the core material in the elastic ring are connected radially at the tip, so that an amount of elastic deformation can be secured at the tip of the elastic ring.

[0009] The core material may be annular in shape. This allows for the suppression of deformation of the elastic ring on the inner diameter side of the core material due to centrifugal force in the circumferential direction.

[0010] The core material has an axial portion extending in the axial direction and a radial portion extending radially from the rear end of the axial portion, and the radial portion may be in axial contact with the radial portion of the holding member. In this case, the position of the core material is stabilized by the radial portion of the core material contacting the radial portion of the holding member.

[0011] The radial portion of the core material may be annular. This ensures that the orientation of the axial portion of the core material is stable in the circumferential direction.

[0012] The core material may be made of the same material as the holding member. In this case, no stress will be generated even if the core material and the holding member undergo thermal expansion and contraction.

[0013] This is a longitudinal cross-sectional view showing a mechanical seal in an embodiment of the present invention. This is a longitudinal cross-sectional view showing the structure of the rotating sealing element. This is a schematic diagram showing a modified example 1 of the cup gasket. This is a schematic diagram showing a modified example 2 of the cup gasket. This is a schematic diagram showing a modified example 3 of the cup gasket. This is a schematic diagram showing a modified example 4 of the cup gasket. This is a schematic diagram showing a modified example 5 of the cup gasket.

[0014] Embodiments for implementing the mechanical seal according to the present invention will be described below based on examples.

[0015] The mechanical seal according to the embodiment will be described with reference to Figures 1 and 2. Note that the left and right sides of Figure 1 will be described as the left and right sides of the mechanical seal.

[0016] The mechanical seal for general industrial machinery shown in Figure 1 is an inside-type seal that seals the fluid to be sealed F that would otherwise leak from the outer space S2 on the outer diameter side of the sliding surface toward the inner diameter side, with the inner space S1, which serves as the leakage space, being open to the atmosphere A. In this embodiment, the example shown is one in which the fluid to be sealed F is a high-pressure liquid and the atmosphere A is a gas at a lower pressure than the fluid to be sealed F.

[0017] The mechanical seal mainly consists of a rotating-side sealing element 10 that is integrally rotatable on the rotating shaft 1, and a stationary-side sealing element 20 that is non-rotatable on the housing 4.

[0018] The stationary sealing ring 21 in the stationary sealing element 20 and the rotating sealing ring 11 in the rotating sealing element 10 are designed to slide in close contact with each other.

[0019] The stationary sealing ring 21 and the rotating sealing ring 11 are typically formed from two SiC (hard material) or a combination of SiC (hard material) and carbon (soft material), but are not limited to these; any sliding material used as a sliding material for mechanical seals can be applied. SiC can be sintered using boron, aluminum, carbon, etc. as sintering aids, or from materials consisting of two or more phases with different components and compositions, such as SiC with dispersed graphite particles, reaction-sintered SiC made of SiC and Si, SiC-TiC, SiC-TiN, etc. Carbon can be a mixture of carbonaceous and graphite, as well as resin-molded carbon, sintered carbon, etc. In addition to the sliding materials mentioned above, metal materials, resin materials, surface modification materials (coating materials), composite materials, etc., can also be applied.

[0020] The stationary sealing element 20 mainly consists of a case 22 fixed to the housing 4, an annular stationary sealing ring 21 provided within the case 22 in a non-rotatable and axially movable state, a bellows 23 that seals the space between the case 22 and the stationary sealing ring 21, and a biasing means 24 that biases the stationary sealing ring 21 to the axial left.

[0021] As shown in Figures 1 and 2, the rotating sealing element 10 comprises a rotating sealing ring 11, a sleeve 12 as a retaining member, and a cup gasket 13 as a gasket.

[0022] The sleeve 12 is an annular member made of a thin metal plate. The sleeve 12 consists of a fixing portion 121, a radial portion 122, and an axial portion 123.

[0023] The fixed portion 121 extends axially along the outer circumferential surface of the rotating shaft 1 and is fixed to the outer circumferential surface of the rotating shaft 1 by a predetermined fixing means. The radial portion 122 extends radially outward from the left end of the fixed portion 121. The axial portion 123 extends axially to the right from the outer diameter end of the radial portion 122. In other words, the fixed portion 121, the radial portion 122, and the axial portion 123 have a U-shaped cross-section that opens to the right.

[0024] The cup gasket 13 mainly consists of an elastic ring 14 made of rubber or the like, and a core material 15 made of a material with higher rigidity than the elastic ring 14, such as metal. The elastic ring 14 is fixed to the core material 15 by heat bonding, and the contact surfaces of the two are bonded together. In this embodiment, the core material 15 is made of the same metal as the sleeve 12.

[0025] The elastic ring 14 has an axial portion 141 that extends axially along the inner circumferential surface of the axial portion 123 of the sleeve 12, and a radial portion 142 that extends inward from the left end of the axial portion 141.

