Reinforced seal for rotary shafts

Abstract

A seal for sealing a space between a housing and a rotatable shaft disposed within the housing includes an annular, elastomeric seal body disposeable about the shaft. The body has a central axis, an outer portion disposeable within a housing recess, and an inner portion with a lip engageable with the shaft. At least a portion of the seal body is configured to bendingly deflect when fluid pressure exerted on the body exceeds a predetermined value such that at least a section of the body inner portion displaces radially outwardly to permit fluid flow between the shaft and the seal body. A rigid support member is disposed within the body outer portion so as to be located at least partially within the housing recess and is configured to reduce bending deflection of the body inner portion so as to prevent disengagement of the body from the recess.

I claim: 
     
         1 . A seal for sealing a space between a housing and a rotatable shaft disposed at least partially within the housing, the housing having an annular recess and the shaft having an outer surface, the seal comprising:
 a generally annular, elastomeric seal body disposeable about the shaft, the body having a central axis, a radially outer portion disposeable at least partially within the housing recess so as to couple the seal with the housing, and a radially inner portion with a lip sealingly engageable with the shaft outer surface, at least a portion of the seal body being configured to bendingly deflect when fluid pressure exerted on the body exceeds a predetermined value such that at least a section of the body inner portion displaces generally radially outwardly with respect to the axis to permit fluid flow between the shaft and the seal body; and   at least one generally rigid support member disposed within the body outer portion so as to be located at least partially within the housing recess when the seal is coupled with the housing, the support member being configured to at least reduce bending deflection of the body inner portion so as to prevent disengagement of the body from the recess.   
     
     
         2 . The seal as recited in  claim 1  wherein the support member includes a generally annular body having an axial portion and a radial portion extending generally radially-inwardly with respect to the axial portion. 
     
     
         3 . The seal as recited in  claim 1  wherein the seal body inner portion is generally angled with respect to the central axis such that the lip is offset axially from a center of the body, the body inner portion having a first end surface facing generally toward the axis at the body first end and a second end surface facing generally away from the axis at the body second end. 
     
     
         4 . The seal as recited in  claim 3  wherein the body inner portion displaces generally radially outwardly with respect to the axis when fluid pressure on the first end surface exceeds the predetermined value such that the lip disengages from the shaft outer surface. 
     
     
         5 . The seal as recited in  claim 1  wherein the seal body further includes a substantially radially-extending central portion extending between and integrally connecting the inner and outer portions. 
     
     
         6 . The seal as recited in  claim 1  wherein:
 the seal body has a high pressure axial end exposable to a relatively higher pressure fluid and an opposing, low pressure axial end exposable to a relatively lower pressure fluid, the body inner portion has a radially outer end connected with the body outer portion and a radially inner end providing the sealing lip, the seal body inner portion being angled with respect to the central axis such that the inner end is spaced axially with respect to the outer end in a direction generally toward the seal body low pressure end; and 
 the support member includes a generally annular body with a generally axial portion and a generally radial portion extending radially-inwardly with respect to the axial portion, the support member being arranged within the seal body outer portion such that support member radial portion is disposed at least generally adjacent to the seal body high pressure end and the support member axial portion extends generally axially from the radial portion in a direction generally toward the seal body low pressure end. 
 
     
     
         7 . The seal as recited in  claim 6  wherein the seal body further includes at least one secondary sealing lip extending at least partially axially from the seal body low pressure end and being engageable with the housing recess to prevent fluid flow between the seal body outer portion and the recess. 
     
     
         8 . The seal as recited in  claim 1  wherein the support member is molded within the seal body. 
     
     
         9 . The seal as recited in  claim 8  wherein the seal body is formed of urethane and the support member is formed of a rigid polymer. 
     
     
         10 . A shaft assembly comprising:
 a housing having an inner circumferential surface defining a central bore and a recess extending generally radially outwardly from the inner surface;   a rotatable shaft disposed within the housing bore such that a generally annular space is defined between the shaft and the housing inner surface;   a bearing disposed within the housing and configured to rotatably support the shaft, the bearing containing a lubricant fluid; and   a seal configured to seal the annular space and including a a generally annular, elastomeric seal body with a central axis and at least one generally rigid support member disposed within the body, the body being disposeable about the shaft and having a radially outer portion disposeable at least partially within the housing recess and a radially inner portion with a lip sealingly engageable with the shaft outer surface, the body being configured to bendingly deflect when fluid pressure on the body exceeds a predetermined value such that the body inner portion displaces generally radially outwardly with respect to the axis to permit fluid flow between the shaft and the body, the at least one support member being disposed within the body outer portion so as to be located at least partially within the housing recess and configured to at least reduce bending deflection of the body inner portion so as to prevent disengagement of the body from the recess.   
     
     
         11 . The seal as recited in  claim 10  wherein the support member includes a generally annular body having an axial portion and a radial portion extending generally radially-inwardly with respect to the axial portion. 
     
     
         12 . The seal as recited in  claim 10  wherein the seal body inner portion is generally angled with respect to the central axis such that the lip is offset axially from a center of the body, the body inner portion having a first end surface facing generally toward the axis at the body first end and a second end surface facing generally away from the axis at the body second end. 
     
     
         13 . The seal as recited in  claim 12  wherein the body inner portion displaces generally radially outwardly with respect to the axis when fluid pressure on the first end surface exceeds the predetermined value such that the lip disengages from the shaft outer surface. 
     
     
         14 . The seal as recited in  claim 10  wherein the seal body further includes a substantially radially-extending central portion extending between and integrally connecting the inner and outer portions. 
     
     
         15 . The shaft assembly as recited in  claim 10  wherein the seal body has opposing first and second axial ends, at least a portion of the body first end being exposable to the fluid within the bearing such that radial displacement of the body inner portion releases a portion of the fluid from the bearing. 
     
     
         16 . The seal as recited in  claim 10  wherein:
 the seal body has a high pressure axial end exposable to a relatively higher pressure fluid and an opposing, low pressure axial end exposable to a relatively lower pressure fluid, the body inner portion has a radially outer end connected with the body outer portion and a radially inner end providing the sealing lip, the seal body inner portion being angled with respect to the central axis such that the inner end is spaced axially with respect to the outer end in a direction generally toward the seal body low pressure end; and 
 the support member includes a generally annular body with a generally axial portion and a generally radial portion extending radially-inwardly with respect to the axial portion, the support member being arranged within the seal body outer portion such that support member radial portion is disposed at least generally adjacent to the seal body high pressure end and the support member axial portion extends generally axially from the radial portion in a direction generally toward the seal body low pressure end. 
 
     
     
         17 . The shaft assembly as recited in  claim 13  wherein the seal body is formed of urethane, the support member is formed of a rigid polymer, and the support member is molded within the seal body. 
     
     
         18 . A seal for sealing a space between a housing and a rotatable shaft disposed at least partially within the housing, the housing having an annular recess and the shaft having an outer surface, the seal comprising:
 a generally annular, elastomeric seal body disposeable about the shaft, the seal body having a central axis, a radially outer portion disposeable at least partially within the housing recess so as to couple the seal with the housing, and a radially inner portion with a lip sealingly engageable with the shaft outer surface, the seal body being configured to bendingly deflect when pressure on the body exceeds a predetermined value such that at least a section of the body inner portion displaces generally radially outwardly with respect to the axis to permit fluid flow between the shaft and the seal body, the body having a high pressure axial end exposable to a relatively higher fluid pressure and an opposing, low pressure axial end exposable to a relatively lower fluid pressure; and   at least one generally rigid support member disposed within the seal body outer portion so as to be located at least partially within the housing recess when the seal is coupled with the housing, the support member including a generally annular body with an axial portion and a radial portion extending radially-inwardly with respect to the axial portion, the support member being arranged within the seal body outer portion such that support member radial portion is disposed at least generally adjacent to the seal body high pressure end and the support member axial portion extends generally axially from the radial portion in a direction generally toward the seal body low pressure end.   
     
     
         19 . The seal as recited in  claim 18  wherein the support member is configured to at least reduce bending deflection of the body inner portion so as to prevent disengagement of the body from the recess. 
     
     
         20 . The seal as recited in  claim 1  wherein the seal body inner portion is generally angled with respect to the central axis such that the lip is offset axially from a center of the body, the body inner portion having a first end surface facing generally toward the axis at the body high pressure end and a second end surface facing generally away from the axis at the body low pressure end, the body inner portion displacing generally radially outwardly with respect to the axis when fluid pressure on the first end surface exceeds the predetermined value such that the lip disengages from the shaft outer surface.