CA1162954A - Rod guide for a suspension strut - Google Patents
Rod guide for a suspension strutInfo
- Publication number
- CA1162954A CA1162954A CA000376991A CA376991A CA1162954A CA 1162954 A CA1162954 A CA 1162954A CA 000376991 A CA000376991 A CA 000376991A CA 376991 A CA376991 A CA 376991A CA 1162954 A CA1162954 A CA 1162954A
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- CA
- Canada
- Prior art keywords
- sleeve
- bearing sleeve
- elastomeric
- piston rod
- strut
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
ABSTRACT
A rod guide for a suspension strut has a bearing sleeve, outer sleeve and a resilient elastomeric sleeve bonded therebetween. The outer sleeve is fixed to the top portion of the strut body. The bearing sleeve has an aperture therethrough sized to slidably receive the piston rod of the strut such that side loads exerted on the body and piston rod of the strut flexes the elastomeric sleeve to maintain alignment of the bearing sleeve with respect to the piston rod extending therethrough. This structure decreases static friction occurring between a sliding piston rod and the rod guide fixed to the strut cylinder.
A rod guide for a suspension strut has a bearing sleeve, outer sleeve and a resilient elastomeric sleeve bonded therebetween. The outer sleeve is fixed to the top portion of the strut body. The bearing sleeve has an aperture therethrough sized to slidably receive the piston rod of the strut such that side loads exerted on the body and piston rod of the strut flexes the elastomeric sleeve to maintain alignment of the bearing sleeve with respect to the piston rod extending therethrough. This structure decreases static friction occurring between a sliding piston rod and the rod guide fixed to the strut cylinder.
Description
~ ~29~9~
ROD GUIDE FOR A SUSPENSION STRUT
This invention relates to a rod guide for a suspension strut and more particularly to a rod guide bearing constructed to reduce the static friction between a sliding piston rod and a fixed rod guide mounted in a strut body.
MacPherson struts and other strut suspensions are popular and are used in a great many automobile models.
The strut design has many advantages such as decreasing the weight of -the automobile, simplifying the packaging, and decreasing the number of components in the suspension system.
One disadvantage which consistently faces an engineer in designing a strut suspension is how to reduce the static friction load between the rod guide at the upper end of the strut body and the piston rod slidably extending through the rod guide. The static friction load is caused by side loads exerted on the piston rod and strut body. Increased static friction, commonly referred to as "stiction", increases the minimum axially directed force exerted on the strut necessary to make the strut function.
The stiction must be overcome to allow the suspension strut to operate in damping any bouncing of the wheel with respect to the vehicle. The problem of stiction is most noticeable on smooth roads where the jounce has minimal force and often does not exceed the threshhold level to overcome the stiction force of the strut. In this mode of travel, the shock absorbing strut is not operating and any damping is done substantially by the tires r the elastomeric upper mount and other elas-tomeric bushings. This friction must be eliminated or mi~imi~ed to allow the strut to operate when a motor vehicle is travelling over a smoother road.
A variety of ways have been conceived to reduce the static friction. Often the previous attempts were ineffective or added considerable cost to the motor vehicle.
Highly polished piston rods and low friction materials ~;; t~ coated on the rod guide are common methods to reduce ,
ROD GUIDE FOR A SUSPENSION STRUT
This invention relates to a rod guide for a suspension strut and more particularly to a rod guide bearing constructed to reduce the static friction between a sliding piston rod and a fixed rod guide mounted in a strut body.
MacPherson struts and other strut suspensions are popular and are used in a great many automobile models.
The strut design has many advantages such as decreasing the weight of -the automobile, simplifying the packaging, and decreasing the number of components in the suspension system.
One disadvantage which consistently faces an engineer in designing a strut suspension is how to reduce the static friction load between the rod guide at the upper end of the strut body and the piston rod slidably extending through the rod guide. The static friction load is caused by side loads exerted on the piston rod and strut body. Increased static friction, commonly referred to as "stiction", increases the minimum axially directed force exerted on the strut necessary to make the strut function.
The stiction must be overcome to allow the suspension strut to operate in damping any bouncing of the wheel with respect to the vehicle. The problem of stiction is most noticeable on smooth roads where the jounce has minimal force and often does not exceed the threshhold level to overcome the stiction force of the strut. In this mode of travel, the shock absorbing strut is not operating and any damping is done substantially by the tires r the elastomeric upper mount and other elas-tomeric bushings. This friction must be eliminated or mi~imi~ed to allow the strut to operate when a motor vehicle is travelling over a smoother road.
A variety of ways have been conceived to reduce the static friction. Often the previous attempts were ineffective or added considerable cost to the motor vehicle.
Highly polished piston rods and low friction materials ~;; t~ coated on the rod guide are common methods to reduce ,
2 9 ~ ~
stiction. In addition) the oil in the stru-t is often used to lubricate the piston rocl passiny through the rod guide.
