Mechanical seal

Abstract

Provided is a mechanical seal which can ensure sliding properties between sliding surfaces regardless of the amount of liquid remaining between the sliding surfaces. The sealing surface (11) of at least one of the slip rings (10) has: an annular base material (12) attached to a member (5) on the housing (4) side or a member (2A) on the rotating shaft (1) side; and a resin material (13) attached to the base material (12), the resin material (13) being configured in a ring shape.

Description

Technical Field

[0001] The present invention relates to a mechanical seal which is applied to high-speed rotating equipment such as vehicles and industrial machinery and divides a sealed fluid space and a leakage space. Background Art

[0002] As a device for preventing leakage of a sealed fluid around a rotating shaft in a rotary machine, for example, a mechanical seal composed of a pair of annular sliding rings that rotate relatively and slide on sliding surfaces thereof is known.

[0003] For example, the mechanical seal shown in Patent Document 1 is installed between the housing of a fluid device and a rotating shaft arranged to penetrate the housing, so that the sliding surface of a stationary seal ring and the sliding surface of a rotating seal ring are in sliding contact in the circumferential direction. The stationary seal ring is fixed to a stationary side element constituted by a housing, etc., and the rotating seal ring rotates together with a rotating side element such as a rotating shaft. Liquid lubrication is performed by means of the sealed fluid entering between the sliding surfaces, which has the function of reducing the friction generated on the sliding surfaces and preventing the leakage of the sealed fluid.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-6788 (page 4, Figure 1 ) Summary of the invention

[0007] Problems to be solved by the invention

[0008] In a mechanical seal such as that disclosed in Patent Document 1, the stationary seal ring and the rotating seal ring are made of hard materials such as SiC to ensure strength and sliding properties. In such a mechanical seal, a sealed fluid that is a cryogenic fluid is sometimes sealed. The cryogenic fluid has a characteristic of a low boiling point, so it is easy to vaporize between the sliding surfaces and cause a phenomenon such as no liquid lubrication. In a mechanical seal such as that disclosed in Patent Document 1, when a phenomenon such as no liquid lubrication between the sliding surfaces occurs, abnormal wear may occur.

[0009] The present invention has been made in view of such a problem, and an object of the present invention is to provide a mechanical seal capable of ensuring sliding properties between sliding surfaces regardless of the amount of residual liquid between the sliding surfaces.

[0010] Means for solving problems

[0011] In order to solve the above-mentioned problems, the mechanical seal of the present invention is arranged between a housing and a rotating shaft rotating relative to the housing, and slides and divides the sealed fluid space and the leakage space by the relative rotation of a stationary sliding ring fixed to the housing side and a rotating sliding ring fixed to the rotating shaft side, wherein the sealing surface of at least one of the sliding rings has: an annular base material, which is mounted on a component on the housing side or a component on the rotating shaft side; and a resin material, which is mounted on the base material, and the resin material is configured to be annular.

[0012] Thus, liquid lubrication can be stably performed between the base materials of the pair of slide rings, and when the amount of residual liquid between the sliding surfaces is small, the sliding properties between the sliding surfaces can be ensured by the resin material.

[0013] At least a portion of the sliding surface of the other sliding ring that slides against the resin material may be formed of a material having a higher hardness than the resin material.

[0014] Thus, the resin material slides with respect to the base material of the other slide ring, so that the base material of the other slide ring and the resin material can slide stably.

[0015] Alternatively, one of the sliding rings may be a stationary sealing ring, and the other sliding ring may be a rotating sealing ring.

[0016] Thus, the resin material is attached to the stationary seal ring, and thus it is possible to avoid the centrifugal force from acting on the resin material.

[0017] At least a portion of the sealing surface of the base may be formed on a side closer to the leakage space than the resin material.

[0018] This makes it easier for the wear powder of the resin material to be supplied to the sealing surface of the base material by the sealed fluid that attempts to flow from the high-pressure sealed fluid space side to the low-pressure leakage space side. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional view showing a mechanical seal according to Example 1 of the present invention.

[0020] Figure 2 yes Figure 1 An enlarged view of the main part.

