Mechanical seal

Abstract

To provide a mechanical seal which enables a cooling structure to be formed simply.SOLUTION: A mechanical seal M1 defines a sealed fluid space F and a leakage space A by rotating a stationary sealing ring 20, attached to the housing 2, and a rotary sealing ring 10, attached to a rotary shaft 1 inserted into a shaft hole 2a of the housing 2, relative to each other. The mechanical seal M1 includes a spring 30 which applies an axial biasing force to the stationary sealing ring 20 or the rotary sealing ring 10. The sparing 30 has a hollow part 30b communicating with an inlet 30a and an outlet 30c and extending in a longitudinal direction. The outlet 30c is arranged at the side of a slide contact area S1 where the stationary sealing ring 20 and the rotary sealing ring 10 tightly contact and slide upon each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mechanical seal used to seal a rotating shaft of a rotary machine. [Background technology]

[0002] Seals are used in various fields to prevent leakage of sealed fluids. A mechanical seal, one example of such a seal, includes a stationary seal ring, a rotary seal ring that rotates with a rotating shaft, and a biasing means such as a coil spring that applies an axial biasing force to the stationary seal ring or the rotary seal ring. The sliding surfaces of the seal rings slide closely against each other to prevent leakage of the sealed fluid. Some mechanical seals also include a cooling structure that introduces the sealed fluid to cool each seal ring to prevent excessive temperature rise of the seal rings.

[0003] For example, the mechanical seal shown in Patent Document 1 has a cooling structure with an inlet flow passage and an outlet flow passage, which is formed by providing a cylindrical member disposed on the outer diameter side of the rotating seal ring and rotating together with the rotary shaft. The inlet flow passage is a flow passage for introducing the sealed fluid from the space on the cooling jacket side to the space on the sliding contact area side where the seal rings slide closely. The outlet flow passage is a flow passage for discharging the sealed fluid from the space on the sliding contact area side to the space on the cooling jacket side.

[0004] The inlet passage is composed of a through passage and an annular passage. The through passage penetrates the retainer and the rotary seal ring in the radial direction. The inner diameter end of the through passage is connected to the space on the cooling jacket side. The annular passage is defined by the rotary seal ring and the cylindrical member and extends in the axial direction. The outlet passage is provided on the outer diameter side of the cylindrical member and is separated from the annular passage by the cylindrical member.

[0005] As a result, the sealed fluid in the space on the cooling jacket side moves radially outward in the through-passage as a result of the rotation of the rotary seal ring and is introduced into the vicinity of the sliding contact area through the annular passage, and is then discharged into the space on the cooling jacket side through the discharge passage. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6886859 (page 10, Figure 2) Summary of the Invention [Problem to be solved by the invention]

[0007] A mechanical seal such as that described in Patent Document 1 can cool each seal ring by circulating the sealed fluid through an inlet passage and an outlet passage between a space on the cooling jacket side and a space on the sliding contact area side of each seal ring. However, forming the inlet passage and the outlet passage requires the formation of through holes in the retainer and the rotary seal ring, as well as the assembly of a cylindrical member. However, the through holes must be formed in a highly rigid portion, and the configuration for guiding the sealed fluid to the vicinity of the sliding contact area of ​​each seal ring is complicated.

[0008] The present invention has been made in view of these problems, and has as its object to provide a mechanical seal that can have a cooling structure that is simple. [Means for solving the problem]

[0009] In order to solve the above problems, the mechanical seal of the present invention comprises: A mechanical seal in which a stationary seal ring attached to a housing and a rotary seal ring attached to a rotary shaft inserted into a shaft hole of the housing rotate relative to each other to separate a sealed fluid space and a leakage space, a spring that applies an axial biasing force to the stationary seal ring or the rotary seal ring, The spring has a hollow portion that communicates with an inlet and an outlet and extends in the longitudinal direction, and the outlet is located on the side of a sliding contact area where the stationary seal ring and the rotary seal ring slide in close contact with each other. With this, the sealed fluid is introduced into the sliding contact area through the inlet, hollow portion, and outlet of the spring to cool the rotary seal ring and the stationary seal ring, thereby simplifying the cooling structure.

[0010] The inlet and the outlet may each open into the sealed fluid space. This allows the sealed fluid to reliably circulate within the sealed fluid space.

[0011] The spring may be in the form of a coil. This allows the sealed fluid, which is at a relatively low temperature and located away from the sliding contact area, to be introduced through the inlet and discharged through the outlet.

