Abstract:
A two-piece interlocked labyrinth seal device for providing a seal between a housing and a shaft formed of two ring members, specifically a rotor and stator, connected to each other by a plastically deforming unitizing element. The rotor further includes one or a series of protrusions and recesses for providing a tortuous passage for fluid travel within the seal device. The system can be used on rotating shafts, rotating bores or as a baffle and has improved oil retention and water exclusion properties.

Description:
BACKGROUND 
     The invention generally relates to a device for providing a seal between a shaft and a housing. In particular, the invention relates to a dynamic, metallic labyrinth seal device for preventing lubricant from leaking out of a housing and/or for preventing contaminants from traveling into the housing. The invention also relates to a labyrinth seal device capable of functioning in high temperature environments. The invention also relates to a method of assembling a sealed system. 
     Prior art devices for sealing a rotating shaft are disclosed in U.S. Pat. No. 4,022,479 (Orlowski) and U.S. Pat. No. 5,024,451 (Borowski). Seal devices of this type may be used to prevent lubricant from escaping out of a bearing housing and/or to prevent contaminants from working their way into the housing. The prior art devices are formed of at least two ring-shaped members that rotate with respect to each other when the shaft is rotated. One of the members is fixed to the housing and does not rotate. The other member rotates with the rotating shaft. 
     The two ring members should be located very close together, particularly when the seal device is used to isolate the bearing from small particulate contaminants. Even small quantities of such contaminants are capable of significantly deteriorating the bearing. To prevent such contamination, the two relatively rotatable ring members must be held together very closely, with only a very narrow space therebetween. 
     The ring members of the Orlowski seal device are connected together by a separate securing means. The ring members themselves have no means for establishing and maintaining a narrow spacing therebetween. Therefore, the Orlowski seal device cannot be manufactured as a unit with a preset, fixed spacing. The spacing between the ring members has to be set when the seal device is installed into the housing. This leaves room for human error outside the control of the device manufacturer. In particular, the Orlowski device can be improperly installed, with the ring members located too far apart to perform satisfactorily. Another problem with the Orlowski device is that the ring members may be separated subsequent to installation, for example by high pressure cleaning spray. 
     The ring members of the Borowski device are held together by a bead and a groove provided on the ring members themselves. The bead fits within the groove with an interference fit. This arrangement is an improvement over the Orlowski system in the sense that no separate securing means is needed. But the Borowski device is still unsatisfactory because the bead must be resiliently deformed to be positioned within the groove, and the groove must be correspondingly enlarged to receive the deformed bead. The deformation of the bead during assembly makes it difficult to achieve the desired close positioning between the two ring members. Further, the Borowski device, which incorporates three members, is unsatisfactory for having a greater number of potential leakage paths than seal devices utilizing only two members. 
     Prior art devices do not disclose unitized labyrinth seals which are capable of operating in high temperature environments, such as during fires. Conventional seal devices composed of TEFLON® or other similar material, when exposed to high temperatures, may warp, deform or disintegrate, causing a failure in the device to dynamically seal. 
     SUMMARY 
     The disadvantages of the prior art are alleviated to a great extent by the present invention which provides a metallic seal device including a rotor and a stator having a plastically deformable unitizing element. 
     In a preferred embodiment of the present invention, the plastically deformable unitizing element is located on the stator and is made to plastically deform radially outwardly to interlock the stator and rotor. 
     In one aspect of the present invention, the rotor has an annular protrusion to aid in the labyrinth sealing effect and the seal may be a severe splash type seal. 
     In another preferred embodiment, the unitizing element of the stator plastically deforms radially inwardly and the stator may contain an annular protruding element to add to the labyrinth sealing effect. 
     In another preferred embodiment, the unitizing element is located on the rotor which interlocks into a recess located in the stator. 
     Another object of the present invention is to use the metallic plastically deformable unitizing element to create a seal which can be used as an internal baffle to control the movement of fluid contaminant. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic view of a seal device constructed in accordance with a first embodiment of the invention. 
