Division type mechanical seal
10077843 ยท 2018-09-18
Assignee
Inventors
Cpc classification
F16J15/3488
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16B19/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16B33/004
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16B13/0858
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16B5/0258
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F16J15/34
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16B19/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
A division type mechanical seal includes a through hole portion formed over two divided sealing rings so as to go over divided contact faces of the two divided sealing rings adjacent to each other in the circumferential direction, and a coupling tool inserted into the through hole portion to couple the two adjacent divided sealing rings. The coupling tool includes a bolt, a nut, and a tube fitted to a shaft portion of the bolt, and the tube is compressed in the axial direction and expanded in the outer diameter direction when the two adjacent divided sealing rings are coupled by fastening the nut.
Claims
1. A division type mechanical seal in which a stationary sealing ring provided on a side of a housing or a rotating sealing ring provided on a rotation shaft which is inserted into the housing is a divided sealing ring divided in the circumferential direction, the division type mechanical seal that does sealing by sealing end faces serving as opposing end faces of the stationary sealing ring and the rotating scaling ring, the division type mechanical seal comprising: a through hole portion formed over two divided sealing rings so as to go over divided contact faces of the two divided sealing rings adjacent to each other in the circumferential direction; and a coupling tool inserted into the through hole portion to couple the two adjacent divided sealing rings, wherein: the coupling tool includes a bolt, a nut, and a tube, the bolt being constituted by a head part, a shaft portion and a centering portion between the head part and the shaft portion, the tube being seamless in a circumferential direction and fitted to the shaft portion of the bolt, the centering portion of the bolt having a diameter which is substantially equal to or slightly smaller than a diameter of the through hole portion and which is smaller than that of the head part of the bolt and larger than that of the shaft portion of the bolt, to keep a centering between the bolt and the through hole portion, the centering portion being fitted into the through hole portion of only one of the two divided sealing rings, a side end face of the tube being abutted with a side end face of the centering portion when the tube is fitted to the shaft portion of the bolt, thereby positioning a middle part of the tube in a vicinity of a border between the two divided sealing rings, and wherein when the bolt and the nut are fastened, the tube is compressed in an axial direction between the centering portion of the bolt and the nut, and as a result the middle part of the tube is expanded in an outer diameter direction so as to separate an inner peripheral surface of the middle part of the tube from a peripheral surface of the shaft portion of the bolt, thereby coupling the two divided sealing rings.
2. The division type mechanical seal as set forth in claim 1, wherein: the tube is formed in a tubular body made of synthetic resin.
3. The division type mechanical seal as set forth in claim 2, wherein: an outer diameter of the shaft portion of the bolt is set to be larger than an inner diameter of the tube.
4. A division type mechanical seal in which a stationary sealing ring provided on a side of a housing or a rotating sealing ring provided on a rotation shaft which is inserted into the housing is a divided sealing ring divided in the circumferential direction, the division type mechanical seal that does scaling by sealing end faces serving as opposing end faces of the stationary sealing ring and the rotating sealing ring, the division type mechanical seal comprising: a through hole portion formed over two divided sealing rings so as to go over divided contact faces of the two divided sealing rings adjacent to each other in the circumferential direction; a female screw portion formed in the through hole portion in one of the two divided sealing rings; and a coupling tool inserted into the through hole portion to couple the two divided sealing rings, wherein: the coupling tool includes a bolt and a tube, the bolt being constituted by a head part, a shaft portion and a centering portion between the head part and the shaft portion, the tube being seamless in a circumferential direction and fitted to the shaft portion of the bolt, the centering portion of the bolt having a diameter which is substantially equal to or slightly smaller than a diameter of the through hole, portion and which is smaller than that of the head part of the bolt and larger than that of the shaft portion of the bolt, to keep a centering between the bolt and the through hole portion, the centering portion being fitted into the through hole portion of only one of the two divided sealing rings, a side end face of the tube is abutted with a side end face of the centering portion of the bolt when the tube is fitted to the shaft portion of the bolt, thereby positioning a middle part of the tube in a vicinity of a border between the two divided sealing rings, and wherein when the bolt and the female screw portion are fastened, the tube is compressed in an axial direction between the centering portion of the bolt and the female screw portion, and as a result the middle part of the tube is expanded in an outer diameter direction so as to separate an inner peripheral surface of the middle part from a peripheral surface of the shaft portion of the bolt, thereby coupling the two divided sealing rings.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1)
(2)
(3)
(4)
(5)
DESCRIPTION OF EMBODIMENTS
(6) Hereinafter, with reference to the drawings, modes for carrying out the present invention will be described and exemplified based on embodiments. However, regarding size, material, shape, and relative arrangement of constituent parts described in the embodiments, and the like, there is no intention to limit the scope of the present invention only to those unless specifically and clearly described.
