Mechanical Seal Device

Abstract

To provide a mechanical seal device excellent in sealing performance.SOLUTION: A mechanical seal device M includes a rotary seal element 1 mounted to a rotary shaft 6, a static seal element 2 mounted to a housing 5 for constituting a primary seal together with the rotary seal element 1, and a secondary seal 3 arranged between an inner peripheral face 54 of the housing 5 and an outer peripheral face 23 of the static seal element 2 while being compressed in the axial direction, at least part of the outer peripheral face 23 of the static seal element 2 being inclined to the inner peripheral face 54 of the housing 5. In a space 7 formed by the outer peripheral face 23 of the static seal element 2 and the inner peripheral face 54 of the housing 5, the secondary seal 3 is arranged which is wedge shaped in a cross section.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a mechanical seal device for sealing between a rotating shaft and a housing of a rotary machine. [Background technology]

[0002] As a mechanical seal device for preventing leakage of a sealed fluid around a rotating shaft in a rotary machine, for example, a mechanical seal device is known which includes a stationary sealing element held in a housing and a rotating sealing element fixed to a rotating shaft inserted into the housing, in which the pair of sealing elements slide relative to one another.

[0003] In some of these mechanical seal devices, a rotation restriction pin or other restriction member is provided to prevent the stationary sealing element from rotating relative to the housing. The provision of a rotation restriction pin can cause uneven stress to act on the stationary sealing element, resulting in distortion.

[0004] For example, in the mechanical seal device shown in Patent Document 1, the stationary sealing element is composed of a stationary seal ring and a retaining ring, and the retaining ring holds the stationary seal ring in a state where the rotation of the stationary seal ring is restricted. The sliding surface of the rotating seal ring and the sliding surface of the stationary seal ring form a primary seal. In addition, an O-ring is disposed between the housing and the retaining ring as a secondary seal. This O-ring prevents leakage of the sealed fluid and restricts the rotation of the retaining ring relative to the housing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-57353 A (page 6, figure 1) Summary of the Invention [Problem to be solved by the invention]

[0006] In the shaft seal device of Patent Document 1, the O-ring also serves as a rotation restriction function, so that the entire device is simply configured, and uniform stress acts on the retaining ring, making it difficult for distortion to occur. The O-ring is arranged in an annular space with a rectangular cross section formed by the inner diameter side step of the housing and the outer diameter side step of the retaining ring in an axially compressed state. Since the O-ring is in approximate line contact with the inner circumferential surface of the housing and the outer circumferential surface of the stationary seal, the effective friction surface of the O-ring is narrow, and when a large torque is applied from the rotating seal ring, the retaining ring may rotate together with the stationary seal ring. In addition, when the O-ring is compressed in the axial direction, it is deformed in the vertical direction and the O-ring itself is also deformed, so it is difficult to sufficiently increase the friction force against the rotational torque, and this also causes the retaining ring to rotate. As a result, the relative rotation speed of the rotating seal ring and the stationary seal ring becomes intermittent, and there is a risk that the sealing performance of the primary seal will deteriorate.

[0007] The present invention has been made in consideration of such problems, and has an object to provide a mechanical seal device with excellent sealing performance. [Means for solving the problem]

[0008] In order to solve the above problems, the mechanical seal device of the present invention comprises: a rotary sealing element attached to the rotary shaft; a stationary sealing element attached to the housing and defining a primary seal with the rotating sealing element; A mechanical seal device comprising: a secondary seal disposed between an inner peripheral surface of the housing and an outer peripheral surface of the stationary sealing element and compressed in an axial direction, An outer circumferential surface of the stationary sealing element is at least partially inclined with respect to an inner circumferential surface of the housing, and the secondary seal, which has a wedge-shaped cross section, is disposed in a space formed by the outer circumferential surface and the inner circumferential surface. According to this, when the secondary seal, which has a wedge-shaped cross section, is compressed in the axial direction, the narrow portion of the secondary seal is wedged between the outer peripheral surface of the stationary sealing element that divides the space and the inner peripheral surface of the housing, forming a wide effective friction surface between the outer peripheral surface and the inner peripheral surface. With this structure, the stationary sealing element is fixed to the housing with a high fixing force. In this way, the stationary sealing element is unlikely to rotate relative to the housing, and the mechanical seal device has excellent sealing properties.

[0009] an inner circumferential surface of the housing and an outer circumferential surface of the secondary seal, which define the space, are in surface contact with each other; an axially inner surface of the housing defining the space and an axially side surface of the secondary seal are in surface contact with each other, An outer circumferential surface of the stationary sealing element and an inner circumferential surface of the secondary seal, which define the space, may be in surface contact with each other. According to this, the secondary seal is subjected to an axial compressive force, so that the stationary sealing element is fixed to the housing with a high fixing force.

[0010] an inner circumferential surface of the housing and an outer circumferential surface of the secondary seal, which define the space, are in surface contact with each other; an axial outer surface of the stationary sealing element that defines the space and an axial side surface of the secondary seal are in surface contact with each other; An outer circumferential surface of the stationary sealing element and an inner circumferential surface of the secondary seal, which define the space, may be in surface contact with each other. According to this, the secondary seal is subjected to an axial compressive force, so that the stationary sealing element is fixed to the housing with a high fixing force.

[0011] an outer circumferential surface of the stationary sealing element that partitions the space is an inclined surface that is inclined from an axial end side of the stationary sealing element toward a center side in the axial direction and toward an outer diameter side; An inner circumferential surface of the housing defining the space may be a parallel surface parallel to the axial direction. According to this, the secondary seal is compressed in the axial direction and is wedged between the inclined surface and the parallel surface on the outer diameter side, so that the effective friction surface has a long circumferential length and the stationary sealing element is fixed to the housing with a high fixing force.

[0012] The wide portion of the secondary seal may be in contact with one of an inner circumferential surface of the housing that defines the space and an outer circumferential surface of the stationary sealing element that defines the space, but not in contact with the other. With this, even if the secondary seal undergoes thermal expansion, the widened portion is the main expansion area, so that the stationary sealing element is not distorted.

[0013] The inner circumferential surface of the housing and the outer circumferential surface of the stationary sealing element may extend parallel to each other, forming a parallel portion between the inner circumferential surface of the housing that defines the space into which the secondary seal is pressed and the outer circumferential surface of the stationary sealing element that defines the space. According to this, the narrow width portion of the secondary seal is more likely to be wedged between the inner peripheral surface of the housing that defines the space and the outer peripheral surface of the stationary sealing element that defines the space.

[0014] The secondary seals may be located axially on opposite sides of the stationary sealing element. According to this, the stationary sealing element is fixed to the housing with a high fixing force, and the stationary sealing element can be disposed on the housing at a distance in the axial direction.