[0026] An annular groove 141a is formed in the axial portion 141, opening to the left. Hereinafter, the inner diameter portion of the annular groove 141a in the axial portion 141 will be referred to as the inner diameter portion 141b, the outer diameter portion of the annular groove 141a will be referred to as the outer diameter portion 141c, and the portion where the right end of the inner diameter portion 141b and the right end of the outer diameter portion 141c are connected radially will be referred to as the tip portion 141d.

[0027] The core material 15 comprises an axial portion 151 and a radial portion 152 extending inward from the left end of the axial portion 151. The axial portion 151 is positioned within the annular groove 141a, and an inner diameter portion 141b, an outer diameter portion 141c, and a tip portion 141d are fixed to the axial portion 151. The radial portion 152 is fixed along the left side of the back surface, i.e., the left side of the left face, of the radial portion 142 of the elastic ring 14.

[0028] In other words, the axial portion 151 is embedded within the axial portion 141 of the elastic ring 14, and the radial portion 152 is exposed on the outside of the elastic ring 14. To put it another way, the axial portion 141 of the elastic ring 14 is divided into an inner diameter portion 141b and an outer diameter portion 141c by the axial portion 151 of the core material 15.

[0029] The rotating sealing ring 11 is fitted inside the cup gasket 13.

[0030] The cup gasket 13 is press-fitted into the inside of the sleeve 12. In this state, the axial portion 141 of the elastic ring 14 is compressed between the axial portion 123 of the sleeve 12 and the outer surface of the rotating sealing ring 11, while the radial portion 142 of the elastic ring 14 is compressed between the radial portion 122 of the sleeve 12 and the back surface of the rotating sealing ring 11. As a result, the gap between the rotating sealing ring 11 and the sleeve 12 is sealed.

[0031] Furthermore, regarding the assembly of the rotating sealing element 10, the cup gasket 13 with the rotating sealing ring 11 fitted may be press-fitted into the inside of the sleeve 12, or the rotating sealing ring 11 may be fitted onto the cup gasket 13 that has been press-fitted into the inside of the sleeve 12.

[0032] Next, we will describe the state in which the rotating sealing element 10 rotates at high speed together with the rotating shaft 1.

[0033] When the rotating sealing element 10 rotates at high speed together with the rotating shaft 1, a force that pushes the axial portion 141 of the elastic ring 14 outward, i.e., centrifugal force, acts on it. Since the cup gasket 13 has a rigid core material 15, the inner diameter portion 141b of the axial portion 141 of the elastic ring 14, which is partitioned on the inner diameter side of the axial portion 151 of the core material 15, hardly deforms even when the centrifugal force acts on it.

[0034] Similarly, the outer diameter portion 141c of the axial portion 141 of the elastic ring 14, which is partitioned on the outer diameter side of the axial portion 151 of the core material 15, hardly deforms even when centrifugal force is applied. Therefore, the sealed state between the sleeve 12 and the rotating sealing ring 11 can be maintained regardless of the centrifugal force.

[0035] Furthermore, since the inner diameter portion 141b and outer diameter portion 141c of the elastic ring 14, which are partitioned by the axial portion 151 of the core material 15, are connected radially at the tip portion 141d, the tip portion 141d of the elastic ring 14 can ensure an amount of elastic deformation. Therefore, the cup gasket 13 can be easily inserted into the inside of the sleeve 12 while deforming the elastic ring 14 radially.

[0036] Furthermore, since the axial portion 151 of the core material 15 is annular, deformation of the inner diameter portion 141b of the axial portion 141 of the elastic ring 14 due to centrifugal force can be suppressed in the circumferential direction. In addition, movement of the axial portion 151 of the core material 15 in the outward diameter direction due to centrifugal force can be avoided.

[0037] Furthermore, since the radial portion 152 of the core material 15 is in axial contact with the radial portion 122 of the sleeve 12, the position of the core material 15 is stabilized. In addition, the insertion direction of the cup gasket 13 relative to the sleeve 12 can be easily positioned.

[0038] Furthermore, the radial portion 152 of the core material 15 is annular and contacts the radial portion 122 of the sleeve 12 in the circumferential direction, thus further stabilizing the position of the core material 15.

[0039] Further, the core material 15 and the sleeve 12 are made of the same metal. According to this, even if the core material 15 and the sleeve 12 thermally expand and contract due to heat generated during the use of the mechanical seal or the temperature of the use environment, stress can be prevented from occurring.

[0040] Next, a modified example of the cup gasket will be described. Hereinafter, the illustration of the stationary-side sealing element will be omitted.

[0041] As shown in FIG. 3, in the cup gasket 13' of the first modified example, the inner peripheral surface of the axial portion 151' of the core material 15' is fixed to the inner diameter portion 141b' of the axial portion 141' of the elastic ring 14', and the outer peripheral surface of the axial portion 151' of the core material 15' is not fixed to the outer diameter portion 141c' of the axial portion 141' of the elastic ring 14'. Further, the right end surface of the axial portion 151' of the core material 15' is not fixed to the tip portion 141d' of the axial portion 141' of the elastic ring 14'.