[0012] The spring may be inserted through the rotary shaft and rotate together with the rotary shaft. This allows the flow passage area in the hollow portion to be increased. Also, when the spring rotates together with the rotary shaft, a pumping action occurs in the hollow portion from the inlet to the outlet, so that the sealed fluid can be efficiently introduced into the vicinity of the sliding contact area.

[0013] The inlet may be open in the direction of rotation. This makes it easier to introduce the sealed fluid through the inlet in the spring.

[0014] The inlet may have an inclined shape that is inclined with respect to the direction of rotation. This makes it easier to introduce the sealed fluid through the inlet at the spring.

[0015] The portion of the spring where the hollow portion is provided may extend further toward the sliding surface side than the back surface of the stationary seal ring or the rotary seal ring to which the biasing force is applied from the spring. This ensures that the sealed fluid is introduced into the vicinity of the sliding contact area.

[0016] The mechanical seal may be of a vertical type in which the rotation axis extends vertically. This allows the sealed fluid to be guided to the sliding contact area and cooled even in a vertical mechanical seal. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view of a mechanical seal according to a first embodiment of the present invention. [Figure 2] 2 is a view of the rotary seal ring in the first embodiment as seen from the axial direction. FIG. [Figure 3] 1A is a view of the coil spring and collar in the first embodiment as seen from the axial direction, and FIG. 1B is a view as seen from the arrow A in FIG. [Figure 4] FIG. 4 is a cross-sectional view of a mechanical seal according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a cross-sectional view of a mechanical seal according to a third embodiment of the present invention. [Figure 6] FIG. 11 is a view of a coil spring and a collar according to a third embodiment as viewed from the axial direction. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mechanical seal according to the present invention will be described below with reference to the following examples. [Example]

[0019] The mechanical seal according to the first embodiment will be described with reference to Figures 1 to 3. In the following description, the top and bottom indicated by the arrows in Figure 1 will be referred to as the top and bottom of the paper and the mechanical seal. In more detail, the top side of the paper will be referred to as the top side of the mechanical seal, and the bottom side of the paper will be referred to as the bottom side of the mechanical seal.

[0020] 1, the mechanical seal M1 is a so-called vertical mechanical seal used, for example, to seal a shaft in a pump having a rotating shaft 1 arranged along the vertical direction. The mechanical seal M1 is an inside type that seals against the sealed fluid that attempts to leak from the outer diameter side toward the inner diameter side of the sliding surfaces 10a, 20a.

[0021] As a result, the area radially outside the mechanical seal M1 forms a sealed fluid space F filled with the sealed fluid. Also, the area radially inside the mechanical seal M1 forms a leakage space A from which the sealed fluid attempts to leak. In this embodiment, the sealed fluid is water, but it may be a fluid other than water, and may be changed as appropriate. Also, the sealed fluid space F does not have to be filled with the sealed fluid.

[0022] The mechanical seal M1 is mainly composed of a rotary seal ring 10, a stationary seal ring 20, a coil spring 30, and a collar 40. The rotary seal ring 10 is attached so as to be rotatable and axially movable together with the rotary shaft 1 inserted into a shaft hole 2a formed in a housing 2 of the pump. The stationary seal ring 20 is non-rotatably mounted on a seal cover 3 which is fixed to the housing 2 in a state where relative rotation is restricted. The coil spring 30 is disposed between the rotary seal ring 10 and the collar 40. This allows the coil spring 30 to press the rotary seal ring 10 against the stationary seal ring 20. In other words, the mechanical seal M1 is a so-called single-spring, rotary type.

[0023] As shown in FIGS. 1 and 2, the rotary seal ring 10 is formed in an annular shape and has a large diameter portion 11, a small diameter portion 12, and an annular protruding portion 13.

[0024] The large diameter portion 11 is located between the small diameter portion 12 and the annular protrusion 13. An annular groove 10b that is open inward and recessed in the outer diameter direction is formed on the inner peripheral surface of the large diameter portion 11. An O-ring 5 disposed in the annular groove 10b is pressed against the outer peripheral surface of the rotating shaft 1. This provides a seal between the rotary seal ring 10 and the rotating shaft 1.

[0025] Furthermore, a single through groove 10c is formed at the outer diameter end of the large diameter portion 11. The through groove 10c is open in the outer diameter direction, recessed in a U-shape in the inner diameter direction, and penetrates in the axial direction. The bottom surface of the through groove 10c is located on the outer diameter side of the small diameter portion 12 and the annular protrusion 13. This ensures the strength of the rotary seal ring 10.

[0026] Small diameter portion 12 extends axially downward from the lower end surface of large diameter portion 11. The outer diameter of small diameter portion 12 is smaller than that of large diameter portion 11. The lower end surface of small diameter portion 12 is back surface 10d.

