CN1228424C - Conductive lubricating grease and rolling device filled with same - Google Patents

Conductive lubricating grease and rolling device filled with same Download PDF

Info

Publication number
CN1228424C
CN1228424C CN 01142511 CN01142511A CN1228424C CN 1228424 C CN1228424 C CN 1228424C CN 01142511 CN01142511 CN 01142511 CN 01142511 A CN01142511 A CN 01142511A CN 1228424 C CN1228424 C CN 1228424C
Authority
CN
China
Prior art keywords
conductive
bearing
grease
oil
conductive grease
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.)
Withdrawn - After Issue
Application number
CN 01142511
Other languages
Chinese (zh)
Other versions
CN1422939A (en
Inventor
传宝功哲
横内敦
八谷耕一
中道治
正田亨
小泉秀树
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NSK Ltd
Original Assignee
NSK Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from JP2000362271A external-priority patent/JP4010109B2/en
Application filed by NSK Ltd filed Critical NSK Ltd
Publication of CN1422939A publication Critical patent/CN1422939A/en
Application granted granted Critical
Publication of CN1228424C publication Critical patent/CN1228424C/en
Anticipated expiration legal-status Critical
Withdrawn - After Issue legal-status Critical Current

Links

Images

Abstract

This invention is to provide a conductive grease which is less to decrease conductivity as a time passes. The conductive grease comprises abase oil, a thickener, a conductive solid powder, and at least one kind of a wear inhibitor, an extreme pressure agent and an oiliness agent, wherein an amount of the conductive solid powder added is 0.1 to 10 wt %, and an amount of the at least one kind of a wear inhibitor, an extreme pressure agent and an oiliness agent added is 0.1 to 10 wt %. A ball bearing to be favorably used at high temperature comprises an inner race and an outer race, and a plurality of balls freely rotating between both races, and the conductive grease packed into a space defined between both races and holding the plural balls therein.

