CA1303659C - Friction control for bearing surface of roller - Google Patents
Friction control for bearing surface of rollerInfo
- Publication number
- CA1303659C CA1303659C CA000552634A CA552634A CA1303659C CA 1303659 C CA1303659 C CA 1303659C CA 000552634 A CA000552634 A CA 000552634A CA 552634 A CA552634 A CA 552634A CA 1303659 C CA1303659 C CA 1303659C
- Authority
- CA
- Canada
- Prior art keywords
- roller
- inner diameter
- diameter surface
- axle
- rotating axle
- 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.)
- Expired - Lifetime
Links
- 239000000314 lubricant Substances 0.000 claims abstract description 32
- 238000005461 lubrication Methods 0.000 description 23
- 230000008901 benefit Effects 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 101100086716 Caenorhabditis elegans ran-3 gene Proteins 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 108010082357 dividin Proteins 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
- B65G39/00—Rollers, e.g. drive rollers, or arrangements thereof incorporated in roller-ways or other types of mechanical conveyors
- B65G39/02—Adaptations of individual rollers and supports therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
- B65G39/00—Rollers, e.g. drive rollers, or arrangements thereof incorporated in roller-ways or other types of mechanical conveyors
- B65G39/02—Adaptations of individual rollers and supports therefor
- B65G39/09—Arrangements of bearing or sealing means
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Rolling Contact Bearings (AREA)
- Sliding-Contact Bearings (AREA)
- Rolls And Other Rotary Bodies (AREA)
Abstract
ABSTRACT
A roller element for a powered-roller transfer system has a plurality of lubricant pressure relief areas about or in the bearing surface to increase and provide consistent rotary drive power transmitted from a powered axle to the roller.
A roller element for a powered-roller transfer system has a plurality of lubricant pressure relief areas about or in the bearing surface to increase and provide consistent rotary drive power transmitted from a powered axle to the roller.
Description
\
13~36S9 0234-IR-AS
FRICTION CONTROL FOR B~.~RING
S~RFA OE OF ROLL~R
This invention relates to the roller element o~ a powered-rollex ~rans~er lin~, an~ mor- par~ieularly ~o tha apparatus anc ~ethod embodia~ by a rollor ha~ing a pluxality o~
lubricant pr~ssure relie~ areas in o- about the bearing sur~aca to provids consis~ent and incr~ased ro~tary powar tran3mission rom z power~d a~le to t~.e rollar.
~ACKC-~U~D OF ~E INVENl'I~N
For certain auto~otive co~ponent3 such as engines or tran~mis~ions, powered xoller t~ar.s~e. line.s are used ~o ~oYa workpi~ces thro~lgh the manufacturing and assembly stations.
Workpieces are moun~ed on pall2~s which are carried through the line by rollers d.i~en ~y slow ~ut continuously rotating axles.
~h~ rollers have a lubricated bushing-typ2 inner dizmat~r b~ring surfacQ ad2pted to ~i~ on the axles. To propel the p~llets, th~ powered a~les cause the roll~r~ to rotate ~y using th,e ~rictian b~een tha a~la and tha baaring sur~ace Oc the roller. At cQrtain p~itions on th~ ~ran3~er line, it is de~ired to 3top th~ pallet~. At th~s in~nd~d stopping points, a stopping ~wchanisul ph~ysicxlly rest-ain~ the pallet. The rollers u~d~r the stoppad pallet al~c 3top rotating and slip on the rotatins a~ . This ~lip~ing is facili~atad by the lubric~nt between th2 axle and ~.a b~a_ing ~urfaca oP the roller.
Th~ dri~g ~rcs to accelerate 2 ~allet fr~n a stopping p~in~ or ~o dr~J~ a pall~t pa~ a ~inor resiPtanc~ ~uch ~s a ~all chang~ in ~levation i~ deter~ined by the coefficien~ of ~riction between the poware~ a~le ænd tne inner di~ et~r bearing surface of the roller. Th~ cae~icient o~ ~ric~ion in turn is af~ected by the lubrication condition e~ist~ng between the axle and the bearing sur~ac2 o~ the roller. The desired lubrication , ," -.