[0021] Figure 3 This is a diagram of the stationary seal ring viewed from the rotating seal ring side in the axial direction.

[0022] Figure 4 It is an enlarged cross-sectional view of a main part showing the state between the sliding surfaces after the running-in operation.

[0023] Figure 5This is an enlarged cross-sectional view showing a state in which the mechanical seal is fully operated in a state in which the amount of liquid remaining between the sliding surfaces is small.

[0024] Figure 6 This is an enlarged cross-sectional view of a main part of a mechanical seal showing a second embodiment of the present invention.

[0025] Figure 7 This is an enlarged cross-sectional view of a main part of a mechanical seal showing a third embodiment of the present invention.

[0026] Figure 8 This is an enlarged cross-sectional view of a main part of a mechanical seal showing a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0027] Hereinafter, modes for implementing the mechanical seal of the present invention will be described based on examples.

[0028] Example 1

[0029] Reference Figures 1 to 5 The mechanical seal of Example 1 is described. In this example, a sealed fluid F1 exists in the outer space S1 of the mechanical seal, and a sealed fluid F2 exists in the inner space S2. The outer diameter side of the sliding ring constituting the mechanical seal is described as the sealed fluid side (in other words, the high-pressure side), and the inner diameter side is described as the leakage side (in other words, the low-pressure side).

[0030] Figure 1 The mechanical seal shown is an inside type mechanical seal that seals a sealed fluid F1 in an external space S1 that is intended to leak from the outer diameter side to the inner diameter side of a sliding surface.

[0031] The mechanical seal mainly comprises a stationary seal ring 10 as one sliding ring and a rotating seal ring 20 as the other sliding ring. The rotating seal ring 20 is annular and is rotatably mounted on a retainer 2A as a rotating shaft member via a sleeve 2.

[0032] The stationary seal ring 10 is annular and is provided in a non-rotating state and axially movable state on a seal cover 5 as a member on the housing side, and the seal cover 5 is fixed to the housing 4 of the mounted device. Specifically, a bellows 7 is installed in a sealed state between the seal cover 5 and the stationary seal ring 10. The bellows 7 applies force to the stationary seal ring 10 in the axial direction.

[0033] The sliding surface 11 of the stationary seal ring 10 and the sliding surface 21 of the rotating seal ring 20 slide in close contact with each other. As described later, the part that slides on the sliding surface 21 is substantially the front surface 12d of the base material 12 constituting the sliding surface 11.

[0034] In addition, in this embodiment 1, the component on the rotating shaft side is described as the retaining frame 2A and the component on the housing side is described as the sealing cover 5, but the component on the rotating shaft side can also be a sleeve or the rotating shaft itself, and similarly, the component on the housing side can also be the housing itself.

[0035] The base material 12 of the stationary seal ring 10 and the rotating seal ring 20 are typically formed of a combination of SiC (hard material) and SiC (hard material) or a combination of SiC (hard material) and carbon (soft material), but are not limited thereto. Any sliding material that can be used as a sliding material for a mechanical seal can be used. In addition, as SiC, there are materials composed of two or more phases with different components and compositions, represented by sintered bodies using boron, aluminum, carbon, etc. as sintering aids, such as SiC with graphite particles dispersed therein, reaction sintered SiC composed of SiC and Si, SiC-TiC, SiC-TiN, etc. As carbon, resin molded carbon, sintered carbon, etc. represented by carbon mixed with carbonaceous and graphite can be used. In addition, in addition to the above-mentioned sliding materials, metal materials, resin materials, surface modified materials (coating materials), composite materials, etc. can also be used.

[0036] like Figure 2 and Figure 3 As shown, the stationary seal ring 10 includes an annular base material 12 and an annular low-friction resin material 13 as a resin material.

[0037] The substrate 12 includes a base 12a, a first convex portion 12b, and a second convex portion 12c as an annular portion. The cross section of the base 12a is rectangular. The first convex portion 12b protrudes from the inner diameter side of the base 12a toward the rotating seal ring 20. The second convex portion 12c further protrudes from the inner diameter side of the first convex portion 12b toward the rotating seal ring 20.