[0015] The space and the secondary seal may each have a plane-symmetric shape on both axial sides. According to this, the stationary sealing element is fixed to the housing with a high fixing force, and since the two secondary seals are deformed in a plane-symmetrical manner when compressed in the axial direction, the fixing force is applied to both sides of the stationary sealing element in a balanced manner.

[0016] The secondary seal in an uninstalled state may be wedge shaped in cross section, preferably with relatively inclined faces each of which is straight. This makes it easy to set the squeeze margin of the secondary seal, and simplifies the structures of the housing and the stationary sealing element.

[0017] The space between the inner peripheral surface of the housing and the outer peripheral surface of the stationary sealing element may be wedge-shaped in cross section, preferably with relatively inclined surfaces each forming a straight line. This makes it easy to set the squeeze margin of the secondary seal, and simplifies the structures of the housing and the stationary sealing element.

[0018] The secondary seal may be made of plastic. This allows the secondary seal to fix the stationary sealing element to the housing with a high fixing force, and also allows for a wide range of options for adding functions such as resistance to chemical changes. [Brief description of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view of a mechanical seal device according to a first embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view of a main part of a mechanical seal device of a first embodiment. [Diagram 3] FIG. 11 is a cross-sectional view for explaining press-fitting of a secondary seal. [Figure 4] FIG. 5 is a cross-sectional view of a main part of a mechanical seal device according to a second embodiment of the present invention. [Diagram 5] FIG. 11 is a cross-sectional view of a main part of a mechanical seal device according to a third embodiment of the present invention. [Figure 6] FIG. 11 is a cross-sectional view of a main part of a mechanical seal device according to a fourth embodiment of the present invention. [Figure 7] FIG. 11 is a cross-sectional view of a main part of a mechanical seal device according to a fifth embodiment of the present invention. [Figure 8] FIG. 11 is a cross-sectional view of a main part of a mechanical seal device according to a sixth embodiment of the present invention. [Figure 9] FIG. 11 is a cross-sectional view of a main part of a mechanical seal device according to a seventh embodiment of the present invention. [Figure 10]13 is a diagram for explaining a secondary seal in the first modified example. FIG. [Figure 11] 13 is a diagram for explaining a secondary seal in Modification 2. FIG. [Figure 12] 13 is a diagram for explaining a secondary seal in Modification 3. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mechanical seal device according to an embodiment of the present invention will be described below with reference to the accompanying drawings. EXAMPLES

[0021] A mechanical seal device according to a first embodiment will be described with reference to Fig. 1 to Fig. 3. In the following description, the left and right sides of Fig. 1 viewed from the front will be referred to as the left and right sides of the mechanical seal device. In particular, the left side of the page will be referred to as the left side of the mechanical seal device, and the right side of the page will be referred to as the right side of the mechanical seal device.

[0022] As shown in FIG. 1, a mechanical seal device M is provided between a housing 5 and a rotating shaft 6 in a rotary machine to prevent leakage of a sealed fluid in the vicinity.

[0023] The mechanical seal device M is mainly composed of a rotating sealing element 1 and a stationary sealing element 2. The rotating sealing element 1 is attached in a state in which it can rotate together with a rotating shaft 6. The stationary sealing element 2 is attached to a housing 5 with secondary seals 3 and 4 interposed therebetween. The rotating sealing element 1 and the stationary sealing element 2 constitute a primary seal. The secondary seals 3 and 4 are arranged between the inner peripheral surface of the housing 5 and the outer peripheral surface of the stationary sealing element 2 while being compressed in the axial direction.

[0024] The rotary sealing element 1 is mainly composed of a rotary sealing ring 10, a collar 11, a set screw 13, a coil spring 15, a drive pin 16, and O-rings 17 and 18.

[0025] The rotary seal ring 10 is made of carbon and has an annular shape, and its right end surface is a sliding surface 10a.

[0026] An annular groove 10b that is open inward and recessed in the outer diameter direction is formed on the inner circumferential surface at the left end of the rotary seal ring 10. An O-ring 17 disposed in the annular groove 10b is pressed against the inner circumferential surface of the annular groove 10b and the outer circumferential surface of the collar 11, providing a tight seal between the rotary seal ring 10 and the collar 11.

[0027] The collar 11 is formed in a cylindrical shape and is fixed to the rotating shaft 6 by a set screw 13.

[0028] An annular groove 11b that is open in the inward direction and recessed in the outward direction is formed on the inner peripheral surface at the right end of the collar 11. An O-ring 18 disposed in the annular groove 11b is pressed against the inner peripheral surface of the annular groove 11b and the outer peripheral surface of the rotating shaft 6, sealing the gap between the collar 11 and the rotating shaft 6.

[0029] In addition, the collar 11 has an annular protrusion extending radially outward at the axial center, and has equally spaced recesses 11c on the right end face thereof, the recesses 11c being open to the right and recessed to the left. A coil spring 15 is inserted into each recess 11c. The coil spring 15 presses the rotary seal ring 10 against the stationary seal ring 20.

[0030] A drive pin 16 is fixed to a side end surface of the annular protrusion of the collar 11. The drive pin 16 is inserted into a groove 10c in the rotary seal ring 10 that is open to the left. This restricts the rotary seal ring 10 from rotating relative to the collar 11. The rotary seal ring 10 is rotatable together with the rotary shaft 6.

[0031] The stationary sealing element 2 is composed of a stationary sealing ring 20 and a retaining ring 21 .

[0032] The stationary seal ring 20 is made of filler-containing PTFE (Polytetrafluoroethylene) and is formed in an annular shape. The left end surface of the stationary seal ring 20 is a sliding surface 20a.

[0033] The sliding surface 10a of the rotary seal ring 10 is in pressure contact with the sliding surface 20a of the stationary seal ring 20. This allows the sliding surfaces 10a, 20a to slide relative to each other when the rotating shaft 6 rotates.

[0034] The rotary seal ring 10 and the stationary seal ring 20 are not limited to those made of a combination of soft materials. Also, materials other than those mentioned above can be used for the sliding members as long as they are used as sliding materials for mechanical seals, and examples of materials that can be used include ceramics, metal materials, resin materials, composite materials, and the like.

[0035] As shown in FIG. 2, the retaining ring 21 is formed in an annular shape having a downward L-shaped cross section.

[0036] The retaining ring 21 has an annular opening 21a formed on the inner diameter side at the left end, which is open in the inner diameter direction and to the left and is recessed in a stepped shape to the right. The stationary seal ring 20 is fixed to the opening 21a by shrink fitting. Note that the stationary seal ring 20 may be fixed to the retaining ring 21 by a method other than shrink fitting.

[0037] The outer peripheral surface of the retaining ring 21 is composed of, from the left, an inner diameter side parallel surface 22, an inclined surface 23, an outer diameter side parallel surface 24, an inclined surface 25, and an inner diameter side parallel surface 26. In this embodiment, the inclined surfaces 23 and 25 are the outer peripheral surfaces of the stationary sealing element that defines the space.

[0038] The inner diameter side parallel surface 22 extends linearly from its left edge toward the right along the axis. The inclined surface 23 extends linearly from the right edge of the inner diameter side parallel surface 22, sloping toward the right and toward the outer diameter direction. The outer diameter side parallel surface 24 extends linearly from the right edge of the inclined surface 23 toward the right along the axis. The inclined surface 25 extends linearly from the right edge of the outer diameter side parallel surface 24, sloping toward the right and toward the inner diameter direction. The inner diameter side parallel surface 26 extends linearly from the right edge of the inclined surface 25 toward the right along the axis.

[0039] An outer angle θ1 formed by the inner diameter side parallel surface 22 and the inclined surface 23 is approximately the same as an outer angle θ2 formed by the inclined surface 25 and the inner diameter side parallel surface 26. Moreover, an inner angle θ3 formed by the inclined surface 23 and the outer diameter side parallel surface 24 is approximately the same as an inner angle θ4 formed by the outer diameter side parallel surface 24 and the inclined surface 25. Moreover, the inner diameter side parallel surfaces 22 and 26 are disposed on approximately the same straight line.

[0040] The retaining ring 21 also has a side end face 27 that extends toward the inner diameter side and is generally perpendicular to the right edge of the inner diameter side parallel face 26 .

[0041] Next, the secondary seals 3 and 4 will be described. Before assembly, the secondary seals 3 and 4 are in an unattached state, i.e., not elastically deformed. The secondary seal 3 is disposed on the rotary seal ring 10 side, and the secondary seal 4 is disposed on the main body 50 side. In addition, since the secondary seals 3 and 4 are plane-symmetrical to each other, the secondary seal 3 will be described as an example, and the description of the secondary seal 4 will be omitted unless otherwise specified.

[0042] The secondary seal 3 is made of PTFE and has a wedge-shaped cross section, roughly speaking a substantially triangular cross section, more specifically a ring-shaped wedge-shaped cross section that is a substantially right-angled trapezoid with the right end cut off. The shape of the secondary seal 3 during and after assembly will be described later.

[0043] 3(a), secondary seal 3 has, in counterclockwise order from the outer diameter edge on the left side, long side end face 30, parallel surface 31 and inclined surface 32 constituting the inner circumferential surface, short side end face 33, and outer circumferential surface 34. In this embodiment, long side end face 30 is the axial side surface of the secondary seal, inclined surface 32 is the inner circumferential surface of the secondary seal, and outer circumferential surface 34 is the outer circumferential surface of the secondary seal.

[0044] The long side end face 30 extends linearly from its outer diameter edge toward the inner diameter direction. The parallel surface 31 extends linearly from the inner diameter edge of the long side end face 30 toward the right direction along the axis, approximately perpendicular to the inner diameter edge. The inclined surface 32 extends linearly from the right edge of the parallel surface 31 toward the right and outer diameter direction, inclining. The short side end face 33 extends linearly from the right edge of the inclined surface 32 toward the outer diameter direction. The outer peripheral surface 34 extends linearly from the outer diameter edge of the short side end face 33 toward the left direction, approximately perpendicular to the outer diameter edge. The long side end face 30 has a longer radial dimension than the short side end face 33.

[0045] The inner angle θ5 between the parallel surface 31 and the inclined surface 32 is substantially the same as the outer angle θ1 (see FIG. 2) between the inner diameter side parallel surface 22 and the inclined surface in the retaining ring .

[0046] In addition, the portion of the secondary seal 3 between the inclined surface 32 and the outer peripheral surface 34 is a narrow width portion 3A having a narrow radial width, and the portion between the parallel surface 31 and the outer peripheral surface 34 is a wide width portion 3B having a wide radial width and including a long side end face 30 facing the portion between the inclined surface 32 and the outer peripheral surface 34 that bites into the corner 8 described later.

[0047] In this specification, the narrow portion refers to a portion of the secondary seal having a wedge-shaped cross section that includes an end portion that bites into corner 8, which will be described later, and the wide portion refers to a portion that includes an end face that faces the end portion that bites into corner 8. In addition, the wedge shape in this specification may have at least a portion that gradually narrows, as exemplified in this embodiment and all other embodiments.

[0048] Next, the housing 5 will be described with reference to Fig. 2. The housing 5 is configured by connecting a cover body 51 to a main body 50 with bolts (not shown).

[0049] The main body 50 is formed in a cylindrical shape. An annular rib 50a is formed at the left end of the main body 50, protruding to the left. The annular rib 50a has a side end surface 50b, an inner peripheral surface 50c, and an outer peripheral surface 50d. In this embodiment, the side end surface 50b is an axially inner surface of the housing that defines a space.

[0050] The side end face 50b extends linearly from its outer diameter edge toward the inner diameter direction. The inner peripheral surface 50c extends linearly toward the right along the axis, generally perpendicular to the inner diameter edge of the side end face 50b. The outer peripheral surface 50d extends linearly toward the right along the axis, generally perpendicular to the outer diameter edge of the side end face 50b.

[0051] The inner diameter D1 of the annular rib 50a is slightly larger than the outer diameter D2 of the inner diameter side parallel surfaces 22, 26 of the retaining ring 21 (D1>D2). The outer diameter D3 of the annular rib 50a is approximately the same as the outer diameter D4 of the outer diameter side parallel surfaces 24 of the retaining ring 21 (D3≈D4). For convenience of illustration, in FIG. 2, the inner and outer diameters are shown as radii.

[0052] The main body 50 has an inner diameter side end face 50e and an outer diameter side end face 50f. The inner diameter side end face 50e extends in the inner diameter direction, generally perpendicular to the inner peripheral surface 50c of the annular rib 50a. The outer diameter side end face 50f extends in the outer diameter direction, generally perpendicular to the outer peripheral surface 50d of the annular rib 50a. The outer diameter side end face 50f is disposed to the left of the inner diameter side end face 50e.

[0053] The cover body 51 is formed in a cylindrical shape. The inner peripheral surface of the cover body 51 is composed of, from the left, an inner diameter side parallel surface 52, an orthogonal surface 53, and an outer diameter side parallel surface 54. In this embodiment, the orthogonal surface 53 is an inner axial side surface of the housing that defines a space, and the outer diameter side parallel surface 54 is an inner peripheral surface of the housing that defines the space.

[0054] The inner diameter side parallel surface 52 extends linearly from its left edge toward the right along the axis. The orthogonal surface 53 extends linearly from the right edge of the inner diameter side parallel surface 52 toward the outer diameter direction, intersecting approximately perpendicularly. The outer diameter side parallel surface 54 extends linearly from the outer diameter edge of the orthogonal surface 53 toward the right along the axis, intersecting approximately perpendicularly. Angle 55 is formed by the intersection of orthogonal surface 53 and outer diameter side parallel surface 54 at a right angle.

[0055] The inner diameter D5 of the inner diameter side parallel surface 52 is approximately the same as the inner diameter D1 of the annular rib 50a of the main body 50 and slightly larger than the outer diameter D2 of the inner diameter side parallel surfaces 22, 26 of the retaining ring 21 (D5 ≈ D1 > D2). The inner diameter D6 of the outer diameter side parallel surface 54 is very slightly larger than the outer diameter D3 of the annular rib 50a of the main body 50 and the outer diameter D4 of the outer diameter side parallel surface 24 of the retaining ring 21 (D6 > D3 ≈ D4).

[0056] As a result, when the cover body 51 is connected to the main body 50, the inner diameter side parallel surface 52 is disposed substantially in the same straight line as the inner circumferential surface 50c of the main body 50. In addition, in this state, the orthogonal surface 53 is disposed opposite to the side end surface 50b of the main body 50.

[0057] The cover body 51 also has a side end surface 51a that extends in the outer diameter direction and is generally perpendicular to the right edge of the outer diameter side parallel surface 54.

[0058] Next, the procedure for assembling the stationary sealing element 2 to the housing 5 will be described.

[0059] First, the secondary seals 3, 4 are attached to the retaining ring 21 to which the stationary seal ring 20 is press-fitted. The outer diameter D7 (see FIG. 2) of the secondary seals 3, 4 in the unattached state is slightly shorter than not only the inner diameter D6 of the outer diameter side parallel surface 54 of the cover body 51 but also the outer diameter D4 of the outer diameter side parallel surface 24 of the retaining ring 21, which is slightly smaller than the inner diameter D6 (D6>D4>D7).

[0060] Next, the retaining ring 21 is inserted from the right side into the inner diameter side of the cover body 51 until the secondary seal 3 abuts against the orthogonal surface 53 of the cover body 51. At this time, the outer diameter side parallel surface 24 of the retaining ring 21 is guided by the outer diameter side parallel surface 54 of the cover body 51.

[0061] Alternatively, the assembly order may be such that the secondary seal 3, the retaining ring 21, and the secondary seal 4 are inserted into the cover body 51 in this order.

[0062] Thereafter, as a bolt (not shown) inserted through the cover body 51 is screwed into a female threaded hole (not shown) in the main body 50, the cover body 51 moves from the position shown in FIG. 3(a) toward the main body 50.

[0063] At this time, the annular rib 50a of the main body 50 is inserted into the inner diameter side of the cover body 51. At this time, the outer peripheral surface 50d of the annular rib 50a is guided by the outer diameter side parallel surface 54 of the cover body 51.

[0064] Thereafter, the side end surface 51a of the cover body 51 abuts against the outer diameter side end surface 50f of the main body 50, whereby the cover body 51 is positioned relative to the main body 50 and is connected to the main body 50.

[0065] 3(b), the secondary seals 3 and 4 bulge as the cover body 51 is connected to the main body 50, providing a seal between the housing 5 and the stationary sealing element 2. Hereinafter, the elastic deformation of the secondary seals 3 and 4 will be described in detail.

[0066] 3(a), in the connection between the main body 50 and the cover body 51, when the secondary seal 3 is not attached, the long side end face 30 of the secondary seal 3 is in face-to-face contact with the orthogonal surface 53 of the cover body 51. Also, the inclined surface 32 of the secondary seal 3 is in face-to-face contact with the inclined surface 23 of the retaining ring 21. Also, the outer peripheral surface 34 of the secondary seal 3 is disposed facing and approximately parallel to, and slightly spaced from, the outer diameter side parallel surface 54 of the cover body 51.

[0067] When the cover body 51 is moved from the state shown in FIG. 3( a ) toward the main body 50 , the long side end face 30 of the secondary seal 3 is pushed rightward by the orthogonal face 53 of the cover body 51 .

[0068] Here, as shown in FIG. 3(a), the inclined surface 23 of the retaining ring 21 is inclined with respect to the outer diameter side parallel surface 54 of the cover body 51, and the inclined surface 23 is positioned so as to approach the outer diameter side parallel surface 54 from the axial left edge toward the axial right side.

[0069] As a result, an annular pre-compression space 70 having a wedge-shaped cross section, more specifically a right-angled trapezoidal cross section, is formed between the cover body 51 and the retaining ring 21. The pre-compression space 70 is defined by the inner diameter side parallel surface 22 and the inclined surface 23 of the retaining ring 21, the outer diameter side parallel surface 54 of the cover body 51, and the orthogonal surface 53 of the cover body 51.

[0070] Further, outer diameter side parallel surface 24 of retaining ring 21 is disposed approximately parallel to outer diameter side parallel surface 54. Outer diameter side parallel surface 24 and outer diameter side parallel surface 54 form parallel portion 9 in this specification. Since outer diameter side parallel surface 24 and outer diameter side parallel surface 54 are formed along the axis, parallel portion 9 is approximately parallel to the axis.

[0071] At the parallel portion 9, the outer diameter side parallel surface 24 is in face-to-face contact with the outer diameter side parallel surface 54, so that the distance therebetween is substantially zero. The inclined surface 23 is continuous with the outer diameter side parallel surface 24, and the right end of the pre-compression space 70 connected to the parallel portion 9 forms an acute angle 8 formed by the inclined surface 23 and the outer diameter side parallel surface 54.

[0072] Since the narrow width portion 3A and the pre-compression space 70 in the secondary seal 3 are each wedge-shaped, the secondary seal 3 easily bites into the corner 8. The short side end face 33 of the secondary seal 3 is pressed into the corner 8 between the retaining ring 21 and the cover body 51 while being elastically deformed (see FIG. 3(b)). In this embodiment, the interior angle between the inclined surface 32 and the outer peripheral surface 34 in the narrow width portion 3A is approximately the same as the interior angle between the inclined surface 23 that defines the pre-compression space 70 and the outer diameter side parallel surface 54.

[0073] Furthermore, the secondary seal 3 is pressed between the inclined surface 23 of the retaining ring 21 and the orthogonal surface 53 of the cover body 51, and is compressed in the axial direction and bulges in the radial direction. As a result, the force with which the inclined surface 32 of the secondary seal 3 is pressed against the inclined surface 23 of the retaining ring 21, the force with which the outer circumferential surface 34 of the secondary seal 3 is pressed against the outer diameter side parallel surface 54 of the cover body 51, and the force with which the long side end surface 30 of the secondary seal 3 is pressed against the orthogonal surface 53 of the cover body 51 all increase.

[0074] 3(b), when the stationary sealing element 2 is completely assembled to the housing 5, the orthogonal surface 53 of the cover body 51 is positioned so as to overlap radially with the apex 21b of the angle formed by the inner diameter side parallel surface 22 and the inclined surface 23 of the retaining ring 21. As a result, a post-compression space 7 having a wedge-shaped cross section, more specifically, a right-angled triangular annular cross section, is formed between the cover body 51 and the retaining ring 21. The post-compression space 7 is defined by the inclined surface 23, the outer diameter side parallel surface 54, and the orthogonal surface 53 of the cover body 51. The post-compression space 7 is the space defined in the present invention.

[0075] After compression, the entire secondary seal 3 is pressed into the space 7. Therefore, the secondary seal 3 is elastically deformed and has a wedge-shaped cross section, more specifically, a right-angled triangle with a part of the inner diameter end cut out. Thus, the secondary seal 3 has a wedge-shaped cross section before and after assembly, but the shape changes slightly due to elastic deformation.

[0076] Specifically, the orthogonal surface 53 of the cover body 51 and the long side end surface 30 of the secondary seal 3 are in face-to-face contact. Also, the outer diameter side parallel surface 54 of the cover body 51 and the outer circumferential surface 34 of the secondary seal 3 are in face-to-face contact. Furthermore, the inclined surface 23 of the retaining ring 21 and the inclined surface 32 of the secondary seal 3 are in face-to-face contact. As a result, the secondary seal 3 is subjected to an axial compressive force, and the stationary sealing element 2 is fixed to the housing 5 with a high fixing force.

[0077] In addition, the corner between the long side end face 30 and the outer peripheral surface 34 of the secondary seal 3 is pressed into the corner 55 of the cover body 51 without any gap, and the short side end face 33 of the secondary seal 3 is pressed into the corner 8 without any gap, but there may be a gap between them.

[0078] In addition, when the stationary sealing element 2 is completely assembled to the housing 5, the narrow portion 3a of the secondary seal 3 is embedded in the corner 8 more than the narrow portion 3A (see FIG. 3(a)) in the unattached state. Therefore, the area of ​​the narrow portion 3a that is in radial pressure contact with the outer diameter side parallel surface 54 of the cover body 51 and the inclined surface 23 of the retaining ring 21 increases.

[0079] In other words, the secondary seal 3 is pressed with strong pressure against the housing 5 and the retaining ring 21 at its narrow portion 3a, particularly at the tip end region, resulting in strong frictional resistance against rotation. In this way, a wide effective friction surface is formed where the secondary seal 3 comes into contact with the housing 5 and the retaining ring 21 with a predetermined or higher level of strong frictional resistance.

[0080] In addition, by forming corner 8 having an acute angle, i.e., a wedge-shaped cross section, a wide effective friction surface is ensured by the wedge effect, and taking into consideration the ease with which secondary seals 3, 4 bite into, when the inner surface of the housing is an outer diameter parallel surface 54 parallel to the axis, it is preferable that the interior angles θ3, θ4 be formed in the range of 110 degrees or more and 170 degrees or less.

[0081] 2, the mechanism for pressing in the secondary seal 4 is symmetrical to that for pressing in the secondary seal 3, and so a detailed description thereof will be omitted. For example, the side end surface 50b of the annular rib 50a of the main body 50 functions in the same manner as the orthogonal surface 53 of the cover body 51. The inner diameter side parallel surface 26 of the retaining ring 21 functions in the same manner as the inner diameter side parallel surface 22 of the retaining ring 21. The inclined surface 25 of the retaining ring 21 functions in the same manner as the inclined surface 23 of the retaining ring 21. Therefore, the secondary seal 4 is pressed in in the same manner as the secondary seal 3, except that the relative direction in which the secondary seal 4 is pressed in is opposite to that of the secondary seal 3.

[0082] As described above, when the assembly of the stationary sealing element 2 to the housing 5 is completed, the stationary sealing element 2 is fixed with a high fixing force to the housing 5 due to the structure that forms a wide effective friction surface as described above. In this way, the stationary sealing element 2 is unlikely to rotate relative to the housing 5, and the mechanical seal device M has excellent sealing properties.

[0083] In addition, the inclined surface 23 of the retaining ring 21 and the outer diameter side parallel surface 54 of the cover body 51 define a wedge-shaped corner 8. Therefore, when the secondary seal 3 is compressed in the axial direction, it is wedged between the inclined surface 23 of the retaining ring 21 and the outer diameter side parallel surface 54 of the cover body 51. As a result, the effective friction surface has a long circumferential length, and the stationary sealing element 2 is fixed to the housing 5 with a high fixing force.

[0084] As shown in FIG. 3(b), when the secondary seal 3 is compressed in the axial direction, a gap S1 is formed as a space having a triangular cross section on the side of the inclined surface 23 of the retaining ring 21, rather than the wide portion 3b of the secondary seal 3. In other words, the wide portion 3b of the secondary seal 3 is not in contact with the inclined surface 23 of the retaining ring 21. Therefore, even if the secondary seal 3 thermally expands, the wide portion 3b is the main expansion margin, and the stationary sealing element 2 is not distorted. Before the compression shown in FIG. 3(b), a gap having a trapezoidal cross section larger than the gap S1 is formed, as shown in FIG. 3(a).

[0085] Furthermore, the inner diameter side parallel surface 52 of the cover body 51 and the inner diameter side parallel surface 22 of the retaining ring 21 are separated by a dimensional difference. This allows the thermally expanded secondary seal 3 to escape more reliably, so that the stationary sealing element 2 is not distorted.

[0086] In addition, a gap is formed between the inner diameter side parallel surface 52 of the cover body 51 and the inner diameter side parallel surface 22 of the retaining ring 21. The orthogonal surface 53 of the cover body 51 and the inclined surface 23 of the retaining ring 21 narrow toward this gap, and the long side end surface 30 of the secondary seal 3 abuts against the orthogonal surface 53 of the cover body 51. For these reasons, even if a relative negative pressure occurs in the space, the secondary seal 3 is sucked in and is unlikely to slip out into the gap.

[0087] 4, for example, in a configuration in which the inclined surface 23 and the outer diameter side parallel surface 24 are not continuous by the orthogonal surface 28 and the inclined surface 23 is not connected to the parallel portion 9, the radial dimension of the inclined surface 23 connected to the parallel portion 9 to the outer diameter side parallel surface 54 becomes narrower as it approaches the parallel portion 9. This makes it easier for the narrow width portion 3A of the secondary seal 3 to bite into the corner 8.

[0088] In addition, the radial dimension of the long side end face 30 of the secondary seal 3 pressed by the orthogonal surface 53 of the cover body 51 is approximately the same as the radial dimension of the inclined surface 32 of the secondary seal 3 pressed by the inclined surface 23 of the retaining ring 21. Therefore, the narrow width portion 3A of the secondary seal 3 is more likely to bite into the corner 8.

[0089] Also, the inner diameter side parallel surface 52 of the cover body 51 and the inner diameter side parallel surface 22 of the retaining ring 21 are separated by a dimensional difference. Also, the inner peripheral surface 50c of the annular rib 50a of the main body 50 and the inner diameter side parallel surface 26 of the retaining ring 21 are separated by a dimensional difference. As a result, contact between the retaining ring 21 and the main body 50 is prevented, and the stationary sealing element 2 is not distorted.

[0090] Further, secondary seals 3, 4 are arranged on both axial sides of the retaining ring 21. As a result, the stationary sealing element 2 is fixed to the housing 5 with a high fixing force.

[0091] 2, the right side end face 27 of the retaining ring 21 and the left inner diameter side end face 50e of the main body 50 are disposed apart from each other in the axial direction. As a result, a gap S2 is formed between the side end face 27 and the inner diameter side end face 50e. This gap S2 prevents contact between the retaining ring 21 and the main body 50. Therefore, the stationary sealing element 2 is not distorted.

[0092] Moreover, a post-compression space 7A is disposed on the axial right side of the retaining ring 21. The post-compression space 7A is formed by the inclined surface 25 of the retaining ring 21, the outer diameter side parallel surface 54 of the cover body 51, and the side end surface 50b of the main body 50. Furthermore, secondary seals 3 and 4 are also disposed on both axial sides. As a result, the stationary sealing element 2 is fixed to the housing 5 with a high fixing force.

[0093] In addition, the post-compression space 7 and the post-compression space 7A have a plane-symmetric shape. Furthermore, the secondary seals 3 and 4 also have a plane-symmetric shape in the unattached state. As a result, the two secondary seals 3 and 4 are deformed in a plane-symmetric manner when compressed in the axial direction. Therefore, the fixing force is applied to both sides of the stationary sealing element 2 in a balanced manner.

[0094] In addition, the secondary seal 3 in the unattached state has a wedge-shaped cross section, which makes it easy to set the squeeze margin of the secondary seal 3 and simplifies the structures of the housing 5 and the stationary sealing element 2.

[0095] In addition, the post-compression space 7 defined by the inclined surface 23 and the outer diameter side parallel surface 54 has a wedge-shaped cross section. Therefore, it is easy to set the crushing allowance of the secondary seal 3, and the structures of the housing 5 and the stationary sealing element 2 are simple.

[0096] In addition, the secondary seal 3 is made of PTFE. Therefore, the secondary seal 3 can fix the stationary sealing element 2 to the housing 5 with a high fixing force, and has a wide range of options for adding functions such as resistance to chemical changes.

[0097] In addition, in the secondary seal 3, which is annular, the outer peripheral surface 34, which has a relatively longer circumferential length and a larger surface area than the parallel surfaces 31 and inclined surfaces 32 that constitute the inner peripheral surface, is pressed against the outer diameter parallel surfaces 54 of the cover body 51 by the inclined surfaces 23 of the retaining ring 21.

[0098] 9, the effective friction surface is wider than that of a configuration in which an inner peripheral surface 631 of the secondary seal 3 is pressed against an inner diameter side parallel surface 22 of a retaining ring 621 by an inclined surface 653 of a cover body 651. The stationary sealing element 2 in this embodiment is fixed to the housing 5 with a high fixing force.

[0099] Further, the orthogonal surface 53 of the cover body 51 that presses the secondary seal 3 is substantially orthogonal to the pushing direction. Therefore, the orthogonal surface 53 efficiently compresses the secondary seal 3 in the axial direction. EXAMPLES

[0100] Next, a mechanical seal device according to a second embodiment will be described with reference to Fig. 4. Note that the same components as those shown in the first embodiment will be denoted by the same reference numerals and duplicated description will be omitted.

[0101] 4, in the retaining ring 121 of the stationary sealing element 102, a radially extending orthogonal surface 28 is formed between the inclined surface 23 and the outer diameter side parallel surface 24. In addition, a radially extending orthogonal surface 29 is formed between the outer diameter side parallel surface 24 and the inclined surface 25. This forms a post-compression space 107 having a wedge-shaped cross section, more specifically, a substantially right-angled trapezoidal cross section.

[0102] When the secondary seal 3 is compressed in the axial direction, the short side end face 33 of the secondary seal 3 is pressed against the orthogonal surface 28 of the retaining ring 121. This restricts compression to reduce the radial dimension, so the orthogonal surface 28 can prevent damage to the secondary seal 3 compared to a configuration in which the secondary seal 3 is pressed into a narrower location.

[0103] In this manner, the space in this specification may have a cross-sectional shape that tapers toward the direction in which the secondary seal is relatively pushed in, and the cross-sectional shape may be appropriately changed. In other words, the "space formed by the outer peripheral surface of the stationary sealing element and the inner peripheral surface of the housing" in the present invention may have at least a portion of the outer peripheral surface of the stationary sealing element and the inner peripheral surface of the housing that form the space inclined relative to the opposing surface. EXAMPLES

[0104] Next, a mechanical seal device according to a third embodiment will be described with reference to Fig. 5. Note that the same components as those shown in the first and second embodiments are given the same reference numerals and the duplicated description will be omitted.

[0105] 5, a retaining ring 221 in the stationary sealing element 202 is formed with an inclined surface 223 that extends in a curved shape protruding outward from the right edge of the inner diameter side parallel surface 22 toward the left edge of the outer diameter side parallel surface 24. Also, a inclined surface 225 is formed that extends in a curved shape protruding outward from the right edge of the outer diameter side parallel surface 24 toward the left edge of the inner diameter side parallel surface 26. In this embodiment, the inclined surfaces 223 and 225 are outer peripheral surfaces of the stationary sealing element that partition a space.

[0106] As a result, the post-compression space 207 narrows in a quadratic manner toward the parallel portion 9. Therefore, the secondary seal 3 is more likely to be wedged between the inclined surface 223 of the retaining ring 221, which defines the post-compression space 207, and the outer diameter side parallel surface 54 of the cover body 51.

[0107] Thus, the inclined surface of the stationary sealing element may be curved or wavy, and the shape may be modified as appropriate. EXAMPLES

[0108] Next, a mechanical seal device according to a fourth embodiment will be described with reference to Fig. 6. Note that the same components as those shown in the first to third embodiments are given the same reference numerals and the duplicated description will be omitted.

[0109] 6, in the main body 350 of the housing 305, an inclined surface 350b is formed on an annular rib 350a, which extends from its outer edge in the inner diameter direction and in the axial right direction. In addition, in the cover body 351 of the housing 305, an inclined surface 353 is formed which extends from the right edge of the inner diameter side parallel surface 52 in the right direction and in the outer diameter direction. In this embodiment, the inclined surfaces 350b, 353 are inner axial surface surfaces of the housing which partition a space.

[0110] As a result, the upper edge of the inclined surface 353 is close to the upper edge of the inclined surface 23 of the retaining ring 21, i.e., the tip of the post-compression space 307. Therefore, the secondary seal 3 pressed against the inclined surface 353 is likely to be wedged between the inclined surface 23, which defines the post-compression space 307, and the outer diameter side parallel surface 54 of the cover body 351.