Description

The lubricating grease of conduction and loaded the tourelle of this conductive grease
Technical field
The present invention relates to a kind of lubricating grease of conduction, particularly the sort of electroconductibility hardly in time passing and the conductive grease that reduces.
The present invention relate to again a kind of have superior electrical conductivity and this electroconductibility hardly in time passing and the conductive grease that reduces particularly the sort ofly is applicable to that various rolling bearings reduce the conductive grease of resistance between inner race and the outer race simultaneously.
The invention still further relates to a kind of rolling bearing, as needle bearing, particularly the sort of utilization has the rolling bearing of the lubricating grease of electroconductibility as lubricant.
The present invention also further relates to and is in rolling bearing under the conductive condition between a kind of outer race and the inner race, the particularly the sort of rolling bearing that performs well in high-temperature part in office machinery or information equipment such as duplicating machine, laser printer or the miscellaneous equipment (toner cartridge (sensitive drum) (mounting block), hot-rolling support).
Background technology
In general information equipment, for example in duplicating machine, movable part uses a lot of rolling bearings.In rotary course, form one deck oil film between the rolling member of raceway face and rolling bearing, a kind of noncontact is provided between the two.In rolling bearing, because accompanying rotation produces static, therefore may cause such trouble, promptly radiated noise causes distortion and other bad influence to the copy image of duplicating machine.
In order to prevent this trouble, prior art is taked a kind of measure, and the lubricating grease that is about to conduction is seated in the rolling bearing, outer races and rolling member conduction in making, and with one of interior outer races ground connection, to remove the static of rolling bearing.
This problem Figure 24 in reference to the accompanying drawings makes an explanation.
The spot contact bearing 121 of Figure 24 comprises outer race 122, inner race 123, rotatably be arranged in a lot of balls 124 between outer race 122 and the inner race 123, fix the cage (support) 125 of these a lot of balls 124, and direct contact seal part 126,126 is installed among the sealed groove 122b of outer race 122.Will be by outer race 122, inner race 123, and sealing member 126,126 surrounds the space filling that (encircling) limit and goes up conductive grease, and spot contact bearing 126 in, seal with sealing member 126.
Raceway face 122a, the 123a of two seat rings 122,123 and the contact surface between the ball 124 are lubricated by conductive grease 127, make outer race 122, inner race 123 and ball 124 conductions simultaneously.In addition, make outer race 122 or inner race 123, as by using the duplicating machine ground connection (not shown) of spot contact bearing 121, thereby eliminate the static that the rotation because of spot contact bearing 121 produces by information equipment.
For instance, common conductive grease is the lubricating grease that has added carbon black thickening material and conductive additive (seeing JP-B-63-24038), and this conductive grease has excellent electroconductibility (term used herein " JP-B " is meant the Japanese patent application of having examined) when the usage period begins.
Yet, use the problem of the conventional conductive grease of sooty to be, when beginning, have excellent electroconductibility, but As time goes on, electroconductibility descends.
In brief, has excellent electroconductibility although loaded the rolling bearing (inside and outside raceway face and rolling member conduct electricity) when beginning of conductive grease, but As time goes on electroconductibility descends, so the resistance value between the interior outer race of rolling bearing becomes bigger.(hereinafter being referred to as " bearing resistance value ")
Up to now, think that always the reason of this phenomenon is as follows.Conductive grease is present between the raceway face of rolling member and antifriction-bearing race when beginning fully, and the carbon black in the conductive grease is being kept the electroconductibility between raceway face and the rolling member, but because the relative movement between raceway face and the rolling member, conductive grease is evicted from contact surface, in addition, the chain structure of carbon black pellet is also broken.Thereby, the problem that electroconductibility descends has taken place, and As time goes on, the bearing resistance value becomes increasing.
And, have realized that the conductive grease of discharging from contact surface is difficult to enter once more contact surface, because the working needle in-degree of this class lubricating grease is low, and conductive additive is the fine granular that is insoluble to base oil.
Recognize also that simultaneously the conductive grease of discharging from contact surface is difficult to enter once more contact surface, because conductive additive is the fine granular that is insoluble to base oil.
JP-A-1-307516 disclose a kind of prevent lubricating grease electroconductibility in time passing and the method that reduces, promptly restraint of labour penetration degree and softening conductive grease are to avoid the lubricating grease sclerosis.(term used herein " JP-A " is meant not examination but disclosed Japanese patent application).If with the fine powder of carbon black as conduction, then its ability as thickening material is unable to catch up with known metallic soap or carbamide compound thickening material, and the separating of oil degree of gained lubricating grease surpasses 2% separately.
But the inventor has carried out conscientious research and has recognized, electroconductibility (resistance value) in time passing and the variation that produces cause by following factor.
Carry out rolling test (radial loading: 19.6N, rotating speed: 150rpm (min with the rolling bearing (internal diameter: 8mm, external diameter: 22mm, the spot contact bearing of width: 7mm) that contains the conventional conductive grease filling of sooty -1), rotational time: 500 hours, test temperature: 25 ℃), after the whirl test, the raceway face of this rolling bearing is studied with scanning electron microscope (SEM) and energy dispersal spectrometer (EDS).As an example, Figure 13 has provided the SEM image of inner race raceway, and Figure 14 has provided the graphic representation that EDS measures.
By the SEM image of Figure 13 as can be seen, the fundamental plane when beginning in the inner race roller surface disappears and wearing and tearing also occur, therefrom recognizes the wearing and tearing on the roller surface.In the EDS of Figure 14 measurement graphic representation, see the oxygen peak, therefrom recognize the oxide film on the roller surface.
Can recognize in the middle of them, electroconductibility in time passing and the reason that changes is the oxide film that forms on the roller surface, this is because the lubricity deficiency of conductive grease, rather than because the mis-behave of conductive grease.
That is to say, because the metallic contact between rolling member surface and the raceway face tiny damage occurs in raceway face.In the part of damaged, expose the surface that makes new advances, and,, form oxide film so it is immediately by airborne dioxygen oxidation because this new surface has high reactivity.This oxide film has destroyed electroconductibility, causes resistance value As time goes on to raise.
From peak that EDS measures graphic representation as can be seen, because the influence of bearing rotation, a small amount of component that is comprised in the carbon black has formed film in raceway face.Similar with oxide film, the film of this a small amount of component has also reduced electroconductibility, and therefore, As time goes on resistance value raises.
This phenomenon also is common problem for employed conductive grease between the parts of relativity.
As the method that prevents this phenomenon, can consider to use full-bodied base oil, form oil film and prevent metallic contact guaranteeing, still, the thickening of oil film can desirably not cause the reduction of the conductive capability of conductive grease.
What the present invention will solve is exactly the problem of conventional conductive grease above-mentioned, therefore, the purpose of this invention is to provide a kind of excellent electric conductivity and not in time passing and reduce the conductive grease of electroconductibility.
The hot-rolling support or the mounting block of office machinery such as duplicating machine, laser printer or miscellaneous equipment often reach about 200 ℃ high temperature.Therefore, the employed conductive grease of the rolling bearing of this parts is difficult to guarantee enough electroconductibility in secular time limit of service, because use common lubricant not have enough thermotolerances as the conductive grease of base oil.
Usually, the lubricant as the conductive grease base oil can adopt as mineral oil, poly-a-olefin oil, ether oil or ester oil, is at most 160 ℃ but use the temperature limitation that goes up these base oils.
Therefore, be used for the rolling bearing on the sort of high-temperature component above-mentioned, still use conduction brush to remove static.
Summary of the invention
What the present invention will solve is the problem that comprises in the prior art, and an object of the present invention is to provide a kind of all have under from room temperature to high temperature superior electrical conductivity can rolling bearing.
(1) a kind of conductive grease, this conductive grease comprises base oil, thickening material, pressed powder and at least a wear inhibitor, extreme pressure agent and the oiliness agent of conduction, wherein the addition of this conductive solid powder is 0.1～10% of a lubricating grease gross weight, and the total addition level of this at least a wear inhibitor, extreme pressure agent and oiliness agent is 0.1～10% of a lubricating grease gross weight.
(2) as the conductive grease described in the item (1), wherein said conductive solid powder is at least a particle, and this particulate main component is fibrous carbon, metallic particles, metal compound particles and carbon nanotube.
(3) as the conductive grease described in the item (2), the particle that wherein said its main component is a fibrous carbon is carbon black or acetylene black.
(4) as the conductive grease described in the item (3), wherein said thickening material is metallic soap or carbamide compound, every kind addition is 5～20% of a lubricating grease gross weight, and the total amount of the pressed powder of thickening material and conduction is 5.1～20.1% of a lubricating grease gross weight.
(5) as the conductive grease described in the item (1), wherein said wear inhibitor is at least a kind of in ortho-phosphoric acid ester and the phosphorous acid ester.
(6) as the conductive grease described in the item (1), wherein said extreme pressure agent is at least a kind of in DTP (dithiophosphates) metallic compound or DTC (dithiocar-bamate) metallic compound.
(7) as the conductive grease described in the item (1), wherein said oiliness agent is at least a kind of in succinate, carboxylic acid anhydride and the alkenyl succinic anhydrides.
(8) as the conductive grease described in the item (1), this conductive grease comprises that also mean diameter is the mineral compound fine granular of 0.05～2 μ m, and this particulate amount is 0.05～7% of a lubricating grease gross weight.
(9) as the conductive grease described in the item (1), wherein said base oil is independent a kind of or at least two kinds a mixture in mineral oil, synthetic hydrocarbon ils, ester oil, fluorocarbon oil, ether oil and the polyoxyethylene glycol oil, and its dynamic viscosity is 5mm in the time of 40 ℃ 2/ s to 120mm 2/ s.
(10) as the conductive grease described in the item (1), the addition of wherein said base oil is 75～90% of a lubricating grease gross weight.
(11) as the conductive grease described in the item (1), wherein this conductive grease is 0.5～2 weight % at 100 ℃ of separating of oil degree after 24 hours.
(12) as the conductive grease described in the item (11), the addition of wherein said conductive solid powder is 0.2～0.9% of thickening material and this conductive solid total weight of powder.
(13) as the conductive grease described in the item (1), wherein said thickening material comprises at least a as main component in silicone compounds and the fluorine cpd, and this lubricating grease comprises the carbon black that accounts for lubricating grease gross weight 0.2～10% amount, as the pressed powder of conduction.
(14) as the conductive grease described in the item (13), wherein said fluorine cpd are tetrafluoroethylene or trifluoro-ethylene.
(15) as the conductive grease described in the item (13), wherein said silicon compound is fine powder silicon-dioxide, synthetic mica, mica or montmorillonite.
(16) as the conductive grease described in the item (13), this conductive grease also comprises and is selected from nitrite, benzotriazole, MgO, calcium sulphonate, fluoro phosphonitrile (fluorophosphazen) derivative and MgS 2In at least any one.
(17) as the conductive grease described in the item (13), wherein said sooty specific surface area is 250m 2/ g or bigger.
(18) as the conductive grease described in the item (13), wherein said sooty DBP (dibutyl phthalate) oil adsorption is 180ml/100g or more.
(19) as the conductive grease described in the item (13), wherein said base oil is the perfluoroalkyl polyethers of the perfluoroalkyl polyethers of straight or branched, perfluoroalkyl polyethers that its end group has been introduced carboxyl or isocyanato, ester modified or pure modification, perhaps be independent a kind of or at least two kinds mixture in fluorocarbon oil, silicone oil and the fluoro silicone oil, and its dynamic viscosity is 15mm in the time of 40 ℃ 2/ s to 500mm 2/ s.
(20) as the conductive grease described in the item (2), wherein said conductive solid powder is the carbon nanotube of diameter 1～24nm, length 0.5～30 μ m.
(21) as the conductive grease described in the item (20), this conductive grease comprises that also as the carbon black of conductive additive or acetylene black be the carbon granule of main component, the metallic particles of gold and silver, copper, tin, zinc or aluminium, the perhaps metal compound particles of silver suboxide, sulfuration niobium or Silver Nitrate.
(22) a kind of tourelle, this device comprises an outer member, an inner member and a lot of rolling body that rotatably is arranged between described outer member and the inner member, this device has also loaded conductive grease between interior external component and rolling body, described conductive grease comprises base oil, thickening material, the pressed powder of conduction, at least a wear inhibitor, extreme pressure agent and oiliness agent, wherein the addition of this conductive solid powder is 0.1～10% of a lubricating grease gross weight, and this at least a wear inhibitor, the total addition level of extreme pressure agent and oiliness agent is 0.1～10% of a lubricating grease gross weight.
(23) tourelle described in item (22), this tourelle also comprises the direct contact seal part between outer member and inner member, described sealing member conducts electricity.
(24) tourelle described in item (22), wherein this tourelle is a rolling bearing, this outer member is an outer race, and this inner member is an inner race.
(25) tourelle described in item (22), wherein this tourelle is a linear guide device, this outer member is a slide unit, and this inner member is a guide rail.
(26) tourelle described in item (22), wherein this tourelle is a ball-screw, this outer member is the ball nut, and this inner member is a screw shaft.
Description of drawings
Fig. 1 is the figure of several additive chemistry formulas;
Fig. 2 has been to use the cross-sectional view of the ball bearing structure of conductive grease of the present invention;
Fig. 3 measures conductive grease resistance schematic representation of apparatus;
Fig. 4 is the graphic representation that concerns between the rotational time of spot contact bearing and the bearing resistance maximum value;
Fig. 5 is the chart that concerns between the additive types in bearing resistance maximum value and the lubricating grease;
Fig. 6 is the graphic representation that concerns between the addition of phosphorous acid ester and the bearing resistance maximum value;
Fig. 7 is the graphic representation that concerns between the addition of alkenyl succinic anhydrides and the bearing resistance maximum value;
Fig. 8 is the graphic representation that concerns between the addition of additive (mixture of phosphorous acid ester and alkenyl succinic anhydrides) and the bearing resistance maximum value;
Fig. 9 is the chart that concerns between the addition of fine inorganic compound particle and the resistance of rotation after 500 hours, the magnesium oxide (MgO) that described meticulous inorganic compound particle is mean diameter 0.1 μ m;
Figure 10 is the graphic representation that concerns between the mean diameter of fine inorganic compound particle and the resistance after 500 hours, and the mean diameter of described fine inorganic compound particle is carried out various changes (addition: 1% of lubricating grease weight, invariable);
Figure 11 is the graphic representation that concerns between the add-on of conductive solid powder and the bearing resistance maximum value;
Figure 12 is the graphic representation that concerns between the maximum value of the dynamic viscosity of base oil and bearing resistance;
Figure 13 is the SEM image that the bearing of having used conventional conductive grease has carried out the interior raceway face after the whirl test in 500 hours;
The bearing that Figure 14 has used conventional conductive grease has carried out the EDS survey sheet of the interior raceway face after the whirl test in 500 hours;
Figure 15 A and Figure 15 B are the concept maps of carbon nanotube;
Figure 16 is the graphic representation that concerns between the maximum value of the rotating speed of spot contact bearing and bearing resistance;
Figure 17 is the graphic representation that concerns between the maximum value of the rotational time of spot contact bearing and bearing resistance;
Figure 18 is the chart that concerns between the kind of additive in the maximum value of bearing resistance and the lubricating grease;
Figure 19 is the graphic representation that concerns between the maximum value of the amount of additive and bearing resistance;
Figure 20 is the graphic representation that concerns between the maximum value of the addition of carbon nanotube and bearing resistance;
Figure 21 is the graphic representation that concerns between the maximum value of the dynamic viscosity of base oil and bearing resistance;
Figure 22 is the graphic representation that concerns between the maximum value of the diameter of carbon nanotube and bearing resistance;
Figure 23 is the graphic representation that concerns between the maximum value of the length of carbon nanotube and bearing resistance;
