CN104895926A - Sintered bearing - Google Patents
Sintered bearing Download PDFInfo
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- CN104895926A CN104895926A CN201410074753.7A CN201410074753A CN104895926A CN 104895926 A CN104895926 A CN 104895926A CN 201410074753 A CN201410074753 A CN 201410074753A CN 104895926 A CN104895926 A CN 104895926A
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- running shaft
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Abstract
The invention provides a sintered bearing capable of reducing rotating shaft resistance. According to the solution, the sintered bearing (20) involved in the invention has a first bearing part (21), a second bearing part (22) and an intermediate part (23), the first bearing part (21) has a first bearing surface (21a) supporting the outer peripheral surface of a rotating shaft (10), a second bearing part (22) has a second bearing surface (22a) supporting the outer peripheral surface of the rotating shaft (10), the intermediate part (23) is disposed between the first bearing part (21) and the second bearing part (22). The inner diameter of the intermediate part (23) is greater than that of the first bearing part (21) and the second bearing part (22). In addition, a plurality of pits (d) are formed on at least one bearing surface (21a, 22a) of the first bearing surface (21a) and the second bearing surface (22a).
Description
Technical field
The present invention relates to a kind of sintered bearing, its by mould to metallic dust carry out press-powder shaping after sinter and formed, and containing being soaked with oiling agent.The present invention especially relates to a kind of sintered bearing that can reduce noise while reducing the surface friction drag between bearing and running shaft.
Background technique
Sintered bearing as low price and the high bearing of reliability be widely used in household electrical appliances motor, on-vehicle motor and OA equipment (business automation equipment) etc.As an example of fan motor (Fan Motor), the vehicle-mounted fan etc. that the cooling fan of the household electric appliance such as electronic computer and television set inside, the circulation of refrigerator inside and the fan cooled, the cooling of storage battery and the attraction of car inner sensor use can be listed, annual all in increase to the demand of fan motor.
Owing to adopting the spreadable life limit for length of the equipment of fan motor, so these fan motors not only need the characteristic with long service life, but also need to have to reduce this important characteristic of power consumption.Especially at mobile device etc. by battery-driven equipment, need to suppress power consumption to greatest extent.
On the other hand, require greatly to improve to the mute of described fan motor in recent years.In general, in order to realize the mute of motor, need to accomplish in sintered bearing: first, the noise produced because of rocking of axle is suppressed by the gap reduced between running shaft and bearing, second, improved the oily film strength produced at internal diameter slip surface by the viscosity improving impregnation oiling agent within the bearing, effectively can realize the mute of fan motor thus.
, in the motor that the running loads such as fan motor are low and torque is little, the surface friction drag between running shaft and bearing depends primarily on the fluid resistance of impregnation oiling agent within the bearing.Therefore, if the gap between running shaft and bearing is too little, then the fluid resistance of oiling agent when axle rotates increases, and causes the power consumption quantitative change of motor large.On the other hand, along with the viscosity of oiling agent improves, fluid resistance increases, and the power consumption quantitative change of motor can be caused equally large.Therefore, there is restriction in the viscosity aspect of alternative oiling agent.
In the prior art, as the sintered bearing of the surface friction drag that can reduce between running shaft and bearing, such as, Patent Document 1 discloses a kind of sintered bearing.
In this sintered bearing, internal diameter running shaft being supported to the axial intermediate portion of the bearing hole that can rotate freely is formed all larger than the internal diameter of axial two end part (hereinafter referred to as " bearing portion ").Thus, because the inner peripheral surface and running shaft can avoiding intermediate portion comes in contact, so the area (hereinafter referred to as " slide area ") of the part corresponding with running shaft of bearing hole inner peripheral surface can be reduced.Due to the contact of bearing hole inner peripheral surface and running shaft can be suppressed, and the fluid resistance of oiling agent when axle can be suppressed to rotate, so the surface friction drag produced between running shaft and bearing can be reduced in.At this, " part corresponding with running shaft " refers to and likely to come in contact with running shaft when running shaft rotates, and the part that when axle rotates, the impact of the fluid resistance of suffered oiling agent is large, instead of refer to the part (following identical) that contacts with running shaft all the time when running shaft rotates.
At first technical paper
Patent documentation
The flat 7-332363 publication of patent documentation 1 Japanese Patent Laid-Open
Summary of the invention
, in existing sintered bearing, in the surface friction drag between reduction running shaft and bearing, there is the limit.