(7) In the best modes for carrying out a division type mechanical seal according to the present invention to be described below, for convenience of description, a complete division type mechanical seal in which both sealing rings of a stationary sealing ring provided on the side of a housing and a rotating sealing ring provided in a rotation shaft which is inserted into the housing are divided will be described as an example. However, the present invention is not limited to this but also includes a division type mechanical seal in which at least one of a stationary sealing ring provided on the side of a housing and a rotating sealing ring provided in a rotation shaft which is inserted into the housing is divided.
(8) First Embodiment
(9)
(10) As shown in
(11) In the first embodiment, the outside mechanical seal is described as an example. However, the present invention is not limited to the outside mechanical seal but can also be applied to other types such as an inside mechanical seal needless to say.
(12) As shown in
(13) The stationary sealing ring 4 has the sealing end face 4a on one end face, and is formed in an annular body as shown in
(14) As well as the stationary sealing ring 4, the rotating sealing ring 7 has the sealing end face 7a on one end face, and is formed in an annular body, divided into divided sealing rings which are divided into a plurality of (two in the present example) arcs in the circumferential direction, and formed in an annular mode in which divided contact faces (circumferential end faces of the arc divided bodies) are closely attached. As described later, the rotating sealing ring is fitted into and held by the division retainer 6.
(15) It should be noted that for convenience of description, the same reference signs 12, 13 as in the case of the stationary sealing ring 4 will be sometimes used for the divided sealing rings forming the rotating sealing ring 7 stylizing as 7 (12, 13).
(16) The division retainer 6 into and by which the rotating sealing ring 7 is fitted and held is fixed and held to the rotating shaft 5 via a rotating ring collar 14 fixed to the rotating shaft 5. That is, the rotating ring collar 14 is divided in the circumferential direction, and fitted and fixed to the rotating shaft 5 by being fastened in a ring shape by a fastening bolt 15.
(17) Between the rotating ring collar 14 and the division retainer 6, a spring 16 that biases the rotating sealing ring 7 rightward so as to press and bring the rotating sealing ring into contact with the stationary sealing ring 4 is placed.
(18) The rotating sealing ring 7 is made of for example a hard material such as silicon carbide. The stationary sealing ring 4 is made of for example carbon having a self-lubricating property which is softer than the rotating sealing ring 7 or the like.
(19) The division retainer 3 into and by which the stationary sealing ring 4 is fitted and held and the division retainer 6 into and by which the rotating sealing ring 7 is fitted and held are attached to the sealing end faces 4a, 7a symmetrically as shown in
(20) Based on
(21) In a sectional shape on the outer circumferential side of the divided sealing rings 4 (12, 13) forming the stationary sealing ring 4, a center portion 20 in the width direction is high, a side face on the opposite side of the sealing end face 4a has a vertical level difference portion 21, and a side face on the side of the sealing end face 4a has a sloping level difference portion 22 having an obtuse angle, so that both the sides are low. The low part having the vertical level difference portion 21 is extended and a division O ring 23 that seals a space from the seal case 2 is installed. On the other side, the above sealing end face 4a is formed in an end of the low part having the sloping level difference portion 22 having an obtuse angle.
(22) The division retainer 3 on the stationary side is an annular body made of stainless steel, and divided into a plurality of (two in the present example) arcs in the circumferential direction, and formed in an annular mode in which the divided contact faces are closely attached. The divided contact faces are closely attached by a fastening bolt 26.