[0027] The annular protrusion 13 extends axially upward from the upper end surface of the large diameter portion 11. The outer diameter of the annular protrusion 13 is smaller than the large diameter portion 11 and the small diameter portion 12. The upper end surface of the annular protrusion 13 is the sliding surface 10a.

[0028] 1, the stationary seal ring 20 is formed in an annular shape, and its lower end surface is a sliding surface 20a.

[0029] In this specification, the sliding surface refers to the entire flat surface including the area that actually comes into sliding contact, that is, it also includes areas that do not actually come into sliding contact.

[0030] Further, the sliding contact area S1 in this specification is an area where the sliding surfaces 10a, 20a of the rotary seal ring 10 and the stationary seal ring 20 slide closely against each other.

[0031] Additionally, the sliding surface 20a of the stationary seal ring 20 has a larger diameter than the sliding surface 10a of the rotary seal ring 10. As a result, an annular recess S2 is formed on the outer diameter side of the sliding contact area S1, which is defined by the large diameter portion 11 of the rotary seal ring 10, the annular protrusion 13, and the stationary seal ring 20. The annular recess S2 is open to the radially outer diameter side and is annularly recessed toward the radially inner diameter side.

[0032] The rotating seal ring 10 and the stationary seal ring 20 are typically formed from a combination of SiC (hard material) or SiC (hard material) and carbon (soft material), but this is not limited thereto; any sliding material used for mechanical seals can be used. Examples of SiC include sintered bodies using boron, aluminum, carbon, or other sintering aids, as well as materials consisting of two or more phases with different components and compositions, such as SiC with dispersed graphite particles, reaction-sintered SiC consisting of SiC and Si, SiC-TiC, and SiC-TiN. Examples of carbon include a mixture of carbonaceous and graphite materials, resin-molded carbon, and sintered carbon. In addition to the above sliding materials, metal materials, resin materials, surface-modified materials (coating materials), composite materials, and other materials are also applicable.

[0033] The coil spring 30 is formed into a coil shape by bending a straight pipe member. The coil spring 30 has a coil portion 31, a radially extending portion 32, and an axially extending portion 33. The coil spring 30 also has a hollow portion 30b that communicates from an inlet 30a provided in the radially extending portion 32 to an outlet 30c provided in the axially extending portion 33. The coil spring 30, including the hollow portion 30b, extends in the longitudinal direction with approximately the same diameter.

[0034] The coil portion 31 is a coil-shaped portion located between the radially extending portion 32 and the axially extending portion 33. The winding diameter of the coil portion 31 is substantially constant.

[0035] In this embodiment, the rotating shaft 1 rotates counterclockwise when viewed from above in the axial direction, as indicated by the black arrow in Fig. 1. With reference to Fig. 1 and Fig. 3(a), the coil portion 31 extends axially upward while being wound clockwise from a lower end that is continuous with the radially extending portion 32 when viewed from above in the axial direction, and its upper end is continuous with the axially extending portion 33.

[0036] 3(a), the radially extending portion 32 extends linearly from the lower end of the coil portion 31 in a counterclockwise direction in the tangential direction as viewed from above in the axial direction. An end face 32a of the radially extending portion 32 is inclined with respect to the rotational direction, i.e., is substantially perpendicular to the circumferential direction. An inlet 30a provided in the end face 32a is open in the rotational direction and has an inclined shape inclined with respect to the rotational direction.

[0037] 1, the axially extending portion 33 extends linearly along the axial direction from the upper end of the coil portion 31. An end face 33a of the axially extending portion 33 has an annular shape that is substantially perpendicular to the radial direction. An outlet 30c provided in the end face 33a has a circular shape.

[0038] The collar 40 is formed in an annular shape and is fixed to the rotary shaft 1 by a set screw 4. As shown in Fig. 3, the collar 40 has a groove 41 and a notch 42. In Fig. 3(a), in order to clearly show the coil spring 30, the groove 41, and the notch 42, a dot pattern is applied to the outer wall 41a and the inner wall 41b that define the groove 41.

[0039] The groove portion 41 is a partially interrupted annular groove formed on the upper end surface of the collar 40, and is open axially upward and recessed axially downward.

[0040] The notch 42 is formed on the upper end surface of the collar 40, and is a cutout portion of the outer wall 41a that defines the groove 41, where the cutout portion corresponds to a substantially quarter arc.

[0041] Here, the assembly of the mechanical seal M1 will be described. First, the seal cover 3 to which the stationary seal ring 20 is assembled is fixed to the housing 2 with reference to FIG.