[0042] Similar to the above-described embodiment, the inner diameter portion 141b' in the axial portion 141' of the elastic ring 14' partitioned on the inner diameter side of the axial portion 151' of the core material 15' hardly deforms even when the rotating-side sealing element 10' rotates at high speed together with the rotating shaft 1' and the centrifugal force acts thereon.

[0043] Further, since the outer diameter portion 141c' of the axial portion 141' of the elastic ring 14' is not fixed to the axial portion 151' of the core material 15', it deforms so as to expand outward by the centrifugal force. As a result, the outer diameter portion 141c' is pressed against the inner peripheral surface of the axial portion 123' of the sleeve 12', and the sealing state between the axial portion 151' of the core material 15' and the sleeve 12' can be maintained. Therefore, the sealing state between the sleeve's 12' and the rotary seal ring 11' can be maintained regardless of the centrifugal force.

[0044] As shown in FIG. 4, in the cup gasket 113 of the second modified example, the radial portion 1152 of the core material 115 is embedded in the radial portion 1142 of the elastic ring 114. That is, the entire core material 115 may be covered with the elastic ring 114.

[0045] As shown in FIG. 5, in the cup gasket 213 of the third modification, the core material 215 has a cylindrical shape and is embedded in the axial portion 2141 of the elastic ring 214. That is, the configuration of the radial portion of the core material may be omitted.

[0046] As shown in FIG. 6, the cup gasket 313 of the fourth modification includes a cylindrical core material 315, an inner diameter side elastic ring 314A disposed on the inner diameter side of the core material 315, and an outer diameter side elastic ring 314B disposed on the outer diameter side of the core material 315. That is, the elastic ring may be divided into an inner diameter side and an outer diameter side by the core material 315. Note that the inner diameter side elastic ring 314A has a substantially L-shaped cross section, and the outer diameter side elastic ring 314B has a cylindrical shape.

[0047] As shown in FIG.7, the cup gasket 413 of the fifth modification may be fitted on the inner diameter side of the rotary seal ring 411. In this case, the axial portion 4141 of the elastic ring 414 is disposed between the rotary seal ring 411 and the fixing portion 4121 of the sleeve 412.

[0048] As described above, the embodiments of the present invention have been described with reference to the drawings. However, the specific configuration is not limited to these embodiments, and modifications and additions within the scope not departing from the gist of the present invention are also included in the present invention.

[0049] For example, in the above embodiment, the axial portion of the core material is exemplified as having an annular shape, but it is not limited thereto, and it may be divided in the circumferential direction or may have a substantially C-shaped cross section in the axial view.

[0050] Also, in the above embodiment, the radial portion of the core material is exemplified as having an annular shape, but it may be divided in the circumferential direction or may have a substantially C-shaped cross section in the axial view.

[0051] Also, in the above embodiment, the form in which the core material and the sleeve are made of the same material is exemplified, but the core material and the sleeve may be made of different materials. Note that the core material is not limited to being made of metal, and the material can be freely changed as long as it has higher rigidity than the elastic ring.

[0052] Furthermore, although the above embodiment described a form in which the gasket is a cup gasket, it is not limited to this, and for example, it may be cylindrical with the radial portion omitted, or it may be an O-ring or the like.

[0053] Furthermore, the inner diameter portion, outer diameter portion, and tip portion of the axial portion of the elastic ring may or may not be fixed to the axial portion of the core material.

[0054] 1 Rotating shaft 4 Housing 10 Rotating side sealing element 11 Rotating sealing ring (rotating side sealing ring) 12 Sleeve (holding member) 13 Cup gasket (gasket) 14 Elastic ring 15 Core material 20 Stationary side sealing element 21 Stationary sealing ring (fixed side sealing ring) 122 Radial portion 123 Axial portion 141 Axial portion 141b Inner diameter portion 141c Outer diameter portion 141d Tip portion 142 Radial portion 151 Axial portion 152 Radial portion

Claims

1. A mechanical seal comprising a fixed sealing ring attached to a housing, a rotating sealing ring attached to a rotating shaft via a retaining member, and a gasket disposed in the radial gap between the retaining member and the rotating sealing ring, wherein the gasket has a core material that is more rigid than an elastic ring, which extends axially and is inserted into the elastic ring.

2. The mechanical seal according to claim 1, wherein the tip of the core material is embedded in the elastic ring.

3. The mechanical seal according to claim 1, wherein the core material is annular in shape.

4. The mechanical seal according to claim 1, wherein the core material has an axial portion extending in the axial direction and a radial portion extending radially from the rear end of the axial portion, and the radial portion abuts the radial portion of the retaining member in the axial direction.

5. The mechanical seal according to claim 4, wherein the radial portion of the core material is annular.

6. The mechanical seal according to claim 1, wherein the core material is made of the same material as the retaining member.

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