Figure 24 is a cross-sectional view of having used the spot contact bearing of conventional conductive grease;
Figure 25 is the cross-sectional view of one of rolling bearing embodiment of the present invention;
Figure 26 is by the figure as a result of resistance value between the outer race in the measurement device rolling bearing shown in Figure 3;
Figure 27 utilizes the figure as a result that concerns between the separating of oil degree of device shown in Figure 3 research conductive grease and its electric conductivity;
Figure 28 utilizes the figure as a result that concerns between the dynamic viscosity of base oil of device shown in Figure 3 research conductive grease and its electric conductivity;
Figure 29 utilizes device shown in Figure 3 to study meticulous conductive powder to be added to the figure as a result that concerns between amount in the conductive grease and the electric conductivity;
Figure 30 is the cross-sectional view as the spot contact bearing of one of rolling bearing embodiment of the present invention;
Figure 31 is the graphic representation that concerns between bearing rotational time and the bearing resistance maximum value;
Figure 32 is the chart that concerns between the kind of additive in bearing resistance maximum value and the lubricating grease;
Figure 33 is the graphic representation that concerns between the amount of the fluoro phosphazene derivative that added and the bearing resistance maximum value;
Figure 34 is the graphic representation that concerns between sooty addition and the bearing resistance maximum value;
Figure 35 is the graphic representation that concerns between sooty specific surface area and the bearing resistance maximum value;
Figure 36 is the graphic representation that concerns between oily adsorptive capacity of sooty DBP (dibutyl phthalate) and the bearing resistance maximum value; With
Figure 37 is the graphic representation that concerns between the dynamic viscosity of base oil and the bearing resistance maximum value.
In the accompanying drawings, label 21 is meant spot contact bearing; 22 are meant outer race; 22a is meant the raceway face of outer race; 23 are meant inner race; 23a is meant the raceway face of inner race; 24 expression balls; 27 expression conductive greases; 12 expression inner races; 13 expression outer races; 14 expression rolling bodys; 15 expression supports; 17,18 expression sealing plates; 31 expression spot contact bearing; 32 expression outer races; 33 expression inner races; 34 expression balls; And 37 the expression conductive grease.
Detailed Description Of The Invention
It forms the oilness that has excellence as the conductive grease that is proposed in (1), and can prevent the metallic contact between the synergistic parts, as the raceway face of rolling bearing and the metallic contact between the rolling body, and oxide film also is difficult to appear on the raceway face, thereby As time goes on rare electroconductibility reduce.
As time goes on reduce for suppress electroconductibility in the long usage period, preferred conductive grease comprises at least a wear inhibitor, extreme pressure agent and the oiliness agent that total amount is a conductive grease weight 0.5～7%.
The every kind of component that is comprised in the conductive grease of the present invention all will be mentioned.
Conductive solid powder as being added in the conductive grease of the present invention should use the powder with electroconductibility, and carbon black can be used as example.Carbon black is added in the conventional conductive grease as thickening material and provides electroconductibility together, and conductive grease restriction conductive solid powder of the present invention such as sooty add-on, inherent thickening material such as lithium soap, aluminium soap, calcium soap, barium soap, lithium compound soap, barium compound soap and carbamide compound are coexisted as in the pressed powder of conduction, so that can As time goes on and advantageously make the conductive solid powder keep disperseing.Can use in the lubricating grease thickening material commonly used and without any difficulty.
Can be the particle of main component with fibrous carbon such as acetylene black, the metallic particles of gold and silver, copper, tin, zinc or aluminium, the metal compound particles of silver suboxide, sulfuration niobium and Silver Nitrate, and carbon nanotube replaces carbon black.
In conductive grease of the present invention, the amount of conductive solid powder is preferably 0.1～10% of lubricating grease gross weight.If less than 0.1 weight %, then the electroconductibility of conductive grease is insufficient.If greater than 10 weight %, then capability of lubricating grease may reduce, penetration degree is diminished cause the conductive grease sclerosis, and when inserting bearing, the moment of torsion of bearing is big.For the electroconductibility of conductive grease is abundant, the conductive solid powder is preferably 1 weight % or more, therefore, and more preferably 1～10% of the lubricating grease gross weight.
In the conductive grease that it is formed as (2) and (20) are proposed, because carbon nanotube has the characteristic of the electroconductibility of giving, the conductive grease that therefore comprises carbon nanotube has excellent electroconductibility.In addition, carbon nanotube also has the characteristic of the oilness of giving, so conductive grease also is excellent aspect oilness.Because because of above-mentioned former thereby have an excellent oilness, therefore the metallic contact between can avoiding mutually between the mutual parts of relative movement, as the metallic contact between the rolling body of raceway face and rolling bearing, cause the film of oxide film or other component to be difficult to be formed on the raceway face, therefore, the As time goes on rare reduction of electroconductibility.
To explain carbon nanotube now.Carbon nanotube is the compound with structure shown in Figure 15 A, and mainly is the piped carbon polyhedron (terminal is sealed) that 6 yuan of isocyclic reticulated structures (seeing Figure 15 B) surround into.At the connection section of different-diameter pipes or the terminal part of sealing, 5 yuan or 7 yuan of carbocyclic rings also are common.Those have the carbon nanotube of globosity, as C 60Or C 70, be called soccerballene (fullerene).
Carbon nanotube is that carbon and carbon pass through sp as graphite 2Hybridized orbital combines, and is the elongated shape that is different from diamond lattic structure, so it is slidably with firm.Use has the carbon nanotube of this specific character as conductive additive, can give lubricating grease with required electroconductibility and oilness.
The amount of carbon nanotube is 0.1～10% of a conductive grease gross weight in the preferred conductive grease of the present invention.If less than 0.1 weight %, then the electroconductibility of conductive grease is insufficient, also lacks oilness, and cause electroconductibility As time goes on to reduce easily.If greater than 10 weight %, capability of lubricating grease may reduce (oilness of difference is as separating of base oil and carbon nanotube), penetration degree is diminished cause the conductive grease sclerosis, and when inserting bearing, the moment of torsion of bearing is big.In order to give conductive grease enough electroconductibility, carbon nanotube is preferably 0.5 weight % or more, therefore, and more preferably 0.5～10% of the lubricating grease gross weight.
In the scope of not damaging the object of the invention, other common conductive additive can be sneaked in the carbon nanotube.For instance, available conductive additive can be that carbon black or acetylene black are the carbon granule of main component, the metallic particles of gold and silver, copper, tin, zinc or aluminium, the metal compound particles of silver suboxide, sulfuration niobium or Silver Nitrate.
For conductive grease of the present invention, if desired, can use thickening material in the mode of combination.Be used in combination and make carbon nanotube As time goes on keep needed dispersion.As thickening material commonly used in the lubricating grease, for example can use lithium soap, calcium soap, aluminium soap, barium soap, barium compound soap, lithium compound soap or carbamide compound and do not have any problem.In addition, when using following fluorocarbon oil, can use fluorine cpd such as tetrafluoroethylene as thickening material as base oil.
The amount of thickening material is preferably 5～20% of lubricating grease gross weight.If the amount of thickening material is less than 5 weight %, the lubricating grease in the bearing spills easily, if should measure greater than 20 weight %, then moment of torsion is big.
From the oilness and the flowability of conductive grease, the total amount of thickening material and conductive solid powder is preferably 5.1～20.1% of lubricating grease gross weight.
And, for conductive grease of the present invention, preferably add at least a in wear inhibitor, extreme pressure agent, oiliness agent and the antioxidant.If add and effectively to prevent the additive that weares and teares, then can avoid taking place each other the metallic contact between the mutual parts of relative movement, as the metallic contact between the rolling body of raceway face and rolling bearing, thereby the electroconductibility passing of having avoided causing because of life-time service in time reduces.
The ratio of mixture of base oil and thickening material is fully for the use temperature of penetration degree that is suitable for and rolling bearing, does not have special restriction, but selects defined No. 1 to No. 3 penetration degree scope of JIS K2220-1999 usually.
Above-mentioned rolling bearing also has secular stability under 180 ℃ or higher temperature.
The functional group of these additives has adsorption to the metal of preparation raceway face, so above-mentioned additive is adsorbed on the metal of raceway face.Because this fact, oilness has improved, and has also prevented the tiny damage that causes because of the metallic contact in the raceway face etc., thereby has had the effect that keeps electroconductibility.
As the wear inhibitor that is added in the conductive grease with above-mentioned (1) described composition, will enumerate the organophosphorus based compound.For example, general formula (RO) 3The ortho-phosphoric acid ester of PO representative (TCP, TOP), phosphorous acid ester such as general formula (RO) 2The diethyl phosphite or the general formula (RO) of P (O) H representative 3The triethyl-phosphite of P representative etc.Above-mentioned " R " represents alkyl, aryl and alkylaryl.
As extreme pressure agent, DTP metallic compound such as Zn-DTP (zinc dithiophosphate) or Mo-DTP (molybdenum dithiophosphate) are arranged, DTC metallic compound such as Ni-DTC or Mo-DTC, the perhaps organometallic compound of sulfur-bearing, phosphorus or chlorine.
In addition,, can adopt compound, organic fatty acid compound such as oleic acid or succinate, carboxylic acid anhydride such as alkenyl succinic anhydrides etc. based on amine as oiliness agent.
As for antioxidant, can use employed those antioxidants in the traditional lubrication fat, and not have any problem as optional compound.The example is an aminated compounds, as the arylamine, particularly dioctyl diphenylamine of aliphatic amide or phenolic group group.
In the middle of them, Fig. 1 shows phosphorous acid ester, TCP, the chemical formula of TOP and DTP metallic compound and DTC metallic compound.Functional group (functional group that dotted line is irised out among Fig. 1) in these chemical formulas beyond the R has adsorption to the metal of preparation raceway face, so above-claimed cpd is adsorbed on the metal of preparation raceway face.Because this fact, oilness has improved, and has also prevented the tiny damage that causes because of the metallic contact in the raceway face etc., thereby has had the effect that keeps electroconductibility.
That iris out except dotted line among Fig. 1 and have a functional group the functional group of above-mentioned effect, as oiliness agent, for example, the functional group that is comprised in oleic acid, succinate or derivatives thereof or the organic fatty acid compounds such as carboxylic acid anhydride such as alkenyl succinic anhydrides, i.e. carboxyl or anhydride group.
In conductive grease of the present invention, need to add above-mentioned additive, be at least a in wear inhibitor, extreme pressure agent and the oiliness agent in brief, add-on is 0.1～10% of a lubricating grease gross weight.If less than 0.1 weight %, then prevent electroconductibility in time passing and reduce insufficiently, detrimentally affect such as electroconductibility reduce or corrosion (corrosion of metal parts such as raceway face) if add-on greater than 10 weight %, then may produce.For between the long usage period, suppress electroconductibility in time passing and reduce, preferably this add-on is 0.5～7% of a lubricating grease gross weight.
For between the long usage period, suppress electroconductibility in time passing and reduce, preferred wear inhibitor and oiliness agent are used in combination.For example, if use phosphorous acid ester as wear inhibitor and use carboxylic acid anhydride as oiliness agent, then avoid electroconductibility in time passing and the effect that reduces is good especially.
In addition, by in forming, adding meticulous inorganic compound particle as the lubricating grease of above-mentioned (1), even oxide film appears at the raceway face of bearing or the surface of rolling body, or the organism absorption that produces owing to the decomposition of lubricating grease and solidifying in the above, because raceway face or rolling body surface are ground by tiny inorganic compound particle on the microcosmic degree, so new total surface exposes, and keeps low resistance value for a long time.
The kind of described mineral compound does not have special restriction, as long as they can grind on the microcosmic degree and appear at the oxide film of metallic surface or organism adhered thereto.
Specific examples has metal oxide such as SiO 2, Al 2O 3, MgO, PZT or TiO 2, clay mineral if you would take off stone, mica, metal nitride such as Si 3N 4Or ZrN, and metallic carbide such as SiC or TiC.
The diameter of fine inorganic compound particle should be advisable not hinder the size of forming as Lubrication of Rolling Contact Bearing fat, if surpass 2 μ m usually, they have just become exotic, so they should be 2 μ m or littler.
If add-on is very little, then be difficult to the formation of inhibited oxidation film, and if too many, then can cause wearing and tearing increases, and therefore is preferably 0.05～7% of lubricating grease gross weight.
As the employed base oil of conductive grease of the present invention, mineral oil is arranged, synthetic hydrocarbon oil such as poly-a-olefin oil (PAO), ester oil, silicone oil, fluorocarbon oil, ether oil or polyoxyethylene glycol, and also they can be independent or two or more mixture.
Because basic oil viscosity too conference produces detrimentally affect to electroconductibility, so its dynamic viscosity in the time of 40 ℃ is preferably 120mm 2/ sec or littler, more preferably 100mm 2/ sec or littler.If surpass 120mm 2/ sec, oil film is thicker, increases resistance value.If its dynamic viscosity is less than 5mm 2/ sec, then inapplicable because of vaporization losses or oilness problem.If basic oil viscosity is too low, then be difficult to form the oil-bound film that is enough to avoid as metallic contact between raceway face during the bearing rotation and the rolling body.In order to make above-mentioned better effects if, wish that especially the dynamic viscosity of base oil in the time of 40 ℃ is 15～60mm 2/ sec.
In conductive grease, the amount of base oil is that the total amount of conductive grease deducts the conductive solid powder, wear inhibitor, and extreme pressure agent, oiliness agent, thickening material, rest parts such as antioxidant, preferred base oil accounts for 75～90% of lubricating grease gross weight.
For conductive grease is loaded in the bearing, can be used in combination the conductive seal plate that conductive rubber etc. is made, and if give sealing plate with electroconductibility, then can suppress electroconductibility in time passing and reduce.
In conductive grease of the present invention, the ratio of mixture of base oil and thickening material is fully for the use temperature of penetration degree that is suitable for and rolling bearing, does not have special restriction, but selects defined No. 1 to No. 3 penetration degree scope of JISK2220-1999 usually.
If have (11) described composition, the waste oil film minimum that detects, and the electroconductibility of conductive grease can stable for extended periods of time, makes and can remove the electrostatic influence for a long time fully, thereby improve reliability.In the present invention, if separating of oil degree surpasses 2%, then a lot of base oils separate during the inner race rotation, and base oil is enriched in the groove of raceway face or interior outer race.As a result, the local carbon black that exists has quickened the destruction of chain structure and has quickened the reduction of electroconductibility in the oil component.On the other hand, if separating of oil degree after 100 ℃ and 24 hours less than 0.5%, the then bad lubricated work-ing life that shortens bearing to heavens.Therefore, the separating of oil degree of conductive grease is preferably smaller or equal to 2% and more than or equal to 0.5%.
By suppressing the low separating of oil degree of conductive grease 100 ℃ and 24 hours after, can suppress that lubricating grease spills or oil consumption diffusing, so that detrimentally affect does not damage employed resin material, this resin material is close to the bearing of information equipment such as office machinery.In addition, conductive grease as routine, can only use carbon black as thickening material, if but make lithium soap or carbamide compound as intrinsic thickening material (when using fluorocarbon oil or tetrafluoroethylene) and carbon black, then As time goes on carbon black can keep good dispersion state, and separating of oil degree also can be controlled.
Basic oil viscosity for have the conductive grease of forming described in above-mentioned (11) does not have special restriction, if but the dynamic viscosity of base oil surpasses 100mm 2/ s, then oil film is thicker, and the resistance between the interior outer race can not keep suitable value.This dynamic viscosity becomes less than 5mm 2/ s, then inapplicable because of vaporization losses or oilness problem, therefore expect that the dynamic viscosity of base oil is 5～200mm 2/ s, preferred 15～100mm 2/ s.
As for the fine grain amount of conductive extract, if the total amount of conductive extract fine particle and thickening material is 1, then desirable ratio is 0.2 to 0.9.
If form as above-mentioned (13) as described in, then rolling bearing has excellent electroconductibility under 180 ℃ or higher temperature, and maintenance favorable conductive state between the interior outer race.