13(~3659 mode for the powered-roller in the transfer line described above is boundary lubrication.
Under some working conditions however, additional lubricant from the work process or the environment may gradually enter the bearing gap. The additional lubricant changes the lubricant mode from boundary to hydrodynamic . Hydrodynamic lubrication substantially reduces the friction between the roller and powared axle. ~herefore the driving force trans~itted from the axles to the rollers is substantially reduced. The reduced driving ~orce provided by the rollers to the pallets causes the pallets to improperly accelerate and move inconsistently. This is undesirable in automated manufacturing and assembly lines.
SUMMARY OF T~E INVENTION
An ob~ect of this invention is to maintain at a consistent and acceptable level the drive force transmitted to a roller ~rom a powered axle.
Another ob~ect i9 to maintain an acceptably high coe~ficient of friction between the powered axle and the roller.
Another ob;ect is to prevent additional lubricant in the bearing gap of a roller ~rom causing undesired transition from boundary to hydrodynamic lubrication.
Another ob~ect is to relieve lubricant pressure locally from about the bearing sur~ace by providing lubricant pressure relie~ areas so as to maintain boundary lubrication about the bearing sur~ace and thus maintain a high coefficient of friction between the powered axle and the roller which results in - - ' ~ . -.
.. :
'' . . . ~ :
.:
- 13~)36S9 consistent rotary power transmission from the powered axle to the intermittently rotating roller.
The objects and advantages of the present invention are attained by having a plurality of lubricant pressure relief areas about the bearing surface of an annular roller.
An unexpected advantage of the present invention is the increase in drive force transmitted from the powered axle to the roller element under operating conditions with excess lubrication present.
According to a broad aspect of the present invention, there is provided a friction drive roller for a continuously rotating axle of a conveyor. The friction drive roller comprises an annular roller element having an outer diameter surface for rollingly transporting articles on the conveyor and an inner diameter surface for frictional drive contact with the rotating axle. Means is provided for reducing the coefficient of friction between the inner diameter surface and the rotating axle when the articles are restrained from movement on the conveyor and comprising a small gap between the rotating axle and the inner diameter surface of the roller element and a film of lubricant disposed in the gap so as to substantially prevent the rotating axle from contacting the inner diameter surface. Means is also provided for increasing the coefficient of friction between the inner diameter surface and the rotating axle when the articles are free to move on the conveyor and comprising a continuous helical groove having circumferential loops spaced three to ten groove widths apart in one of the inner diameter surface and said rotating axle for reducing the B
i3t136S9 - 3a -lubricant pressure so as to allow frictional drive contact of the rotating axle with the inner diameter surface.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
Figure 1 is a partial cross-sectional and a partial elevation of a portion of a transfer line;
Figure 2 is a front view of the roller;
Figure 3 is a cross-sectional side view of the roller of the present invention;
Figure 4 is an enlargement of the circled portion of the roller in Figure 3; and Figure 5 is another embodiment of the present invention.
B
. . :
13036Sg DETAILED DESCRIPTION OF THE INVENTION
A typical powered axle-roller subassembly o~ a transfer line is shown in Figure 1. The axle 12 is support for rotation by bearings 14 in the frame member 16. A bevel gear arrangement 18 and 20 provides constant rotational power to the axle from a power source, such as a motor, connected to drive shaft 22.
Two rollers 30 are mounted on the axle in the transfer line shown in Figure 1. A spacer 24 and two collars 26 position the rollers on the axle. Other configurations are possible. A
front view o~ a rcller is shown in Figure 2. The roller is usually a solid metal annular cylinder having outer and inner diameter surfaces. The outer diameter surface 32 provides the roller contact sur~ace to carry a pallet such as 28 in Figure 1. The inner diameter sur~ace 34 provides a bearing surface for the axle 12. The bearing surface 34 is formed by a bore through the center of the roller and i9 usually concentric with the outer diameter roller sur~ace.