     FIG. 2 is another schematic view of the seal device of FIG.  1 . 
     FIG. 3 is another schematic view of the seal device of FIG.  1 . 
     FIG. 4 is a schematic view of a seal device constructed in accordance with a second embodiment of the invention. 
     FIG. 5 is a schematic view of a seal device constructed in accordance with a third embodiment of the invention. 
     FIG. 6 is a schematic view of a seal device constructed in accordance with a fourth embodiment of the invention. 
     FIG. 7 is a schematic view of a seal device constructed in accordance with a fifth embodiment of the invention. 
     FIG. 8 is a schematic view of a seal device constructed in accordance with a sixth embodiment of the invention. 
     FIG. 9 is a schematic view of a seal device constructed in accordance with a seventh embodiment of the invention. 
     FIG. 10 is a schematic view of a seal device constructed in accordance with an eighth embodiment of the invention. 
     FIG. 11 is a schematic view of a seal device constructed in accordance with a ninth embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIGS. 1-3 illustrate a ring-shaped seal device  20  constructed in accordance with a preferred embodiment of the invention. The seal device  20  includes a rotor member, or rotor,  30  and a stator member, or stator,  50  in an unassembled position, as seen in FIG.  1 . The rotor  30  has an outer surface  32 , an inner surface  34 , and an inner protrusion  36 . A recess  38  is formed between the inner surface  34  and the inner protrusion  36 . The rotor  30  also has a shaft sealing groove  40  which receives a sealing element, such as an O-ring  77  (FIG.  4 ), for providing a tight seal between the rotor  30  and a rotatable shaft  221 . Moreover, the radial compression of the sealing element  77  between the shaft  221  and rotor  30  is sufficient to make the rotor  30  rotate in unison with the shaft  221 . 
     The stator  50  includes a stator housing mating surface  52 , housing sealing grooves  54 ,  56 , annular grooves  58 ,  60 , annular protrusions  62 ,  64 , and a unitizing element  70 . The housing sealing grooves  54 ,  56  are designed to allow sealing elements, such as O-rings,  79 ,  81  (FIG. 4) to be placed between a housing  111  and the stator  50 . The radial compression of the sealing elements  79 ,  81  between the housing  111  and stator  50  is sufficient to prevent the stator  50  from rotating with respect to the housing  111 . The annular grooves  58 ,  60  and the annular protrusions  62 ,  64  work with an axial groove  68  to return fluid to the housing  111 . 
     Although it is preferred to provide the seal device  20  with sealing elements, such as the O-rings  77 ,  79 ,  81 , the seal device  20  may be machined to close tolerances and press fit, by an arbor press or by hammering the device  20  into place, around the shaft. Further, the seal design can be made as small as {fraction (3/16)}″ in shaft to bore cross-section and the seal width can be reduced when there is a space limitation where the seal  20  is to be used. 
     In operation the stator  50  sealing elements  79  and  81  inhibit oil from escaping out of the housing  111  around the outside of the stator  50  and the rotor sealing element  77  inhibits contaminants from traveling into the housing  111  along the surface of the shaft  221 . Oil and contaminants are dynamically prevented from traveling through the interface between the rotor  30  and stator  50 . 
     The unitizing element  70  has a locking portion  72  and a deformable portion  74 . The locking portion  72  is designed and sized to fit within the recess  38  in a manner which locks the rotor  30  and stator  50  together and provide a close positioning between the rotor  30  and stator  50 . Specifically, the unitizing element  70  is designed and sized to maintain a gap  75  (FIG. 4) between the locking portion  72  and the inner protrusion  36  and a gap  82  (FIG. 4) between the rotor  30  and the stator  50 . The deformable portion  74  is designed and sized to allow for deformation during assembly yet still maintain its strength after deformation to lock together the rotor  30  and the stator  50  and thus unitize the seal  20 . 