[0038] The low friction resin material 13 is a PTFE component that is softer than the base material 12 and has low friction properties. The thermal expansion coefficient of the low friction resin material 13 is higher than that of the base material 12. The low friction resin material 13 is not limited to PTFE, and preferably has low friction properties, and may be made of other resins.

[0039] The low friction resin material 13 has a cylindrical axial portion 13a extending in the axial direction and an annular radial portion 13b extending radially inward from the end of the axial portion 13a on the rotating seal ring 20 side, i.e., the front side of the stationary seal ring 10. That is, the low friction resin material 13 has a substantially inverted L shape in cross-section.

[0040] The low friction resin material 13 is externally embedded in the first convex portion 12b and the second convex portion 12c. Specifically, the axial portion 13a abuts against the outer peripheral surface of the first convex portion 12b, and the radial portion 13b abuts against the front surface of the first convex portion 12b. At room temperature, the inner diameter side end surface 13c of the radial portion 13b is in close contact with the outer peripheral surface 12e of the second convex portion 12c.

[0041] The front face 13d of the radial portion 13b is substantially the same plane as the front face 12d of the second convex portion 12c when viewed in the axial direction, that is, substantially continuous in the radial direction. However, as described later, in detail, when viewed in the radial direction, the front face 13d of the radial portion 13b is slightly recessed in the axial direction than the front face 12d of the second convex portion 12c. That is, the sliding surface 11 of the stationary seal ring 10 is constituted by the axial end face of the stationary seal ring 10, that is, the front face 12d of the second convex portion 12c. Therefore, the front face 12d of the stationary seal ring 10 functions as the sliding surface 11, and functions as a sealing surface for sealing between the external space S1 and the internal space S2.

[0042] Furthermore, at room temperature, when viewed from the axial direction, the front surface 13d formed by the low-friction resin material 13 is substantially continuous in the radial direction with the front surface 12d formed by the base material 12. That is, there is almost no radial gap between the low-friction resin material 13 and the base material 12, and there is a small step in the axial direction.

[0043] The low friction resin material 13 of this embodiment is arranged on the outer diameter side of the first convex portion 12 b in a state of thermal expansion by heating, and then contracts by cooling to a state of room temperature, thereby closely contacting and fitting on the first convex portion 12 b .

[0044] and, Figure 2 The shape at room temperature is shown. Figure 2 In the embodiment of the present invention, the axial dimension of the radial portion 13b of the low-friction resin material 13 is slightly smaller than the axial dimension of the second convex portion 12c of the base material 12, and the low-friction resin material 13 is slightly recessed from the sliding surface of the base material 12 in the axial direction, but the two dimensions may be the same, or the dimension of the former may be larger than the dimension of the latter. In the case where the dimension of the former is larger than the dimension of the latter, the low-friction resin material 13 will be worn immediately and function as a solid lubricant. After that, after the low-friction resin material 13 is worn, the base material 12 and the rotary seal ring 20 slide, and the situation where the low-friction resin material 13 slides and wears is basically eliminated.

[0045] Furthermore, at extremely low temperatures, a gap is formed between the back surface of the axial portion 13 a and the front surface 12 d (ie, the sliding surface side end surface) of the base portion 12 a of the base 12 .

[0046] Next, regarding actions, we mainly use Figure 4 , Figure 5 The change in the state between the sliding surfaces 11 and 21 will be described. Figure 4 and Figure 5 In the figure, for the sake of convenience of explanation, the gap between the sliding surfaces 11 and 21 is shown to be larger than the actual gap.

[0047] After assembling the mechanical seal, perform a run-in operation. When performing the run-in operation, if Figure 4 As shown, the sliding surfaces 11 (i.e., the front surface 12d) and 21 are smooth and the gap S10 between the sliding surfaces 11 and 21 is small, i.e., a good contact state. After the running-in operation, the mechanical seal is officially operated. In addition, Figure 4 The shape at room temperature is shown.