As base oil, cited have a perfluoroalkyl polyethers (straight chain or side chain); Its end group has been introduced the perfluoroalkyl polyethers of carboxyl or isocyanato; The perfluoroalkyl polyethers of ester modified or pure modification; Fluorocarbon oil such as fluoro phosphonitrile oil; Silicone oil such as aminomethyl phenyl silicon, dimethyl-silicon and fluoro silicone oil.These materials can use separately, also can use with two or more mixture.
Basic oil viscosity is not had special restriction, but base oil is 500mm at 40 ℃ dynamic viscosity 2/ s or lower suiting.If greater than 500mm 2/ s, then the oil film between raceway face and the bearing element spare becomes thicker, even at high temperature also be so, and can not keep suitable electroconductibility.If but this dynamic viscosity is less than 15mm 2/ s, then oilness deficiency.
Fluorine cpd as thickening material are fluoro-resin, as tetrafluoroethylene or trifluoro-ethylene.Silicon compound is meticulous powder silicon-dioxide or synthetic mica (fluorine four silicon micas), and the lamellar compound (clay mineral) that promptly has the solid lubrication performance is as mica, montmorillonite.
Not to have only fluorine cpd or silicon compound as thickening material, if but limit to a number or amount and carbon black and thickening material are coexisted, then As time goes on carbon black can keep good dispersion state.
As long as do not hinder purpose of the present invention, known thickening material can be used in combination with above-mentioned thickening material.For example, known thickening material has lithium soap, silicon-dioxide, calcium soap, aluminium soap, lithium compound soap, aluminium compound soap, calcium compound soap, polyureas, wilkinite.
Sooty add-on as conductive additive is preferably 0.2～10% of conductive grease gross weight.Less than 0.2 weight %, then can not obtain enough electroconductibility, and greater than 10 weight %, then the working needle in-degree of conductive grease become too big (it is too hard that conductive grease becomes).The sooty kind is not limit, from the dispersive angle, and the preferred carbon black of enrichment in oil absorption.Preferred use has bigger serface and (is preferably 250m 2/ g or bigger) and lipophilic carbon black.
Available wear inhibitor, extreme pressure agent and oiliness agent are restricted because of thermotolerance with the compatibility of thickening material (fluorine cpd, silicon compound), but for example use above-mentioned fluorocarbon oil as base oil, and then following material is operable.As oiliness agent, the compound based on amine is arranged, fatty acid cpds such as oleic acid, succinate etc.
Except these additives, also have solid lubricant such as nitrite, benzotriazole MgO, calcium sulphonate, fluoro phosphazene derivative, lamellar compound such as mica or MoS 2Because they and the consistency of fluorocarbon oil and poorly soluble, so be that its consumption is not fully with 10% or higher amount of lubricating grease gross weight.
If the direct contact seal part is installed between the interior outer race of rolling bearing of the present invention, then electroconductibility can better be improved, and wherein said sealing member is to be made of the conductive rubber that comprises carbon black etc.
With reference to the accompanying drawings conductive grease embodiment of the present invention is carried out detailed explanation.
Fig. 2 is the cross-sectional view of structure with spot contact bearing 21 of conductive grease of the present invention.Spot contact bearing 21 comprises outer race 22, inner race 23, a plurality of balls 24 that rotatably are arranged between outer race 22 and the inner race 23, the cage (support) 25 of fixing a plurality of balls 24, and direct contact seal part 26,26 is installed among the sealed groove 22b of outer race 22.Load by outer race 22 with conductive grease 27, the space that is limited around inner race 23 and the sealing member 26,26, and also sealed 26 of this lubricating grease is sealed in the spot contact bearing 21.
Raceway face 22a, the 23a of seat ring 22,23 and the contact surface between the ball 24 are lubricated by conductive grease 27, and outer race 22, inner race 23 and rolling body 24 conduct electricity simultaneously.In addition, outer race 22 or inner race 23 are (not shown) of ground connection, so that eliminate the static that is produced by the rotation of spot contact bearing 21.
As conductive grease 27, (dynamic viscosity is 30.0mm in the time of 40 ℃ to use poly-a-olefin oil 2/ sec) as base oil, can account for the lithium soap of lubricating grease gross weight 7% as thickening material to wherein adding respectively, the carbon black that accounts for lubricating grease gross weight 5.0% is as conductive additive, and the phosphorous acid ester that accounts for lubricating grease gross weight 5.0% is as wear inhibitor (remaining be base oil).
Conductive grease 27 has excellent oilness and electroconductibility, cause rare metallic contact between raceway face 22a, the 23a of spot contact bearing 21 and the ball 24, and oxide film does not appear on raceway face 22a, the 23a yet, therefore, is difficult to take place electroconductibility and As time goes on reduces.
As conductive grease 27, (dynamic viscosity is 26mm in the time of 40 ℃ to use ester oil 2/ sec) as base oil, to the lithium soap that wherein adds respectively as thickening material, as the carbon nanotube of conductive additive (lubricating grease gross weight 5.0%), and succinyl oxide (lubricating grease gross weight 2.5%), making the working needle in-degree is 249.
Conductive grease 27 comprises carbon nanotube and has excellent oilness and electroconductibility, cause rare metallic contact between raceway face 22a, the 23a of spot contact bearing 21 and the ball 24, and oxide film do not appear on raceway face 22a, the 23a yet, therefore, being difficult to take place electroconductibility As time goes on reduces.
For electroconductibility is provided, sealing member 26 is made of conductive rubber, and it can suppress more electroconductibility in time passing and reduce.
So this conductive grease 27 can prevent the static of employed rolling bearing in the office machinerys such as duplicating machine, laser printer as a kind of measure that remarkable purposes is arranged.
The present embodiment is embodiments of the invention, but the invention is not restricted to this embodiment.
For example, the present embodiment is the example that conductive grease is applied to spot contact bearing, but conductive grease of the present invention is not limited to concrete purposes, but need to can be applicable to other purposes of the electrical pickoff of conductive grease.
As mentioned above, the generation that electroconductibility reduces is that the relative movement of a plurality of parts makes the raceway face of these parts produce oxide film, and in the relative movement process, the degree of formation oil film and the reduction of electroconductibility have confidential relation between the parts.
Therefore, conductive grease of the present invention is specially adapted to have the tourelle that carries out relative movement part, as rolling bearing, ball-screw, linear guide device or linear ball bearing.
Figure 25 is the cross-sectional view of structure of the rolling bearing of relevant another embodiment of the present invention.Equally, rolling bearing 11 has inner race 12, and the outside of the axle (as moving the drum axle of drum) that needs support is installed, and outer race 13, is installed in the periphery of inner race 12.Inner race and outer race are all made by the bearing steel metallic substance, and one of them is a ground connection.
Rolling bearing 11 has a plurality of balls (rolling body) 14 that rotatably are arranged between inner race 12 and the outer race 13, and the fixing cage 15 of rolling member 14.At the middle part of the inner periphery of the middle part of the excircle of inner race 12 and outer race 13, the rolling groove 16 of rolling body is formed on the whole circumference, with the raceway face of restriction rolling body 14.In addition, rolling bearing 11 has annular sealing plate 17,18, the space of outer race 12,13 in being used for sealing.
Sealing plate the 17, the 18th by what make such as electro-conductive materials such as conductive rubbers, and is arranged on the excircle with accessory 17a, 18a, and in the groove 19,20 that removably is assemblied in the fixing seal plate, described groove arrangement is on the inner periphery of outer race 13.
In by 19,20 sections enclosed spaces that go out of sealing plate, filling rolling member 14, interior outer race 12 and 13 and conductive grease 27.For conductive grease 27, (dynamic viscosity is 30.0mm in the time of 40 ℃ to use poly-a-olefin oil 2/ sec) as base oil, can be to wherein adding lithium soap as thickening material (account for lubricating grease gross weight 7%) respectively and as the carbon black of meticulous conductive powder (account for lubricating grease gross weight 5.0%), making separating of oil degree as JIS K2200-19995.7 defined, is 2% or lower at 100 ℃ after 24 hours.
If specifying the separating of oil degree that fills in the conductive grease 27 in the rolling bearing 11 is 2% or lower, then the waste oil film can be controlled to be minimum, and the electroconductibility of conductive grease 27 maintains a long-term stability.By the separating of oil degree of the lower conductive grease 27 of control, can suppress that lubricating grease spills or oil consumption is loose, employed resin material around the employed rolling bearings of information equipment such as office machinery is not produced detrimentally affect.
Figure 30 is the longitudinal diagram of structure of the spot contact bearing 31 of another embodiment of the present invention.
Spot contact bearing 31 comprises outer race 32, inner race 33, a plurality of balls that rotatably are arranged between outer race 32 and the inner race 33, the cage (support) 35 of fixing a plurality of balls 34, and sealing member 36,36.
On the sealed groove 32b of sealing member 36 attached to outer race 32, the excircle sliding contact of its lip and inner race 33.
With conductive grease 37 filling by outer race 32, inner race 33, and the space that is limited around the sealing member 36,36, and by sealing member 36,36 with grease sealing in spot contact bearing 31.
Raceway face 32a, the 33a of seat ring 32,33 and the contact surface between the ball 34 are lubricated with conductive grease 37, and outer race 32, inner race 33 and ball 34 conduct electricity again simultaneously.In addition, outer race 32 or inner race 33 are (not shown) of ground connection, so that eliminate the static that is produced by the rotation of spot contact bearing 31.
In conductive grease 37, perfluoro polyether is a base oil, and polytetrafluoroethylene (PTFE) is a thickening material, and carbon black is the additive (conductive grease gross weight 0.2～10%) of conduction.Resulting lubricating grease has electroconductibility.The kind of base oil and thickening material is not limited to above-mentioned base oil and thickening material, but can appropriate change.For example, thickening material can be a silicon compound.
This conductive grease 37 has excellent oilness and electroconductibility, cause rare metallic contact between raceway face 32a, the 33a of spot contact bearing 31 and its ball 34, and oxide film do not appear on raceway face 32a, the 33a yet, therefore, being difficult to take place electroconductibility As time goes on reduces.And added resemble PTFE fluorine cpd as thickening material, so conductive grease 37 has high heat resistance, can at high temperature keep excellent electroconductibility for a long time.
In spot contact bearing 31, the electroconductibility between the seat ring 32,33 is in the good order and condition that does not electrify, and keeps this state for a long time.Especially, electroconductibility even can keep excellent long-term up to 180 ℃ or under the higher temperature.
Because spot contact bearing 31 is difficult to electrify,, the static noise radiation cause dysgenic possibility very little to the machine that uses spot contact bearing 31 so taking place.Therefore, this spot contact bearing can be used for hard disk drive and other motor of office machinerys such as duplicating machine, laser printer, information equipment.
The present embodiment is one embodiment of the present of invention, but the present invention is not subjected to the restriction of this embodiment.
For example, in the present embodiment, the spot contact bearing that dark groove is arranged as the example of rolling bearing, but rolling bearing of the present invention can be applied in other various rolling bearings, for example, radiation formula rolling bearing such as columniform roller bearing, the roller bearing of taper, the spot contact bearing of angular contact, or the rolling bearing of push type such as ball thrust bearing, thrust roller bearing.
To describe several structures and above-mentioned spot contact bearing 21 similar spot contact bearing below, measure the resistance of inner race and outer race during the rotation, estimate the relation between rotating speed and the electroconductibility, and the intensity of variation of definite electroconductibility passing in time.
The device of measuring resistance describes with reference to Fig. 3.
Equally, the spot contact bearing (being also referred to as rolling bearing) that label 1 representative will be measured makes bearing 1 rotation attached to the spindle unit on the inner race 1a 2 by motor 3 drivings.Between spindle unit 2 that has connected inner race 1a and outer race 1b, apply predetermined constant voltage by source of stable pressure 4, and resistance apparatus 5 is in parallel with source of stable pressure 4.
Resistance apparatus 5 is exported to A/D change-over circuit 6 with measured magnitude of voltage (analogue value), this A/D change-over circuit 6 the predetermined sample period in the future the magnitude of voltage of self-resistance surveying instrument 5 change into digital voltage value, and the numerary signal that will transform is exported to operation processing unit 7.In this embodiment, the sample period of A/D change-over circuit 6 is made as 50kHz (sample interval is 0.02ms).
Operation processing unit 7 comprises maximum resistance calculating part 7A, 7B of threshold process portion and wave number count section 7C.Maximum resistance calculating part 7A calculates maximum resistance value according to the numerary signal of input.The 7B of threshold process portion handles threshold value when the predetermined threshold of supplied with digital signal, so that eliminate noise.Wave number count section 7C, in brief, be exactly with respect to from the increase of the pulse counting of the 7B of threshold process portion and the variation of reduction by time-delay (time-passing) pulse value, the crest variable number of counting each set time unit is a wave number, so that obtain the mean value of the wave number of each set time unit.Operation processing unit 7 with resultant to maximum value and the mean value of the wave number of each set time unit output on the display unit 8.
The unit time of the counting wave number that this embodiment is determined is 0.328 second.
Display unit 8 is made of indicating meter etc., and demonstrates the mean value of the wave number of the operation processing unit 7 resultant maximum values that arrive and each set time unit.
With further with reference to the method for resistance between the inner race of the instrument evaluation spot contact bearing 1 that uses said structure and the outer race.
In the rotation of motor 3 drive shaft sub-assemblies 2, promptly under the situation of inner race 1a with the desired speed rotation, the required constant voltage from source of stable pressure 4 applied and interior outer race 1a, the 1b of bearing 1 between.At this moment, electric current flows between interior outer race 1a, 1b, but voltage fluctuates up and down and with spark.Measure these voltages by resistance apparatus 5, change into digital value by A/D change-over circuit 6 subsequently, and according to this numerary signal, operation processing unit 7 obtains the mean value of the wave number of maximum value that display unit 8 will show and each set time unit.
Prepare the bearing ( embodiment 1 and 2, reference example 1, and Comparative Examples 1 to 5) that 8 kinds of lubricating grease have nothing in common with each other, and with the resistance (maximum value) between every kind of bearing of apparatus measures of said structure per 100 hours interior outer race 1a, the 1b.
Each of 8 kinds of bearings is rolling bearing, has the internal diameter of 8mm, the external diameter of 22mm and the width of 7mm.The composition of 8 kinds of lubricating grease as shown in Table 1 and Table 2, and loadings is 155～165mg.
The diameter of employed carbon nanotube is 1～3nm, and length is 0.5～5 μ m (seeing Figure 15 A as for this diameter and length).
Table 1
Embodiment 1 Comparative Examples 1 Comparative Examples 2 Comparative Examples 3
Thickening material Kind Lithium soap Lithium soap Lithium soap Lithium soap
Quantity 7 weight % 12 weight % 7 weight % 12 weight %
Base oil Kind PAO 2) PAO 2) PAO 2) PAO 2)
Viscosity 1) 30.0 30.0 30.0 30.0
The pressed powder of conduction Kind Carbon black Do not have Carbon black Do not have
Quantity 5.0 weight % 0 weight % 5.0 weight % 0 weight %
Wear inhibitor Kind Phosphorous acid ester 3) Phosphorous acid ester 3) Do not have Do not have
Quantity 5.0 weight % 5.0 weight % 0 weight % 0 weight %
The working needle in-degree 249 245 245 250
Body resistivity (Ω cm) 7×10 3 8×10 12 9×10 3 1×10 12
1) base oil is at 40 ℃ dynamic viscosity, and unit is mm 2/ sec
2) PAO: poly-a-olefin oil
3) bi-ester of phosphite: (C 24H 49O) 2P (O) H
The measuring condition of embodiment 1 and Comparative Examples 1 to 3 is as follows.
The rotating speed of spindle unit 2: 150rpm (divides -1)
Load on the radial loading (Fr) on the bearing 1: 19.6N
Rotational time: 500 hours
Applied voltage: 6.2V
Maximum current: 100 μ A
Free air temperature: 25 ℃
Atmospheric moisture: 50%RH
Sample period: 50kHz, 0.328 second
Next step, Fig. 4 the results are shown in the curve its research contents.In same figure, the result of embodiment 1 illustrates with diamond sign (◆), and Comparative Examples 1 result illustrates with square sign (■), and Comparative Examples is 2 results illustrate with trilateral sign (▲), and Comparative Examples 3 results illustrate with X-type sign (*).
Embodiment 1 and Comparative Examples 2 are to have loaded the bearing that contains the sooty conductive grease, and as shown, the initial resistivity value of these bearings is low, because contain carbon black, so reduced body resistivity (seeing Table 1).But Comparative Examples 2 contains carbon black and does not but contain wear inhibitor, thus resistance value in time passing and increase.
Comparative Examples 1 and 3 is used and is not contained sooty lubricating grease, just has high resistance value from the initial stage.This bearing causes radiated noise, and when being applied to duplicating machine or printer, they may produce detrimentally affect, as the image distortion of duplicating or printing.