     The unitizing element  70  is preferably machined to form the locking portion  72  at an angle  73  so that when the rotor  30  is pressed against it in a direction  71 , as in an arbor press, it is forced to move plastically outward into the recess  38  in the rotor  30 . The unitizing element  70  instead may be machined straight and then partially preformed prior to assembly, with the final forming occurring during assembly of the rotor  30  and stator  50 . The unitizing element  70  optionally may have a drainage passage  76  cutout to allow passage of contaminants out of the seal  20 . When the drainage passage  76  is cut out of the unitizing element  70  the ends may flare out, however, the edges of the ends may be removed by grinding prior to assembly. 
     The rotor  30  and stator  50  may be made of a suitable high temperature material such as a metallic substance, most preferably bronze. The stator  50  and rotor  30  may also be comprised of metallic alloys. The sealing elements or O-rings  77 ,  79 ,  81  may be made of a suitable elastomeric material or material suitable for high temperatures. 
     FIGS. 2-3 show various stages of assembly and specifically the deformation of the unitizing element  70 . As seen in FIG. 2, the locking portion  72  meets the inner surface  34  of the rotor  30 . When enough force is applied to the rotor  30  during assembly, the inner surface  34  pushes against the locking portion  72  of the unitizing element  70 . As shown in FIG. 3, the unitizing element  70 , specifically the deformable portion  74 , is bent or deformed allowing the locking portion  72  to enter the recess  38  of the rotor  30 . 
     The material composition of the unitizing element  70  should be such that force may be used to shape, or plastically deform, it. The range of possible compositions may be increased if heat is used in the forming stage. The unitizing element  70 , depending upon its material composition, may however have a certain degree of elastic rebound. The unitizing element  70  is to be formed such that its elastic rebound takes into account the desire to maintain gaps  75  and  82  to maintain axial play greater than zero. Further, when fit together, the rotor  30  and the stator  50  may be in relaxed contact with each other via the unitizing element  70 . By relaxed contact is meant that there are no or minimal compression forces between the rotor  30  and the stator  50 . In operation and/or during assembly, any contact between the rotor  30  and the stator  50  is likely to be broken and the rotor  30  and the stator  50  will remain interconnected, with only intermittent contact, which is unnecessary for sealing. 
     FIG. 4 shows a seal  120  wherein the unitizing element  70 , specifically the locking portion  72 , is locked into the recess  38  of a rotor  130 . The rotor  130  includes an annular protruding ridge  139 , adds to the labyrinth sealing effect of the seal  120 . The deformable portion  74  of unitizing element  70  is bent plastically to allow the locking portion  72  to set itself into the recess  38  of rotor  30 . Since the deformation of the unitizing element  70  is a plastic deformation, as compared to an elastic deformation, the unitizing element  70  is permanently deformed. An elastically deformed element would continue to apply a constant force to reform to its original shape. 
     Illustrated in FIG. 5 is a severe splash type seal  220 , which includes a stator  150  having a splash recess  152  which is fluidly connected to a drainage passage  154 . The stator  150  further includes a housing sealing groove  156 , its corresponding sealing element  158 , and shaft sealing grooves  160 ,  162 . 
     A severe splash seal  320  is shown in FIG.  6  and includes a rotor  230  and a stator  250  having a unitizing element  270  which plastically deforms radially inwardly toward the shaft  221 . A severe splash seal, such as the seal  320 , is one which includes a remote drain back to the fluid side of the housing. The rotor  230  includes a protrusion  232  with a slanted tip portion  234 , a shaft sealing groove  236 , an outer portion  238 , and an inner protrusion  240 . An annular recess  242  is formed between the outer portion  238  and the protrusion  232 . Further a recess  244  is formed between an inner surface  246  and the inner protrusion  240 . The shaft sealing groove  236  is designed to receive a sealing element  237 . 
     The stator  250  shown in FIG. 6 contains a splash recess  252  with a corresponding fluid drainage passage  254 , annular grooves  256 ,  258 , annular ridges  260 ,  262 , a housing sealing groove  264  and its corresponding sealing element  266 , a stator housing mating surface  268 , and the unitizing element  270 . The unitizing element  270  includes a locking portion  272 , a deformable portion  274 , an optional drainage passageway  276 , and an annular lip protrusion  269 . The stator  250  could also be in the form of a nonsevere splash embodiment as depicted in FIGS. 1-3. 