~ Another way of reducing the static friction is to dispose the strut as close to the wheel as possible to minimize the side load on the strut. Another design feature has been to counteract any side loads on the strut by placing the suspension spring in an eccentric or tilted fashion with respect to the strut body. The spring creates an equal but oppositely directed side load which negates the original side load. However, these features have vast implications in the geometry and handling of the car to alleviate the one problem of static friction.
Struts have also been designed with the rod guide itself placed on bearings or shaped like a balljoint so that it rotates with the piston rod such that the side load between the rod guide and piston rod is minimized.
See U.S. Patent No. 2,660,449, issued to MacPherson on November 24, 1953. In addition, other attempts to minimize static friction pivotably mounted the piston onto the piston rod as disclosed in ~.S. Patent No. 2,390,389 to Beckwith issued on December 4, 1945 and Reissue Patent 19,904 issued to Donaldson on March 31, 1936. However, the side loads which cause the static friction in the first place tend to lock up any mechanical bearing which is designed to float the rod guide in position. There-fore, the ball bearings or balljoint guide bearings tend not to function in their designed fashion and the "stiction"
is still present in the strut.
It is desired that a rod guide for a suspension strut~incorporates a bearing that resiliently and pivotably flexes with respect to the strut body under side load forces to minimize static friction between the rod guide and piston rod but will not lock up from to the same side load forces. In addition, a system is needed to reduce static friction in a suspension strut that will have little consequence in the suspension geometry of the motor vehicle.
t 3 9 ~
In accordance with one aspect of the present inven-tion, there is provided a rod gu.ide for a suspension strut having a body portion, with a piston and piston rod slidably mounted with respect to the body portion, the rod guide 5 comprising: an annular bearing sleeve, having a central -tubular openi.ng sized to slidably receive the piston rod;
an annular elastomeric sleeve having its inner surface abutting and secured to the outer surface of the bearing sleeve;
the annular elastome.ric sleeve having its outer surface 10 fixed with respect to the body of the strut; the elastomeric sleeve constructed to resiliently flex under side loads exerted on the piston rod and body such that the bearing sleeve maintains alignment with respect to the piston rod extending therethrough; the elastomeric sleeve having a 15 varying thickness with the thinnest portion substantially at a midsection between the axial ends of the sleeve; the elastomeric sleeve having its inner surface bonded to the outer surface of the bearing sleeve; the elastomeric sleeve having its outer surface bonded to a sur:Eace fixed with 20 respect to the strut bodyî the outer surface of the bearing sleeve and the fixed surface being shaped to conform to the sh'ape of the elastomeric sleeve.
In accordance with another aspect of the present invention, there is provided a rod guide for a suspension 25 strut having a body portion with a piston ana a piston rod mounted thereon slidable with respect to the body portion : and the rod guide, the rod guide comprising: an annular bearing sleeve having its annular tubular opening slidably receiving the piston rod; an annular elastomeric sleeve 30 having its inner surface abutting and secured to the outer surface of the bearing sleeve; the annular elastomeric sleeve hav~ng its outer surface fixed with respect to the , body of the strut; the elastomeric sleeve constructed to resiliently flex under side loads exerted on the pi~ton 35 rod and bodyi such that the bearing sleeve maintains alignment with respect to the piston rod extending therethrough;
the elastomeric sleeve having a varying thic~ness with its thinnest portion subs-tantially on a midsection between the axial ends of the sleeve; the elastomeric sleeve havin~ its inner ~ ~29~
surface bonded to the outer surface of the bearing sleeve;
the elastomeric sleeve having its outer surface bonded to a surface fixed with respect to the strut bodyi the outer surface of thelbearing sleeve and the fixed surface 5 being shaped to con~orm to the.shape of the elastomeric sleevei and the bearing sleeve and the fixed surface being axially interlocked with each other with the elastomeric sleeve disposed therebetween to prevent the bearing sleeve from axially moving away from the fixed surface as the piston 10 rod axially slides through the bearing.
Reference now will be made to the following drawings in which:
Figure 1 is a partially segmented view of an upper portion of a strut incorporating one embodiment of the inven-15 tion;
Figure 2 is a partially segmented section of an upper section of a strut incorporating a second embodiment of the inverltion.
Referring to Figure 1, an upper portion oE a suspen-20 sion strut 4 includes a piston rod 6 slidably extending into body portion 8. Cap 10 closes off the top ends of working cylinder 12 and reservoir tube 14. The piston rod 6 passes through a rod guide assembly 16 which includes an elastomeric sleeve 18 interposed between an inner sleeve 25 assembly 20 and an outer sleeve 21 fixed with respect to the strut body 14.