[0048] Next, the case where the sealed fluid F1 is a liquid at room temperature is described. During normal operation of the mechanical seal when the sealed fluid F1 is a liquid at room temperature, the sliding surfaces 11 and 21 slide smoothly (not shown) by means of liquid lubrication of the sealed fluid F1 that flows into the gap S10 mainly from the outer space S1 side. Specifically, the sliding surfaces 11 and 21 slide stably mainly on the front surface 12d of the second convex portion 12c and the portion of the sliding surface 21 that is opposite to the front surface 12d.

[0049] Next, the case where the sealed fluid F1 is a cryogenic liquid is described. When the mechanical seal is in full operation, if the sealed fluid F1 is a cryogenic liquid, the temperature between the sliding surfaces 11 and 21 rises, causing the sealed fluid F1 to vaporize, and immediately the sealed fluid F1 between the sliding surfaces 11 and 21 is less, that is, the state where liquid lubrication is not performed between the sliding surfaces 11 and 21. Here, the cryogenic temperature is below 0°C, preferably below -100°C.

[0050] like Figure 5 As shown, when the sealed fluid F1 between the sliding surfaces 11 and 21 is small, the inner diameter sides of the sliding surfaces 11 and 21, that is, the front surface 12d of the second convex portion 12c and the portion of the sliding surface 21 facing the front surface 12d are worn. Figure 5 Shows the shape at extremely low temperatures.

[0051] On the other hand, the outer diameter sides of the sliding surfaces 11 and 21, that is, the front surface 13d of the low-friction resin material 13 and the portion of the sliding surface 21 facing the front surface 13d, ensure sliding properties due to the low-friction resin material 13 functioning as a solid lubricant.

[0052] The low friction resin material 13 generates wear powder P by sliding with the sliding surface 21. The wear powder P enters the small gap S10 between the sliding surfaces 11 and 21. The wear powder P enters the gap S10 as a solid lubricant, thereby improving the sliding performance between the sliding surfaces 11 and 21.

[0053] Furthermore, since the hardness of the low-friction resin material 13 is lower than that of the substrate 12, it is easy to wear, and although the friction coefficient of the low-friction resin material 13 itself is higher than that of the substrate 12, after becoming wear powder (in other words, powdered), the friction coefficient becomes lower and becomes easy to slide. Here, the friction coefficient of the resin material in powdered form is smaller than that of the substrate 12. Therefore, compared with the direct sliding between the substrate 12 and the rotating seal ring 20, in the case of sliding with the wear powder mixed between the sliding surfaces 11 and 21, the friction coefficient is reduced, showing low friction. Here, the hardness can be any hardness calculated by various hardness measurements (for example, Vickers hardness, Knoop hardness, etc.), and the wear powder is obtained by crushing the low-friction resin material 13 as a solid.

[0054] Furthermore, since the low-friction resin material 13 has a high non-adhesive property (in other words, the adhesion between the base material 12 and the rotary seal ring 20 is lower than that of other polymer materials such as rubber), the wear powder is in a state of functioning as a solid lubricant in a powdered state, so the friction becomes good. On the other hand, the rubber used for O-rings has a high adhesive property and is difficult to be powdered, and even if it is powdered, it will cause high friction.

[0055] Furthermore, when the wear of the low-friction resin material 13 intensifies and the wear powder as a solid lubricant is supplied between the sliding surfaces, even if the low-friction resin material 13 is axially recessed relative to the front surface 12d of the substrate 12, the substrate 12 is immediately worn out during the sliding between the substrate 12 and the rotating seal ring 20 at extremely low temperatures. As a result, the low-friction resin material 13 is ground off again and acts as a solid lubricant.

[0056] As described above, when the temperature between the sliding surfaces 11 and 21 is low, the outer space S1 and the inner space S2 can be sealed while the base material 12 of the stationary seal ring 10 and the rotating seal ring 20 are stably lubricated with liquid. On the other hand, when the temperature between the sliding surfaces 11 and 21 rises and the liquid lubrication between the sliding surfaces 11 and 21 is not performed, the sliding property between the sliding surfaces 11 and 21 can be ensured by the low-friction resin material 13, and the outer space S1 and the inner space S2 can be sealed.

[0057] Furthermore, the sliding property can be improved by supplying the wear powder P of the low-friction resin material 13 as a solid lubricant to the gap S10 between the sliding surfaces 11 and 21 .