The lubricating grease of embodiment 1 comprises the carbon black that accounts for lubricating grease gross weight 5% and accounts for the thickening material of lubricating grease gross weight 7%, accounts for 12% of lubricating grease gross weight altogether.About the various combinations of the penetration degree that the provides content suitable with described lubricating grease with oilness are provided, this situation can assume carbon black and thickening material is respectively 1 weight % and 11 weight %, 3 weight % and 9 weight %, perhaps 7 weight % and 2 weight % (content of base oil many 2 weight %) all are based on the gross weight of lubricating grease under every kind of situation.
Illustrate with reference to Fig. 5 below, in the bearing of embodiment 1, used when wear inhibitor changed over the lubricating grease of other additive (extreme pressure agent or oiliness agent) result of institute's measuring resistance value (maximum value).The resistance value of Fig. 5 is 200 hours resistance values afterwards of rotation.The addition of every kind of additive is 5.0% of lubricating grease gross weight.
Mark among Fig. 5 " A " is not for there being the situation of additive, mark " B to G " is for having added the situation of extreme pressure agent, mark " H and I " is for having added the situation of wear inhibitor, mark " J and K " is for having added the situation of oiliness agent, and mark " L " is for having added the situation of wear inhibitor " H " and oiliness agent " J ".
Do not have " A " resistance value after 200 hours of additive very big, " B to L " that added additive is then suppressing to have significant effect aspect the resistance value rising, no matter be what additive.
In the middle of them, the situation that adds phosphorous acid base wear inhibitor (H and I), stop resistance value in time passing and have big effect aspect the variation, and, the situation (L) of having mixed phosphorous acid base wear inhibitor and oiliness agent can the controlling resistance value in time passing and change.
Sum up the result of Fig. 5, the degree of above-mentioned effect is by following built-up sequence, promptly by wearing and tearing inhibitor and oiliness agent, wear inhibitor, the built-up sequence of oiliness agent and extreme pressure agent is good, and particularly the combination of the combination of wear inhibitor and oiliness agent and wear inhibitor is excellent.
In every kind of situation of the combination (phosphorous acid ester: alkenyl succinic anhydrides is 1: 1 a mixture) of wear inhibitor (phosphorous acid ester), oiliness agent (alkenyl succinic anhydrides) and wear inhibitor and oiliness agent, with reference to Fig. 6 to Fig. 8, (other is identical with embodiment 1) measured resistance value describes when changing the addition of lubricating grease component.The resistance value of Fig. 6 to Fig. 8 is rotation 200 hours or 600 hours resistance values afterwards.Resistance value after 200 hours represents that with diamond indicia the resistance value after 600 hours is represented with square mark.
As seen from Figure 6, when the consumption of wear inhibitor (phosphorous acid ester) be the lubricating grease gross weight 0.1% or when higher, aspect its resistance value after controlling 200 and 600 hours is effective, and when add-on be the lubricating grease gross weight 0.5% or when higher, the rising of resistance value has obtained sufficient inhibition.Incidentally, the upper limit of phosphorons acid compound because etching problem (owing to be tart, so phosphorons acid compound has corrodibility to metal) and be the lubricating grease gross weight 10% or lower.
To pay close attention to the situation of oiliness agent (alkenyl succinic anhydrides) below.From the curve of Fig. 7 as can be seen, when the consumption of alkenyl succinic anhydrides be the lubricating grease gross weight 0.1% or when higher, aspect its resistance value after controlling 200 and 600 hours is effective, and when add-on be the lubricating grease gross weight 0.5% or when higher, the rising of resistance value has obtained sufficient inhibition.Particularly for 600 hours resistance values afterwards, it was more effective than phosphorous acid ester.
To pay close attention to the situation of wear inhibitor and oiliness agent combination (phosphorous acid ester: alkenyl succinic anhydrides is 1: 1 a mixture) below.From the curve of Fig. 8 as can be seen because the interaction of two kinds of additives, this situation stop aspect the resistance value increase more effective than independent a kind of additive.As can be seen, the contribution of alkenyl succinic anhydrides is big.
Below with reference to Fig. 9 and Figure 10, measured resistance value (maximum value) describes when using the lubricating grease identical with embodiment 1 just to change the addition of fine inorganic compound particle and mean diameter.
Fig. 9 is the chart of mutual relationship between the addition of fine inorganic compound particle and the resistance value of rotation after 500 hours, and the magnesium oxide (MgO) that uses mean diameter 0.1 μ m is as meticulous inorganic compound particle.In Fig. 9, the longitudinal axis does not illustrate the value of measured resistance value, but has carried out performance judgment and drawn on the top of figure preferably and judged.◎ is equivalent to maximum resistance less than 40k Ω, and zero is equivalent to 40k Ω extremely less than 50k Ω, and it is that 50k Ω is extremely less than 200k Ω that △ is equivalent to resistance value.
In Fig. 9,, then can stop resistance value to increase along with the increase of bearing rotational time if the add-on of fine inorganic compound particle is 0.05～7% of a lubricating grease gross weight.In addition, when add-on be the lubricating grease gross weight 0.5～3% the time, resistance value can the controlling resistance value be followed the increase of bearing rotational time and be increased forr a short time less than 40k Ω.
Figure 10 is the graphic representation of mutual relationship between the mean diameter of fine inorganic compound particle and the resistance of rotation after 500 hours, wherein prepared lubricating grease comprises the fine inorganic compound particle (addition: 1% of lubricating grease gross weight, invariable) of various mean diameters.In Figure 10, the compound that mean diameter is little is magnesium oxide (MgO), and the compound that mean diameter is big is aluminum oxide (Al 2O 3), what mean diameter was medium is the mixture of magnesium oxide and aluminum oxide.The longitudinal axis of figure shows the observed value of resistance, and ◎ is equivalent to resistance value less than 40k Ω, and zero to be equivalent to resistance value be 40k Ω to less than 50k Ω, and it is 50k Ω to less than 200k Ω that △ is equivalent to resistance value, * be equivalent to resistance value to be not less than 200k Ω.
In Figure 10,, just can stop resistance value to increase along with the increase of bearing rotational time if the mean diameter of fine inorganic compound particle is 0.05～2 μ m.
Measured resistance value when using the altered lubricating grease of carbon black addition in the bearing of embodiment 1 is described with reference to Figure 11 below.Resistance value when the resistance value among Figure 11 is the initial stage.
Because even carbon black also can provide electroconductibility during for a small amount of of lubricating grease gross weight 0.1% effectively, thus can and add a large amount of thickening materials by restriction sooty add-on, so that As time goes on carbon black still keeps required dispersion state.As can be seen, when add-on be the lubricating grease gross weight 1% or when higher, resistance value is reduced fully.
But,, will be broken as the sooty reticulated structure of electroconductibility origin, and conductivity just changes in early days easily if the carbon black that adds is too many.Cancellated breaking will cause lubricating grease to leak or separating of oil problem.For suitable working needle in-degree is provided, the sooty add-on be preferably the lubricating grease gross weight 10% or lower.
That is to say that if the sooty add-on is big, then the working needle in-degree is little, make the lubricating grease sclerosis.In table 1, the working needle in-degree of lubricating grease is about 250, if add the carbon black of lubricating grease gross weight 15%, then the working needle in-degree is 200 or lower, therefore, considers boundary, preferred sooty add-on be the lubricating grease gross weight 10% or lower.
Illustrate with reference to Figure 12 below, in the bearing of embodiment 1, use the base oil viscosity-modifying lubricating grease the time measured resistance value.Resistance value among Figure 12 is 200 hours resistance values afterwards of rotation.
As can be seen from Figure 12, the dynamic viscosity of base oil in the time of 40 ℃ is high more, and then resistance value is big more.As mentioned above, if the dynamic viscosity of base oil is too high, then the oil film thickening raises resistance value, and preferred dynamic viscosity is 120mm 2/ sec or lower, more preferably 60mm 2/ sec or lower is very little because resistance value becomes.
In order to form lubricant film, prevent raceway face and the rolling body metallic contact during bearing rotation, the dynamic viscosity of base oil should be high to a certain degree, and preferred 5mm 2/ sec or higher, more preferably 15mm 2/ sec or higher.In other words, more preferably the dynamic viscosity of base oil in the time of 40 ℃ is 15～60mm 2/ sec.
Table 2
Embodiment 2 Reference example 1 Comparative Examples 4 Comparative Examples 5
Thickening material Lithium soap Lithium soap Lithium soap Lithium soap
Base oil Kind Ester oil Ester oil Ester oil Ester oil
Viscosity 1) 26 26 26 26
Conductive additive Kind Carbon nanotube Carbon nanotube Do not have Carbon black
Quantity 5.0 weight % 5.0 weight % 0 weight % 5.0 weight %
Additive Kind Succinyl oxide Do not have Do not have Do not have
Quantity 2.5 weight % 0 weight % 0 weight % 0 weight %
The working needle in-degree 249 245 245 245
1) dynamic viscosity of base oil in the time of 40 ℃, unit is mm 2/ sec
The measuring condition of embodiment 2, reference example 1 and Comparative Examples 4 and 5 is as follows.
Rotating speed: 1000rpm (min -1) (when measure electroconductibility in time passing and when changing)
Load on the thrust load (Fa) of bearing 1: 29.4N
Applied voltage: 6.2V
Maximum current: 100 μ A
Series resistance: 62k Ω
Free air temperature: 25 ℃
Atmospheric moisture: 50%RH
Sample time: 50kHz, 0.328 second.
Below evaluation result is shown in the graphic representation, so that its content is studied.
The evaluation result that concerns between rotating speed and the electroconductibility is described with reference to Figure 16.In same figure, the result of embodiment 2 illustrates with diamond sign (◆), and reference example 1 result illustrates with square sign (■), and Comparative Examples is 4 results illustrate with trilateral sign (▲), and Comparative Examples 5 results illustrate with X-type sign (*).
From this graphic representation, as can be seen, in the embodiment 2 and reference example 1 of the lubricating grease that has loaded carbon nanotubes, suppressed the increase of bearing maximum resistance, even also be like this during big rotating speed.But in the bearing of Comparative Examples 4 and 5, the maximum resistance of bearing is along with the change of rotating speed increases greatly, and its reason is that the carbon black component that forms in oil film or the lubricating grease is squeezed surface in contact.
Below with reference to the graphic representation of Figure 17, to electroconductibility in time passing and the evaluation result of the degree that changes describe.Also be in same figure, the result of embodiment 2 illustrates with diamond sign (◆), and reference example 1 result illustrates with square sign (■), and Comparative Examples is 4 results illustrate with trilateral sign (▲), and Comparative Examples 5 results illustrate with X-type sign (*).
In the embodiment 2 and reference example 1 of the lubricating grease that has loaded carbon nanotubes, suppressed resistance value and As time goes on increased.On the other hand, in the bearing of filling sooty Comparative Examples 5, As time goes on the maximum value of bearing resistance increases.
In the bearing of the Comparative Examples 4 of using the lubricating grease that does not contain conductive additive, the maximum value of bearing resistance is just very big from the initial stage.This bearing causes radiated noise, and when being applied to duplicating machine or printer, they may produce detrimentally affect, as make the anamorphose of duplicating or printing.
Figure 18 shows and will add the result that succinyl oxide in embodiment 2 bearing greases changes over other kind additive (wear inhibitor, extreme pressure agent, oiliness agent) to, and resistance value (rotate 200 hours after bearing resistance maximum value) is measured.Each numerical value is relative value, and the value when not having additive is 1.The addition of every kind of additive is 2.5% of lubricating grease gross weight.
As can be seen from Figure 18, in every kind of additive, the maximum value of bearing resistance is all little than the situation that does not have additive, and has found the effect of every kind of additive.
Result when Figure 19 shows the succinyl oxide quantity that is added in the bearing of embodiment 2 in the lubricating grease and changes, and resistance value (rotate 200 hours bearing resistance maximum values afterwards) measured.Each numerical value is relative value, and the value when wherein the quantity of succinyl oxide is 0 weight % is 1.
Based on the angle of electroconductibility, as can be seen from Figure 19, suitable addition be the lubricating grease gross weight 10% or lower.Be because the etching problem of metal parts such as raceway face equally, be preferably the lubricating grease gross weight 10% or lower.
Measured resistance value (rotate 200 hours bearing resistance maximum values afterwards) result when Figure 20 shows the addition that changes carbon nanotube in the lubricating grease.
Because even carbon nanotube also can provide effective electroconductibility during for a small amount of of lubricating grease gross weight 0.1%, so can be by the add-on and a large amount of thickening material of adding of restriction carbon nanotube, so that As time goes on carbon nanotube still keeps required dispersion state.As can be seen, when add-on be the lubricating grease gross weight 0.5% or when higher, resistance value is reduced fully.
But,, will be broken as the reticulated structure of the carbon nanotube of electroconductibility origin, and conductivity just changes in early days easily if add too many carbon nanotube.Cancellated breaking will cause lubricating grease to leak or separating of oil problem.
If the add-on of carbon nanotube is big, then the working needle in-degree is little, makes lubricating grease sclerosis, and when being loaded in the bearing, the moment of torsion of bearing is big.
Based on foregoing, the add-on of carbon nanotube be preferably the lubricating grease gross weight 10% or lower.
Figure 21 shows resistance value (rotate 200 hours bearing resistance maximum values afterwards) measured when changing basic oil viscosity in the lubricating grease in the bearing of embodiment 2.
As can be seen from Figure 21, the dynamic viscosity of base oil in the time of 40 ℃ is high more, and then resistance value is big more.As mentioned above, if the dynamic viscosity of base oil is too high, then the oil film thickening raises resistance value, and preferred dynamic viscosity is 100mm 2/ sec or lower.
In order to form lubricant film, prevent raceway face and the rolling body metallic contact during bearing rotation, the dynamic viscosity of base oil should be high to a certain degree, and preferred 5mm 2/ sec or higher.
Measured resistance value (rotate 200 hours bearing resistance maximum values afterwards) when Figure 22 and Figure 23 show in the bearing of embodiment 2 kind of carbon nanotube carried out different the change.The resistance value that each resistance value shown in the figure is embodiment 2 is 1 o'clock a relative value.
With reference to Figure 22, the situation that changes the carbon nanotube diameter is described.In Figure 22, diameter is that the result of the carbon nanotube (embodiment 2) of 1～3nm illustrates with diamond sign (◆), diameter is that the result of the carbon nanotube of 3～24nm illustrates with square sign (■), illustrates with trilateral sign (▲) and diameter is the result of the carbon nanotube of 7～12nm.The length of every kind of carbon nanotube is 0.5～5 μ m.
As can be seen from Figure 22, shown electroconductibility is excellent, and no matter the diameter of carbon nanotube how.
With reference to Figure 23, the situation that changes length of carbon nanotube is described.In Figure 23, length is that the result of the carbon nanotube (embodiment 2) of 0.5～5 μ m illustrates with diamond sign (◆), length is that the result of the carbon nanotube of 0.5～10 μ m illustrates with square sign (■), illustrates with trilateral sign (▲) and length is the result of the carbon nanotube of 10～30 μ m.The diameter of every kind of carbon nanotube is 1～3nm.
As can be seen from Figure 23, shown electroconductibility is excellent, and no matter the length of carbon nanotube how.When the length of carbon nanotube was 10～30 μ m, resistance value was big a little, but this degree can be to be applied in the reality.
For the similar rolling bearing of rolling bearing several and shown in Figure 25, the resistance value measuring result during rotation of inside and outside seat figure will be described below, and to electroconductibility in the conductive grease in time passing and the degree that changes is estimated.
Identical among the instrument of measured resistance value and Fig. 3.Simultaneously, use the instrument of said structure, by method as hereinbefore, the resistance value between the interior outer race of measurement and evaluation rolling bearing 1.
Change the separating of oil degree of the conductive grease that is loaded in every kind of bearing, so that utilize the inner race 12 of every kind of bearing during the apparatus measures shown in Figure 3 rotation and the resistance value between the outer race 13.This bearing is a rolling bearing, internal diameter 8mm, external diameter 22mm, width 7mm.The component of lubricating grease is as shown in table 3, and loadings is 155～165mg.
Table 3
Lubricating grease Reference example 2
Thickening material Lithium soap
Base oil Kind PAO
Viscosity 1) 30.0
Conductive powder, weight % Carbon black, 5.0
The working needle in-degree 245
1) dynamic viscosity of base oil in the time of 40 ℃, unit is mm 2/ sec
The measuring condition of this moment is as follows.
The rotating speed of spindle unit 2: 150rpm (min -1)
Load on the radial loading (Fr) on the bearing 1: 19.6N
Applied voltage: 6.2V
Maximum current: 100 μ A
Free air temperature: 25 ℃
Atmospheric moisture: 50%RH
Above-mentioned measuring result is shown among Figure 26, and wherein transverse axis is represented conductive grease at 100 ℃ of separating of oil degree (%) after 24 hours, and the longitudinal axis is represented the resistance value (k Ω) between inner race and the outer race.The resistance value at initial stage is with diamond sign (◆) expression, and the resistance value after 300 hours is represented with square sign (■).