In more detail, the body portion 8 includes a working tube 12 and an outer rese~voir tube 14 closed by the cap 10. The cap 10 is secured to the body portion 14 30 by means of a threaded extension tube 22 which is welded onto the outer reservoir tube 14. The cap 10 has a threaded section 24 which engages a complementary threaded section 26 of the extension tube 22. Alternatively, the outer res~r-. voir tube 14 can extend upward and the cap 10 can be welded 35 directly thereto.: The cap 10 has a central opening 26 and houses a double lipped seal 28 which snugly fits about the piston rod 12~ The double lipped seal 28 has a lower sealing lip 29(a) and an upper scraper lip 29(b).
The inner sleeve assembly 20 comprises an inter- ~
40 mediate sleeve 34 and an inner low friction sleeve 32 J
a 5 ~
press fitted therein. The inner sleeve 32 forms a central opening 33 through which piston rod 6 slidably extends. The inner surface 36 of sleeve 32 has a low friction teflon coating thereon. The outer surface 38 of the intermediate sleeve 34 is bonded to the resilient elastomeric sleeve 18.
The outer surface 42 of the elastomeric sleeve 18 is bonded to an inner surface ~4 o~ the outer sleeve 21. The inner surface 44 o~ the outer sleeve 21 has a continuously varying diameter with the smallest diameter section indicated at point 60 situated at a midpoint between the axial ends 62 and 64 o~ the inner sleeve assembly 20. The outer sleeve 21 has a seat portion 48 which positions the sleeve 21 on the working tube 12 of the strut 4. The outer sleeve 21 has an upper shoulder 56 and lower shoulder 58 which are tightly in~erposed between the cap 20 and working tube 12 respectively such that sleeve 21 is fixed with respect to the body portion 14. In addition, the outer surface 50 o~ the outer sleeve 21 in combination with the cap 10 and extension tube 22 seals off the reservoir chamber 52 with respect to the working cylinder interior 54 and the exterior of the strut.
The elastomeric sleeve 18 can be made from a suitable elastomeric material such as neoprene rubber with a 50 durome~er reading. The elastomeric sleeve 18 is most commonly molded between the sleeve assembly 20 and outer sleeve 21 such that it has a continuously varying outer diameter and continuously var~ing thic~ness with its thinnest section 65 positioned adjacent the inner diameter section 60 of sleeve 21 at an axial midpoint between the two ends 62 and 64 of the bearing sleeve assembly 41.
In operation, the elastomeric guide bearing assembly 16 minimizes static friction or "stiction" between the inner sleeve 32 an~ the piston rod 6 when side loads are exerted on the piston rod 6 with respect to the body 8. For example, if the piston rod has a side load e~erted at its top end toward
stiction. In addition) the oil in the stru-t is often used to lubricate the piston rocl passiny through the rod guide.
~ Another way of reducing the static friction is to dispose the strut as close to the wheel as possible to minimize the side load on the strut. Another design feature has been to counteract any side loads on the strut by placing the suspension spring in an eccentric or tilted fashion with respect to the strut body. The spring creates an equal but oppositely directed side load which negates the original side load. However, these features have vast implications in the geometry and handling of the car to alleviate the one problem of static friction.
Struts have also been designed with the rod guide itself placed on bearings or shaped like a balljoint so that it rotates with the piston rod such that the side load between the rod guide and piston rod is minimized.
See U.S. Patent No. 2,660,449, issued to MacPherson on November 24, 1953. In addition, other attempts to minimize static friction pivotably mounted the piston onto the piston rod as disclosed in ~.S. Patent No. 2,390,389 to Beckwith issued on December 4, 1945 and Reissue Patent 19,904 issued to Donaldson on March 31, 1936. However, the side loads which cause the static friction in the first place tend to lock up any mechanical bearing which is designed to float the rod guide in position. There-fore, the ball bearings or balljoint guide bearings tend not to function in their designed fashion and the "stiction"
is still present in the strut.
It is desired that a rod guide for a suspension strut~incorporates a bearing that resiliently and pivotably flexes with respect to the strut body under side load forces to minimize static friction between the rod guide and piston rod but will not lock up from to the same side load forces. In addition, a system is needed to reduce static friction in a suspension strut that will have little consequence in the suspension geometry of the motor vehicle.
t 3 9 ~
In accordance with one aspect of the present inven-tion, there is provided a rod gu.ide for a suspension strut having a body portion, with a piston and piston rod slidably mounted with respect to the body portion, the rod guide 5 comprising: an annular bearing sleeve, having a central -tubular openi.ng sized to slidably receive the piston rod;
an annular elastomeric sleeve having its inner surface abutting and secured to the outer surface of the bearing sleeve;
the annular elastome.ric sleeve having its outer surface 10 fixed with respect to the body of the strut; the elastomeric sleeve constructed to resiliently flex under side loads exerted on the piston rod and body such that the bearing sleeve maintains alignment with respect to the piston rod extending therethrough; the elastomeric sleeve having a 15 varying thickness with the thinnest portion substantially at a midsection between the axial ends of the sleeve; the elastomeric sleeve having its inner surface bonded to the outer surface of the bearing sleeve; the elastomeric sleeve having its outer surface bonded to a sur:Eace fixed with 20 respect to the strut bodyî the outer surface of the bearing sleeve and the fixed surface being shaped to conform to the sh'ape of the elastomeric sleeve.