     The unitizing element  270  differs from the unitizing element  70  in that the unitizing element  270  deforms toward the shaft  221 . The unitizing element  270  is locked into the recess  244  of the rotor  230 . The annular lip protrusion  269  along with the annular recess  242  create a tortuous passage for fluid or contaminants to flow, thereby enhancing the labyrinth sealing effect. The slanted portion  234  of the protrusion  232  aids in the movement of the unitizing element  270  during assembly. The locking portion  272  may come into contact with the slanted portion  234  which would then guide the locking portion  272  towards the recess  244 . 
     FIG. 7 shows another seal device  420  with a rotor  330  and a stator  350 . A unitizing element  370  extends from the stator  350 . The rotor  330  further includes an inner space  332 , a recess or groove  334 , and a shaft sealing groove  336  with its corresponding sealing element  338 . The unitizing element  370  has a locking portion  372  and a deformable portion  374 . The stator  350  has a stator mating surface  352 , an optional drainage passage  354 , an protrusion  356 , a recess  358  formed between the protrusion  356  and the main portion of the stator  350 . 
     The stator  350  further includes a splash recess  360 , a drainage passage  362 , a housing sealing groove  364  with its corresponding sealing element  366 , annular grooves  342 ,  344 , and annular protrusions  343 ,  345 . 
     During assembly, the rotor  330  is forced to mate with the stator  350 . The forced mating of the rotor  330  and stator  350  causes the locking portion  372  to contact the inner portion  368  of the stator  350 . The unitizing element  370 , when sufficiently pressed against the inner portion  368 , begins to plastically deform at the deformable portion  374 . The plastic deformation permanently locks the locking portion  372  into the recess  358 . 
     FIG. 8 illustrates a seal device  520  a stator  450  with an outer surface  452 , an inner surface  454 , a main stator body portion  456 , a housing sealing groove  458  with its corresponding sealing element  460 , and a shaft sealing recess  462 . The seal  520  further includes a rotor  430  having a rotor outer surface  432 , a series of recesses  434 ,  436 ,  438 , a series of annular protrusions or ridges  440 ,  442 ,  444 , a unitizing element  470 , and a shaft sealing groove  446  with its corresponding sealing element  448 . The unitizing element  470  includes a locking portion  472  and a deformable portion  474 . 
     The unitizing element  470  is locked into an annular recess  466  formed between the inner surface  454  and an inner protrusion  469 . The stator  450  also has a drainage passage  468  fluidly connected to recess  466 . The recesses  434 ,  436 ,  438  and the annular protrusions or ridges  440 ,  442 ,  444  create a torturous passageway thus enhancing the labyrinth effect of the seal. Also, the stator  450  includes a slanted surface  464  which allows the seal  520  to be seated deep within a housing. 
     A seal device  620  is shown in FIG.  9 . The seal device  620  includes a rotor  530  and a stator  550 . A unitizing element  570  is on the rotor  530  and unitizing element  580  is on the stator  550 . The stator  550  has a stator cover portion  552 , a main stator body portion  554 , an outer surface  556 , an inner surface  558 , a bore sealing groove  560  with its corresponding sealing element  562 , and a main stator body shoulder  564 . The stator unitizing element  580  has a locking portion  582  and a deformable portion  584 . 
     The rotor  530  includes a rotor outer surface  532 , a shaft sealing recess  534  with its corresponding sealing element  536 , a series of recesses  538 ,  540 ,  542 , and a series of ridges or protrusions  544 ,  546 ,  548 . The rotor unitizing element  570  is comprised of a locking portion  572  and a deformable portion  574 . 