(23) A sectional shape of the inner circumferential side of the division retainer 3 on the stationary side which opposes to the outer circumferential side of the divided sealing ring 4 (12, 13) on the stationary side is formed in a shape substantially matching the sectional shape on the outer circumferential side of the divided sealing ring 4 (12, 13). A groove 27 having a rectangular section is formed over the entire circumference at a position corresponding to the vertical level difference portion 21 of the divided sealing ring 4 (12, 13), and a fitting hole having a rectangular section for fitting a division split ring 32 to be described later is fitted is formed by the vertical level difference portion 21 of the divided sealing ring 4 (12, 13) and the rectangular groove 27 of the division retainer 3.
(24) The inner circumferential side of the division retainer 3 corresponding to the sloping level difference portion 22 having an obtuse angle of the divided sealing ring 4 (12, 13) on the stationary side is formed at a substantially right angle so as to form a substantially triangle gap.
(25) A sectional shape on the outer circumferential side of the rotating sealing ring 7 is formed in the same shape as the stationary sealing ring 4 yet symmetrically. On the inner circumferential side, a groove 30 is provided in such a manner that a division O ring 29 that seals a space from an outer circumferential face of the rotating shaft 5 is installed. The rotating sealing ring 7, the O ring 29, a backup ring 31, and the rotating ring collar 14 are stably held by the spring 16 installed between the rotating ring collar 14 and the division retainer 6 and a drive pin 49. Thus, the division O ring 29 is also surely held in the groove 30 in a state of being pressed in the axial direction by the backup ring 31.
(26) Into the division split ring fitting hole formed by the vertical level difference portion 21 of the divided sealing ring 4 (12, 13), 7 (12, 13) and the rectangular groove 27 of the division retainer 3, 6, the division split ring 32 made of stainless steel having a rectangular section and formed in an arc having the same length as arc length of the division split ring fitting hole is fitted.
(27) It should be noted that the division split ring 32 is described in detail in Japanese Patent Application No. 2010-511040 (WO2009/136539) already filed by the applicant, and detailed description thereof will be omitted in the present application.
(28) Next, with reference to
(29)
(30) In
(31) Upon forming the through hole portion 50, the through hole portion 50 is formed in an annular state before dividing the stationary sealing ring 4 or the rotating sealing ring 7 and then the sealing ring is divided to be divided sealing rings, or the through hole portion 50 is formed after dividing the stationary sealing ring 4 or the rotating sealing ring 7 and then combining the divided sealing rings into an annular form with high precision. Thereby, at the time of assembling on the shaft, the highly precise annular stationary sealing ring 4 or rotating sealing ring 7 can be obtained.
(32) Next, a configuration of the coupling tool 54 will be described.
(33) As shown in
(34) The sum of axial length 11 of the centering portion 55c and axial length 12 of the tube 57 is set to be larger than thickness 2d of the flange portions 52, 52 of the divided sealing rings 12, 13.
2d<11+12
(35) Therefore, as shown in
(36) In the present, example, there is no gap on the inner diameter side of the tube 57 but there is a gap on the outer diameter side. Thus, the tube is not expanded in the inner diameter direction but expanded in the outer diameter direction as shown by arrows.
(37) The relationship between the sum of the axial length 11 of the centering portion 55c and the axial length 12 of the tube 57 and the thickness 2d of the flange portions 52, 52 of the divided sealing rings 12, 13 is not limited to the above expression. The relationship may be anything as long as the tube is expanded on the outer diameter side when the tube is compressed in the axial direction. For example, a shape of a centering portion to be inserted into the through hole portion may be provided in the nut 56, or a maximum outer diameter of the nut may be smaller than inner diameter size of the through hole portion and the bolt, the tube, and the nut may be capable of being integrally inserted into the through hole portion.
(38) A material of the tube 57 is selected from flexible and to some extent corrosive materials. For example, as synthetic resin, the materials include polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), a copolymer of tetrafluoroethylene and hexafluoropropylene (FEP), vinyl resin, and urethane resin.
(39) As metal, any metal materials are acceptable as long as the materials are elastically deformable and corrosive to some extent. Shapes include a spiral shape linear body having a spring function and a tubular body having a cut face in the longitudinal direction.
(40) In order to make the tube 57 easily expandable in the outer diameter direction, in a case where the material is synthetic resin, the diameter of the shaft portion 55a of the bolt is slightly larger than the inner diameter of the tube 57, so that deformation toward the inner diameter side is prevented and the tube can be efficiently deformed to the outer diameter side.