In accordance with another aspect of the present invention, there is provided a rod guide for a suspension 25 strut having a body portion with a piston ana a piston rod mounted thereon slidable with respect to the body portion : and the rod guide, the rod guide comprising: an annular bearing sleeve having its annular tubular opening slidably receiving the piston rod; an annular elastomeric sleeve 30 having its inner surface abutting and secured to the outer surface of the bearing sleeve; the annular elastomeric sleeve hav~ng its outer surface fixed with respect to the , body of the strut; the elastomeric sleeve constructed to resiliently flex under side loads exerted on the pi~ton 35 rod and bodyi such that the bearing sleeve maintains alignment with respect to the piston rod extending therethrough;
the elastomeric sleeve having a varying thic~ness with its thinnest portion subs-tantially on a midsection between the axial ends of the sleeve; the elastomeric sleeve havin~ its inner ~ ~29~
surface bonded to the outer surface of the bearing sleeve;
the elastomeric sleeve having its outer surface bonded to a surface fixed with respect to the strut bodyi the outer surface of thelbearing sleeve and the fixed surface 5 being shaped to con~orm to the.shape of the elastomeric sleevei and the bearing sleeve and the fixed surface being axially interlocked with each other with the elastomeric sleeve disposed therebetween to prevent the bearing sleeve from axially moving away from the fixed surface as the piston 10 rod axially slides through the bearing.
Reference now will be made to the following drawings in which:
Figure 1 is a partially segmented view of an upper portion of a strut incorporating one embodiment of the inven-15 tion;
Figure 2 is a partially segmented section of an upper section of a strut incorporating a second embodiment of the inverltion.
Referring to Figure 1, an upper portion oE a suspen-20 sion strut 4 includes a piston rod 6 slidably extending into body portion 8. Cap 10 closes off the top ends of working cylinder 12 and reservoir tube 14. The piston rod 6 passes through a rod guide assembly 16 which includes an elastomeric sleeve 18 interposed between an inner sleeve 25 assembly 20 and an outer sleeve 21 fixed with respect to the strut body 14.
In more detail, the body portion 8 includes a working tube 12 and an outer rese~voir tube 14 closed by the cap 10. The cap 10 is secured to the body portion 14 30 by means of a threaded extension tube 22 which is welded onto the outer reservoir tube 14. The cap 10 has a threaded section 24 which engages a complementary threaded section 26 of the extension tube 22. Alternatively, the outer res~r-. voir tube 14 can extend upward and the cap 10 can be welded 35 directly thereto.: The cap 10 has a central opening 26 and houses a double lipped seal 28 which snugly fits about the piston rod 12~ The double lipped seal 28 has a lower sealing lip 29(a) and an upper scraper lip 29(b).
The inner sleeve assembly 20 comprises an inter- ~
40 mediate sleeve 34 and an inner low friction sleeve 32 J
a 5 ~
press fitted therein. The inner sleeve 32 forms a central opening 33 through which piston rod 6 slidably extends. The inner surface 36 of sleeve 32 has a low friction teflon coating thereon. The outer surface 38 of the intermediate sleeve 34 is bonded to the resilient elastomeric sleeve 18.
The outer surface 42 of the elastomeric sleeve 18 is bonded to an inner surface ~4 o~ the outer sleeve 21. The inner surface 44 o~ the outer sleeve 21 has a continuously varying diameter with the smallest diameter section indicated at point 60 situated at a midpoint between the axial ends 62 and 64 o~ the inner sleeve assembly 20. The outer sleeve 21 has a seat portion 48 which positions the sleeve 21 on the working tube 12 of the strut 4. The outer sleeve 21 has an upper shoulder 56 and lower shoulder 58 which are tightly in~erposed between the cap 20 and working tube 12 respectively such that sleeve 21 is fixed with respect to the body portion 14. In addition, the outer surface 50 o~ the outer sleeve 21 in combination with the cap 10 and extension tube 22 seals off the reservoir chamber 52 with respect to the working cylinder interior 54 and the exterior of the strut.
The elastomeric sleeve 18 can be made from a suitable elastomeric material such as neoprene rubber with a 50 durome~er reading. The elastomeric sleeve 18 is most commonly molded between the sleeve assembly 20 and outer sleeve 21 such that it has a continuously varying outer diameter and continuously var~ing thic~ness with its thinnest section 65 positioned adjacent the inner diameter section 60 of sleeve 21 at an axial midpoint between the two ends 62 and 64 of the bearing sleeve assembly 41.