[0111] In this way, the shape of the end face of the housing that presses the secondary seal is not limited to being approximately perpendicular to the pushing direction as in the first to third embodiments, and may be changed as appropriate. EXAMPLES

[0112] Next, a mechanical seal device according to a fifth embodiment will be described with reference to Fig. 7. Note that the same components as those shown in the first to fourth embodiments are given the same reference numerals and the duplicated description will be omitted.

[0113] 7, the retaining ring 421 of the stationary sealing element 402 is formed with an inclined surface 423 that extends in a straight line, inclined rightward and in the inner diameter direction, from the right edge of the inner diameter side parallel surface 22. Also, an inclined surface 425 that extends in a straight line, inclined rightward and in the outer diameter direction, from the right edge of the inclined surface 25. In this embodiment, the inclined surfaces 423 and 425 are outer peripheral surfaces of the stationary sealing element that partition a space.

[0114] In this way, the retaining ring 421 has a groove formed by the inclined surfaces 423 and 23 and a groove formed by the inclined surfaces 25 and 425. By fitting the secondary seals 403 and 404 into these grooves, the retaining ring 421 can be inserted into the cover body 51 while retaining the secondary seals 403 and 404. Therefore, the stationary sealing element 402 can be easily assembled to the housing 5.

[0115] Moreover, the shape of the post-compression space 407 formed by the housing 5 and the retaining ring 421 in a state in which the stationary sealing element 402 is assembled to the housing 5 has a right-angled trapezoidal cross section. In this manner, the shape of the space in this specification may be changed as appropriate.

[0116] Secondary seal 403 is formed with an inclined surface 431 that extends linearly from the lower edge of long side end face 30 and inclines rightward and inward in the radially inward direction. Secondary seal 404 has a plane-symmetrical shape to secondary seal 403. In this embodiment, inclined surface 431 is the inner peripheral surface of the secondary seal.

[0117] Here, narrow portion 403a of secondary seal 403 is the portion between inclined surface 32, which is the right end of secondary seal 403, and outer circumferential surface 34, and wide portion 403b of secondary seal 403 is the portion including long side end surface 30.

[0118] In this manner, the cross-sectional shape of the secondary seal may be appropriately changed depending on the inner peripheral surface of the housing and the outer peripheral surface of the stationary sealing element. EXAMPLES

[0119] Next, a mechanical seal device according to a sixth embodiment will be described with reference to Fig. 8. Note that the same components as those shown in the first to fifth embodiments are given the same reference numerals and the duplicated description will be omitted.

[0120] As shown in FIG. 8, like the spaces on both axial sides formed by the housing 505 and the retaining ring 21, the shapes of the spaces formed on both axial sides in this specification may be asymmetric.

[0121] Similarly, the cross-sectional shapes of the secondary seals disposed on either axial side may be asymmetric. EXAMPLES

[0122] Next, a mechanical seal device according to a seventh embodiment will be described with reference to Fig. 9. Note that the same components as those shown in the first to sixth embodiments are given the same reference numerals and the duplicated description will be omitted.

[0123] 9, the retaining ring 621 of the stationary sealing element 602 has an orthogonal surface 623 extending from a right edge of the inner diameter side parallel surface 622 toward the outer diameter direction, and is formed with an orthogonal surface 625 extending from a right edge of the outer diameter side parallel surface 624 toward the inner diameter direction, and is formed with an orthogonal surface 625 extending from a right edge of the outer diameter side parallel surface 624 toward the inner diameter direction, and is formed with a lower edge of the orthogonal surface 625 continuing to an inner diameter side parallel surface 626. In this embodiment, the inner diameter side parallel surfaces 622 and 626 are outer peripheral surfaces of the stationary sealing element, and the orthogonal surfaces 623 and 625 are axially outer surfaces of the stationary sealing element.

[0124] In the main body 650, an inclined surface 650b is formed on an annular rib 650a, which extends from its outer edge in the inner diameter direction and in the axial right direction at an angle. In addition, in the cover body 651 of the housing 605, an inclined surface 653 is formed which extends from the right edge of the inner diameter side parallel surface 52 in the right direction and in the outer diameter direction at an angle. In this embodiment, the inclined surfaces 650b and 653 are the inner peripheral surfaces of the housing.

[0125] That is, the orthogonal surface 623 of the stationary sealing element 602 is inclined relative to the inclined surface 653 of the cover body 651. Similarly, the orthogonal surface 625 of the stationary sealing element 602 is inclined relative to the inclined surface 650b of the main body 650.

[0126] As a result, the tapered tip of the post-compression space 607 formed by the perpendicular surface 623 and the inclined surface 653 is located on the right axial side, and the tapered tip of the post-compression space 607A formed by the perpendicular surface 625 and the inclined surface 650b is located on the left axial side.

[0127] Further, the secondary seal 603 has an inner circumferential surface 631, a side end surface 632, and an inclined surface 634. The inner circumferential surface 631 is in surface contact with an inner diameter side parallel surface 622 of the retaining ring 621. The side end surface 632 is in surface contact with an orthogonal surface 623 of the retaining ring 621. The inclined surface 634 is in surface contact with an inclined surface 653 of the cover body 651. Further, the secondary seal 604 has a plane-symmetrical shape to the secondary seal 603.

[0128] In this embodiment, the inner circumferential surface 631 is the inner circumferential surface of the secondary seal, the side end surface 632 is the axial side surface of the secondary seal, and the inclined surface 634 is the outer circumferential surface of the secondary seal. Furthermore, in this embodiment, the narrow width portion 603a is the portion between the side end surface 632 and the inclined surface 634, and the wide width portion 603b is the portion including the inner circumferential surface 631 that faces the portion between the side end surface 632 and the inclined surface 634.

[0129] As a result, the effective friction surfaces of the secondary seals 603 and 604 are located toward the center in the axial direction.

[0130] Furthermore, the inner diameter side parallel surface 622 of the stationary sealing element 602 is also inclined relative to the inclined surface 653 of the cover body 651. Similarly, the inner diameter side parallel surface 626 of the stationary sealing element 602 is also inclined relative to the inclined surface 650b of the main body 650.

[0131] As a result, the tapered tip of the post-compression space 607 formed by the inner diameter side parallel surface 622 and the inclined surface 653 is also provided on the left axial side, and the tapered tip of the post-compression space 607A formed by the inner diameter side parallel surface 626 and the inclined surface 650b is also provided on the right axial side.

[0132] This provides a good balance in retaining the stationary sealing element 602 by providing the effective friction surfaces of the secondary seals 603, 604 at separate axial positions.

[0133] Although the first to seventh embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to the first to seventh embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0134] For example, in the above-mentioned Examples 1 to 7, a so-called rotary type mechanical seal in which a coil spring is included in the rotary sealing element has been described, but this is not limited thereto, and a so-called stationary type mechanical seal in which a coil spring is included in the stationary sealing element may also be used.

[0135] In addition, in the above-described first to seventh embodiments, the stationary sealing element forming the space is a retaining ring. However, the present invention is not limited to this, and may be a member other than a retaining ring, for example, a stationary seal ring.