As shown in same figure, for having used separating of oil degree to surpass the bearing of 2% conductive grease, resistance value between the interior outer race is different widely when beginning and 300 hours afterwards, therefrom as can be seen, when the separating of oil degree of conductive grease surpassed 2%, As time goes on the resistance value between the interior outer race raise.On the contrary, be 2% or the bearing of lower conductive grease for having used separating of oil degree, the resistance value between the interior outer race at 300 hours later on also with not ing the resistance value when initial raise a lot.Based on this fact, if separating of oil degree is controlled to be 2% or lower, As time goes on the electroconductibility that then can suppress conductive grease raise.
As can be seen from Figure 26, carbon black is evenly dispersed in the bearing during beginning, because the chain structure of solid particulate is not also broken, resistance value between the interior outer race is not subjected to the domination of separating of oil degree, but when surpassed 300 hours duration of service, carbon black was squeezed the contact surface of two seat rings and rolling body, in other words, the base oil that discharges oil rests near the contact component, so resistance value raises rapidly between two seat rings.Therefore, in order to make the electroconductibility stable for extended periods of time of conductive grease, the separating of oil degree of preferably controlling conductive grease is 2% or lower, is preferably 2% or more be low to moderate 0.5% or higher.
From using beginning, after 300 hours bearing is taken out from the instrument of Fig. 3, left standstill 200 hours, refill on the instrument that is fitted on Fig. 3 and test, and measure resistance value between 300 hours latter two seat rings.The results are shown among Figure 27, wherein ◆ the resistance value that separating of oil degree is used in expression when being 1% conductive grease the resistance value that ■ represents to use separating of oil degree when being 3% conductive grease.
As can be seen from Figure 27, the resistance value of every kind of bearing on ressembling the test apparatus of Fig. 3 after, demonstrate low resistance value immediately, no matter be that separating of oil degree is that 1% conductive grease or separating of oil degree are 3% conductive grease, all like this.This raceway that can suppose rolling body is different slightly, and in other words, the sooty chain structure has obtained recovery during leaving standstill.But soon, the resistance value of bearing increases immediately after beginning again, and is in the bearing of 3% conductive grease using separating of oil degree, and the rising of resistance value is that the bearing of 1% conductive grease is rapider than using separating of oil degree.Therefore, again based on this fact, if the separating of oil degree that control fills in the conductive grease in the bearing is 2% or lower, be preferably 2% or more be low to moderate 0.5% or higher, As time goes on the electroconductibility that then can suppress conductive grease raise.
The experimental result that the base oil that Figure 28 shows conductive grease concerns between 40 ℃ viscosity and bearing resistance value.In same figure, ◆ represent that separating of oil degree is the result of 1% conductive grease, ■ represents that separating of oil degree is 1% and further comprises the result of the succinyl oxide of lubricating grease gross weight 2.5% as the conductive grease of oiliness agent, and ▲ the separating of oil degree of expression is the result of 3% conductive grease.
As shown in figure 28, if basic oil viscosity raises in the conductive grease, then the resistance value of bearing raises, and if separating of oil degree raise simultaneously, then this trend is significant.This can be assumed to be carbon black in the lubricating grease as influence that electro-conductive material caused.
Be used for the specific volume resistivity that grease base plinth oil had and usually surpass 10 10Ω cm, and most contact part that leaks base oil that rests on promptly increase resistance value therefrom.Reducing basic oil viscosity is worthless aspect oilness.If have metallic contact between interior outer race and the rolling body, then the resistance value of bearing reduces, and bearing wear surface greatly.Because active high, the formation oxide films that react such as the tiny new surface of wearing and tearing and airborne oxygen cause resistance value to increase.So basic oil viscosity is preferably 5～200mm 2/ s, more preferably 15～100mm 2/ s.
In addition, if effective additives in wear inhibitor is added in the conductive grease, then can prevent surface damage, and can increase the life-span of electroconductibility.Amount to this additive does not have special restriction, but from corrodibility or to the affinity of contiguous resin, all is rational up to the amount of lubricating grease gross weight 10%.For lubricating grease, adjust sooty amount, the amount of thickening material (lithium soap) and the amount of additive (succinyl oxide) in the conductive grease, and make the working needle in-degree meet 245, Figure 29 shows the comparing result of maximum resistance and the specific volume resistivity after 300 hours, and correlated basis is amounts of carbon black adds amounts of thickener to amounts of carbon black a ratio.In same figure, the separating of oil degree of ▲ expression is the maximum resistance of 1% conductive grease, the separating of oil degree of * expression is the maximum resistance of 3% conductive grease, ◆ represent that separating of oil degree is the specific volume resistivity of 1% conductive grease, ■ represents that separating of oil degree is the specific volume resistivity of 3% conductive grease.
As shown in figure 29, for conductive grease with low separating of oil degree, although allow the certain freedom of specific volume resistivity, because the contact ratio height on their contact black surfaces, so can keep low resistance value.If determine that the separating of oil degree of conductive grease is 2% or lower, amounts of carbon black and amounts of carbon black add that the ratio of amounts of thickener is 0.2 to 1.0, and be preferred 0.2 to 0.9, then can make the resistance value between the interior outer race remain low-resistance value for a long time.
Based on foregoing, if the separating of oil degree of the conductive grease that loads in definite bearing is 2% or lower, then can suppress its electroconductibility and As time goes on reduce, make the electroconductibility stable for extended periods of time thus, so that can accurately remove the electrostatic influence for a long time and improve reliability.
In the superincumbent reference example 2 (table 3), such situation of having demonstrated promptly adds lithium soap as thickening material with the situation of carbon black as thickening material, if separating of oil degree is 2% or lower, then can obtain identical effect rice.
Method as the separating of oil degree that changes conductive grease, multiple mode is arranged, when for example using lithium soap as thickening material, base oil and lithium stearate were descended abundant stir about 1 hour in the temperature of setting (for example 120 ℃), fully dehydration, and heating (as 1 to 3 ℃ of per minute) at leisure under 230 ℃ are so that be dissolved in the base oil lithium soap, after the intensification, base oil is cooled off.At this moment, thickening material has formed, and lubricating grease has also prepared, and makes it and reagent mix and it is rolled and kneading.Like this, lubricating grease has just been finished.
When preparing former lubricating grease, depend on control to temperature or the agitation condition control of speed of cooling (particularly to), if speed of cooling is low, the soap component of lithium soap is wound in macrofiber, and when speed of cooling is fast, then is wound in staple fibre, therefore, although the add-on of thickening material is identical, the working needle in-degree of lubricating grease can be adjusted to a certain degree, and separating of oil degree also can carry out some adjustment.Long stapled lubricating grease tends to bigger separating of oil degree.In addition, have such trend, if promptly the amount of thickening material is big, then the amount of base oil reduces basically relatively, and separating of oil degree diminishes.
Have only carbon black if comprise meticulous conductive particle (carbon black) and thickening material, can when conductive particle is in base oil, mix and kneading so.For example, needn't be warming up to 230 ℃, and when (100 ℃ according to appointment) stir under optimal temperature, add carbon black bit by bit to prepare former lubricating grease.When adding lithium soap and carbon black, can use following any means:
(1) between the temperature raising period in the former lubricating grease process of preparation, adds carbon black bit by bit;
(2) heat up after also heat the time (before the cooling), add carbon black bit by bit; With
(3) after the cooling, carbon black is added with additive.
The test-results of the spot contact bearing (reference example 3,4 and Comparative Examples 6 to 8) that the basic and above-mentioned spot contact bearing of several structures 31 is identical will be described below.
Test bearing is of a size of internal diameter 30mm, external diameter 42mm, and width 7mm, and surround the space that the limits amount of having loaded by outer race, inner race and sealing member and be the conductive grease of this spatial content 28～41%.This conductive grease is made up of base oil, thickening material and carbon black, and is as shown in table 4.
Table 4
Reference example 3 Reference example 4 Comparative Examples 6 Comparative Examples 7 Comparative Examples 8
Base oil A The fluoro siloxanes A Polyalphaolefin Silicone oil
Thickening material PTFE 1) CB 2) PTFE CB PTFE Lithium soap CB CB
CB 3)Amount 5.0 5.0 0 5.0 5.0
Acoustic experiment ○ ○ ○ × ×
A: perfluoro polyether
1) PTFE: tetrafluoroethylene
2) CB: carbon black
3) unit: weight %
Reference example 3 and 4 bearing use polytetrafluoroethylene (PTFE) and carbon black (CB) thickening material as conductive grease.The consumption of CB is 5% of a conductive grease gross weight.The base oil of reference example 3 is a perfluoro polyether, and the base oil of reference example 4 is the fluoro siloxanes.
The bearing of Comparative Examples 6 is identical with reference example 3 almost, and just lubricating grease does not comprise CB and do not have electroconductibility.The bearing of Comparative Examples 7 neither uses silicon compound also not use the thickening material of fluorine cpd as conductive grease, and is to use a kind of known thickening material.The bearing of Comparative Examples 8 only uses the thickening material of CB as conductive grease.
Make these spot contact bearing under 180 ℃ the high temperature and Fr=19.6N and rotation number be under the situation of per minute 100, rotated 400 hours.Rotation is carried out acoustic experiment by anderometer after finishing, to check the wear pattern of spot contact bearing.The results are shown in the table 4, wherein good result represents with zero, bad result with * represent.
Bearing rotates 200 and 400 hours under high temperature after, when bearing rotates, the resistance value (bearing resistance value) in measuring between the outer race, and estimate electroconductibility in time passing and the degree that changes.
Measure the instrument of bearing resistance value identical with shown in Fig. 3.The evaluation method also mode with the resistance value of the instrument evaluation spot contact bearing 1 of above-mentioned use said structure is identical.
About these 5 kinds of bearings (reference example 3,4 and Comparative Examples 6 to 8), the resistance value (maximum value) when rotating between interior outer race 1a and the 1b with the apparatus measures of said structure.
Measuring condition is as follows.
The rotating speed of parts of bearings 2: 100rpm (min -1)
Applied voltage: 6.2V
Maximum current: 100 μ A
Series resistance: 62k Ω
Free air temperature: 40 ℃
Atmospheric moisture: 50%RH
Sample period: 50kHz, 0.328 second
Measuring result is shown in the graphic representation of Figure 31, and wherein the result of reference example 3 is with ◆ expression, and the ■ as a result of reference example 4 represents, the result of Comparative Examples 6 is with ▲ expression, and the result of Comparative Examples 7 is with * expression, and the result of Comparative Examples 8 is with zero expression.
From the graphic representation of Figure 31 as can be seen, each contains sooty bearing (rotational time: 0 hour) when beginning all little bearing maximum resistance.On the other hand, use the Comparative Examples 6 that does not contain carbon black lubricating grease to have big bearing resistance maximum value.In bearing, accompanying rotation and the static that produces electrify easily, if use this bearing on duplicating machine or printer, the electrostatic rotation noise may provide detrimentally affect, as the distortion of image (as the copy image of duplicating machine).
Because Comparative Examples 7 does not use silicon compound or fluorine cpd as thickening material, the thermotolerance deficiency of conduction lubricating ester, when envrionment temperature rose to 180 ℃, the conduction lubricating ester worsened significantly, and resistance value also increases because of the formation of the damage on ball track surface and oxide film.The result of acoustic experiment is bad equally.
In addition, in the Comparative Examples 8 of carbon black as thickening material of only using as electroconductibility origin, although electroconductibility in order, the sooty reticulated structure destroys easily, causes lubricating ester to spill or separating of oil.Owing to be solid, carbon black pellet damages the raceway face of bearing easily and reduces the acoustics life-span.
Contain the spot contact bearing of the conduction lubricating ester of some kinds of additives for use, the measuring result of bearing resistance value will be described below.Make spot contact bearing be similar under the above-mentioned high temperature rotation 200 hours, measure the maximum value of bearing resistance then.
Used additive is Sodium Nitrite (NaNO 2), MoS 2, synthetic mica and fluoro phosphazene derivative.Addition is 2.5% of a conductive grease gross weight.As for the structure of test bearing, except that the addition of additive, all the bearing with reference example 3 is identical.
The results are shown in the graphic representation of Figure 32, therefrom as can be seen, the maximum value when adding additive is little during than not doping.Especially, the fluoro phosphazene derivative reduces the maximum value of bearing resistance.
Estimate the maximum value of bearing resistance by the addition that changes the fluoro phosphazene derivative.The results are shown among Figure 33.Addition is had no particular limits, still,, be preferably lubricating grease gross weight 10% or lower addition based on solubility problem.
Below with reference to estimating the peaked result of bearing resistance by changing the carbon black addition.Make bearing being similar under the above-mentioned high temperature rotation 200 hours, measure the maximum value of bearing resistance by being similar to above-mentioned mode then.The structure of test bearing is identical with the bearing of reference example 3, has just changed the sooty addition.
The results are shown among Figure 34, therefrom as can be seen, even carbon black also is effective when a small amount of.Therefore, it can coexist with inherent thickening material (silicon compound or fluorine cpd), and can suppose that carbon black can keep required dispersion state owing to this coexistence.
In order to relax the working needle in-degree of lubricating grease, the sooty amount be preferably the lubricating grease gross weight 10% or lower.If be higher than this amount, it is too hard that lubricating grease just becomes.In order to guarantee enough electroconductibility, 0.2% or higher addition of lubricating grease gross weight are essential.
Also will quote and change carbon black specific surface (value of nitrogen adsorption method) and estimate the peaked result of bearing resistance.Make bearing being similar under the above-mentioned high temperature rotation 200 hours, measure the maximum value of bearing resistance by being similar to above-mentioned mode then.The structure of test bearing is identical with the bearing of reference example 3, just sooty specific surface area difference.
The results are shown in the graphic representation of Figure 35, therefrom as can be seen, 250m 2/ g or higher carbon black specific surface are preferred.
Also will quote and change sooty DBP oil adsorptive capacity (value of dibutyl phthalate adsorption meter) and estimate the peaked result of bearing resistance.Make bearing being similar under the above-mentioned high temperature rotation 200 hours, measure the maximum value of bearing resistance by being similar to above-mentioned mode then.The structure of test bearing is identical with the bearing of reference example 3, just sooty DBP oil adsorptive capacity difference.
The results are shown in the graphic representation of Figure 36, therefrom as can be seen, 180ml/100g or higher carbon black DBP oil adsorptive capacity are preferred.
Also quote and change the dynamic viscosity of employed base oil in the time of 40 ℃ and estimate the peaked result of bearing resistance.Make bearing being similar under the above-mentioned high temperature rotation 200 hours, measure the maximum value of bearing resistance by being similar to above-mentioned mode then.The structure of test bearing is identical with the bearing of reference example 3, is the dynamic viscosity difference of employed base oil in the time of 40 ℃.
The results are shown in the graphic representation of Figure 37, therefrom as can be seen, the dynamic viscosity of employed base oil in the time of 40 ℃ is preferably about 15～500mm 2/ s.
As mentioned above, conductive grease of the present invention is difficult to cause electroconductibility As time goes on to reduce.
Separating of oil degree is confirmed as 2% or lower, so that can guarantee the electroconductibility of conductive grease for a long time and remove the electrostatic influence fully.Therefore, rolling bearing of the present invention can improve reliability.
The bearing of being mentioned as item (13) of the present invention is being excellent aspect the electroconductibility, even also be so under up to 180 ℃ temperature, so the conduction state between the interior outer race can obtain secular maintenance well.
Although with reference to its specific embodiment the present invention is described in detail, under the situation that does not break away from the spirit and scope of the present invention, can make various changes and modification to the present invention, this concerning ability and the technician, will be conspicuous.