In operation, the elastomeric guide bearing assembly 16 minimizes static friction or "stiction" between the inner sleeve 32 an~ the piston rod 6 when side loads are exerted on the piston rod 6 with respect to the body 8. For example, if the piston rod has a side load e~erted at its top end toward
3~ the right as shown in Figure 1, the static friction would increase in the area 66 and 68 if the sleeve was held ~j ~ ~2~
rigid as in conventional rod guides. However, the exerted force in the area 66 and 68 tends to pivot the bearing sleeve assembly 20 against the ~esilien-t forces of the elastomeric sleeve 18 iIl a clockwise dixection about the area of greatest resistance, namely section 65, such that the sleeve assembly 20 becomes aligned with the piston rod 6 with a negligible increase in static friction therebetween. If the side load is directed to the left, pivoting forces against areas 67 and 69 pivots the sleeve assembly 20 in the opposing counter clockwise direction to minimize the increase in static friction. The resilient elastomeric sleeve 18 returns the sleeve assembly 20 to its normal position when the side load is alleviated.
Referring to Figure 2, a second embodiment of the invention is shown. For simplicity, corresponding parts will have the same numerals as shown in the first embodiment illustrated in Figure 1. The second embodiment, like the first, has an inner sleeve assembly 20, outer sleeve 21 and elastomeric sleeve 18 interposed therebetween.
The inner sleeve assembly 20 has an inner sleeve 32 and intermediate sleeve 34.
The inner sleeve 32 has its ends 71 and 73 bevelled outwardly to form tapered edges 70 and 72 about central opening 33. The outer wall of sleeve 32 has two crimped edges 74 and 76. Edges 74 and 76 extend over tapered edges 78 and 80 respectively of the inter-mediate sleeve 34 to axially lock up sleeves 32 and 34 of the inner s~eeve assembly 20. The outer surface 38 of the intermediate sleeve 34 has an enlarged diameter section 82.
The outer sleeve 21 has a convoluted inner surfa ~ 84 with enlarged inner diameter section 86, a lower smaller inner diameter section 88 and an upper smaller inner diameter section 90. The smaller inner 3S diameter of section 90 is diametrically smaller than the enlarged outer diameter section 82 of the intermèdiate sleeve 34. The outer surface 38 of the sleeve 34 and inner surface 84 of sleeve 21 are relatively and coaxially spaced from each other such that the thinnest gap 91 between the sleeve 21 and sleeve 34 is formed between the enlarged diameter section 82 and the enlarged diameter seciion 86.
The elastomeric sleeve 18 is bonded therebetween to conform to the relative positions of sleeve 34 and outer sleeve 21 such that its thinnest portion lies in section 91 between diameter sections 82 and 86.
The outer sleeve 21 has a lower cylindrical protruding section 92 which circumscribes a separate seat portion 94 which is seated upon working tube 12.
The sleeve 21 has a lower shoulder 93 which sits upon seat portion 94. The seat portion 94 has an internal diameter 96 which is less than the e~ternal diameter of the sleeve assembly 20 to form a shoulder 98 which the sleeve assembly 20 can abut.
In operation, the side loads of the piston rod 6 relative to the strut body 8 are minimized in the same fashion as the first embodiment in that the inner bearing sleeve assembly 20 will pivot about its enlarged diameter section 82 to ali~n itself with the piston rod 6 and minimize the static friction therebetween.
In addition, if any bond of the elastomeric sleeve between the intermediate sleeve 34 and outer sleeve 46 becomes separated, the sleeve assembly 20 is prevented from moving upward hitting the double lip seal 28 by the opposing enlarged diameter section 82 and the inner diameter Isection 90 in conjunction with the compression of the elastomeric sleeve portion interposed therebetween. In addition, the sleeve assembly 20 is prevented from moving substan-tially downward by abutting the inner shoulder 98 ofthe seat portion 94.
In this fashion, a rod guide bearing sleeve is resiliently mounted by an elastomeric medium to maintain align~ent and minimize static friction with respect to a piston rod which slides therethrough. In addition, the bearing sleeve can be interlocked in the bearing assembly even `
' .
', .
, ~
' 9~a~
when the elastome~ic bonds between the bearing sleeve assembly and outer sleeve are severed.
Variations and modifications of the present invention are possible without departing from its spirit and scope as 5 defined by the appended claims.
rigid as in conventional rod guides. However, the exerted force in the area 66 and 68 tends to pivot the bearing sleeve assembly 20 against the ~esilien-t forces of the elastomeric sleeve 18 iIl a clockwise dixection about the area of greatest resistance, namely section 65, such that the sleeve assembly 20 becomes aligned with the piston rod 6 with a negligible increase in static friction therebetween. If the side load is directed to the left, pivoting forces against areas 67 and 69 pivots the sleeve assembly 20 in the opposing counter clockwise direction to minimize the increase in static friction. The resilient elastomeric sleeve 18 returns the sleeve assembly 20 to its normal position when the side load is alleviated.