(41) In a case where the material is a deformable metal material, with the tube formed in a spiral shape linear body having a spring function, desirably, a taper is provided on parts in contact with the tube so as to prevent both end faces of the tube from escaping to the outer diameter side, that is, on the side face 55e of the centering portion 55c and the inner side face of the nut 56, or a shape of the spiral shape linear body is preliminarily formed in a drum shape in which the center portion in the axial direction of the bolt is expanded to the outer diameter side. Further, with the tube formed in a tubular body having a cut face in the longitudinal direction, desirably, a taper is provided on the parts in contact with the tube so as to prevent both the end faces of the tube from escaping to the outer diameter side, that is, on the side face 55e of the centering portion 55c and the inner side face of the nut 56.
(42) As shown in
(43) Second Embodiment
(44) Next, with reference to
(45) The coupling configuration of the divided sealing rings 12, 13 according to the second embodiment is different from the first embodiment in a point where the nut is omitted in the coupling tool. However, other basic configurations are the same as the first embodiment. The same members will be given the same reference signs and duplicated description will be omitted.
(46) In
(47) A bolt 55 is inserted from the side where the through hole portion 50 is formed over the entire width. The flange portions 52, 52 can be fastened by screwing a male screw portion 55d on a leading end of the bolt 55 into the female screw portion 60.
(48) As shown in
(49) As shown in
(50) In the second embodiment, no nut is required in comparison to the first embodiment. Thus, the number of parts can be reduced, and a task of screwing the bolt can be easily performed even upon fastening the flange portions 52, 52 by the coupling tool.
(51) It should be noted that the second embodiment is suitable for a case where the divided sealing rings 12, 13 are made of metal.
(52) As described above, according to the configurations of the first and second embodiments, the coupling tool 54 exerts the same function as the conventionally known metal taper pin in terms of assembling precision. Thus, assembling precision on the divided contact faces of the divided sealing rings 12, 13 is ensured in the radial direction and in the axial direction as a matter of course, and effects as described below are exhibited in comparison to the taper pin.
(53) (1) Unlike in the conventionally known metal taper pin, confirmation of abutment and an abutment refining task (surface finishing) can be deleted. Thus, a processing time can be shortened to a great extent.
(54) (2) In a case of the conventionally known metal taper pin, there is a need for a task of improving precision. However, in a case of the coupling tool 54, since the tube 57 follows the shape and the size of the through hole portion 50, there is no need for the task of improving precision and hence a processing property is refined.
(55) (3) A temporary assembling state of the divided sealing rings 12, 13 can be maintained by utilizing friction between the outer face and the inner face of the through hole portion 50 due to deformation of the tube 57. Thus, at the time of a task of adjusting the divided contact faces of the divided sealing rings 12, 13 in a state where the nut 56 of the coupling tool 54 is not fastened or the like, the divided sealing rings 12, 13 can be stably held.
(56) (4) In case of the conventionally known metal taper pin, when an excessive load is applied to the divided sealing rings 12, 13 made of a brittle material at the time of assembling, this leads to breakage of the divided sealing rings 12, 13. However, in a case of the coupling tool 54, even when an excessive load is applied, the tube 57 serves as a buffering member and hence no breakage is caused.
(57) (5) At the time of disassembling the divided sealing rings 12, 13, in a case of the conventionally known metal taper pin, too close attachment generates large resistance, and thus detachment becomes difficult at the worst. However, in a case of the coupling tool 54, since the tube 57 is deformed, the detachment is easily performed.
(58) (6) In a case where the tube 57 is made of synthetic resin, a property of inserting the coupling tool into the through hole portion of the divided sealing rings and contradicting resistance are moderately favorable. Thus, workability can be improved.
(59) Next, an assembling procedure up to final assembling of the stationary sealing ring 4 fixed to the seal case 2 via the division retainer 3 and the rotating sealing ring 7 fixed to the rotating shaft 5 via the division retainer 6 will be described.
(60) Work Step 1: Temporary Assembling
(61) The divided parts (the retainers 3, 6 and the divided sealing rings 12, 13) are assembled on the rotating shaft 5. The divided contact faces of the divided sealing rings 12, 13 are in contact with each other but not completely fastened by a fastening member such as a coupling tool.
(62) Work Step 2: Divided Contact Face Precision Adjustment 1
(63) The temporarily assembled divided contact faces of the divided sealing rings 12, 13 are adjusted one by one so as to improve precision of the divided contact faces. After the work, the divided contact faces are inclose contact with each other and matching precision of the divided contact faces is improved. However, the divided contact faces are not completely fastened by the fastening member such as the coupling tool.
(64) Work Step 3: Retainer Temporary Assembling
(65) The retainers 3, 6 on the outer circumferential side of the divided sealing rings 12, 13 are fastened. The bolts of the retainers 3, 6 are fastened.
(66) Work Step 4: Divided Contact Face Precision Adjustment 2
(67) After temporarily assembling the divided sealing rings 12, 13 to the retainers 3, 6, the divided sealing rings are pushed in the axial direction by using a set jig (not shown) until axial length thereof becomes attachment length. Precision in the axial direction is improved.
(68) Work Step 5: Fixing of Divided Sealing Ring 12, 13
(69) In a state where the divided sealing rings 12, 13 are retained by the retainers 3, 6, the divided contact faces of the divided sealing rings 12, 13 are coupled and fixed by the coupling tool 54.
(70) Work Step 6: Fixing of Rotation Sealing Ring to Rotating Shaft
(71) The bolt 15 of the rotating ring collar 14 is fastened. The rotating sealing ring 7 is fixed to the rotating shaft 5.
(72) The embodiments of the present invention are described above with the drawings. However, specific configurations are not limited to these embodiments but modifications and additions that are made within the range not departing from the gist of the present invention are also included in the present invention.
(73) For example, the case where the division retainer 3 is installed on the outer circumferential side of the stationary sealing ring 4 and the division retainer 6 is installed on the outer circumferential side of the rotating sealing ring 7 is described in the embodiments. However, the present invention is not limited to this but can also be applied to a type where the division retainers 3, 6 on the outer circumferential side are not installed.
(74) For example, the case where the stationary sealing ring 4 and the rotating sealing ring 7 are divided is described in the embodiments. However, the present invention is not limited to this but any one of the stationary sealing ring 4 and the rotating sealing ring 7 may be divided.
(75) For example, the case where the through hole portion 50 is positioned in the vicinity of the center portion 20 in the width direction of the divided sealing rings 12, 13 and positioned on the slightly outer diameter side of the center of the thickness in the radial direction is described in the embodiments. However, the present invention is not limited to this but the through hole portion is positioned anywhere the through hole portion 50 can be formed.
(76) For example, the bolt 55 is used as a constituent member of the coupling tool 54 in the embodiments. The bolt in this case indicates a mechanical element for fastening and fixing a part and another part, including a shaft portion threaded to make a male screw and a head portion to be used for fastening together with a mechanical element called nut or being screwed into a hole (tap) threaded to make a female screw. The bolt is not limited to a hexagon bolt but includes a thumbscrew, a pin with a head portion, and the like.
REFERENCE SIGNS LIST
(77) 1 Housing
(78) 2 Seal case
(79) 3 Division retainer
(80) 4 Stationary sealing ring
(81) 5 Rotating shaft
(82) 6 Division retainer
(83) 7 Rotating sealing ring
(84) 8 Spring
(85) 9 O ring
(86) 12 Divided sealing ring
(87) 12a Divided contact face
(88) 13 Divided sealing ring
(89) 13a Divided contact face
(90) 14 Rotating ring collar
(91) 15 Fastening bolt
(92) 16 Spring
(93) 20 Center portion in width direction of divided sealing ring
(94) 21 Vertical level difference portion of divided sealing ring
(95) 22 Sloping level difference portion of divided sealing ring
(96) 23 Division O ring
(97) 26 Fastening bolt
(98) 27 Rectangular groove of division retainer
(99) 29 Division O ring
(100) 30 Groove
(101) 31 Backup ring
(102) 32 Division split ring
(103) 36 Buffering member
(104) 50 Through hole portion
(105) 51 Concave portion
(106) 52 Flange portion
(107) 53 Outer side face of flange portion
(108) 54 Coupling tool
(109) 55 Bolt
(110) 56 Nut
(111) 57 Tube
(112) 60 Female screw portion
(113) 61 Step portion