[0058] Furthermore, since the low-friction resin material 13 is attached to the base material 12 having high hardness, the low-friction resin material 13 can be stably supported, and deformation of the low-friction resin material 13 can be suppressed.

[0059] Furthermore, the base material 12 and the low-friction resin material 13 can be handled as an integral component during disassembly and assembly at room temperature, thereby preventing the low-friction resin material 13 from falling off. Furthermore, even during use, the low-friction resin material 13 is stably attached to the base material 12, so even when the low-friction resin material 13 slides, the sliding characteristics are stable.

[0060] Furthermore, since there is almost no gap between the base material 12 and the low-friction resin material 13 , the wear powder P of the low-friction resin material 13 can be reliably supplied between the front surface 12 d of the second convex portion 12 c and the sliding surface 21 .

[0061] Furthermore, since the low-friction resin material 13 is in a shape that is externally fitted to the base material 12 , even if thermal shrinkage occurs at extremely low temperatures, no voids are formed.

[0062] Furthermore, since the low-friction resin material 13 has high toughness, it is not damaged at the contact portion with the base material 12 of the outer fitting portion.

[0063] In other words, the front surface 13d of the low friction resin material 13 is continuously formed on the sliding surface 11 in the circumferential direction, so that the sliding surfaces 11 and 21 can be reliably sealed in the entire circumferential direction.

[0064] Furthermore, the base material of the rotary seal ring 20 is made of a material having a higher hardness than the low-friction resin material 13. As a result, the low-friction resin material 13 slides relative to the sliding surface 21 of the rotary seal ring 20, and thus wear can be suppressed compared to the relative sliding of the low-friction resin material 13 and the rotary seal ring made of a soft material. Furthermore, the sliding between the base material of the rotary seal ring 20 and the base material 12 of the stationary seal ring 10 (i.e., the front surface 12d of the second convex portion 12c) made of the same material is stable.

[0065] Furthermore, since the low-friction resin material 13 is attached to the base material 12 of the stationary seal ring 10 , it is possible to prevent the centrifugal force from acting on the low-friction resin material 13 .

[0066] Furthermore, since the second protrusion 12c of the substrate 12 is arranged on the low-pressure side, i.e., the inner diameter side, of the low-friction resin material 13, it is easy to use the sealed fluid F1 that wants to flow from the outer space S1 toward the inner space S2 to provide wear powder P of the low-friction resin material 13 between the front face 12d of the second protrusion 12c and the sliding surface 21.

[0067] Furthermore, since the low-friction resin material 13 is externally fitted to the first convex portion 12 b by thermal shrinkage, the low-friction resin material 13 can be easily assembled to the base material 12 .

[0068] Furthermore, since the low-friction resin material 13 is attached to the base material 12 , the stationary seal ring 10 can be formed more easily than when a low-friction resin coating is formed on the base material.

[0069] Example 2

[0070] Next, refer to Figure 6 The mechanical seal of Example 2 is described. In addition, the description of the same and repeated structures as those of the previous embodiment is omitted. Figure 6 The shape at room temperature is shown.

[0071] The base 212 of the stationary seal ring 210 of the second embodiment has a shape in which a convex portion 212b protrudes from the inner diameter side of a base portion 212a toward the rotating seal ring 20. A concave portion 212c opening toward the rotating seal ring 20 is formed in the convex portion 212b.

[0072] The low friction resin material 213 is a ring member having a rectangular cross section. The low friction resin material 213 is pressed into the recessed portion 212c. Thus, the low friction resin material 213 is pressed into the recessed portion 212c, so that the base material 212 and the low friction resin material 213 can be firmly attached.

[0073] Furthermore, at extremely low temperatures, gaps are formed between the inner peripheral surface of the recessed portion 212 c and the outer peripheral surface of the low-friction resin material 213 and between the bottom surface of the recessed portion 212 c and the back surface of the low-friction resin material 213 .

