Mechanical seal

Abstract

To provide a mechanical seal capable of suppressing generation of noise or vibration.SOLUTION: A mechanical seal 1 is configured such that a stationary seal ring 40 attached to a housing 3, and a rotary seal ring 10 attached to a rotational shaft 2 inserted into the housing 3 slide relative to each other to separate a sealed fluid space S1 and a leakage space S2. Between the rotational shaft 2 and the rotary seal ring 10, a secondary seal 30 is arranged. A friction member 20 is arranged radially so as to overlap the rotary seal ring 10 and the secondary seal 30, and is in contact with the rotational shaft 2 and the rotary seal ring 10 to prevent relative rotation between them. The friction member 20 has a tapered shape with a contact part 23 with the rotary seal ring 10 inclined toward the rotary seal ring 10.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Mechanical seals are used by being installed between a housing of a fluid device and a rotating shaft arranged to pass through the housing. More specifically, mechanical seals have the function of preventing leakage of the sealed fluid by bringing the sliding surface of a stationary seal ring attached to the housing into sliding contact with the sliding surface of a rotating seal ring attached to the rotating shaft and rotating in the circumferential direction.

[0003] For example, a mechanical seal as shown in Patent Document 1 includes a stationary seal ring, a rotating seal ring, and a cup gasket. The rotating seal ring is fitted into a hollow rotating shaft with the cup gasket interposed therebetween. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 124252 (page 6, Figure 2) Summary of the Invention [Problem to be solved by the invention]

[0005] In the mechanical seal of Patent Document 1, the cup gasket serves as a so-called secondary seal and provides a seal between the rotating seal ring and the rotating shaft. The cup gasket also transmits the rotation of the rotating shaft to the rotating seal ring, so that the rotating seal ring rotates together with the rotating shaft.

[0006] In the mechanical seal of Patent Document 1, frictional force generated by the close sliding between the stationary seal ring and the rotating seal ring acts on the cup gasket when the rotating shaft rotates. As a result, in the mechanical seal, the cup gasket may repeatedly undergo torsional deformation and return to its original state. At this time, a so-called stick-slip phenomenon occurs in which the rotating seal ring repeatedly stops and moves relative to the stationary seal ring, which may cause squealing or vibration.

[0007] The present invention has been made in consideration of these problems, and has an object to provide a mechanical seal capable of suppressing the occurrence of squeal and vibration. [Means for solving the problem]

[0008] 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 member and a rotary seal ring attached to a rotary shaft member inserted into the housing slide relative to each other to separate a sealed fluid space and a leakage space, a secondary seal is disposed between the one seal ring and a member on the housing side or a member on the rotating shaft side to which the one seal ring is attached, a friction member is provided which is disposed radially overlapping the one seal ring and the secondary seal and which abuts against a member on the housing side or a member on the rotating shaft side and the one seal ring to prevent relative rotation therebetween, The friction member has a tapered shape in which the portion that comes into contact with the one seal ring is inclined toward the one seal ring. According to this, the friction member prevents relative rotation between one of the seal rings and the member on the housing side or the member on the rotating shaft side, thereby reducing torsional deformation of the secondary seal and suppressing the generation of squeal and vibration.

[0009] The friction member may be disposed so as to cover an inner diameter side of the housing member or the rotary shaft member and the one of the seal rings. This allows the mechanical seal to have a compact structure.

[0010] The mechanical seal may be an outside type in which the sealed fluid space is located radially inward of the one seal ring. According to this, the fluid pressure acts on the contact portion, so that the frictional force can be increased.

[0011] The member on the rotating shaft side may be the hollow rotating shaft, and the hollow space of the rotating shaft may be the sealed fluid space. According to this, the swirling flow of the sealed fluid is easily maintained, so that the fluid pressure can be applied to the contact portion more efficiently, and the structure of the mechanical seal can be made compact.

[0012] The friction member may have an elastic contact portion. According to this, the frictional force can be increased by the elastic force of the contact portion that contacts one of the seal rings.

[0013] The friction member may have a piece-like shape with the contact portion extending in the axial direction, and a plurality of the contact portions may be arranged in the circumferential direction. This makes it possible to prevent the occurrence of an overload when the abutting portion is fitted into one of the seal rings.

[0014] The friction member may be disposed so as to cover an inner diameter side of the rotary shaft member and the rotary seal ring. This increases the frictional force because the centrifugal force generated during rotation acts on the contact portion.

[0015] The friction member may have a radially extending portion extending radially at a tip end of the abutment portion, the radially extending portion abutting against the one seal ring in the axial direction. This allows the friction member to be attached easily.