Specifically, in existing sintered bearing, reduced the scope of two bearing portions by the scope expanding intermediate portion in the axis of sintered bearing, now, more reduce the scope of two bearing portions, more can reduce slide area.But if the axial dimension of each bearing portion (each bearing surface) is too small, then the hydraulic pressure produced by chock effect can be escaped from the axial two ends of each bearing surface, makes to keep oily film strength.Further, along with film strength declines, become between bearing surface and running shaft and easily come in contact, its result, the surface friction drag produced between bearing surface and running shaft not only can be caused to increase, and noise generation can be encouraged.Therefore, in existing sintered bearing, in the surface friction drag between reduction running shaft and bearing, there is the limit.
Problem of the present invention is to provide a kind of sintered bearing that can reduce surface friction drag between running shaft and bearing.
Technological scheme
In order to solve the problem, sintered bearing involved by first invention, by in mould to metallic dust carry out press-powder shaping after sinter and formed, there is the bearing hole being supported to by running shaft and can rotate freely, and containing being soaked with oiling agent, the feature of described sintered bearing is, there is clutch shaft bearing portion, second bearing portion and intermediate portion, described clutch shaft bearing portion has the clutch shaft bearing face supporting described running shaft, described second bearing portion has the second bearing surface supporting described running shaft, described intermediate portion is arranged between described clutch shaft bearing portion and described second bearing portion, the internal diameter of described intermediate portion be formed as than the internal diameter in described clutch shaft bearing portion and the internal diameter of described second bearing portion all large, the bearing surface of at least one party in described clutch shaft bearing face and described second bearing surface is formed with multiple pit.
In the sintered bearing involved by the first invention, between clutch shaft bearing portion and the second bearing portion, be provided with intermediate portion, and the internal diameter of intermediate portion is formed as all larger than the internal diameter of each bearing portion.
Thereby, it is possible to avoid the inner peripheral surface of intermediate portion and running shaft to come in contact, make it possible to the slide area reduced in the inner peripheral surface of bearing hole.Therefore, compared with the sintered bearing (hereinafter referred to as " linear bearing ") all identical in the total length of axis with the internal diameter of bearing hole, not only the inner peripheral surface of bearing hole and the contact of running shaft are inhibited, but also reduce the fluid resistance of oiling agent when axle rotates, so the surface friction drag produced between bearing and running shaft can be reduced in.
Especially, in the sintered bearing involved by the first invention, bearing surface running shaft being supported at least one party in the clutch shaft bearing face and the second bearing surface that can rotate freely is provided with multiple pit.
Because the part (scope) being provided with each pit of bearing surface can not come in contact with running shaft, so can reduce the slide area in bearing surface.Therefore, not only the contact of bearing surface and running shaft is inhibited, but also reduces the fluid resistance of oiling agent when axle rotates, thus can be reduced in the surface friction drag produced between bearing surface and running shaft.
Therefore, it is possible to reduce the slide area in bearing hole inner peripheral surface when not reducing the axial dimension of bearing surface, while the oily film strength of suppression declines, the surface friction drag produced between bearing surface and running shaft can be reduced in.
In addition, in the sintered bearing involved by the first invention, owing to being provided with multiple pit at bearing surface, so can store containing the oiling agent be immersed in sintered bearing in each pit.When running shaft rotates, the oiling agent stored in each pit attracted between bearing surface and running shaft.Therefore, when running shaft rotates, especially at initial operating stage, the formation of oil film can be made to become easy, thus the friction factor of bearing surface can be reduced.
In addition, in the sintered bearing involved by the first invention, owing to being provided with multiple pit at bearing surface, so the mean gap between bearing surface and the outer circumferential face of running shaft can be increased.Thus, when running shaft rotates, the fluid resistance of the oiling agent be present between bearing surface and running shaft can be reduced.
As mentioned above, according to the sintered bearing involved by the first invention, owing to can suppress to come in contact between bearing surface and running shaft and reduce the fluid resistance of oiling agent, so the surface friction drag produced between bearing surface and running shaft can be reduced in.
Especially, by applying the sintered bearing involved by the first invention, the characteristic of the little motor of driving torque can be improved.That is, in the ordinary course of things, the driving torque of motor is less, and the impact of size on motor characteristic of the surface friction drag produced between bearing surface and running shaft is larger.