Claims (14)

1. conductive grease, this conductive grease comprises:
Base oil;
Thickening material;
The conductive solid powder, this conductive solid powder is at least a in the following material: (a) main component is the particle of fibrous carbon, (b) be selected from the metallic particles of gold and silver, copper, tin, zinc or aluminium, (c) be selected from the metal compound particles of silver suboxide, sulfuration niobium or Silver Nitrate, (d) carbon nanotube, and the addition of this conductive solid powder is 0.1～10% of a lubricating grease gross weight; With
At least a wear inhibitor, extreme pressure agent and oiliness agent, the total addition level of this at least a wear inhibitor, extreme pressure agent and oiliness agent is 0.1～10% of a lubricating grease gross weight,
Wherein said thickening material is metallic soap or carbamide compound, and every kind addition is 5～20% of a lubricating grease gross weight, and the total amount of the pressed powder of thickening material and conduction is 5.1～20.1% of a lubricating grease gross weight; Described wear inhibitor is at least a in ortho-phosphoric acid ester and the phosphorous acid ester; Described extreme pressure agent is at least a in dithiophosphates metallic compound or the dithiocar-bamate metallic compound; And described oiliness agent is at least a in succinate, carboxylic acid anhydride and the alkenyl succinic anhydrides.
2. the conductive grease of claim 1, the particle that wherein said its main component is a fibrous carbon is carbon black or acetylene black.
3. the conductive grease of claim 1, this conductive grease comprises that also mean diameter is the mineral compound fine granular of 0.05～2 μ m, this particulate amount is 0.05～7% of a lubricating grease gross weight.
4. the conductive grease of claim 1, wherein said base oil are independent a kind of or at least two kinds mixture in mineral oil, synthetic hydrocarbon ils, ester oil, fluorocarbon oil, ether oil and the polyoxyethylene glycol oil, and its dynamic viscosity is 5mm in the time of 40 ℃ 2/ s to 120mm 2/ s.
5. the conductive grease of claim 1, the addition of wherein said base oil is 75～90% of a lubricating grease gross weight.
6. the conductive grease of claim 1, wherein this conductive grease is 0.5～2 weight % at 100 ℃ of separating of oil degree after 24 hours.
7. the conductive grease of claim 6, the addition of wherein said conductive solid powder is 0.2～0.9% of thickening material and this conductive solid total weight of powder.
8. the conductive grease of claim 1, wherein said conductive solid powder is the carbon nanotube of diameter 1～24nm, length 0.5～30 μ m.
9. the conductive grease of claim 8, this conductive grease comprises that also as the carbon black of conductive additive or acetylene black be the carbon granule of main component, the metallic particles of gold and silver, copper, tin, zinc or aluminium, the perhaps metal compound particles of silver suboxide, sulfuration niobium or Silver Nitrate.
10. tourelle, this device comprises an outer member, an inner member and a plurality of rolling body that rotatably is arranged between described outer member and the inner member, this device has also loaded conductive grease between interior external component and rolling body, described conductive grease comprises:
Base oil;
Thickening material;
The conductive solid powder, this conductive solid powder is at least a in the following material: (a) main component is the particle of fibrous carbon, (b) be selected from the metallic particles of gold and silver, copper, tin, zinc and aluminium, (c) be selected from the metal compound particles of silver suboxide, sulfuration niobium and Silver Nitrate, (d) carbon nanotube, and the addition of this conductive solid powder is 0.1～10% of a lubricating grease gross weight; And
At least a wear inhibitor, extreme pressure agent and oiliness agent, the total addition level of this at least a wear inhibitor, extreme pressure agent and oiliness agent is 0.1～10% of a lubricating grease gross weight,
Wherein said thickening material is metallic soap or carbamide compound, and every kind addition is 5～20% of a lubricating grease gross weight, and the total amount of the pressed powder of thickening material and conduction is 5.1～20.1% of a lubricating grease gross weight; Described wear inhibitor is at least a in ortho-phosphoric acid ester and the phosphorous acid ester; Described extreme pressure agent is at least a in dithiophosphates metallic compound or the dithiocar-bamate metallic compound; And described oiliness agent is at least a in succinate, carboxylic acid anhydride and the alkenyl succinic anhydrides.
11. the tourelle of claim 10, this tourelle also comprise the direct contact seal part between outer member and inner member, described sealing member conducts electricity.
12. the tourelle of claim 10, wherein this tourelle is a rolling bearing, and this outer member is an outer race, and this inner member is an inner race.
13. the tourelle of claim 10, wherein this tourelle is a linear guide device, and this outer member is a slide unit, and this inner member is a guide rail.
14. the tourelle of claim 10, wherein this tourelle is a ball-screw, and this outer member is the ball nut, and this inner member is a screw shaft.
CN 01142511 2000-11-29 2001-11-29 Conductive lubricating grease and rolling device filled with same Withdrawn - After Issue CN1228424C (en)