The inner diameter bearing surface 34 is dimensioned such that a small bearing gap exists between the powered axle 12 and the bearing sur~ace. A lubricant is provided in the bearing gap. In a pre~erred embodiment, the roller is constructed of a lubricant-Lmpregnated sintered material. Alternatively, lubricant may be Lntroduced into the bearing gap by other conventional means such as a lubricant wick or pump. Another known means of providing lubricant to the bearing gap is by a supply passageway such as a supply groove on the axle or the bearing sur~ace o~ the roller. A lubricant supply groove has large dimensions and is widely spaced on the axle or roller surfaces so as to best perform its supply function.
In normal operation a roller having a smooth bearing .~....... , , ~ .
surface operates as follows. The powered axle 12 rotates continuously. A thin film of lubricant occupies the bearing gap between the axle and bearing surface of the roller. The axle rotational speed and other factors are such that the lubricant effect is in the boundary lubrication mode. The coefficient of friction between the axle and the bearing sur~ace of the roller is high. This is well known from the Stribeck curve which relates lubrication mode to coefficient of friction for sliding bearings. Thus the axle causes the roller to rotate and tangentially propel the pallet forward. The coefficient of friction in the boundary lubrication mode is high enough that the drive force supplied by the axle to the roller can overcome any minor resistance a pallet may encounter on the line.
Furthermore, in normal operation, the lubrication about the bearing sur~ace of the roller allows the roller to slip on the axle if the pallet encounters a stif~ resistance such as a ~topping mechanism. The lubrication in the bearing gap facilitates the continued rotation of the powered axle relative to the stopped roller.
During operation of the line, excess lubrication may gradually enter the bearing gap. The increased lubrication causes the lubrication effect to change from the boundary mode to the hydrodynamic mode. The coefficient of friction between the axle and the roller decreases as the lubrication mode changes from boundary to hydrodynamic lubrication. Again this is known from the Stribeck curve.
In a hydrodynamic lubrication mode, the drive for~e supplied by the axle to the roller is not strong enough to overcome minor resistance. Thus the rollers begin to slip on the axles and the pallets in the line are subject to ` i3036~g 0234-~R-AS
inconsistent movement. In other words, when excess lubrication enters the bearing gap the rollers tend to slip on the powered axle rather than drive the pallets.
The present invention overcomes the above problem. Even with excess lubrication, the lubricant can be maintained in the boundary lubrica~ion mode ~y dividin~ the hearing surface into narrow lands separated by narrow lubricant pressure relief areas. The recessed relief areas bleed off the excess lubricant pressure and prevents transition to hydrodynamic lubrication.
In the preferred embodiment of the roller 30A shown in Figure 3, and enlarged in Figure 4, narrow or thin grooves 36 having a substantially circumferential orientation provide localized lubricant pressure bleed off. The grooves preferably are narrow so as not to substantially reduce the bearing area. The bearing lands between the grooves are also relatively narrcw but preferably are three to ten times the groove width. This relationship appears important to provide both adequate bearing support area and relief area to bleed off lubricant pressure.
It is apparent that these narrcw, closely spaced lubricant pressure relief grooves differ substantial in construction, purpase an~ e~ect from the large, widely spaced lubricant supply groove~ discussed earlier.
A thread-like helical groove on the inner diameter bearing sur~ace of the roller, as shown in Figures 3 and 4, is the preferred embodiment for providing lubricant relief areas for the bearing sur~ace of the roller. The groove has a groove root width of about .005", a thread pitch between .015" and .050", and a thread depth between .003" and .006". The groove sideWalls have a 60 included angle. A helical thread configuration is preferred due to ease of machining.
Unexpectedly, it was found that dividing the bearing ~ .. .
-surface into narrow lands surrounded by lubr1cant pressure relief areas such as circumferential grooves machined into the bearing surface increased the drive force transmitted to the rollers when excess lubricant is present. For example, a new roller having a smooth, ungrooved bearing sur~ace was found to initially generate about 25 lbs. of drive force on a pallet with 450 lbs. of weight. When excess lubrication was introduced into the bearing gap the drive force was reduced to 4-7 lbs.