[0016] The friction member may be attached by being press-fitted into a member on the housing side or a member on the rotating shaft side. According to this, the friction member can be prevented from rotating relative to the member on the housing side or the member on the rotating shaft side by simply press-fitting the friction member into one of the seal rings. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a cross-sectional view of a mechanical seal according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a side view of the friction member in the first embodiment. [Diagram 3] FIG. 2 is an enlarged cross-sectional view of a main part of the mechanical seal in the first embodiment. [Figure 4] FIG. 1 is a cross-sectional view of a mechanical seal according to a second embodiment of the present invention. [Diagram 5] FIG. 11 is a cross-sectional view of a mechanical seal according to a third embodiment of the present invention. [Figure 6] FIG. 11 is a cross-sectional view of a mechanical seal according to a fourth embodiment of the present invention. [Figure 7] FIG. 11 is a cross-sectional view of a mechanical seal according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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. EXAMPLES

[0019] A mechanical seal according to a first embodiment will be described with reference to Fig. 1 to Fig. 3. In the following description, the left side of Fig. 1 will be referred to as the left side, and the right side of Fig. 1 will be referred to as the right side.

[0020] As shown in Fig. 1, the mechanical seal 1 of this embodiment is for sealing between a hollow rotating shaft 2 and a housing 3 in a fluid device. The mechanical seal 1 is an outside type in which sliding surfaces 11, 41 seal between an inner space S1 and an outer space S2. The inner space S1 is a sealed fluid space into which a sealed fluid F flows. The outer space S2 is a leakage space communicating with the atmosphere A. Note that this embodiment illustrates an example in which the sealed fluid F is a high-pressure liquid and the atmosphere A is at a lower pressure than the sealed fluid F.

[0021] The mechanical seal 1 is mainly composed of a rotating element 4 and a stationary element 5 .

[0022] The rotating element 4 is mainly composed of a rotating seal ring 10 as one of the seal rings, a friction member 20, and a cup gasket 30 as a secondary seal.

[0023] The rotary seal ring 10 is provided in a state capable of rotating together with the rotary shaft 2 via a friction member 20 and a cup gasket 30 .

[0024] The stationary element 5 is mainly composed of a stationary seal ring 40 as the other seal ring, a seal cover 50, a biasing member 60, a bellows 70, a band 80, and a retainer 90. That is, the mechanical seal 1 of this embodiment is of the stationary type.

[0025] The stationary seal ring 40 is attached to the seal cover 50 via a biasing member 60, a bellows 70, a band 80, and a retainer 90. The stationary seal ring 40 is provided so as to be movable in the axial direction relative to the seal cover 50, which is fixed to the housing 3, while being restricted from rotating. In addition, the space between the stationary seal ring 40 and the seal cover 50 is sealed by the bellows 70.

[0026] The stationary seal ring 40 is biased in the axial direction by a biasing member 60. A sliding surface 41 of the stationary seal ring 40 and a sliding surface 11 of the rotary seal ring 10 are adapted to slide closely against each other.

[0027] In detail, the rotating shaft 2 has a through hole 2a that passes through the radial center of the rotating shaft 2 in the axial direction, making the rotating shaft 2 hollow.

[0028] The right end of the through hole 2a is an enlarged annular recess 6, which is recessed axially leftward from the right end face of the rotating shaft 2 and is open axially rightward and toward the inner diameter side.

[0029] Further, an annular groove 7 is formed on an inner circumferential surface 6a (see FIG. 3) that defines the recessed portion 6 in the rotating shaft 2. The annular groove 7 is recessed toward the outer diameter side from the inner circumferential surface 6a and is annularly recessed and open toward the inner diameter side.

[0030] Hereinafter, a detailed description will be given of the configuration of the rotating element 4. The rotating seal ring 10 is formed into a cylindrical shape having a cross section shaped like a laterally inverted L, and includes an annular seal portion 12 extending radially on the sliding surface 11 side, and a cylindrical body portion 13 extending axially on the inner diameter side.

[0031] Additionally, the right axial end of the seal portion 12 protrudes axially to the right beyond the body portion 13. As a result, an annular recess 14 that is open axially to the right and toward the inner diameter side is formed in the rotary seal ring 10, on the inner diameter side beyond the right axial end of the seal portion 12.

[0032] 1 and 2, friction member 20 is made of metal, and is formed in a cylindrical shape including base 21, annular wall 22, and ten abutment pieces 23 as abutment portions. Note that friction member may be made of resin or may be appropriately changed, but is preferably a member having a higher hardness than cup gasket 30.

[0033] The base portion 21 has a cylindrical shape extending in the axial direction. The outer diameter of the base portion 21 is substantially the same as or slightly larger than the diameter of the through hole 2a in the rotating shaft 2.