Specifically, along with surface friction drag increases, the rotating speed of motor reduces, and not only can make cannot realize target rotating speed, but also the power consumption of motor can be caused to increase.On the other hand, according to the sintered bearing involved by the first invention, as mentioned above, the surface friction drag produced between bearing surface and running shaft can be reduced in.Therefore, by applying the sintered bearing involved by the first invention, even if when the driving torque of motor reduces, the reduction of motor speed also can be suppressed, and can reduce power consumption.
In addition, by applying the sintered bearing involved by the first invention, the motor that gap between bearing surface and the outer circumferential face of running shaft is little can be configured to.That is, in the ordinary course of things, in the motor, along with the gap shrinks between bearing surface and the outer circumferential face of running shaft, the fluid resistance of oiling agent when axle rotates increases, thus the surface friction drag produced between bearing surface and running shaft is increased.Now, the rotating speed of motor not only can be caused to reduce and make cannot realize target rotating speed, and the power consumption of motor can be caused to increase.On the other hand, according to the sintered bearing involved by the first invention, as mentioned above, the fluid resistance of oiling agent when axle rotates can be reduced.Therefore, by applying the sintered bearing involved by the first invention, even if when gap shrinks between bearing surface and the outer circumferential face of running shaft, the reduction of motor speed also can be suppressed.In addition, the increase of the power consumption of motor can also be suppressed.Further, due to the gap between bearing surface and the outer circumferential face of running shaft can be reduced, so can suppress to shake in the gap of running shaft between bearing surface and the outer circumferential face of running shaft, the noise of motor can be reduced thus.
In addition, by applying the sintered bearing involved by the first invention, more full-bodied oiling agent can be used.That is, in the ordinary course of things, in the motor, along with the viscosity of used oiling agent increases, the fluid resistance being present in the oiling agent between bearing surface and running shaft increases.Now, the rotating speed of motor not only can be caused to reduce and make cannot realize target rotating speed, and the power consumption of motor can be caused to increase.On the other hand, according to the sintered bearing involved by the first invention, as mentioned above, the fluid resistance of the oiling agent be present between bearing surface and running shaft can be reduced.Therefore, by applying the sintered bearing involved by the first invention, even if use full-bodied oiling agent, the reduction of motor speed also can be suppressed.In addition, the increase of the power consumption of motor can also be suppressed.Further, due to full-bodied oiling agent can be used, so can while the wear resistance performance improving bearing, oiling agent is suppressed at high temperature to evaporate, can suppress aging, and can lubricant leakage be suppressed, thus the working life of motor can be extended.Especially, by using full-bodied oiling agent, the oily film strength generated at internal diameter slip surface can be improved, and the noise of motor can be reduced.
According to the sintered bearing involved by the first invention, the feature of the sintered bearing involved by the second invention is, described multiple pit is formed by plastic working.
In the sintered bearing involved by the second invention, form multiple pit by making bearing surface generation plastic deformation.Thereby, it is possible to improve the machining accuracy of each pit.
Especially, because sintered bearing is formed by sintering metallic dust, so have porous structure.Therefore, form each pit by plastic working, crushed element can be absorbed by micropore, thus can prevent bearing surface from bloating.
Except plastic working, as the method forming pit, laser beam machining and etching (local etching) processing etc. can also be listed, but these methods not only need to use main equipment, and manufacturing procedure can be caused to increase.On the other hand, plastic working is not owing to needing to use main equipment, and manufacturing procedure is few, so originally can carry out large batch of processing with lower one-tenth.
According to the sintered bearing involved by the first invention or the second invention, the feature of the sintered bearing involved by the 3rd invention is, the end setting spaced apart of the axis of described pit and described bearing surface.
According to the sintered bearing involved by the 3rd invention, due to the end setting spaced apart of the axis of pit and bearing surface, so hydraulic pressure can be suppressed to escape from the end of the axis of bearing surface, oily film strength can be suppressed thus to decline.
According to the sintered bearing involved by the first invention to any one invention in the 3rd invention, the feature of the sintered bearing involved by the 4th invention is, the gap be provided with between the bearing surface of described multiple pit and the outer circumferential face of described running shaft is set as less than 6 μm.
In general, in the motor that fan motor etc. drives with underload, if the gap between bearing surface and the outer circumferential face of running shaft is greater than 6 μm, then running shaft may be caused to shake in this gap, thus make noise become large.On the other hand, if the gap between bearing surface and the outer circumferential face of running shaft is arranged on less than 6 μm, then the fluid resistance of oiling agent when axle rotates increases, thus the surface friction drag produced between bearing surface and running shaft can be caused to increase.