Applications Claiming Priority (12)

Application Number Priority Date Filing Date Title
JP2000362271A JP4010109B2 (en) 2000-06-22 2000-11-29 Conductive grease and rolling device
JP362271/00 2000-11-29
JP2000384186 2000-12-18
JP384186/2000 2000-12-18
JP384186/00 2000-12-18
JP2001062974 2001-03-07
JP062974/01 2001-03-07
JP062974/2001 2001-03-07
JP105269/01 2001-04-03
JP2001105269 2001-04-03
JP105269/2001 2001-04-03
JP362271/2000 2001-11-29

Related Child Applications (1)

Application Number Title Priority Date Filing Date
CNB2005100669204A Division CN1307293C (en) 2000-11-29 2001-11-29 Conductive grease and rolling apparatus packed with the same

Publications (2)

Publication Number Publication Date
CN1422939A CN1422939A (en) 2003-06-11
CN1228424C true CN1228424C (en) 2005-11-23

Family

ID=27481826

Family Applications (1)

Application Number Title Priority Date Filing Date
CN 01142511 Withdrawn - After Issue CN1228424C (en) 2000-11-29 2001-11-29 Conductive lubricating grease and rolling device filled with same

Country Status (1)

Country Link
CN (1) CN1228424C (en)

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010044386A1 (en) * 2008-10-17 2010-04-22 Ｎｏｋクリューバー株式会社 Lubricating grease composition and manufacturing method therefor
JP2010121123A (en) * 2008-10-22 2010-06-03 Dow Corning Toray Co Ltd Perfluoropolyether compound composition
KR101569236B1 (en) 2008-12-19 2015-11-13 두산인프라코어 주식회사 Sintered bush
DE102009036856A1 (en) * 2009-08-10 2011-02-17 Magna Steyr Fahrzeugtechnik Ag & Co. Kg Electric machine with anti-electric shock protected rolling bearing and geared motor with such
JP5747230B2 (en) * 2011-06-17 2015-07-08 Ｎｏｋクリューバー株式会社 Conductive grease composition
CN102604723B (en) * 2012-02-09 2013-09-25 中山大学 Lubricating grease composition and preparation method thereof
CN103413590A (en) * 2013-07-23 2013-11-27 吴江龙硕金属制品有限公司 Heat-resisting electric conduction metal paste and preparing method thereof
DE102014216691A1 (en) * 2014-08-22 2016-02-25 Aktiebolaget Skf Lubricants for rolling bearings, rolling bearings and processes for producing and repairing rolling bearings
CN104530976A (en) * 2014-12-24 2015-04-22 中山大学惠州研究院 Lubricating coating composition for enhancing antistatic property of polyformaldehyde and use method
CN105331434A (en) * 2015-11-23 2016-02-17 北京国电富通科技发展有限责任公司 Conductive grease composition and preparation method thereof
CN106635333A (en) * 2016-12-11 2017-05-10 新乡市恒星科技有限责任公司 Low-temperature torque conductive lubricating grease and preparation method thereof
CN107267261A (en) * 2017-05-25 2017-10-20 曹平 A kind of freeze proof conductive grease
CN108715769A (en) * 2018-06-29 2018-10-30 中国石油化工股份有限公司 A kind of half fluorine element lubricant composition of high temperature and its preparation method and application
CN109825344A (en) * 2019-02-28 2019-05-31 中山大学惠州研究院 A kind of high thermal conductivity lubricating additive and preparation method thereof
CN110797178A (en) * 2019-10-31 2020-02-14 大连北方互感器集团有限公司 Current transformer primary winding fastening device
CN111876218B (en) * 2020-06-19 2022-07-19 中国石油化工股份有限公司 Conductive bearing lubricating grease composition and preparation method thereof
CN111944594A (en) * 2020-08-26 2020-11-17 惠州市阿特斯润滑技术有限公司 Guide rod conductive grease
CN113514722B (en) * 2021-06-29 2023-08-15 杭州电子科技大学 Rolling bearing conductivity detection method

Also Published As

Publication number Publication date
CN1422939A (en) 2003-06-11

Similar Documents

Publication Publication Date Title
CN1228424C (en) Conductive lubricating grease and rolling device filled with same
CN1246426C (en) Fluid composition for cutting or grinding system employing trace amount of fluid
CN1292060C (en) Grease composition for precision equipment and timepiece containing the same
CN1244670C (en) Cooling device
CN1252756C (en) Nitrided niobium powders and niobium electrolytic capacitors
CN100341988C (en) Conductive lubricant composition
CN1767917A (en) Main shaft device and machine tool with the same
CN1690180A (en) Conductive grease and rolling apparatus packed with the same
CN1215269C (en) Rolling bearing and bearing unit
CN1092742A (en) Fluorinated carbon particle and method for making thereof and usage
CN1388327A (en) Rolling slider and rolling device
CN1616575A (en) Polishing composition
CN87103471A (en) The method of mechanical workout aluminium and aluminium alloy and cooling lubricant enriched material in the presence of cooling lubricant
CN1052502A (en) Perfluoropolyether lubricant with antiwear properties
CN1468295A (en) Threaded component for seizure-resistant tubular threaded joint
CN1858294A (en) Preparation for forming protective layer on metal friction and wear-out surface and its preparing method
CN101044228A (en) Lubricating oil composition
CN1132781A (en) Grease composition
CN1262773C (en) Linear motion device
CN1010413B (en) Cold rolling oil for steels
CN1108456C (en) Compressor for refrigerator
CN1922125A (en) Alkyl acetal compound, process for producing the same, and lubricating oil composition
CN1131752C (en) Guide tube and method for forming hard carbon film on internal surface of tube
CN1082563C (en) Rolling member and rolling device comprising same
CN1524119A (en) Lubricant composition and analysis method for same

Legal Events

Date Code Title Description
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
AV01 Patent right actively abandoned
AV01 Patent right actively abandoned

Granted publication date: 20051123

Effective date of abandoning: 20170614