[0042] Next, the rotary seal ring 10, the coil spring 30, and the collar 40 are fitted onto the rotary shaft 1 in this order.

[0043] More specifically, the upper end of the coil portion 31 of the coil spring 30 is fitted onto the small diameter portion 12 of the rotary seal ring 10. Furthermore, the notch 42 of the collar 40 is aligned with the radially extending portion 32 of the coil spring 30, and the lower end of the coil portion 31 of the coil spring 30 is inserted into the groove 41 of the collar 40. As a result, the radially extending portion 32 is positioned within the notch 42.

[0044] In this state, the rotary seal ring 10, coil spring 30, and collar 40 are inserted onto the rotary shaft 1, and the collar 40 is fixed to the rotary shaft 1 at a desired axial position with the set screw 4. In this manner, the mechanical seal M1 can be assembled.

[0045] When the mechanical seal M1 is assembled, the inlet 30a and the outlet 30c of the coil spring 30 communicate with the sealed fluid space F.

[0046] Next, the introduction of the sealed fluid into the sliding contact area S1 side by the coil spring 30 will be described.

[0047] When the rotary shaft 1 rotates, the collar 40 rotates integrally therewith. Accordingly, the coil spring 30 rotates together with the collar 40. The outer wall 41a of the collar 40 abuts against the radially extending portion 32, and has a function of restricting rotation of the coil spring 30.

[0048] Furthermore, the rotary seal ring rotates together with the coil spring 30. An axially extending portion 33 of the coil spring 30 is inserted into the through groove c and has a function of restricting rotation of the rotary seal ring .

[0049] In this way, the coil spring 30 also functions as a stopper for preventing the rotary seal ring 10 from rotating relative to the rotary shaft 1 .

[0050] As described above, the coil portion 31 is inclined axially upward in the counter-rotation direction. As a result, when the coil spring 30 starts to rotate, the sealed fluid in the hollow portion 30b of the coil portion 31 is subjected to centrifugal force and moves toward the outlet 30c. In other words, the entire coil portion 31 can generate a pumping action.

[0051] The flow of the sealed fluid generated in the hollow portion 30b draws the sealed fluid from the sealed fluid space F into the hollow portion 30b at the inlet 30a. In this way, the sealed fluid can be efficiently introduced into the hollow portion 30b through the inlet 30a.

[0052] As the rotating shaft 1 rotates, the sealed fluid in the sealed fluid space F also flows in the same rotational direction, but the rotational speed of the rotating shaft 1 is faster than the flow speed of the sealed fluid. Therefore, the inlet 30a, which is open in the rotational direction, makes it easier to introduce the sealed fluid into the hollow portion 30b.

[0053] The inclined end face 32a of the radially extending portion 32 can guide the sealed fluid toward the inlet 30a. Furthermore, the inlet 30a has an inclined shape, which provides a larger opening area than a circular inlet. This makes it easier to introduce the sealed fluid through the inlet 30a.

[0054] In addition, the inlet 30a is provided along a direction perpendicular to the rotating shaft 1 and is open in the direction of rotation, making it easier to introduce the sealed fluid. In other words, it is easier to introduce the fluid than in a structure in which the inlet is open in a direction parallel to the rotating shaft 1. Furthermore, in this embodiment 1, the radially extending portion 32 extends radially relative to the rotating shaft 1, and the distance between the rotating shaft 1 and the inlet 30a is long, so that the amount of circumferential movement of the inlet 30a per unit time during rotation is large, making it even easier to introduce the sealed fluid.

[0055] The sealed fluid in the hollow portion 30b is discharged from the outlet 30c toward the sliding surface 20a.

[0056] In the sliding contact region S1, frictional heat is generated by the sliding contact between the sliding surfaces 10a, 20a due to the relative rotation of the rotary seal ring 10 and the stationary seal ring 20. The temperature of the sealed fluid around the rotary seal ring 10 and the stationary seal ring 20 is relatively higher than that of the sealed fluid spaced apart from the rotary seal ring 10 and the stationary seal ring 20.

[0057] The sealed fluid, which is relatively low in temperature, is introduced into the annular recess S2 through the coil spring 30. This allows the rotary seal ring 10 and the stationary seal ring 20, particularly the sliding contact area S1 facing the annular recess S2, to be cooled. Furthermore, as the rotary seal ring 10 rotates, the outlet 30c also moves circumferentially, so the sealed fluid discharged from the outlet 30c is supplied to the entire circumference of the annular recess S2.

[0058] Furthermore, the coil spring 30 is fitted onto the small diameter portion 12 of the rotary seal ring 10 and abuts against the bottom surface and inner peripheral surface of the through groove 10c of the rotary seal ring 10. This facilitates heat exchange between the sealed fluid in the hollow portion 30b and the rotary seal ring 10 via the coil spring 30. In this way, the contact of the coil spring 30 with the rotary seal ring 10 also allows the rotary seal ring 10 to be cooled.

[0059] As described above, the mechanical seal M1 of this embodiment can simply configure a cooling structure that can guide the sealed fluid near the sliding contact area S1 between the rotating seal ring 10 and the stationary seal ring 20 by using the hollow coil spring 30.

[0060] The inlet 30a and outlet 30c of the coil spring 30 each open to the sealed fluid space F. Therefore, the sealed fluid, which is relatively high temperature around the rotary seal ring 10 and the stationary seal ring 20, is caused to flow in a direction away from the rotary seal ring 10 and the stationary seal ring 20 by the sealed fluid introduced from the outlet 30c. In this way, the sealed fluid can be reliably circulated in the sealed fluid space F.

[0061] The spring in this embodiment is a coil spring 30. Therefore, it is easier to ensure the axial dimension compared to a coiled wave spring or the like. As a result, the coil spring 30 can introduce a relatively low-temperature sealed fluid located at a distance from the inlet 30a. Furthermore, by appropriately changing the axial dimension of the coil portion 31, the inlet 30a can be positioned in a desired area.

[0062] The coil spring 30 has a larger diameter than the rotating shaft 1. Furthermore, the coil spring 30 is larger than a coil spring (see FIG. 6) used in a so-called multi-spring type mechanical seal in which multiple coil springs are arranged circumferentially on the outer diameter side of the rotating shaft. This allows the coil spring 30 to have a hollow portion 30b with a large flow path area. Therefore, the coil spring 30 allows the sealed fluid to easily flow from the inlet 30a to the outlet 30c.

[0063] Furthermore, the axially extending portion 33 of the coil spring 30 extends further toward the sliding surface 10a than the back surface 10d of the rotary seal ring 10 with which the coil spring 30 abuts. Therefore, compared to a configuration in which the outlet of the coil spring is located on the back surface 10d side of the large diameter portion 11, for example, the sealed fluid can be reliably introduced near the sliding contact area S1.

[0064] Furthermore, since the mechanical seal M1 is a vertical type, the water surface of the sealed fluid in the sealed fluid space F may not reach the sliding contact area S1. Even in such a case, as described above, the inlet 30a is located on the lower side of the sealed fluid space F, so the sealed fluid can be supplied to the annular recess S2 through the coil spring 30. In this way, not only can the rotary seal ring 10 and the stationary seal ring 20 be cooled, but poor lubrication due to a shortage of the sealed fluid can also be prevented.

[0065] Furthermore, in a configuration such as that described in Patent Document 1, in which a flow passage is formed in a rotary seal ring and a separate cylindrical member is further attached, achieving a cooling structure with a vertical mechanical seal requires extending the rotary seal ring and cylindrical member in the axial direction. This increases their weight, which in turn requires the biasing means to be larger. This can result in adverse effects such as an increase in the energy required to rotate the rotating shaft 1. In contrast, in the mechanical seal M1 of the present invention, the cooling structure is primarily formed by providing the inlet 30a, hollow portion 30b, and outlet 30c in the coil spring 30, so the impact on the rotation of the rotating shaft 1 is minimal.

[0066] The axially extending portion 33 of the coil spring 30 extends substantially parallel to the axis of the coil spring 30. In contrast, if the coil spring were configured to detour around the outside along the large diameter portion 11 of the rotary seal ring 10, the distance from the back surface 10d of the rotary seal ring 10 to the outlet would be longer. In addition, the end portion where the outlet is provided would extend from the outer diameter side toward the inner diameter side. In this case, the sealed fluid would tend to flow from the outer diameter side toward the inner diameter side toward the outlet, but centrifugal force would act on the sealed fluid, making it difficult to be discharged from the outlet. As a result, the coil spring 30 allows a smooth flow of the sealed fluid in the hollow portion 30b.

[0067] In addition to the above, the outlet 30c is disposed opposite the sliding surface 20a of the stationary seal ring 20. Therefore, the sealed fluid supplied from the outlet 30c can easily reach the sliding surface 20a.

[0068] Furthermore, the end face 33a of the axially extending portion 33 of the coil spring 30 is disposed substantially flush with the upper end face of the large diameter portion 11 of the rotary seal ring 10. On the other hand, if the end face of the axially extending portion were spaced lower than the upper end face of the large diameter portion 11, it is conceivable that the sealed fluid discharged from the outlet would adhere to the outer circumferential surface of the large diameter portion 11, which defines the through groove 10c, before reaching the annular recess S2. In this case, the sealed fluid adhering to the outer circumferential surface may be blown away by centrifugal force before reaching the annular recess S2. As a result, the coil spring 30 can efficiently supply the sealed fluid to the annular recess S2. [Example]

[0069] Next, the mechanical seal of the second embodiment will be described with reference to Fig. 4. In the following description, the left and right sides indicated by the arrows in Fig. 4 will be referred to as the left and right sides of the paper and the mechanical seal. In more detail, the left side of the paper will be referred to as the left side of the mechanical seal, and the right side of the paper will be referred to as the right side of the mechanical seal. Note that descriptions of configurations that are the same as those of the first embodiment will be omitted.

[0070] 4, the mechanical seal M2 is a so-called horizontal mechanical seal used, for example, to seal a shaft in a pump having a rotating shaft 1 arranged horizontally. The mechanical seal M2 is an outside type that seals against the sealed fluid that attempts to leak from the inner diameter side toward the outer diameter side of the sliding surfaces 110a, 120a.

[0071] As a result, the area radially inward of the mechanical seal M2 constitutes a sealed fluid space F. Also, the area radially outward of the mechanical seal M2 constitutes a leakage space A.

[0072] The mechanical seal M2 is mainly composed of a rotary seal ring 110, a stationary seal ring 120, a coil spring 130, and a collar 140. The mechanical seal M2 is a so-called single spring type rotary seal.

[0073] The rotary seal ring 110 has an annular groove 114 and a through hole 115 on the inner diameter side of the annular protrusion 113. The annular groove 114 is formed on the back surface 110d of the rotary seal ring 110, is open to the left, and is recessed to the right. The through hole 115 is drilled approximately parallel to the axis of the rotary seal ring 110, and communicates with the annular groove 114 and the annular recess S12.

[0074] A right end portion of a coil portion 131 of the coil spring 130 is disposed in the annular groove 114. Furthermore, an axial extension portion 133 of the coil spring 130 is inserted into the through hole 115.

[0075] Collar 140 has a cylindrical wall portion 140a that fits around rotary seal ring 110. An O-ring 105 seals between wall portion 140a and rotary seal ring 110. An O-ring 104 seals between collar 140 and rotary shaft 1.

[0076] An annular wall 143 is provided on the inner diameter side of the collar 140. The left end of the coil portion 131 of the coil spring 130 is fitted onto the annular wall 143.

[0077] The wall portion 140a is formed with a protrusion 144 that bulges out in the radial direction. The protrusion 144 is arranged so as to be able to come into contact with the radially extending portion 132 of the coil spring .

[0078] As a result, when the rotary shaft 1 rotates, the coil spring 130 , in which the protrusion 144 of the collar 140 is in contact with the radial extension 132 , also rotates together with the collar 140 .

[0079] Furthermore, the rotary seal ring 110 , whose axially extending portion 133 of the coil spring 130 is inserted into the through hole 115 , also rotates together with the coil spring 130 .

[0080] In this way, the coil spring 130 also functions as a stopper for preventing the rotary seal ring 110 from rotating relative to the rotary shaft 1 .

[0081] The mechanical seal M2 of this embodiment configured as described above can introduce the sealed fluid into the sliding contact area S11 side through the inlet 130a, hollow portion 130b, and outlet 130c of the coil spring 130 by rotating the rotary shaft 1. This allows the mechanical seal M2 to cool the rotary seal ring 110 and the stationary seal ring 120.

[0082] Although the mechanical seal M1 in the first embodiment has been described as being of a vertical type, the present invention is not limited to this and may be used as a horizontal type similar to the mechanical seal M2 in this embodiment.

[0083] Furthermore, although the mechanical seal M2 in this embodiment has been described as being of a horizontal type, it is not limited to this and may be of a vertical type. [Example]

[0084] Next, a mechanical seal according to a third embodiment will be described with reference to Figures 5 and 6. Note that a description of the same configuration as in the first embodiment will be omitted.

[0085] 5, the mechanical seal M3 is a so-called vertical mechanical seal. The mechanical seal M3 is an inside type that seals against the sealed fluid that attempts to leak from the outer diameter side toward the inner diameter side of the sliding surfaces 210a and 220a.