Referring to Figure 2, a second embodiment of the invention is shown. For simplicity, corresponding parts will have the same numerals as shown in the first embodiment illustrated in Figure 1. The second embodiment, like the first, has an inner sleeve assembly 20, outer sleeve 21 and elastomeric sleeve 18 interposed therebetween.
The inner sleeve assembly 20 has an inner sleeve 32 and intermediate sleeve 34.
The inner sleeve 32 has its ends 71 and 73 bevelled outwardly to form tapered edges 70 and 72 about central opening 33. The outer wall of sleeve 32 has two crimped edges 74 and 76. Edges 74 and 76 extend over tapered edges 78 and 80 respectively of the inter-mediate sleeve 34 to axially lock up sleeves 32 and 34 of the inner s~eeve assembly 20. The outer surface 38 of the intermediate sleeve 34 has an enlarged diameter section 82.
The outer sleeve 21 has a convoluted inner surfa ~ 84 with enlarged inner diameter section 86, a lower smaller inner diameter section 88 and an upper smaller inner diameter section 90. The smaller inner 3S diameter of section 90 is diametrically smaller than the enlarged outer diameter section 82 of the intermèdiate sleeve 34. The outer surface 38 of the sleeve 34 and inner surface 84 of sleeve 21 are relatively and coaxially spaced from each other such that the thinnest gap 91 between the sleeve 21 and sleeve 34 is formed between the enlarged diameter section 82 and the enlarged diameter seciion 86.
The elastomeric sleeve 18 is bonded therebetween to conform to the relative positions of sleeve 34 and outer sleeve 21 such that its thinnest portion lies in section 91 between diameter sections 82 and 86.
The outer sleeve 21 has a lower cylindrical protruding section 92 which circumscribes a separate seat portion 94 which is seated upon working tube 12.
The sleeve 21 has a lower shoulder 93 which sits upon seat portion 94. The seat portion 94 has an internal diameter 96 which is less than the e~ternal diameter of the sleeve assembly 20 to form a shoulder 98 which the sleeve assembly 20 can abut.
In operation, the side loads of the piston rod 6 relative to the strut body 8 are minimized in the same fashion as the first embodiment in that the inner bearing sleeve assembly 20 will pivot about its enlarged diameter section 82 to ali~n itself with the piston rod 6 and minimize the static friction therebetween.
In addition, if any bond of the elastomeric sleeve between the intermediate sleeve 34 and outer sleeve 46 becomes separated, the sleeve assembly 20 is prevented from moving upward hitting the double lip seal 28 by the opposing enlarged diameter section 82 and the inner diameter Isection 90 in conjunction with the compression of the elastomeric sleeve portion interposed therebetween. In addition, the sleeve assembly 20 is prevented from moving substan-tially downward by abutting the inner shoulder 98 ofthe seat portion 94.
In this fashion, a rod guide bearing sleeve is resiliently mounted by an elastomeric medium to maintain align~ent and minimize static friction with respect to a piston rod which slides therethrough. In addition, the bearing sleeve can be interlocked in the bearing assembly even `
' .
', .
, ~
' 9~a~
when the elastome~ic bonds between the bearing sleeve assembly and outer sleeve are severed.
Variations and modifications of the present invention are possible without departing from its spirit and scope as 5 defined by the appended claims.
Claims (9)
1. A rod guide for a suspension strut having a body portion, with a piston and piston rod slidably mounted with respect to said body portion, said rod guide comprising:
an annular bearing sleeve having a central tubular opening sized to slidably receive said piston rod;
an annular elastomeric sleeve having its inner surface abutting and secured to the outer surface of said bearing sleeve;
said annular elastomeric sleeve having its outer surface fixed with respect to said body of said strut;
said elastomeric sleeve constructed to resiliently flex under side loads exerted on said piston rod and body such that the bearing sleeve maintains alignment with respect to said piston rod extending therethrough;
said elastomeric sleeve having a varying thickness with the thinnest portion substantially at a midsection between the axial ends of said sleeve;
said elastomeric sleeve having its inner surface bonded to said outer surface of said bearing sleeve;
said elastomeric sleeve having its outer surface bonded to a surface fixed with respect to said strut body;
said outer surface of said bearing sleeve and said fixed surface being shaped to conform to said shape of said elastomeric sleeve.
an annular bearing sleeve having a central tubular opening sized to slidably receive said piston rod;
an annular elastomeric sleeve having its inner surface abutting and secured to the outer surface of said bearing sleeve;
said annular elastomeric sleeve having its outer surface fixed with respect to said body of said strut;
said elastomeric sleeve constructed to resiliently flex under side loads exerted on said piston rod and body such that the bearing sleeve maintains alignment with respect to said piston rod extending therethrough;
said elastomeric sleeve having a varying thickness with the thinnest portion substantially at a midsection between the axial ends of said sleeve;
said elastomeric sleeve having its inner surface bonded to said outer surface of said bearing sleeve;
said elastomeric sleeve having its outer surface bonded to a surface fixed with respect to said strut body;
said outer surface of said bearing sleeve and said fixed surface being shaped to conform to said shape of said elastomeric sleeve.