[0136] In addition, in the above embodiments 1 to 7, the secondary seal and space are described as being arranged on both axial sides of the stationary sealing element, but this is not limited thereto, and they may be arranged on only one axial side.

[0137] In addition, in the above-described first to seventh embodiments, the side end surface of the retaining ring is configured to be spaced apart from the side end surface of the main body, but this is not limiting and the side end surfaces may be in contact with each other.

[0138] In addition, in the above-mentioned embodiments 1 to 7, the secondary seal is described as being made of PTFE, but it is not limited to this and may be made of other resin materials. Furthermore, the secondary seal may be made of rubber. In other words, the material of the secondary seal may be changed as appropriate.

[0139] The cross-sectional shape of the secondary seal is preferably complementary to the inner peripheral surface of the housing and the outer peripheral surface of the stationary sealing element. This is true not only for the inner peripheral surface of the secondary seal, but also for each side end surface and the outer peripheral surface.

[0140] In addition to the above-described examples 1 to 7, the cross-sectional shape of the secondary seal before mounting may be appropriately changed as long as it is wedge-shaped. For example, as shown in FIG. 10, the secondary seal 703 of modified example 1 may be in a non-mounted state in which the inclined surface 732 and the outer circumferential surface 734 are directly connected to each other to form an acute angle. As shown in FIG. 11, the secondary seal 803 of modified example 2 may be in a non-mounted state in which the inner angle θ6 between the parallel surface 831 and the inclined surface 832 is different from the outer angle θ1 between the inner diameter side parallel surface 22 and the inclined surface 23 of the retaining ring 21. Furthermore, as shown in FIG. 12, the secondary seal 903 of modified example 3 may have an inclined surface 934 that extends in a curved shape protruding from the upper edge of the short side end surface 33 toward the left and the inner diameter side in the outer diameter direction. In this way, the shape of the secondary seal before compression may be appropriately changed.

[0141] In addition, in the above Examples 1 to 7, the secondary seal before compression is in non-contact with at least a portion of the inner surface of the housing that defines the space and the outer circumferential surface of the stationary sealing element that defines the space, and the secondary seal after compression is in contact with the inner surface of the housing that defines the space and in non-contact with at least a portion of the outer circumferential surface of the stationary sealing element. However, the present invention is not limited to this, and the secondary seal may be in contact with the inner surface of the housing that defines the space and the outer circumferential surface of the stationary sealing element both before and after compression.

[0142] In addition, in the above-described first to seventh embodiments, the parallel portion is parallel to the axis, but the present invention is not limited to this, and the parallel portion may be inclined with respect to the axis.

[0143] In addition, in the above-mentioned Examples 1 to 7, the gap at the parallel portion is substantially zero, but the present invention is not limited to this, and a gap may be formed. Even in such a configuration, a wedge action can be obtained by pressing the tip of the secondary seal into the gap. [Explanation of symbols]

[0144] 1 Rotating sealing element 2 Stationary sealing elements 3 Secondary Seal 3A,3a Narrow part 3B,3b wide part 4 Secondary Seal 5. Housing 6 Rotation Axis 7,7A Post-compression space (space) 8 corners (corners where the secondary seal is pressed in) 9 Parallel Sections 22, 26 Inner diameter parallel surface (part of the outer circumferential surface of the stationary sealing element) 23, 25 Inclined surface (part of the outer circumferential surface of the stationary sealing element) 24 Outer diameter parallel surface (part of the outer peripheral surface of the stationary sealing element) 30 Long side end face (side face at secondary seal) 31 Parallel surface (part of inner peripheral surface of secondary seal) 32 Inclined surface (part of the inner peripheral surface of the secondary seal) 34 Outer surface (outer surface at secondary seal) 50b Side end surface (part of the inner peripheral surface of the housing) 53 Orthogonal surface (part of the inner peripheral surface of the housing) 54 Outer diameter parallel surface (part of the inner peripheral surface of the housing) 102~602 Static sealing element 403,603~903 Secondary seal 404,604 Secondary Seal 305,505,605 Housing 107~407,607 Compressed space (space) M Mechanical seal device S1 Gap

Claims

1. a rotary sealing element attached to the rotary shaft; a stationary sealing element attached to the housing and defining a primary seal with the rotating sealing element; A mechanical seal device comprising: a secondary seal disposed between an inner peripheral surface of the housing and an outer peripheral surface of the stationary sealing element and compressed in an axial direction, A mechanical seal device in which an outer peripheral surface of the stationary sealing element is at least partially inclined relative to an inner peripheral surface of the housing, and the secondary seal having a wedge-shaped cross section is disposed in a space formed by the outer peripheral surface and the inner peripheral surface.

2. an inner circumferential surface of the housing that defines the space and an outer circumferential surface of the secondary seal are in surface contact with each other, an axially inner surface of the housing defining the space and an axially side surface of the secondary seal are in surface contact with each other, 2. The mechanical seal device according to claim 1, wherein an outer peripheral surface of the stationary sealing element defining the space and an inner peripheral surface of the secondary seal are in surface contact with each other.

3. an inner circumferential surface of the housing that defines the space and an outer circumferential surface of the secondary seal are in surface contact with each other, an axial outer surface of the stationary sealing element that defines the space and an axial side surface of the secondary seal are in surface contact with each other; 2. The mechanical seal device according to claim 1, wherein an outer peripheral surface of the stationary sealing element defining the space and an inner peripheral surface of the secondary seal are in surface contact with each other.

4. an outer circumferential surface of the stationary sealing element that partitions the space is an inclined surface that is inclined from an axial end side of the stationary sealing element toward a center side in the axial direction and toward an outer diameter side; 4. The mechanical seal device according to claim 1, wherein an inner circumferential surface of the housing defining the space is a parallel surface extending in the axial direction.

5. 5. A mechanical seal device as described in any one of claims 1 to 4, wherein the wide portion of the secondary seal contacts one of the inner circumferential surface of the housing that defines the space and the outer circumferential surface of the stationary sealing element that defines the space, but does not contact the other.

6. 6. The mechanical seal device according to claim 1, wherein an inner circumferential surface of the housing and an outer circumferential surface of the stationary sealing element extend parallel to each other, the inner circumferential surface of the housing defining the space into which the secondary seal is pressed is connected to a portion of the inner circumferential surface of the housing that is parallel to the outer circumferential surface of the stationary sealing element, and the outer circumferential surface of the stationary sealing element defining the space is connected to a portion of the outer circumferential surface of the stationary sealing element that is parallel to the inner circumferential surface of the housing.

7. 7. The mechanical seal device according to claim 1, wherein the secondary seals are disposed on both axial sides of the stationary sealing element.

8. 8. The mechanical seal device according to claim 7, wherein the space and the secondary seal are plane-symmetric on both sides in the axial direction.

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