[0086] The mechanical seal M3 is mainly composed of a rotary seal ring 210, a static seal ring 220, multiple coil springs 230, and a collar 240. Eight of the multiple coil springs 230 are evenly spaced between the rotary seal ring 210 and the collar 240. In other words, the mechanical seal M3 is a so-called multi-spring rotary type. The number of coil springs 230 arranged is not important. Furthermore, the coil springs 230 do not have to be evenly spaced.

[0087] The rotary seal ring 210 is provided with a protrusion 210e that protrudes axially downward from the back surface 210d. The collar 240 is provided with a through-hole recess 245 on its axial upper end surface, which is open axially upward, recessed axially downward, and penetrates radially. The protrusion 210e is inserted into the opposing through-hole recess 245. This prevents the rotary seal ring 210 from rotating relative to the collar 240. In other words, the rotary seal ring 210 and the collar 240 are prevented from rotating by a clutch mechanism, allowing relative movement in the axial direction. Note that there may be multiple protrusions 210e and multiple through-hole recesses 245, and in that case, their arrangement is not critical.

[0088] The rotary seal ring 210 and the collar 240 may be prevented from rotating by using a rotation prevention pin instead of a clutch mechanism, or by each coil spring 230, and the rotation prevention means may be changed as appropriate. This also applies to the other embodiments.

[0089] 6, collar 240 has hole 241 and slit 242. Hole 241 is formed in the upper end surface of a protruding portion of collar 240 that protrudes radially outward, is open axially upward, and is recessed axially downward.

[0090] The inner diameter side of the slit 242 is in communication with the hole portion 241. The slit 242 also penetrates from the hole portion 241 in the outer diameter direction so that the radially extending portion 232 of the coil spring 230 can be inserted when the lower end of the coil spring 230 is inserted into the hole portion 241. As a result, when the radially extending portion 232 is inserted into the slit 242, the coil spring 230 is prevented from rotating.

[0091] The radially extending portion 232 extends in a roughly radial direction of the rotating shaft 1 with its tip bent in the circumferential direction, but is not limited to this, and may have a tip curved in the circumferential direction, or may extend linearly only in the radial direction without being bent or curved, or may extend at an angle in both the radial and circumferential directions. In any case, it is preferable that the inlet 230a is open in the rotation direction, as in the radially extending portion 232 in this embodiment.

[0092] An axially extending portion 233 of the coil spring 230 is inserted into a through hole 215 in the rotary seal ring 210 formed on the outer diameter side of the sliding contact area S1.

[0093] In the mechanical seal M3 configured as described above, when the rotating shaft 1 is rotated, the sealed fluid flows into the inlet 230a, causing the sealed fluid in the hollow portion 230b to move and be supplied to the vicinity of the sliding contact area S1 through the outlet 230c.

[0094] Furthermore, the multi-spring mechanical seal M3, in which the coil springs 230 are evenly spaced, can simultaneously supply the sealed fluid from multiple locations in the circumferential direction. Therefore, the mechanical seal M3 can cool the sliding surfaces 210a and 220a more uniformly than the single-spring mechanical seals of Examples 1 and 2. Furthermore, by appropriately changing the axial dimension of the coil portion 231, the inlet 230a can be positioned in a desired area.

[0095] In this embodiment, the mechanical seal M3 has been described as being an inside type with a multi-coil spring configuration, but is not limited to this and may be an outside type with a multi-coil spring configuration.

[0096] Furthermore, although the mechanical seal M3 in this embodiment has been described as being of a vertical type, it is not limited to this and may be of a horizontal type.

[0097] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0098] For example, in the first to third embodiments, the vicinity of the sliding contact area is described as an annular recess facing the sliding contact area, but the present invention is not limited to this and may be any space facing the sliding contact area.

[0099] Furthermore, in the above-described first to third embodiments, the springs have been described as being coil springs, but this is not limited thereto, and the springs may be appropriately changed to coiled wave springs or the like as long as they have an inlet, a hollow portion, and an outlet.

[0100] Furthermore, in the first to third embodiments, the inlet of the coil spring is described as being open in the rotation direction, but this is not limiting, and the inlet may be open in a direction different from the rotation direction.

[0101] In addition, in the first to third embodiments, a hollow portion is provided along the length of the coil spring, but this is not limiting, and the coil spring may have at least one of an inlet and an outlet at a midpoint away from the ends thereof, and a hollow portion communicating with the inlet and outlet may be provided in a portion of the coil spring. In addition, the inlet and outlet may be provided at positions away from the longitudinal ends of the hollow portion.

[0102] Furthermore, in the above-described Examples 1 to 3, the end portion where the inlet of the coil spring is provided is described as being a radially extending portion that extends linearly in the tangential direction from the coil portion, but this is not limited to this, and the end portion may be provided in a curved or broken line shape.

[0103] In addition, in the first to third embodiments, the inlet is provided in the axially extending portion of the coil spring, but this is not limiting, and the inlet may be provided in the coil portion, and the shape of the inlet may be changed as appropriate. The outlet may also be provided in the coil portion.

[0104] Similarly, in Examples 1 to 3, the end portion of the coil spring where the outlet is provided is described as being an axially extending portion that extends linearly along the axial direction, but this is not limited to this and the end portion may be provided in a curved or broken line shape.

[0105] In addition, in the first to third embodiments, the end of the coil spring where the outlet is provided is described as extending to the sliding surface, but this is not limited thereto, and the outlet does not have to extend to the sliding surface of the rotary seal ring. In such a configuration, it is preferable that the outlet is arranged so as to be able to communicate with, for example, a through hole or through groove that extends to the sliding surface of the rotary seal ring.

[0106] Furthermore, in the first embodiment, the axially extending portion of the coil spring is described as being inserted into the through groove in the rotary seal ring, but this is not limited to this. The rotary seal ring may not be provided with a through groove and the axially extending portion may be arranged along its outer circumferential surface, or as in the second and third embodiments, the axially extending portion may be inserted into a through hole that passes through the rotary seal ring in the axial direction, and the arrangement may be changed as appropriate.

[0107] Furthermore, in the above-described first and second embodiments, the radially extending portion of the coil spring abuts against the outer wall or protrusion of the collar, and the axially extending portion of the coil spring is inserted into the through groove or through hole of the rotary seal ring, thereby preventing the coil spring from rotating relative to the rotary shaft. However, this is not limited to this, and the coil spring may be prevented from rotating by fixing a part of the coil spring to the collar by welding or the like and fixing another part of the coil spring to the rotary seal ring by welding or the like, or any other suitable modification may be made as long as the prevention of rotation is possible.

[0108] Furthermore, in the first and second embodiments, examples have been described in which the coil spring has a function of preventing rotation of the rotary seal ring. However, the coil spring may not have a function of preventing rotation, and another anti-rotation member may be used to prevent rotation of the rotary seal ring relative to the rotary shaft.

[0109] Furthermore, in the above-described Examples 1 to 3, the coil spring has been described as having a substantially constant winding diameter, but this is not limited to this, and the coil spring may be conical or barrel-shaped, with the diameter decreasing or increasing from the inlet side to the outlet side, or may be modified as appropriate. [Explanation of symbols]

[0110] 1 Rotation axis 2. Housing 2a shaft hole 10 Rotating seal ring 10a Sliding surface 10d back 20 Stationary sealing ring 20a sliding surface 30 coil spring 30a entrance 30b Hollow part 30c exit 110,210 Rotating seal ring 110a,210a sliding surface 120,220 Stationary sealing ring 120a,220a sliding surface 130,230 coil spring 130a,230a entrance 130b,230b Hollow part 130c,230c exit A Leakage space F Sealed fluid space M1 Mechanical Seal M2 Mechanical Seal M3 Mechanical Seal S1 sliding contact area S11 Sliding contact area

Claims

1. A mechanical seal in which a stationary seal ring attached to a housing and a rotary seal ring attached to a rotary shaft inserted into a shaft hole of the housing rotate relative to each other to separate a sealed fluid space and a leakage space, a spring that applies an axial biasing force to the rotary seal ring; The spring has a hollow portion extending in the longitudinal direction and communicating with an inlet and an outlet, and the outlet is located on the sliding contact area side where the stationary seal ring and the rotary seal ring slide in close contact with each other.

2. 2. The mechanical seal according to claim 1, wherein the inlet and the outlet each open into a sealed fluid space.

3. 2. The mechanical seal according to claim 1, wherein the spring is in the form of a coil.

4. The mechanical seal according to claim 3 , wherein the spring is inserted through the rotary shaft and rotates together with the rotary shaft.

5. The mechanical seal according to claim 4, wherein the inlet is open in the direction of rotation.

6. The mechanical seal according to claim 5, wherein the inlet has an inclined shape inclined with respect to the direction of rotation.

7. 2. The mechanical seal according to claim 1, wherein the hollow portion of the spring extends to a sliding surface side of the back surface of the rotary seal ring to which the biasing force from the spring is directly applied.

8. 8. The mechanical seal according to claim 1, wherein the mechanical seal is of a vertical type in which the rotary shaft extends vertically.

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