2. A rod guide for a suspension strut having a body portion with a piston and a piston rod mounted thereon slidable with respect to said body portion and said rod guide, said rod guide comprising:
an annular bearing sleeve having its annular tubular opening slidably receiving said piston rod;
an annular elastomeric sleeve having its inner surface abutting and secured to the outer surface of said bearing sleeve;
said annular elastomeric sleeve having its outer surface fixed with respect to said body of said strut;
said elastomeric sleeve constructed to resiliently flex under side loads exerted on said piston rod and body, such that the bearing sleeve maintains alignment with respect to said piston rod extending therethrough;
said elastomeric sleeve having a varying thickness with its thinnest portion substantially on a midsection between the axial ends of said sleeve;
said elastomeric sleeve having its inner surface bonded to said outer surface of said bearing sleeve;
said elastomeric sleeve having its outer surface bonded to a surface fixed with respect to said strut body;
said outer surface of said bearing sleeve and said fixed surface being shaped to conform to said shape of said elastomeric sleeve; and said bearing sleeve and said fixed surface being axially interlocked with each other with said elastomeric sleeve disposed therebetween to prevent said bearing sleeve from axially moving away from said fixed surface as said piston rod axially slides through said bearing.
an annular bearing sleeve having its annular tubular opening slidably receiving said piston rod;
an annular elastomeric sleeve having its inner surface abutting and secured to the outer surface of said bearing sleeve;
said annular elastomeric sleeve having its outer surface fixed with respect to said body of said strut;
said elastomeric sleeve constructed to resiliently flex under side loads exerted on said piston rod and body, such that the bearing sleeve maintains alignment with respect to said piston rod extending therethrough;
said elastomeric sleeve having a varying thickness with its thinnest portion substantially on a midsection between the axial ends of said sleeve;
said elastomeric sleeve having its inner surface bonded to said outer surface of said bearing sleeve;
said elastomeric sleeve having its outer surface bonded to a surface fixed with respect to said strut body;
said outer surface of said bearing sleeve and said fixed surface being shaped to conform to said shape of said elastomeric sleeve; and said bearing sleeve and said fixed surface being axially interlocked with each other with said elastomeric sleeve disposed therebetween to prevent said bearing sleeve from axially moving away from said fixed surface as said piston rod axially slides through said bearing.
3. A rod guide as defined in Claim 2, further com-prising:
said annular bearing sleeve having its outer surface being of enlarged diameter at an axial midsection of said sleeve;
said fixed surface having an enlarged inner diameter section opposing said enlarged diameter midsection of said bearing sleeve;
said fixed surface having a smaller inner diameter section of dimension less than said enlarged diameter mid-section of said bearing sleeve and being axially spaced therefrom;
an inwardly extending shoulder fixed with respect to said strut body and axially spaced from said enlarged diameter section of said bearing sleeve in an opposite direc-tion from said smaller inner diameter section of said fixed surface and engageable with said bearing sleeve such that said bearing sleeve is axially interlocked between said smaller diameter of said fixed surface and said inwardly extending shoulder.
said annular bearing sleeve having its outer surface being of enlarged diameter at an axial midsection of said sleeve;
said fixed surface having an enlarged inner diameter section opposing said enlarged diameter midsection of said bearing sleeve;
said fixed surface having a smaller inner diameter section of dimension less than said enlarged diameter mid-section of said bearing sleeve and being axially spaced therefrom;
an inwardly extending shoulder fixed with respect to said strut body and axially spaced from said enlarged diameter section of said bearing sleeve in an opposite direc-tion from said smaller inner diameter section of said fixed surface and engageable with said bearing sleeve such that said bearing sleeve is axially interlocked between said smaller diameter of said fixed surface and said inwardly extending shoulder.
4. A rod guide as defined in Claim 3, further comprises:
said fixed surface being an inner surface of a tubular outer seat member coaxially mounted about said elas-tomeric sleeve;
said shoulder being a part of a tubular lower seat member coaxially mounted below said outer seat member;
said outer seat member and lower seat member fixedly securable between said cap and said body of said strut.
said fixed surface being an inner surface of a tubular outer seat member coaxially mounted about said elas-tomeric sleeve;
said shoulder being a part of a tubular lower seat member coaxially mounted below said outer seat member;
said outer seat member and lower seat member fixedly securable between said cap and said body of said strut.