In the above situation, installing rollers with circumferential grooves machined into the bearing surface as provided by the present invention produced 28-30 lbs. of drive force. When excess lubrication was introduced into the bearing gap, the grooved roller produced 25-30 lbs. o~ force, about 4 times the drive force transmitted by the smooth ungrooved bearing sur~ace with excess lubricant.
Other configurations o~ lubricant pressure relief areas are possible and are considered within the scope of this invention. Thin axial grooves on the roller inner diameter would also allow the excess lubricant pressure to bleed off.
Alternatively, as shown by Figure 5, axial or circumferential grOOVQS 38 can be prov~ded on the axle 12A, oppo~ite the bearing sur~ace o~ the roller inner diameter.
Obviously, many modi~ications and variations of the present ihvention are possible in light of the above teachings.
It is there~ore to be understood that, within the scope of the ;appended claims, the invention may be practiced otherwise than as specifically described.
13~36S9 0234-IR-AS
FRICTION CONTROL FOR B~.~RING
S~RFA OE OF ROLL~R
This invention relates to the roller element o~ a powered-rollex ~rans~er lin~, an~ mor- par~ieularly ~o tha apparatus anc ~ethod embodia~ by a rollor ha~ing a pluxality o~
lubricant pr~ssure relie~ areas in o- about the bearing sur~aca to provids consis~ent and incr~ased ro~tary powar tran3mission rom z power~d a~le to t~.e rollar.
~ACKC-~U~D OF ~E INVENl'I~N
For certain auto~otive co~ponent3 such as engines or tran~mis~ions, powered xoller t~ar.s~e. line.s are used ~o ~oYa workpi~ces thro~lgh the manufacturing and assembly stations.
Workpieces are moun~ed on pall2~s which are carried through the line by rollers d.i~en ~y slow ~ut continuously rotating axles.
~h~ rollers have a lubricated bushing-typ2 inner dizmat~r b~ring surfacQ ad2pted to ~i~ on the axles. To propel the p~llets, th~ powered a~les cause the roll~r~ to rotate ~y using th,e ~rictian b~een tha a~la and tha baaring sur~ace Oc the roller. At cQrtain p~itions on th~ ~ran3~er line, it is de~ired to 3top th~ pallet~. At th~s in~nd~d stopping points, a stopping ~wchanisul ph~ysicxlly rest-ain~ the pallet. The rollers u~d~r the stoppad pallet al~c 3top rotating and slip on the rotatins a~ . This ~lip~ing is facili~atad by the lubric~nt between th2 axle and ~.a b~a_ing ~urfaca oP the roller.
Th~ dri~g ~rcs to accelerate 2 ~allet fr~n a stopping p~in~ or ~o dr~J~ a pall~t pa~ a ~inor resiPtanc~ ~uch ~s a ~all chang~ in ~levation i~ deter~ined by the coefficien~ of ~riction between the poware~ a~le ænd tne inner di~ et~r bearing surface of the roller. Th~ cae~icient o~ ~ric~ion in turn is af~ected by the lubrication condition e~ist~ng between the axle and the bearing sur~ac2 o~ the roller. The desired lubrication , ," -.
13(~3659 mode for the powered-roller in the transfer line described above is boundary lubrication.
Under some working conditions however, additional lubricant from the work process or the environment may gradually enter the bearing gap. The additional lubricant changes the lubricant mode from boundary to hydrodynamic . Hydrodynamic lubrication substantially reduces the friction between the roller and powared axle. ~herefore the driving force trans~itted from the axles to the rollers is substantially reduced. The reduced driving ~orce provided by the rollers to the pallets causes the pallets to improperly accelerate and move inconsistently. This is undesirable in automated manufacturing and assembly lines.
SUMMARY OF T~E INVENTION
An ob~ect of this invention is to maintain at a consistent and acceptable level the drive force transmitted to a roller ~rom a powered axle.
Another ob~ect i9 to maintain an acceptably high coe~ficient of friction between the powered axle and the roller.
Another ob;ect is to prevent additional lubricant in the bearing gap of a roller ~rom causing undesired transition from boundary to hydrodynamic lubrication.
Another ob~ect is to relieve lubricant pressure locally from about the bearing sur~ace by providing lubricant pressure relie~ areas so as to maintain boundary lubrication about the bearing sur~ace and thus maintain a high coefficient of friction between the powered axle and the roller which results in - - ' ~ . -.
.. :
'' . . . ~ :
.:
- 13~)36S9 consistent rotary power transmission from the powered axle to the intermittently rotating roller.
The objects and advantages of the present invention are attained by having a plurality of lubricant pressure relief areas about the bearing surface of an annular roller.
An unexpected advantage of the present invention is the increase in drive force transmitted from the powered axle to the roller element under operating conditions with excess lubrication present.
According to a broad aspect of the present invention, there is provided a friction drive roller for a continuously rotating axle of a conveyor. The friction drive roller comprises an annular roller element having an outer diameter surface for rollingly transporting articles on the conveyor and an inner diameter surface for frictional drive contact with the rotating axle. Means is provided for reducing the coefficient of friction between the inner diameter surface and the rotating axle when the articles are restrained from movement on the conveyor and comprising a small gap between the rotating axle and the inner diameter surface of the roller element and a film of lubricant disposed in the gap so as to substantially prevent the rotating axle from contacting the inner diameter surface. Means is also provided for increasing the coefficient of friction between the inner diameter surface and the rotating axle when the articles are free to move on the conveyor and comprising a continuous helical groove having circumferential loops spaced three to ten groove widths apart in one of the inner diameter surface and said rotating axle for reducing the B
i3t136S9 - 3a -lubricant pressure so as to allow frictional drive contact of the rotating axle with the inner diameter surface.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
Figure 1 is a partial cross-sectional and a partial elevation of a portion of a transfer line;
Figure 2 is a front view of the roller;
Figure 3 is a cross-sectional side view of the roller of the present invention;
Figure 4 is an enlargement of the circled portion of the roller in Figure 3; and Figure 5 is another embodiment of the present invention.
B
. . :
13036Sg DETAILED DESCRIPTION OF THE INVENTION
A typical powered axle-roller subassembly o~ a transfer line is shown in Figure 1. The axle 12 is support for rotation by bearings 14 in the frame member 16. A bevel gear arrangement 18 and 20 provides constant rotational power to the axle from a power source, such as a motor, connected to drive shaft 22.
Two rollers 30 are mounted on the axle in the transfer line shown in Figure 1. A spacer 24 and two collars 26 position the rollers on the axle. Other configurations are possible. A
front view o~ a rcller is shown in Figure 2. The roller is usually a solid metal annular cylinder having outer and inner diameter surfaces. The outer diameter surface 32 provides the roller contact sur~ace to carry a pallet such as 28 in Figure 1. The inner diameter sur~ace 34 provides a bearing surface for the axle 12. The bearing surface 34 is formed by a bore through the center of the roller and i9 usually concentric with the outer diameter roller sur~ace.
The inner diameter bearing surface 34 is dimensioned such that a small bearing gap exists between the powered axle 12 and the bearing sur~ace. A lubricant is provided in the bearing gap. In a pre~erred embodiment, the roller is constructed of a lubricant-Lmpregnated sintered material. Alternatively, lubricant may be Lntroduced into the bearing gap by other conventional means such as a lubricant wick or pump. Another known means of providing lubricant to the bearing gap is by a supply passageway such as a supply groove on the axle or the bearing sur~ace o~ the roller. A lubricant supply groove has large dimensions and is widely spaced on the axle or roller surfaces so as to best perform its supply function.
In normal operation a roller having a smooth bearing .~....... , , ~ .
surface operates as follows. The powered axle 12 rotates continuously. A thin film of lubricant occupies the bearing gap between the axle and bearing surface of the roller. The axle rotational speed and other factors are such that the lubricant effect is in the boundary lubrication mode. The coefficient of friction between the axle and the bearing sur~ace of the roller is high. This is well known from the Stribeck curve which relates lubrication mode to coefficient of friction for sliding bearings. Thus the axle causes the roller to rotate and tangentially propel the pallet forward. The coefficient of friction in the boundary lubrication mode is high enough that the drive force supplied by the axle to the roller can overcome any minor resistance a pallet may encounter on the line.
Furthermore, in normal operation, the lubrication about the bearing sur~ace of the roller allows the roller to slip on the axle if the pallet encounters a stif~ resistance such as a ~topping mechanism. The lubrication in the bearing gap facilitates the continued rotation of the powered axle relative to the stopped roller.
During operation of the line, excess lubrication may gradually enter the bearing gap. The increased lubrication causes the lubrication effect to change from the boundary mode to the hydrodynamic mode. The coefficient of friction between the axle and the roller decreases as the lubrication mode changes from boundary to hydrodynamic lubrication. Again this is known from the Stribeck curve.
In a hydrodynamic lubrication mode, the drive for~e supplied by the axle to the roller is not strong enough to overcome minor resistance. Thus the rollers begin to slip on the axles and the pallets in the line are subject to ` i3036~g 0234-~R-AS
inconsistent movement. In other words, when excess lubrication enters the bearing gap the rollers tend to slip on the powered axle rather than drive the pallets.
The present invention overcomes the above problem. Even with excess lubrication, the lubricant can be maintained in the boundary lubrica~ion mode ~y dividin~ the hearing surface into narrow lands separated by narrow lubricant pressure relief areas. The recessed relief areas bleed off the excess lubricant pressure and prevents transition to hydrodynamic lubrication.
In the preferred embodiment of the roller 30A shown in Figure 3, and enlarged in Figure 4, narrow or thin grooves 36 having a substantially circumferential orientation provide localized lubricant pressure bleed off. The grooves preferably are narrow so as not to substantially reduce the bearing area. The bearing lands between the grooves are also relatively narrcw but preferably are three to ten times the groove width. This relationship appears important to provide both adequate bearing support area and relief area to bleed off lubricant pressure.
It is apparent that these narrcw, closely spaced lubricant pressure relief grooves differ substantial in construction, purpase an~ e~ect from the large, widely spaced lubricant supply groove~ discussed earlier.
A thread-like helical groove on the inner diameter bearing sur~ace of the roller, as shown in Figures 3 and 4, is the preferred embodiment for providing lubricant relief areas for the bearing sur~ace of the roller. The groove has a groove root width of about .005", a thread pitch between .015" and .050", and a thread depth between .003" and .006". The groove sideWalls have a 60 included angle. A helical thread configuration is preferred due to ease of machining.
Unexpectedly, it was found that dividing the bearing ~ .. .
-surface into narrow lands surrounded by lubr1cant pressure relief areas such as circumferential grooves machined into the bearing surface increased the drive force transmitted to the rollers when excess lubricant is present. For example, a new roller having a smooth, ungrooved bearing sur~ace was found to initially generate about 25 lbs. of drive force on a pallet with 450 lbs. of weight. When excess lubrication was introduced into the bearing gap the drive force was reduced to 4-7 lbs.
In the above situation, installing rollers with circumferential grooves machined into the bearing surface as provided by the present invention produced 28-30 lbs. of drive force. When excess lubrication was introduced into the bearing gap, the grooved roller produced 25-30 lbs. o~ force, about 4 times the drive force transmitted by the smooth ungrooved bearing sur~ace with excess lubricant.
Other configurations o~ lubricant pressure relief areas are possible and are considered within the scope of this invention. Thin axial grooves on the roller inner diameter would also allow the excess lubricant pressure to bleed off.
Alternatively, as shown by Figure 5, axial or circumferential grOOVQS 38 can be prov~ded on the axle 12A, oppo~ite the bearing sur~ace o~ the roller inner diameter.
Obviously, many modi~ications and variations of the present ihvention are possible in light of the above teachings.
It is there~ore to be understood that, within the scope of the ;appended claims, the invention may be practiced otherwise than as specifically described.
Claims (2)
1. A friction drive roller for a continuously rotating axle of a conveyor comprising: an annular roller element having an outer diameter surface for rollingly transporting articles on the conveyor and an inner diameter surface for frictional drive contact with the rotating axle; means for reducing the coefficient of friction between said inner diameter surface and said rotating axle when said articles are restrained from movement on the conveyor comprising a small gap between the rotating axle and the inner diameter surface of the roller element and a film of lubricant disposed in the gap so as to substantially prevent the rotating axle from contacting the inner diameter surface; and means for increasing the coefficient of friction between said inner diameter surface and said rotating axle when said articles are free to move on the conveyor comprising a continuous helical groove having circumferential loops spaced three to ten groove widths apart in one of said inner diameter surface and said rotating axle for reducing the lubricant pressure so as to allow frictional drive contact of the rotating axle with the inner diameter surface.
2. The friction drive roller of claim 1 further characterized in that said circumferential loops have a groove root width of 0.005", a thread pitch between 0.015" and 0.050", a thread depth between 0.003" and 0.006" and groove side walls having a 60° included angle.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US313587A | 1987-01-14 | 1987-01-14 | |
| US003,135 | 1987-01-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1303659C true CA1303659C (en) | 1992-06-16 |
Family
ID=21704343
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000552634A Expired - Lifetime CA1303659C (en) | 1987-01-14 | 1987-11-24 | Friction control for bearing surface of roller |
Country Status (5)
| Country | Link |
|---|---|
| CA (1) | CA1303659C (en) |
| DE (1) | DE3800922A1 (en) |
| FR (1) | FR2609457B1 (en) |
| GB (1) | GB2199923B (en) |
| IT (1) | IT1224646B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3943381A1 (en) * | 1989-12-20 | 1991-06-27 | Krause Johann A Maschf | Friction roller support for transport track |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2673131A (en) * | 1950-11-24 | 1954-03-23 | Norton Co | Cylindrical liner |
| DE1229791B (en) * | 1964-12-28 | 1966-12-01 | Licentia Gmbh | Safety coupling with shrink ring |
| US3497044A (en) * | 1967-08-14 | 1970-02-24 | Formsprag Co | Torque responsive brake with pivoted friction inserts |
| DE2624849C3 (en) * | 1976-06-03 | 1981-12-03 | Skf Kugellagerfabriken Gmbh, 8720 Schweinfurt | Self-pressure generating radial plain bearing |
| DE2834042A1 (en) * | 1977-08-09 | 1979-02-22 | Mayfran Inc | Belt conveyor roller assembly - has hub with lubricated tapering portion between sealing flanges at ends |
| GB1601910A (en) * | 1978-05-16 | 1981-11-04 | Ekstrand G Transportteknik Ab | Roller conveyors |
| DE2947290C2 (en) * | 1979-11-23 | 1982-04-08 | Industrietechnik Kalenborn Gmbh, 5461 Kalenborn | Overload protection for conveyor systems |
| DE3013893A1 (en) * | 1980-04-10 | 1982-01-28 | Robert Bosch Gmbh, 7000 Stuttgart | COUPLING FOR ROTATABLE PARTS |
| GB2127525A (en) * | 1982-09-21 | 1984-04-11 | Eurowide Engineering Group Lim | Roller assemblies for conveyors |
-
1987
- 1987-11-24 CA CA000552634A patent/CA1303659C/en not_active Expired - Lifetime
- 1987-12-22 IT IT8723165A patent/IT1224646B/en active
- 1987-12-29 GB GB8730264A patent/GB2199923B/en not_active Expired - Lifetime
-
1988
- 1988-01-13 FR FR888800324A patent/FR2609457B1/en not_active Expired - Lifetime
- 1988-01-14 DE DE3800922A patent/DE3800922A1/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| GB8730264D0 (en) | 1988-02-03 |
| GB2199923B (en) | 1990-11-21 |
| FR2609457B1 (en) | 1992-07-31 |
| DE3800922A1 (en) | 1988-07-28 |
| FR2609457A1 (en) | 1988-07-15 |
| IT8723165A0 (en) | 1987-12-22 |
| GB2199923A (en) | 1988-07-20 |
| IT1224646B (en) | 1990-10-18 |
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