[0074] In addition, in the second embodiment, the low friction resin material 213 is attached to the base material 212 of the stationary seal ring 210, but the present invention is not limited thereto. A convex portion and a concave portion may be formed on the rotary seal ring, and the low friction resin material may be attached to the concave portion of the rotary seal ring. In this case, the annular portion of the convex portion is disposed on the outer diameter side of the low friction resin material. Therefore, even if the low friction resin material is attached to the rotary seal ring side, the low friction resin material is not easily affected by centrifugal force.

[0075] Example 3

[0076] Next, refer to Figure 7The mechanical seal of the third embodiment will be described. In addition, the description of the same or repeated structures as those of the first embodiment will be omitted. Figure 7 The shape at room temperature is shown.

[0077] The base material 312 of the stationary seal ring 310 of the third embodiment has an annular recessed portion 312 f opened toward the outer diameter side formed between the first protruding portion 312 b and the base portion 312 a .

[0078] The low-friction resin material 313 is provided with an annular convex stripe 313e protruding toward the inner diameter side at the end of the axial portion 313a on the side opposite to the rotary seal ring 20. The convex stripe 313e is fitted into the annular concave portion 312f.

[0079] Furthermore, at extremely low temperatures, a gap is formed between the back surface of the annular recessed portion 321f and the axial end surface on the sliding surface side of the convex strip portion 313e.

[0080] In this way, since the convex stripe portion 313 e is clamped and fixed to the annular recessed portion 312 f , the axial movement of the low-friction resin material 313 relative to the base material 312 is restricted, and the low-friction resin material 313 is firmly fixed to the base material 312 .

[0081] Example 4

[0082] Next, refer to Figure 8 The mechanical seal of the fourth embodiment is described. In addition, the description of the same or repeated structures as those of the third embodiment is omitted. Figure 8 The shape at room temperature is shown.

[0083] In the mechanical seal of the fourth embodiment, a sealed fluid F1 exists in the outer space S1 and a sealed fluid F2 exists in the inner space S2.

[0084] The base 412 of the stationary seal ring 410 of the fourth embodiment has a first protrusion 412b and a second protrusion 412c. The first protrusion 412b protrudes from the inner diameter side of the base 412a toward the rotating seal ring 20. The second protrusion 412c protrudes from the outer diameter side of the first protrusion 412b toward the rotating seal ring 20.

[0085] Furthermore, an annular recessed portion 412 g opening toward the rotary seal ring 20 is formed between the first protruding portion 412 b and the second protruding portion 412 c .

[0086] The low friction resin material 413 has an axial portion 413a, a radial portion 413b, and a convex stripe portion 413e. The axial portion 413a is arranged along the inner peripheral surface of the first convex portion 412b. The radial portion 413b is arranged along the front surface of the first convex portion 412b.

[0087] The convex stripe 413e extends from the outer diameter end of the radial portion 413b to the side opposite to the rotary seal ring 20 and is gripped and fixed to the annular recessed portion 412g.

[0088] As a result, the convex stripe portion 413 e is gripped and fixed to the annular concave portion 412 g , so that the radial movement of the low-friction resin material 413 relative to the base material 412 is restricted, and the low-friction resin material 413 is firmly fixed to the base material 412 .

[0089] Furthermore, since the low-friction resin material 413 has high toughness, it will not be damaged at the gripping portion that contacts the base material 412 .

[0090] Furthermore, in the fourth embodiment, since the low-friction resin material 413 is disposed on the low-pressure side, deformation of the low-friction resin material 413 caused by the sealed fluid F1 on the high-pressure side can be suppressed.

[0091] Furthermore, at extremely low temperatures, gaps are formed between the inner circumferential surface of the annular recess 412g and the outer circumferential surface of the convex strip 413e, between the bottom surface of the annular recess 412g and the back surface of the convex strip 413e, between the inner circumferential surface of the first convex portion 412b and the outer circumferential surface of the axial portion 413a, and between the axial end surface on the sliding surface side of the first convex portion 412b and the back surface of the axial portion 413a.

[0092] As mentioned above, although the embodiment of the present invention is described with reference to the drawings, the specific structure is not limited to these embodiments, and the change and addition within the range which does not deviate from the summary of the present invention are also included in the present invention.