5. A rod guide for a suspension strut having a body portion with a piston and a piston rod mounted thereon slidable with respect to said body portion and said rod guide, said rod guide comprising:
an annular bearing sleeve having a central tubular opening sized to slidably receive said piston rod;
an annular outer sleeve coaxially mounted about said bearing sleeve;
said outer sleeve fixedly securable to said body of said strut;
an elastomeric sleeve disposed between said bearing sleeve and outer sleeve and abutting the outer surface of said bearing sleeve and inner surface of said outer sleeve and constructed to resiliently flex under side loads transmitted through said piston rod and body such that said bearing sleeve maintains alignment with said piston rod as said piston rod slides through said bearing sleeve;
said elastomeric sleeeve has a varying thickness with the thinnest portion located at a midsection between the axial ends of said elastomeric sleeve; and said outer surface of said bearing sleeve and said inner surface of said outer sleeve shaped to conform to the shape of said elastomeric sleeve.
an annular bearing sleeve having a central tubular opening sized to slidably receive said piston rod;
an annular outer sleeve coaxially mounted about said bearing sleeve;
said outer sleeve fixedly securable to said body of said strut;
an elastomeric sleeve disposed between said bearing sleeve and outer sleeve and abutting the outer surface of said bearing sleeve and inner surface of said outer sleeve and constructed to resiliently flex under side loads transmitted through said piston rod and body such that said bearing sleeve maintains alignment with said piston rod as said piston rod slides through said bearing sleeve;
said elastomeric sleeeve has a varying thickness with the thinnest portion located at a midsection between the axial ends of said elastomeric sleeve; and said outer surface of said bearing sleeve and said inner surface of said outer sleeve shaped to conform to the shape of said elastomeric sleeve.
6. A rod guide as defined in Claim 5, wherein said elastomeric sleeve has a continuously varying thickness axially aligned with said bearing sleeve.
7. A rod guide as defined in Claim 5, wherein said elastomeric sleeve is bonded to said bearing sleeve and outer sleeve.
8. A rod guide for a suspension strut having a body portion, with a piston and piston rod slidably mounted with respect to said body portion and said rod guide comprising:
an annular bearing sleeve having a central tubular opening sized to slidably receive said piston rod;
an annular elastomeric sleeve having its inner surface abutting and secured to the outer surface of said bearing sleeve;
said annular elastomeric sleeve having its outer surface fixed with respect to said body of said strut;
said elastomeric ring constructed to resiliently pivot under side loads exerted on said piston rod and body such that the bearing sleeve maintains alignment with respect to said piston rod extending there-through;
said elastomeric sleeve having a continuously varying thickness with the thinnest portion substantially at a midsection between the axial ends of said sleeve;
said elastomeric sleeve having its inner surface bonded to said outer surface of said bearing sleeve;
said elastomeric sleeve having its outer surface bonded to a surface fixed with respect to said strut body;
said outer surface of said bearing sleeve and said fixed surface shaped to conform to said shape of said elastomeric sleeve with the thinnest portion of said elastomeric sleeve interposed between the thinnest gap between said surface of said bearing sleeve and said fixed surface.
an annular bearing sleeve having a central tubular opening sized to slidably receive said piston rod;
an annular elastomeric sleeve having its inner surface abutting and secured to the outer surface of said bearing sleeve;
said annular elastomeric sleeve having its outer surface fixed with respect to said body of said strut;
said elastomeric ring constructed to resiliently pivot under side loads exerted on said piston rod and body such that the bearing sleeve maintains alignment with respect to said piston rod extending there-through;
said elastomeric sleeve having a continuously varying thickness with the thinnest portion substantially at a midsection between the axial ends of said sleeve;
said elastomeric sleeve having its inner surface bonded to said outer surface of said bearing sleeve;
said elastomeric sleeve having its outer surface bonded to a surface fixed with respect to said strut body;
said outer surface of said bearing sleeve and said fixed surface shaped to conform to said shape of said elastomeric sleeve with the thinnest portion of said elastomeric sleeve interposed between the thinnest gap between said surface of said bearing sleeve and said fixed surface.
9. A rod guide as defined in Claim 8, wherein said bearing sleeve and said fixed surface being axially inter-locked with each other with said elastomeric sleeve disposed therebetween.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US15999880A | 1980-06-16 | 1980-06-16 | |
| US159,998 | 1980-06-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1162954A true CA1162954A (en) | 1984-02-28 |
Family
ID=22575040
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000376991A Expired CA1162954A (en) | 1980-06-16 | 1981-05-06 | Rod guide for a suspension strut |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5737003A (en) |
| CA (1) | CA1162954A (en) |
-
1981
- 1981-05-06 CA CA000376991A patent/CA1162954A/en not_active Expired
- 1981-06-15 JP JP9208381A patent/JPS5737003A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5737003A (en) | 1982-03-01 |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |