U.S. patent application number 14/370398 was filed with the patent office on 2015-06-11 for lubrication capsule, machine element & method.
The applicant listed for this patent is AKTIEBOLAGET SKF. Invention is credited to Frank Fiddelaers, Ingemar Strandell.
Application Number | 20150159112 14/370398 |
Document ID | / |
Family ID | 48745317 |
Filed Date | 2015-06-11 |
United States Patent
Application |
20150159112 |
Kind Code |
A1 |
Strandell; Ingemar ; et
al. |
June 11, 2015 |
LUBRICATION CAPSULE, MACHINE ELEMENT & METHOD
Abstract
A capsule containing at least one component of a lubricant for a
machine element, whereby the capsule comprises an external wall
including a first substance that is arranged to perish during the
use of the machine element when the capsule is placed in and/or
around the machine element and/or into lubricant being used to
lubricate the machine element.
Inventors: |
Strandell; Ingemar;
(Savedalen, SE) ; Fiddelaers; Frank; (Gorinchem,
NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AKTIEBOLAGET SKF |
Goteborg |
|
SE |
|
|
Family ID: |
48745317 |
Appl. No.: |
14/370398 |
Filed: |
December 17, 2012 |
PCT Filed: |
December 17, 2012 |
PCT NO: |
PCT/SE2012/000204 |
371 Date: |
July 2, 2014 |
Current U.S.
Class: |
508/110 |
Current CPC
Class: |
F16N 9/00 20130101; F16B
2001/0021 20130101; F16G 13/00 20130101; F01M 9/02 20130101; C10M
169/042 20130101; F16C 33/6625 20130101; F16B 33/008 20130101; F16B
33/06 20130101; F16C 33/6659 20130101; F16C 33/6603 20130101 |
International
Class: |
C10M 169/04 20060101
C10M169/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 2, 2012 |
SE |
1200012-1 |
Claims
1. A capsule containing at least one component of a lubricant for a
machine element, whereby the capsule comprises an external wall
comprising a first substance that is arranged to perish during the
use of the machine element when the capsule is placed in at least
one of: in the machine element, and/or around the machine element,
and into lubricant being used to lubricate the machine element.
2. The capsule according to claim 1, comprising at least one inner
encapsulating wall comprising a second substance that is arranged
to perish during the use of the machine element when subjected to a
first condition.
3. The capsule according to claim 1, whereby at least one of the
first substance and the second substance is oil-soluble.
4. The capsule according to claim 1, whereby at least one of the
first substance the second substance is arranged to dissolve on
contact with a liquid at, at least one of: a pre-determined
temperature and a predetermined pressure.
5. The capsule according to claim 1, whereby at least one of the
first substance and the second substance is arranged to be
mechanically destroyed by the machine element.
6. The capsule according to claim 2 whereby the capsule comprises a
plurality of inner encapsulating walls and a first number of the
plurality of inner encapsulating walls comprises the second
substance that is arranged to perish when subjected to a first
condition, and a second number of the plurality of inner
encapsulating walls comprises a third substance that is arranged to
perish when subjected to a second condition.
7. The capsule according to claim 1, whereby the capsule comprises
a fluid lubricant, including at least one of: mineral oil,
synthetic oil, vegetable oil, a polyalphaolefin, an ester, and a
polyether.
8. The capsule according to claim 1, whereby the capsule comprises
at least one of the following: a polymeric thickener,
polypropylene, polyethylene, polyalkylene glycol, polyethylene
glycol, polyolefin phenol, lanolin, lanoline polyethylene glycol,
polyoxyethylene lanolin, silicon oil, ionic soap, urea soap, and
metal organic soap.
9. The capsule according to claim 1, whereby the capsule comprises
at least one of the following: a tackifier, an elastomer, an
anti-wear additive, an anti-corrosion additive, an EP additive, and
an anti-oxidant.
10. A machine element containing at least one capsule, wherein the
at least one capsule contains: at least one component of a
lubricant for a machine element, whereby the capsule comprises an
external wall comprising a first substance that is arranged to
perish during the use of the machine element when the capsule is
placed in at least one of: in the machine element, around the
machine element, and into lubricant being used to lubricate the
machine element.
11. The machine element according to claim 10, whereby it is at
least part of a one of the following: a shaft, coupling, key,
spline, gear, fastener, spring, seal, belt, clutch, brake, chain, a
bearing element, a ball bearing, a roller bearing, a needle
bearing, a tapered roller bearing, a spherical roller bearing, a
toroidal roller bearing, a ball thrust bearing, a roller thrust
bearing, a tapered roller thrust bearing, a wheel bearing, a hub
bearing unit, a slewing bearing, a ball screw, and a component for
an application in which it is subjected to alternating Hertzian
stresses, including a rolling contact, a combined rolling and
sliding, and an application that requires at least one of a high
wear resistance, an increased fatigue, and a tensile strength.
12. A method for lubricating a machine element, comprising a step
of placing at least one capsule having an external wall which
includes a first substance that is arranged to perish during the
use of the machine element when the capsule is placed into at least
one of: in the machine element, around the machine element, and
into a lubricant being used to lubricate the machine element.
13. A method according to claim 12, whereby the at least one
capsule comprises at least one inner encapsulating wall including a
second substance that is arranged to perish during the use of the
machine element when subjected to a first condition.
14. A method according to claim 12, whereby at least one of the
first substance and the second substance is oil-soluble.
15. A method according to claim 12, whereby at least one of the
first substance and the said second substance is arranged to
dissolve on contact with a liquid at, at least one of a
pre-determined temperature and predetermined pressure.
16. A method according to claim 12, whereby at least one of the
first substance and the second substance is arranged to be
mechanically destroyed by the machine element.
17. A method according to claim 12 whereby the capsule comprises a
plurality of inner encapsulating walls and a first number of the
plurality of inner encapsulating walls includes the second
substance that is arranged to perish when subjected to a first
condition, and a second number of the plurality of inner
encapsulating walls comprises a third substance that is arranged to
perish when subjected to a second condition.
18. A method according to claim 12, whereby the capsule comprises a
fluid lubricant, wherein the fluid lubricant includes at least one
of: mineral oil, synthetic oil, vegetable oil, polyalphaolefin, an
ester, and a polyether.
19. A method according to claim 12, whereby the capsule comprises
at least one of the following: a polymeric thickener,
polypropylene, polyethylene, polyalkylene glycol, polyethylene
glycol, polyolefin phenol, lanolin, lanoline polyethylene glycol,
polyoxyethylene lanolin, silicon oil, ionic soap, urea soap, and
metal organic soap.
20. A method according to claim 12, whereby the capsule comprises
at least one of the following additives: a tackifier, an elastomer,
an anti-wear additive, an anti-corrosion additive, an EP additive,
and an anti-oxidant.
21. A method according to claim 12, whereby the machine element is
at least part of a one of the following: a shaft, coupling, key,
spline, gear, fastener, spring, seal, belt, clutch, brake, chain, a
bearing element, a ball bearing, a roller bearing, a needle
bearing, a tapered roller bearing, a spherical roller bearing, a
toroidal roller bearing, a ball thrust bearing, a roller thrust
bearing, a tapered roller thrust bearing, a wheel bearing, a hub
bearing unit, a slewing bearing, a ball screw, and a component for
an application in which it is subjected to alternating Hertzian
stresses, including a rolling contact, a combined rolling and
sliding, and an application that requires at least one of a high
wear resistance, an increased fatigue, and a tensile strength.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This is a National Stage application claiming the benefit of
International Application Number PCT/SE2012/000204 filed on 17 Dec.
2012 (17.12.2012), which claims the benefit of Sweden Patent
Application 1200012-1 filed on 2 Jan. 2012, both of which are
incorporated herein by reference in their entireties.
FIELD OF THE INVENTION
[0002] The present invention concerns a lubrication capsule and a
machine element comprising at least one such lubrication capsule.
The present invention also concerns a method for lubricating a
machine element using at least one such lubrication capsule.
BACKGROUND OF THE INVENTION
[0003] An automatic lubrication system, often referred to as a
centralized lubrication system, generally comprises a controller or
timer, a pump and lubricant reservoir, metering valves and
fittings, and supply and feed lines, typically delivers a
controlled amount of lubricant, such as grease or oil, to one or
more specific locations in a machine while the machine is
operating, at specific times from a central location.
[0004] The term grease, in the context of lubrication, is used to
describe a semi-solid lubricant consisting of a thickener,
typically a soap, emulsified with mineral or vegetable oil and/or
other fluid lubricant. Grease possesses a high initial viscosity,
which upon the application of shear, drops to give the effect of
oil lubrication of approximately the same viscosity as the base oil
used in the grease. Greases are applied to machine elements that
can only be lubricated infrequently and where a lubricating oil
would not stay in position.
[0005] Grease also protects the machine elements that it lubricates
against corrosion and wear, it helps to dissipate heat, seal out
solid and liquid contamination, and reduces noise. Adequate
lubrication allows for smooth continuous operation of equipment,
with only mild wear, and without excessive stresses or seizures at
components such as bearings. When lubrication fails, components can
rub destructively over each other, causing damage, heat, and
failure. Lubrication failure can be caused by insufficient
lubricant quantity or viscosity, deterioration due to prolonged
service without replenishment, excessive temperatures,
contamination with foreign matter, the use of an incorrect grease
for a particular application and/or over-lubricating.
[0006] To ensure that a machine element is correctly lubricated,
the grease used has to be precisely selected for the particular
application and applied in the right amount, at the right frequency
and to the right place(s) in the machine elements. Factors
influencing the choice of grease for a bearing application for
example, include the bearing's rotational speed, service
temperature range, running noise requirements, re-lubrication
intervals, sealing, starting torque, load and running conditions
and environmental influences.
[0007] Over time, the grease may leak, evapourate and/or harden.
Oil may be depleted from the grease leaving a thick waxy substance
with little or no ability to lubricate. New grease may be applied,
however, to prevent premature wear and damage, manufacturers
recommend that old grease is removed and replaced with new grease
on a periodic basis, which can be a complex and time consuming
process since it often requires equipment to be dismantled and
carefully cleaned.
SUMMARY OF THE INVENTION
[0008] An object of the invention is to overcome or ameliorate at
least one of the disadvantages of the prior art, or to provide a
useful alternative.
[0009] At least one of these objects is achieved by a capsule
containing at least one component of a lubricant for a machine
element, whereby the capsule comprises an external wall comprising
a first substance that is arranged to perish (i.e. to become at
least partly destroyed or ruined whereby the contents of the
capsule will no longer be encapsulated therein) during the use of
the machine element when the capsule is placed in and/or around the
machine element and/or into lubricant being used to lubricate the
machine element.
[0010] Such a capsule may for example contain a liquid, semi-liquid
or solid lubricant (such as a dry powder) and/or lubricant part
(such as the liquid lubricant part of a grease) and/or a lubricant
additive. The capsule may for example be in the form of a pellet,
tablet or spheroid and/or may have a hard or soft external wall,
such as an external wall made from an aqueous solution of a gelling
agent such as animal protein (gelatin), a plant polysaccharide or
its derivative, such as a carrageenan and/or a modified form of
starch and cellulose. The external wall may comprise a plasticizer
such as glycerin and/or sorbital. The external wall itself may
comprise said at least one component of a lubricant. The capsule
may be of any suitable size and shape, depending on the
application, ranging from a few mm in maximum transverse dimension
to a few centimeters in maximum transverse dimension.
[0011] According to an embodiment of the invention the capsule
comprises at least one inner encapsulating wall comprising a second
substance that is arranged to perish during the use of the machine
element when subjected to a first condition. A capsule may namely
comprise one or more inner encapsulating walls comprising (i.e.
containing and/or comprising) the same, or a different at least one
component of a lubricant.
[0012] According to another embodiment of the invention the first
substance and/or said second substance is/are oil-soluble, is/are
arranged to dissolve on contact with a liquid at a pre-determined
temperature and/or predetermined pressure, and/or is/are arranged
be mechanically destroyed by the machine element.
[0013] At least one capsule may namely be added to the lubricant
lubricating a machine element and/or placed in and/or around the
machine element. The at least one capsule is arranged to perish
if/when needed. For example, when a machine element's lubricant
that contains or consists of oil reaches a predetermined
temperature, an oil-soluble external wall of the at least one
capsule may be arranged to perish by dissolving in oil at that
temperature. If a capsule comprises at least one inner
encapsulating wall comprising a second substance, the second
substance may be arranged to dissolve in oil at a different
temperature. A capsule may comprise one smaller capsule, or a
plurality of smaller capsules of the same size or of a different
size, which small capsule(s) is/are arranged to perish under
different conditions than the external wall and/or at least one
other inner encapsulating wall.
[0014] Additionally, or alternatively, a capsule may be arranged to
perish by being crushed by the machine element it is lubricating.
For example, at least one capsule may be provided in and/or around
the machine element (such as between a rolling element bearing's
rolling elements and outer ring) before it is put into use so that
the machine element will be lubricated once it is put into use,
i.e. the lubricant will fill the spaces in the machine element not
already occupied by lubricant. Additionally, or alternatively at
least one capsule may be supplied to a machine element during its
use to lubricate/re-lubricate the machine element or to add at
least one component of a lubricant, such as an additive, to the
lubricant lubricating the machine element.
[0015] According to a further embodiment of the invention the
capsule comprises a plurality of inner encapsulating walls and a
number of the plurality of inner encapsulating walls comprises the
second substance that is arranged to perish when subjected to a
first condition, and a number of the plurality of inner
encapsulating walls comprises a third substance that is arranged to
perish when subjected to a second condition.
[0016] The external wall of a capsule may be arranged to have a
first thickness and at least one inner encapsulating wall of a
capsule may be arranged to have a second thickness, whereby the
second thickness may be the same as or different to the first
thickness. The thickness and/or composition of an external wall
and/or an inner encapsulating wall need not necessarily be
uniform.
[0017] According to an embodiment of the invention the capsule
comprises a fluid lubricant, such as mineral oil, synthetic oil
and/or vegetable oil, a polyalphaolefin, an ester, a polyether. If
grease is used as to lubricate a machine element, re-lubricating
the machine element is simplified since old grease does not have to
be removed from a machine element and the amount of waste grease is
reduced since the grease's thickener is re-used.
[0018] According to another embodiment of the invention the capsule
comprises at least one of the following: a polymeric thickener,
polypropylene, polyethylene, polyalkylene glycol, polyethylene
glycol, polyolefin phenol, lanolin, lanoline polyethylene glycol,
polyoxyethylene lanolin, silicon oil, ionic soap, urea soap, metal
organic soap.
[0019] According to a further embodiment of the invention the
capsule comprises at least one of the following: a tackifier, an
elastomer, an anti-wear additive, an anti-corrosion additive, an EP
additive, an anti-oxidant. Some greases are labeled "EP", which
indicates "extreme pressure". Under high pressure or shock loading,
normal grease can be compressed to the extent that the greased
parts come into physical contact, causing friction and wear. EP
grease contains solid lubricants, usually graphite and/or
molybdenum disulfide, to provide protection under heavy loadings.
The solid lubricants bond to the surface of metal components, and
prevent metal-to-metal contact and the resulting friction and wear
when the lubricant film gets too thin.
[0020] Teflon may for example be added to improve the lubricating
properties of the lubricant. Glycerol and sorbitan esters may be
added to lubricant that is intended to be used in low temperature
conditions. Copper may be added to lubricant intended for a high
pressure applications.
[0021] According to an embodiment of the invention the lubricant
comprises a thickener comprising at least one polyolefin component,
for example comprising polyethylene or polypropylene or mixtures of
these substances, at least one fluid lubricant component such as
mineral oil, vegetable oil, synthetic oil-like polyalphaolefins,
esters or polyethers, and at least one additive component which is
selected from the group antioxidants, corrosion inhibitors,
anti-wear agents or extreme pressure/load carrying capacity
increasing additives. The content of the thickener component(s) may
be between 5% and 30% by weight, preferably between 9 and 15% by
weight, the content of the fluid lubricant(s) is between 60% and
90% by weight and the additive component(s) by weight between 0.2
and 15%, preferably between 1 and 8% by weight.
[0022] According to an embodiment of the invention the lubricant
comprises a high molecular weight component and a low molecular
weight component. For example, the thickener may comprise a mixture
of a) a (co- or homo-)polymer of propylene with a weight average
molecular weight greater than 200,000 and (b) a (co- or
homo-)polymer of propylene with a weight average molecular weight
less than 100,000. The ratio between the high molecular weight
component and the low molecular weight component may be 1:40-1:5,
preferably 1:25-1:15, more preferably 1:19. The low molecular
weight component may be a polypropylene homopolymer. The low
molecular weight component may have an average molecular weight
between 50,000 and 100,000 with a melt flow rate (ASTM D-1238) of
500-1000, preferably 750-850. The high molecular weight component
may be a polypropylene homopolymer or a
propylene/ethylene-copolymer. The high molecular weight component
may have an average molecular weight of 200,000-250,000 and a melt
flow rate (ASTM D-1238) of 1.5-15, preferably 1.5-7.
[0023] According to another embodiment of the invention the
lubricant comprises a mineral oil, at least one of the following: a
thickening agent, oil-soluble polypropylene, oil-soluble propylene
or mineral, metal soaps (soap-salt thickener), oil-soluble
polypropylene, oil-soluble propylene or amorphous polyolefine
polymers or semicrystalline polyolefine polymers e.g. isotactic or
atactic polyolefin polymers.
[0024] Esters can effect solubility and boost oil-solubility of
additives and thickening agents like polymers. Esters may be
derived from carboxylic acids, branched, unbranched, straight or
with cyclic alkyl group, aryl, alkaryl or aralkyl group group with
1-30 carbons, cyclic fatty esters, alkyl esters, saturated and
unsaturated esters, diesters (from dicarboxylic organic compounds),
disebacic acide esters, polyol esters, synthetic esters, phthalate
esters, carboxylic acid esters. Alkylated napthalenes may be used
as a synthetic fluid lubricant.
[0025] According to an embodiment of the invention the lubricant
may comprise a paraffin based wax of a carbon chain length up to
C40, either in pure form or in mixtures of different alkenes, or
mixed with other polyolefin polymers (polyethylene) or ester waxes
like cetyl myristoleate esters or cetyl palmitate esters. Waxes are
natural, organic compounds that characteristically consist of long
alkyl chains.
[0026] The present invention also concerns a machine element
containing at least one capsule according to any of the embodiments
of the invention. The machine element is at least part of a one of
the following: a shaft, coupling, key, spline, gear, fastener,
spring, seal, belt, clutch, brake, chain, or a bearing element,
such as a ball bearing, a roller bearing, a needle bearing, a
tapered roller bearing, a spherical roller bearing, a toroidal
roller bearing, a ball thrust bearing, a roller thrust bearing, a
tapered roller thrust bearing, a wheel bearing, a hub bearing unit,
a slewing bearing, a ball screw, or a component for an application
in which it is subjected to alternating Hertzian stresses, such as
rolling contact or combined rolling and sliding and/or an
application that requires high wear resistance and/or increased
fatigue and tensile strength.
[0027] The present invention also concerns a method for lubricating
a machine element, which comprises the steps of placing at least
one capsule that comprises an external wall comprising a first
substance that is arranged to perish during the use of the machine
element when the capsule is placed in and/or around the machine
element and/or into lubricant being used to lubricate the machine
element, in and/or around the machine element and/or into lubricant
being used to lubricate the machine element. The at least one
capsule may be placed in and/or around the machine element and/or
into lubricant being used to lubricate the machine element before
and/or during and/or after (i.e. during a pause in operation or a
maintenance/repair stop for example) the use of the machine
element.
[0028] Further embodiments of the method according to the present
invention are recited in the dependent method claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The present invention will hereinafter be further explained
by means of non-limiting examples with reference to the appended
figures where;
[0030] FIG. 1 shows a bearing that is lubricated and/or
re-lubricated using at least one capsule according to an embodiment
of the invention, and
[0031] FIGS. 2 & 3 show capsules according to embodiments of
the invention.
[0032] It should be noted that the drawings have not been drawn to
scale and that the dimensions of certain features have been
exaggerated for the sake of clarity.
DETAILED DESCRIPTION OF EMBODIMENTS
[0033] FIG. 1 schematically shows an example of a bearing 10,
namely a rolling element bearing, that may range in size from 10 mm
in diameter to a few metres in diameter and have a load-carrying
capacity from a few tens of grams to many thousands of tonnes. The
bearing element 10 may namely be of any size and have any
load-carrying capacity. The bearing element 10 has an inner ring
12, an outer ring 14 and a set of rolling elements 16.
[0034] Prior to the use of the bearing 10, a suitable lubricant,
such as grease, is applied between the rolling elements 16 and the
innner ring 12 and outer ring 14 to lubricate the bearing 10. The
grease may for example comprise a thickener, such as at least one
of the following: a polymeric thickener, polypropylene,
polyethylene, polyalkylene glycol, polyethylene glycol, polyolefin
phenol, lanolin, lanoline polyethylene glycol, polyoxyethylene
lanolin, silicon oil, ionic soap, urea soap, metal organic soap.
The thickener may for example comprise polypropylene having both
molecules of a high molecular weight and molecules of a low
molecular weight. The grease may also comprise a fluid lubricant
comprising at least one of the following: mineral oil, synthetic
oil and/or vegetable oil. The grease may for example comprise
60-90% of the fluid lubricant. For example, the optimum grease for
the application in which the rolling element bearing 10 is to be
used comprises 85% mineral oil and 15% soap.
[0035] At least one capsule 18 according to an embodiment of the
invention may be used to lubricate and/or re-lubricate the bearing
10. At least one capsule 18 may namely be placed between the inner
ring 12 and the outer ring 14 of the bearing 10 before, during
and/or after (during a pause in operation or a maintenance/repair
stop for example) the use of the bearing 10.
[0036] During the use of the bearing 10, analysis means may for
example be used to determine which component of the grease that is
being used to lubricate the bearing 10 has been depleted. For
example, one or more sensors of an analysis means may determine
that the grease composition in or around the bearing 10 has changed
during the use of the bearing and for example comprises 70% mineral
oil and 30% soap, i.e. mineral oil has been depleted. One or more
capsules containing an amount of mineral oil to return the
lubricant to its original composition (85% mineral oil and 15%
soap) may then be added to the lubricant lubricating the machine
element and/or be placed in/around the machine element.
Furthermore, a sensor of the analysis means may also be arranged to
determine whether there is an increased amount of iron in the
lubricant being used to lubricate the machine element, indicative
of rust in some part of the machine comprising the machine element.
One or more capsules comprising an anti-corrosion additive may then
be added to the lubricant lubricating the machine element and/or be
placed in/around the machine element.
[0037] FIG. 2 shows a capsule 18 containing at least one component
20 of a lubricant for a machine element, the at least one component
20 may for example be mineral oil containing an anti-corrosion
additive. The capsule 18 comprises an external wall 22 comprising a
substance that is arranged to perish during the use of the machine
element when the capsule 18 is placed in and/or around the machine
element and/or into lubricant being used to lubricate the machine
element, and/or when the capsule 18 has been subjected to a
particular condition.
[0038] In the illustrated embodiment the capsule 18 also comprises
an inner encapsulating wall 24 comprising a second substance that
is arranged to perish during the use of the machine element when
subjected to a first condition. The inner encapsulating wall 24 may
contain and/or comprise another component 26 of a lubricant such as
mineral oil of a different composition to that contained
immediately inside the capsule's external wall 22. The first
substance and the second substance may be oil-soluble and arranged
to dissolve on contact with oil at a pre-determined temperature
and/or predetermined pressure for example. For example, the
external wall 22 may be arranged to dissolve in oil at 50.degree.
C. and the inner encapsulating wall may be arranged to dissolve in
oil at 100.degree. C. A capsule 18 according to the present
invention may comprise any number of inner capsules placed one
inside the other.
[0039] FIG. 3 shows a capsule 18 that comprises an external wall 22
comprising a first substance that is arranged to perish when
subjected to a particular condition and a plurality of inner
encapsulating walls 24 each encapsulating at least one component 26
of a lubricant. The capsule 18 may comprise at least two different
types of inner encapsulating walls: a type comprising a second
substance that is arranged to perish when subjected to a first
condition, and a type comprising a third substance that is arranged
to perish when subjected to a second condition.
[0040] Further modifications of the invention within the scope of
the claims will be apparent to a skilled person.
* * * * *