     The seal device  620  shown in FIG. 9 is assembled by pushing the stator  550  and rotor  530  together in a manner which plastically deforms the rotor unitizing element  570  and the stator unitizing element  580 . The plastic deformation of the unitizing elements  570 ,  580  causes a permanent deformation which interlocks the stator  550  and the rotor  530 . The ridges or protrusions  544 ,  546 ,  548  and recesses  538 ,  540 ,  542  create a torturous passageway which enhances the labyrinth sealing effect of the seal. 
     FIG. 10 shows a seal device  720  having a stator  650  and a rotor  630 , each containing a unitizing element  670 ,  680 . The stator  650  includes a stator cover surface  652 , a housing sealing groove  654  with a corresponding sealing element  656 , a shoulder portion  658 , a radial inner protrusion  660 , an outer surface  662 , an inner surface  664 , and a recess  666  formed between the outer surface  662  and the radial inner protrusion  660 . The stator  650  also contains the unitizing element  670  which includes a locking portion  672  and a deformable portion  674 . 
     The rotor  630  has a shaft sealing groove  632  with a corresponding sealing element  634 , multiple recesses  636 ,  638 ,  640 , and multiple protrusions or ridges  642 ,  644 ,  646 . A recess or void  647  is created between the ridge  646  and an inner surface  648  of a rotor outer wall  649 . The rotor unitizing element  680  includes a locking portion  682  and a deformable portion  684 . 
     During assembly, the unitizing elements  670 ,  680  are plastically and permanently deformed into their corresponding recess  666 ,  647 . The multiple protrusions or ridges  642 ,  644 ,  646  and multiple recesses  636 ,  638 ,  640 ,  647  create a torturous passageway which enhances the labyrinth sealing effect of the seal  720 . 
     A seal device  820  is shown in FIG. 11, and it includes a rotor  730  and a stator  750 . Multiple unitizing elements  770 ,  780  are used to interlock the stator  750  and the rotor  730 . The stator  750  has a cover portion  752 , which contains an optional cover portion drainage passage  754 , a main stator body  756  with a main stator body drainage passage  758 , a housing sealing groove  760  with a corresponding sealing element  761 , a mounting hole  762  for mounting onto a bore housing (not shown), an inner protrusion  763 , an outer surface  764 , and an inner surface  766 . A recess  767  is formed between the inner surface  766  and the inner protrusion  763 . The stator  750  also has a stator unitizing element  770  which includes a locking portion  772  and a deformable portion  774 . 
     The rotor  730  has a shaft sealing groove  732  with its corresponding sealing element  733 , an inner surface  734 , an outer wall  735 , an inner protrusion  736 , multiple recesses  737 ,  739 ,  741 ,  743 , and multiple protrusions or ridges  738 ,  740 ,  742 ,  744 . A recess or void  745  is formed between protrusion  744  and the outer wall  735 . The rotor  730  also contains a unitizing element  780  which has a locking portion  782  and a deformable portion  784 . 
     The stator  750  and rotor  730  are interlocked via the unitizing elements  770 ,  780 . The unitizing element  780 , specifically the locking portion  782 , is locked into the recess  767 . The unitizing element  770 , specifically the locking portion  772  is locked into recess  745 . During assembly, the unitizing elements  770 ,  780  are plastically deformed, specifically at the deformable portions  774 ,  784 . The plastic deformation of the unitizing elements  770 ,  780  permanently locks the stator  750  and rotor  730  together. The protrusions or ridges  738 ,  740 ,  742 ,  744  and the recesses  737 ,  739 ,  741 ,  743 ,  745  create a torturous passageway for fluid or contaminants thereby providing a labyrinth sealing effect for the seal  820 . 
     While the foregoing has described in detail preferred embodiments known at the time, it should be readily understood that the invention is not limited to the disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. For example, while seal devices which have only intermittent contact between their constituent members have been described, it is to be understood that the unitizing elements described herein may be used in seal devices which contain non-labyrinth type seal features, both a labyrinth portion and a contact portion such as a lip seal. Additionally, although annular grooves for receiving sealing elements have been described an illustrated in pairs, in some circumstances a single such groove, with or without a sealing element, may be sufficient. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.