[0034] The annular wall portion 22 is flat and annular and extends radially outward from the right end of the base portion 21 .

[0035] The abutment pieces 23 are equally spaced and have a piece shape extending axially rightward from the outer diameter end of the annular wall portion 22. In addition, the abutment pieces 23 are curved plates that are arc-shaped when viewed in the axial direction, with the circumferential center protruding furthest toward the outer diameter side.

[0036] Furthermore, before being fitted into the rotary seal ring 10, i.e., in a natural state, the abutment pieces 23 are inclined toward the outer diameter side toward the annular wall portion 22, i.e., from the left side to the right side in the axial direction, as shown by the two-dot chain line in Fig. 3. In other words, the ten abutment pieces 23 have a tapered shape that expands in diameter from the annular wall portion 22 toward the right side in the axial direction. Note that in Figs. 2 and 3, the abutment pieces 23 are exaggerated to clearly show that they are inclined.

[0037] In the present invention, the tapered shape may be any shape that is inclined in the radial direction. In other words, as long as the shape of a cross section cut in the radial direction is inclined in the radial direction, the shape may be either linear or curved, or may be a combination of these.

[0038] Further, a notch 24 that is open toward the axial right side and on both radial sides is formed between two circumferentially adjacent contact pieces 23 in the circumferential direction.

[0039] As shown in FIG. 1, cup gasket 30 has a cross section formed in an upside-down L-shape, and includes an axially extending portion 31 extending in the axial direction, and a radially extending portion 32 extending toward the inner diameter side, approximately perpendicular to the left end of axially extending portion 31.

[0040] Next, an assembly method for the rotating element 4 will be described with reference to Fig. 3. First, the cup gasket 30 is fitted onto the left end in the axial direction of the body portion 13 of the rotating seal ring 10.

[0041] Next, the rotary seal ring 10 is fitted into the recess 6 in the rotary shaft 2 together with the cup gasket 30. As a result, the gap between the rotary seal ring 10 and the rotary shaft 2 is sealed by the cup gasket 30.

[0042] The cup gasket 30 is in a state where the axially extending portion 31 is sandwiched between the outer peripheral surface 13a of the body portion 13 of the rotary seal ring 10 and the inner peripheral surface 6a of the rotary shaft 2 and compressed in the radial direction. More specifically, of the axially extending portion 31, an annular protruding portion 31a protruding outwardly at the axial center is engaged with the annular groove 7 and compressed in the radial direction. This makes it difficult for the cup gasket 30 to slip out of the recessed portion 6. Also, the portion of the axially extending portion 31 that radially overlaps with the protruding portion 31a is mainly compressed in the radial direction.

[0043] Furthermore, the cup gasket 30 is compressed in the axial direction as the radially extending radially extending portion 32 is sandwiched between the left end surface 13b of the body portion 13 of the rotating seal ring 10 and the inner surface 6b that defines the recess 6 in the rotating shaft 2. The inner diameter end of the inner surface 6b extends further toward the inner diameter side than the inner diameter end edge of the radially extending portion 32, and this portion is exposed.

[0044] Thereafter, the friction member 20 is fitted and fixed to the rotating shaft 2. More specifically, the friction member 20 has the base 21 press-fitted into the through hole 2a of the rotating shaft 2. Note that the base 21 may be fixed to the rotating shaft 2 by welding or the like in a state where it is press-fitted or inserted into the through hole 2a.

[0045] Each abutment piece 23 of the friction member 20 has a tapered shape that expands in diameter toward the right in the axial direction, making it easy to press-fit into the rotary seal ring 10. Furthermore, each abutment piece 23 of the friction member 20 has its outer circumferential surface 23a abutting against the inner circumferential surface 13c of the body portion 13 of the rotary seal ring 10, and elastically deforms toward the inner diameter side.

[0046] Then, the annular wall portion 22 of the friction member 20 comes into contact with the inner surface 6b of the rotating shaft 2, whereby the friction member 20 is positioned in the axial direction, and the assembly method of the rotating element 4 is completed.

[0047] The assembly method of the rotating element 4 may be such that the cup gasket 30 is first fitted onto the rotating shaft 2, and then the rotating seal ring 10 is fitted onto the cup gasket 30, or as in Example 3 described later, the friction member 20 may be attached to the rotating shaft 2, and then the rotating seal ring 10 may be fitted onto the friction member 20, or may be modified as appropriate.

[0048] As described above, the mechanical seal 1 of this embodiment is attached to the rotating shaft 2 with the friction member 20 stretched across the rotating shaft 2 and the rotary seal ring 10. Each abutment piece 23 of the friction member 20 abuts against the rotary seal ring 10 in the radial direction. Frictional force, more specifically static frictional force, generated between each abutment piece 23 and the rotary seal ring 10 prevents relative rotation between the rotary seal ring 10 and the rotating shaft 2. This reduces torsional deformation of the cup gasket 30, suppressing the occurrence of squeal and vibration.

[0049] In addition, since the friction member 20 has each abutment piece 23 provided on the radially opposite side of the axially extending portion 31 of the cup gasket 30 with the rotary seal ring 10 in between, the elastic force of the axially extending portion 31, which is compressed in the radial direction, is prevented from being impaired. This makes it possible to prevent relative rotation between the rotary seal ring 10 and the rotating shaft 2 not only by the frictional force generated between the each abutment piece 23 and the rotary seal ring 10, but also by the frictional force generated between the cup gasket 30 and the rotary seal ring 10.

[0050] Furthermore, since the friction member 20 is disposed so as to cover the inner diameter sides of the rotating shaft 2 and the rotating seal ring 10, the structure of the mechanical seal 1 can be made compact.

[0051] Furthermore, each abutment piece 23 is fitted inside the rotary seal ring 10 in an elastically deformed state, and a resilient force that attempts to return to its original shape acts in the radial direction on the rotary seal ring 10. This makes it possible to increase the frictional force generated between each abutment piece 23 and the rotary seal ring 10.

[0052] Furthermore, the ten abutment pieces 23 are tapered, which makes it easy to fit them inside the rotary seal ring 10 and also makes it easy to obtain a resilient force when they abut on the rotary seal ring 10 when fitted inside the rotary seal ring 10.

[0053] Furthermore, the ten abutment pieces 23 have a tapered shape that expands in diameter toward the right in the axial direction, so that the more they are press-fitted into the rotary seal ring 10, the stronger the resilient force becomes.

[0054] In addition, the ten abutment pieces 23 press-fitted into the rotary seal ring 10 attempt to elastically return to their original position by rotating counterclockwise. That is, the ten abutment pieces 23 apply not only a force toward the outer diameter side of the rotary seal ring 10, but also a force toward the left in the axial direction, which is the insertion direction of the rotary seal ring 10. This increases the frictional force generated between each abutment piece 23 and the rotary seal ring 10, making it possible to suppress movement of the rotary seal ring 10 and cup gasket 30 to the right in the axial direction, which is the removal direction.

[0055] Furthermore, since the ten abutment pieces 23 have a cantilever shape with the notches 24 formed between them in the circumferential direction, they are easily elastically deformed, and the occurrence of overload when fitted into the rotating seal ring 10 can be prevented.

[0056] Furthermore, since the friction member 20 is fitted inside the rotary seal ring 10 and the ten abutment pieces 23 have a one-piece shape, the ten abutment pieces 23 are pressed against the rotary seal ring 10 by centrifugal force generated by rotation together with the rotating shaft 2. This further increases the frictional force generated between each abutment piece 23 and the rotary seal ring 10.

[0057] Furthermore, since the ten abutment pieces 23 are of a one-piece shape and the mechanical seal 1 is of the outside type, the ten abutment pieces 23 are pressed against the rotary seal ring 10 by the fluid pressure of the sealed fluid F acting on the inner circumferential surface 23b (see FIG. 3). This further increases the frictional force generated between each abutment piece 23 and the rotary seal ring 10.

[0058] Furthermore, since the rotating shaft 2 is hollow and the swirling flow of the sealed fluid F within the rotating shaft 2 is easily maintained, the fluid pressure can be applied to each of the contact pieces 23 more efficiently.

[0059] Furthermore, because the ten abutment pieces 23 are in the shape of a curved plate, when the rotary seal ring 10 moves in the circumferential direction relative to the friction member 20, even if they are slightly elastically deformed in response to this, they quickly elastically return to their original position relative to the friction member 20. This allows the rotary seal ring 10 to return to its original circumferential position relative to the friction member 20. Therefore, the ten abutment pieces 23 can restrict the circumferential movement of the rotary seal ring 10.

[0060] In addition, the ten abutment pieces 23 are each in the shape of a curved plate, and thus are prevented from being excessively elastically deformed in the radial direction. This allows elastic deformation to be permitted, while still allowing a resilient force to be applied reliably to the rotary seal ring 10.

[0061] In addition, since the ten abutment pieces 23 are each in a one-piece shape and are evenly arranged, the force compressing the axially extending portion 31 of the cup gasket 30 in the radial direction can be made approximately uniform in the circumferential direction. This reduces the torsional deformation of the cup gasket 30, and suppresses the occurrence of squealing and vibration.

[0062] Moreover, the friction member 20 can be prevented from rotating relative to the rotating shaft 2 and the rotary seal ring 10 simply by being press-fitted into them.

[0063] Furthermore, since the friction member 20 is positioned in the axial direction by abutting its annular wall portion 22 against the inner surface 6 b of the rotating shaft 2, not only is the assembly method simple, but the elastic force acting on the rotating seal ring 10 in each rotating element 4 can be stabilized.

[0064] Furthermore, the structural strength of the friction member 20 is increased by the annular wall portion 22, and unintended deformation is prevented, so that the friction member 20 can be brought into stable contact with the rotary seal ring 10.

[0065] The wall portion does not have to be annular, and may have a structure in which ten portions are provided in the circumferential direction corresponding to the contact pieces 23.

[0066] Furthermore, since the friction member 20 is provided on the side of the rotating seal ring 10 where the cup gasket 30 is prone to torsional deformation, the occurrence of squeal and vibration can be efficiently suppressed.

[0067] Furthermore, since the rotating shaft 2 is hollow, it is possible to omit a sleeve or the like for mounting to the rotating shaft 2, as in the case of the embodiment 3 described below, so that the structure of the mechanical seal 1 can be made compact and simple.

[0068] The rotating element may include a member such as a case for mounting to the rotating shaft. EXAMPLES

[0069] Next, a mechanical seal according to a second embodiment will be described with reference to Fig. 4. Note that a description of the same configuration as in the first embodiment will be omitted.

[0070] 4, in the mechanical seal 101 of the second embodiment, the friction member 120 in the rotating element 104 has ten radially extending portions 125. The radially extending portions 125 extend substantially perpendicularly from the tip of the abutting piece 123, i.e., the right end of the abutting piece 123 in the axial direction, toward the outer diameter side.

[0071] The radially extending portion 125 is disposed in the recess 14 of the rotary seal ring 10, and a left end face 125a of the radially extending portion 125 abuts in the axial direction against a right end face 13d of the body portion 13, which is the side face of the recess 14. The frictional force generated between the radially extending portion 125 and the rotary seal ring 10 prevents relative rotation between the rotary seal ring 10 and the rotating shaft 2. This reduces torsional deformation of the cup gasket 30, and suppresses the occurrence of squeal and vibration.

[0072] In addition, the friction member 120 is provided with the radially extending portion 125 on the axially opposite side of the rotary seal ring 10 from the radially extending portion 32 of the cup gasket 30, so that the elastic force of the axially compressed axially extending portion 31 is prevented from being impaired. As a result, relative rotation between the rotary seal ring 10 and the rotating shaft 2 can be prevented not only by the frictional force generated between the radially extending portion 125 of the friction member 120 and the rotary seal ring 10, but also by the frictional force generated between the cup gasket 30 and the rotary seal ring 10.

[0073] In addition, the radially extending portion 125 of the friction member 120 presses the right end surface 13d of the body portion 13 toward the left in the axial direction. This makes it possible to increase the frictional force generated between the radially extending portion 125 and the rotary seal ring 10.

[0074] In addition, the elastic force generated by axial compression of radially extending portion 32 of cup gasket 30 acts in a direction opposite to the direction in which radially extending portion 125 presses against right end face 13d of body portion 13, thereby increasing the frictional force generated between radially extending portion 125 and the rotating seal ring 10.

[0075] In addition, the ten abutment pieces 123 press-fitted into the rotary seal ring 10 attempt to elastically return to their original position by rotating counterclockwise. This increases the frictional force generated between each abutment piece 123 and the rotary seal ring 10, making it possible to suppress movement of the rotary seal ring 10 and the cup gasket 30 to the right in the axial direction, which is the removal direction.

[0076] In addition, the centrifugal force causes the abutment piece 123 to elastically deform, generating a moment that rotates the radial extension portion 125 toward the rotary seal ring 10, and the radial extension portion is pressed against the rotary seal ring 10. This increases the frictional force generated between the radial extension portion 125 and the rotary seal ring 10.

[0077] In addition, in the assembly method for the rotating element 104, the friction member 120 can be press-fitted onto the rotating shaft 2 by pressing the radially extending portion 125, and therefore, attachment is easy.

[0078] In addition, since the friction member 120 is positioned in the axial direction by the annular wall portion 22 abutting against the inner surface 6 b of the rotating shaft 2, not only is the assembly method simple, but the radial extension portions 32 of the cup gasket 30 can be compressed with approximately the same force in each of the rotating side elements 104.

[0079] In addition, the radial extension portion 125 of the friction member 120 has been described as simply being a plate-like member extending approximately perpendicularly from the axial right end of the abutment piece 123 to the outer diameter side. However, the present invention is not limited to this, and the friction member 120 may have a structure in which, in a natural state, the radial extension portion 125 extends from the axial right end of the abutment piece 123 to the outer diameter side at a slight inclination to the axial left side, that is, a structure in which the radial extension portion 125 is inclined at an acute angle to the abutment piece 123.

[0080] With this structure, the radially extending portion is pressed against the rotating seal ring 10 and elastically deforms so as to be approximately perpendicular to the abutment piece 123, thereby allowing a resilient force to act on the rotating seal ring 10 toward the left in the axial direction.

[0081] In addition, the friction member 120 has been described as having a configuration in which the annular wall portion 22 abuts against the inner surface 6b of the rotating shaft 2, but is not limited thereto, and the annular wall portion 22 may be spaced apart from the inner surface 6b of the rotating shaft 2 as long as the radially extending portion 32 of the cup gasket 30 is sufficiently compressed. With such a configuration, the friction member can be easily manufactured. EXAMPLES

[0082] Next, a mechanical seal according to a third embodiment will be described with reference to Fig. 5. Note that a description of the same configuration as in the first embodiment will be omitted.

[0083] 5, the mechanical seal 201 of this embodiment is for sealing between a solid rotating shaft 202 and a housing 203. The mechanical seal 201 is mainly composed of a rotating sealing element 204 and a stationary sealing element 205.

[0084] The rotating sealing element 204 is mainly composed of a rotating sealing ring 210 , a sleeve 215 , a friction member 220 , and a cup gasket 230 .

[0085] The rotary seal ring 210 is formed in an annular shape having a rectangular cross section.

[0086] The sleeve 215 includes an inner cylinder 216, an annular wall 217, and an outer cylinder 218. The inner cylinder 216 is cylindrical and extends in the axial direction, and is fitted onto the rotating shaft 202. The annular wall 217 is annular and flat and extends radially outward from the left end of the inner cylinder 216. The outer cylinder 218 is cylindrical and extends axially rightward from the outer end of the annular wall 217, and has a larger diameter than the inner cylinder 216.

[0087] The friction member 220 includes an annular wall portion 222 and ten abutment pieces 223. The annular wall portion 222 is fixed by welding to the annular wall 217 of the sleeve 215. Each abutment piece 223 extends to the right in the axial direction, generally perpendicular to the inner diameter end of the annular wall portion 222.

[0088] When friction member 220 is fitted inside rotary seal ring 210, rotary seal ring 210 is inserted outside in a state in which each abutment piece 223 is first elastically deformed toward the inner diameter side, and then each abutment piece 223 is elastically restored to abut against rotary seal ring 210. Relative rotation between rotary seal ring 210 and sleeve 215 is prevented by frictional force generated between each abutment piece 223 and rotary seal ring 210. This reduces torsional deformation of cup gasket 230 and suppresses the occurrence of squeal and vibration.

[0089] In addition, the ten abutment pieces 223 press-fitted into the rotary seal ring 210 attempt to elastically return to their original position by rotating in a counterclockwise direction, thereby increasing the frictional force generated between each abutment piece 223 and the rotary seal ring 210, thereby making it possible to suppress movement of the rotary seal ring 210 and the cup gasket 230 to the right in the axial direction, which is the removal direction.

[0090] Alternatively, the free ends of the contact portions, i.e., the right end in the axial direction, may be bent toward the inner diameter side, so that the rotary seal ring 210 can be pressed toward each contact portion. Also, the friction member may be wedge-shaped in cross section and pressed into between the rotary seal ring 210 and the inner cylinder 216 of the sleeve 215. EXAMPLES

[0091] Next, a mechanical seal according to a fourth embodiment will be described with reference to Fig. 6. Note that a description of the same configuration as in the first embodiment will be omitted.

[0092] 6, the mechanical seal 301 of this embodiment is for sealing between a solid rotating shaft 302 and a housing 303. The mechanical seal 301 is mainly composed of a rotating element 304 and a stationary element 305.

[0093] The rotating element 304 is mainly composed of a rotating seal ring 310, a sleeve 350, a biasing member 360, a rubber bellows 370, a drive ring 380, and a collar 390. That is, the mechanical seal 301 of this embodiment is of a rotating type.

[0094] The rotary seal ring 310 is attached to the rotary shaft 302 via a sleeve 350 and a rubber bellows 370. The sleeve 350 and the rubber bellows 370 are prevented from rotating with respect to the rotary shaft 302 by a drive ring 380.

[0095] As a result, the rotary seal ring 310 is provided in a non-rotating state but movable in the axial direction relative to the rotary shaft 302. Furthermore, rubber bellows 370 seal between the rotary seal ring 310 and the rotary shaft 302 and between the rotary seal ring 310 and the sleeve 350.

[0096] In addition, the rotary seal ring 310 is biased in the axial direction by a biasing member 360 disposed between the sleeve 350 and the collar 390. This allows a sliding surface 311 of the rotary seal ring 310 and a sliding surface 341 of the stationary seal ring 340 to slide closely against each other.

[0097] The stationary element 305 is mainly composed of a stationary seal ring 340 as one of the seal rings, a friction member 320 , and a cup gasket 330 .

[0098] The stationary seal ring 340 is formed in an annular shape having a rectangular cross section.

[0099] Here, a through hole 303a is formed in the housing 303, penetrating the radial center in the axial direction. A recess 306 in the housing 303 is recessed axially leftward from the right end face of the housing 303, and is open axially rightward and toward the inner diameter side. That is, the recess 306 communicates with the through hole 303a.

[0100] Regarding the assembly method of the stationary element 305, first, the cup gasket 330 is fitted onto the stationary seal ring 340 from the outside.

[0101] The stationary sealing ring 340 is then fitted together with the cup gasket 330 into the recess 306 in the housing 303 .

[0102] Thereafter, the base portion 321 of the friction member 320 is press-fitted into the through-hole 303a of the housing 303 and attached.

[0103] Further, each abutment piece 323 of the friction member 320 is press-fitted into the stationary seal ring 340. The friction member 320 is positioned in the axial direction by the annular wall portion 322 abutting against the inner side surface 306b of the housing 303.

[0104] Frictional forces generated between each abutment piece 323 and stationary seal ring 340 prevent relative rotation between stationary seal ring 340 and housing 303. This reduces torsional deformation of cup gasket 330, suppressing the occurrence of squealing and vibration.

[0105] In this way, even if the friction member of the present invention is applied to the stationary element, the occurrence of squeal and vibration can be suppressed.

[0106] Furthermore, the ten abutment pieces 323 press-fitted into the stationary seal ring 340 attempt to elastically return to their original position so as to rotate counterclockwise. This increases the frictional force generated between each abutment piece 323 and the stationary seal ring 340, making it possible to suppress movement of the stationary seal ring 340 and the cup gasket 330 to the right in the axial direction, which is the removal direction. EXAMPLES

[0107] Next, a mechanical seal according to a fifth embodiment will be described with reference to Fig. 7. Note that a description of the same configuration as in the first embodiment will be omitted.

[0108] As shown in Fig. 7, the mechanical seal 401 of this embodiment is for sealing between a solid rotating shaft 402 and a housing 3. The mechanical seal 401 is an inside type in which sliding surfaces 411, 41 seal between an inner space S11 and an outer space S12. The inner space S11 is a leakage space communicating with the atmosphere A. The outer space S12 is a sealed fluid space into which the sealed fluid F flows.

[0109] The rotating shaft 402 is formed in a cylindrical shape with an outer step, and has a large diameter body portion 402a, a medium diameter body portion 402b, and a small diameter body portion 402c. The large diameter body portion 402a and the medium diameter body portion 402b form a step portion 406. The small diameter body portion 402c is inserted into the housing 3.

[0110] Cup gasket 430 has its axially extending portion 431 fitted onto outer circumferential surface 406a which defines step portion 406. Further, cup gasket 430 has its radially extending portion 432 abutting against side surface 406b which defines step portion 406.

[0111] Rotary seal ring 410 has its body portion 413 fitted onto axially extending portion 431 of cup gasket 430. Body portion 413 also presses radially extending portion 432 of cup gasket 430 against side surface 406b.

[0112] The friction member 420 has a base portion 421 press-fitted into the large diameter body portion 402a of the rotating shaft 402. The friction member 420 has an annular wall portion 422 abutting against a side surface 406b of the rotating shaft 402.

[0113] The friction member 420 has ten abutment pieces 423. Each abutment piece 423 has a tapered shape that reduces in diameter toward the right in the axial direction. Each abutment piece 423 is press-fitted into the body portion 413 of the rotating seal ring 410, and abuts against an outer circumferential surface 413c of the body portion 413, elastically deforming toward the outer diameter side.

[0114] The frictional force generated between each abutment piece 423 and rotary seal ring 410 prevents relative rotation between rotary seal ring 410 and rotary shaft 402. This reduces torsional deformation of cup gasket 430, suppressing the occurrence of squeal and vibration.

[0115] Furthermore, the ten abutment pieces 423 press-fitted into the rotary seal ring 410 attempt to elastically return to their original position so as to rotate in a clockwise direction. That is, the ten abutment pieces 423 apply not only a force toward the inner diameter side of the rotary seal ring 410, but also a force toward the left in the axial direction, which is the insertion direction of the rotary seal ring 410. This increases the frictional force generated between each abutment piece 423 and the rotary seal ring 410, making it possible to suppress movement of the rotary seal ring 410 and the cup gasket 430 toward the right in the axial direction, which is the removal direction.

[0116] Furthermore, since the ten abutment pieces 423 have a one-sided shape and the mechanical seal 401 is an inside type, the ten abutment pieces 423 are pressed against the rotary seal ring 410 by the fluid pressure of the sealed fluid F acting on the outer circumferential surface 423b of the ten abutment pieces 423. This further increases the frictional force generated between the abutment pieces 423 and the rotary seal ring 410.

[0117] Furthermore, since the ten contact pieces 423 are in contact with the outer circumferential surface 413c of the body portion 413 of the rotating seal ring 410, the contact area tends to be large.

[0118] 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.

[0119] For example, in the first to fourth embodiments, the mechanical seal is described as an outside type, but is not limited to this and may be an inside type. Also, in the fifth embodiment, the mechanical seal is described as an inside type, but is not limited to this and may be an outside type.

[0120] In addition, in the above-mentioned embodiments 1 to 5, the secondary seal has been described as being a cup gasket, but this is not limited thereto, and may be a rubber bellows, a packing, or the like, and may be modified as appropriate.

[0121] In addition, in the above-mentioned Examples 1 to 4, the structure in which the friction member is disposed on the inner diameter side of one of the seal rings has been described, but the present invention is not limited to this, and the friction member may be disposed on the outer diameter side of one of the seal rings. In such a configuration, it is preferable that the secondary seal is disposed on the inner diameter side of one of the seal rings.

[0122] In addition, in the above-described first to fifth embodiments, the contact portion of the friction member is described as having a one-piece shape, but the present invention is not limited to this and may be annular.

[0123] In the second embodiment, the radially extending portion of the friction member is divided in the circumferential direction. However, the present invention is not limited to this, and the radially extending portion may be annular. [Explanation of symbols]

[0124] 1 Mechanical seal 2 Rotation Axis 2a Through hole 3. Housing 6 Recess 10 Rotary seal ring 20 Friction materials 23 Contact piece (contact part) 30 Cup gasket (secondary seal) 40 Stationary sealing ring 101 Mechanical seal 120 Friction materials 123 Contact piece (contact part) 125 Radial extension part 201 Mechanical seal 202 Rotational axis 203 Housing 210 Rotating seal ring 215 Sleeve 220 Friction materials 223 Contact piece (contact part) 230 Cup gasket (secondary seal) 301 Mechanical seal 302 Rotational axis 303 Housing 310 Rotating seal ring 320 Friction materials 323 Contact piece (contact part) 330 Cup gasket (secondary seal) 340 Stationary sealing ring 410 Rotating seal ring 420 Friction materials 423 Contact piece (contact part) 430 Cup gasket (secondary seal) A. Atmosphere F Sealed fluid S1,S11 inner space S2,S12 Outside space

Claims

1. A mechanical seal in which a stationary seal ring attached to a housing member and a rotary seal ring attached to a rotary shaft member inserted into the housing slide relative to each other to separate a sealed fluid space and a leakage space, a secondary seal is disposed between the one seal ring and a member on the housing side or a member on the rotating shaft side to which the one seal ring is attached, a friction member is provided that is disposed so as to overlap the one seal ring and the secondary seal in the radial direction and that comes into contact with the member on the housing side or the member on the rotating shaft side and the one seal ring to prevent relative rotation therebetween, The friction member is a mechanical seal having a tapered shape inclined toward the one of the seal rings at a contact portion with the one of the seal rings.

2. 2. The mechanical seal according to claim 1, wherein the friction member is disposed so as to cover an inner diameter side of the housing member or the rotary shaft member and the one of the seal rings.

3. 3. The mechanical seal according to claim 2, wherein the mechanical seal is an outside type in which the sealed fluid space is located radially inward of the one seal ring.

4. 4. The mechanical seal according to claim 3, wherein the member on the rotating shaft side is the hollow rotating shaft, and the hollow space of the rotating shaft is the sealed fluid space.

5. 2. The mechanical seal according to claim 1, wherein the friction member has an elastic contact portion.

6. 6. The mechanical seal according to claim 5, wherein the friction member has a one-piece shape in which the contact portion extends in the axial direction, and a plurality of the contact portions are arranged in the circumferential direction.

7. 7. The mechanical seal according to claim 6, wherein the friction member is disposed so as to cover an inner diameter side of the member on the rotating shaft side and the rotary seal ring.

8. 2. The mechanical seal according to claim 1, wherein the friction member has a radially extending portion extending radially at a tip end of the abutment portion, the radially extending portion abutting against the one of the seal rings in the axial direction.

9. 9. The mechanical seal according to claim 1, wherein the friction member is press-fitted into the housing member or the rotary shaft member.

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