[0093] For example, in the above-mentioned first to fourth embodiments, the low-friction resin material is exemplified as being in a ring shape, but a plurality of low-friction resin materials may be arranged in the circumferential direction of the sliding surface.

[0094] Furthermore, the rotating seal ring may be made of a base material different from that of the stationary seal ring, or may be made of the same material as that of the stationary seal ring, and is preferably made of a material harder than the low-friction resin material.

[0095] Furthermore, in the above-mentioned embodiments 1 to 4, the low friction resin material is illustrated as being mounted on the base material of the stationary seal ring, but the low friction resin material may be mounted on the base material of the rotating seal ring, or may be mounted on both seal rings. In addition, it is preferred that the low friction resin material is provided on only one of the sliding rings.

[0096] Furthermore, in the above-mentioned Examples 1 to 4, the low-friction resin material is fixed to the base material by heat shrinkage, pressing, or gripping, but it may also be welded, bonded, etc., and the fixing method can be freely selected.

[0097] Furthermore, in the above-mentioned first to fourth embodiments, the sealed fluid F1 is exemplified as having a higher pressure than the sealed fluid F2 , but the sealed fluid F1 may be at a lower pressure than the sealed fluid F2 , or may be at the same pressure.

[0098] Furthermore, the sealed fluids F1 and F2 may be in any state of gas, liquid, or a mixture of gas and liquid. Furthermore, the sealed fluids F1 and F2 are not limited to cryogenic fluids, but may be fluids at room temperature or high temperature.

[0099] Furthermore, in the above-mentioned Examples 1 to 4, an example is given of a state in which the liquid vaporizes due to the temperature rise between the sliding surfaces, resulting in less liquid remaining between the sliding surfaces. However, it can also be applied to a situation in which the liquid remaining between the sliding surfaces decreases due to the structure of the mechanical seal or the use environment.

[0100] Furthermore, in the above-mentioned Embodiments 1 to 4, the inner-type mechanical seal is used as an example for description, but the invention is not limited thereto, and an outer-type mechanical seal may also be used.

[0101] Furthermore, in the above-mentioned Examples 1 to 4, the sealing surface is illustrated as being composed of a substrate and a resin material, but it is sufficient as long as it includes at least a substrate and a resin material. For example, the sealing surface may also be composed of a substrate, a resin material, and different components arranged on the outside of them.

[0102] Description of symbols

[0103] 1: rotating shaft; 2A: retaining frame (component on the rotating shaft side); 4: housing; 5: sealing cover (component on the housing side); 10: stationary sealing ring (sliding ring on one side); 11: sliding surface (sealing surface); 12: base material; 12d: front side (sliding surface); 13: low-friction resin material (resin material); 20: rotating sealing ring; 21: sliding surface; 210: stationary sealing ring (sliding ring on one side); 213: low-friction resin material (resin material); 310: stationary sealing ring (sliding ring on one side); 313: low-friction resin material; 410: stationary sealing ring (sliding ring on one side); 412: base material; 413: low-friction resin material; F1, F2: sealed fluid; P: wear powder; S1: external space (sealed fluid side); S2: internal space (leakage side); S10: gap.

Claims

1. A mechanical seal, which is arranged between a housing and a rotating shaft rotating relative to the housing, and slides and divides a sealed fluid space and a leakage space by a stationary sliding ring fixed to the housing side and a rotating sliding ring fixed to the rotating shaft side rotating relative to each other, wherein: The sealing surface of at least one of the sliding rings has: an annular base material mounted on the housing side member or the rotating shaft side member; and a resin material, which is mounted on the substrate, The resin material is configured in a ring shape.

2. The mechanical seal according to claim 1, wherein: At least a portion of the sliding surface of the other sliding ring that slides against the resin material is made of a material having a higher hardness than the resin material.

3. The mechanical seal according to claim 1, wherein: The sliding ring on one side is a stationary sealing ring, and the sliding ring on the other side is a rotating sealing ring.

4. The mechanical seal according to any one of claims 1 to 3, wherein: At least a portion of the sealing surface of the base material is formed on the leakage space side relative to the resin material.

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