; in sintered bearing involved in the present invention; as mentioned above; even if due to the gap between bearing surface and the outer circumferential face of running shaft is arranged on less than 6 μm; also the fluid resistance of oiling agent when axle rotates can be reduced; so the surface friction drag produced between bearing surface and running shaft can be reduced in, the power consumption of motor can be suppressed, noise when running shaft rotates can also be reduced simultaneously.
According to the sintered bearing involved by the first invention to any one invention in the 4th invention, the feature of the sintered bearing involved by the 5th invention is, is provided with the average microhardness (MHv) of the bearing surface of described multiple pit in the scope of 50 ~ 200.
Specifically, when the average microhardness (MHv) of bearing surface is less than 50, the wear resistance performance of sintered bearing is deteriorated, and durability is reduced.On the other hand, if the average microhardness of bearing surface (MHv) is greater than 200, then, when forming each pit, the surrounding of each pit can be caused to bloat, thus size and the precision of regulation cannot be obtained.
Therefore, be set in the scope of 50 ~ 200 by the average microhardness (MHv) of the bearing surface by being provided with multiple pit, can decline avoiding the durability of sintered bearing, and when avoiding size and the precise decreasing of sintered bearing, form pit at bearing surface.
According to the sintered bearing involved by the first invention to any one invention in the 5th invention, the feature of the sintered bearing involved by the 6th invention is, described sintered bearing is applied to fan motor.
According to the sintered bearing involved by the 6th invention, the characteristic of the little fan motor of driving torque can not only be improved, but also can power consumption be reduced.In addition, due to the less fan motor in gap between bearing surface and the outer circumferential face of running shaft can be configured to, so can suppress to shake in the gap of running shaft between bearing surface and the outer circumferential face of running shaft, the noise of fan motor can be reduced.Further, due to more full-bodied oiling agent can be used, so can while the wear resistance performance improving bearing, oiling agent is suppressed at high temperature to evaporate, can suppress aging, and can lubricant leakage be suppressed, the working life of motor can be extended thus.Especially, by using full-bodied oiling agent, the oily film strength generated at internal diameter slip surface can be improved, and the noise of motor can be reduced further.
Beneficial effect
According to sintered bearing involved in the present invention, the surface friction drag between bearing and running shaft can be reduced, and can noise be reduced.
Accompanying drawing explanation
Fig. 1 is the partial section of the fan motor involved by embodiments of the present invention.
Fig. 2 is the sectional view of the sintered bearing that the fan motor shown in Fig. 1 has.
Fig. 3 is the partial enlarged drawing of the bearing surface of the sintered bearing shown in Fig. 2.
Symbol description
1 fan motor
2 shell holder
2a cylindrical part
3 laminations are unshakable in one's determination
3a coil
4 rotor yoke irons
5 magnets
6 impellers
7 thrust plates
10 running shafts
20 sintered bearings
21 clutch shaft bearing portions
22 second bearing portions
23 intermediate portions
21a clutch shaft bearing face
22a second bearing surface
23a inner peripheral surface
H bearing hole
D pit
Embodiment
Referring to accompanying drawing, the sintered bearing 20 involved by embodiments of the present invention is described.
Sintered bearing 20 can be widely used in various home appliance, vehicle-mounted etc. various motor and OA equipment (business automation equipment) etc.Show example sintered bearing 20 being applied to fan motor 1 in the present embodiment.
(structure of fan motor 1)
Fig. 1 is the partial section of the fan motor involved by embodiments of the present invention, and Fig. 2 is the sectional view of the sintered bearing that the fan motor shown in Fig. 1 has, and Fig. 3 is the partial enlarged drawing of the bearing surface of the sintered bearing shown in Fig. 2.
Fan motor 1 shown in Fig. 1 has shell holder 2, the sintered bearing 20 kept by shell holder 2 and supports to rotatable running shaft 10 by sintered bearing 20.
Shell holder 2 has the cylindrical part 2a keeping sintered bearing 20 therein.Winding coil 3a and the lamination iron core (stator) 3 that formed is provided with at the outer circumferential face of cylindrical part 2a.
Running shaft 10 is made up of metal (alloyed steel of carbon steel and stainless steel etc.), and is formed cylindric.Running shaft 10 is provided with magnet (rotor) 5 by rotor yoke iron 4.Magnet 5 is arranged relatively with the lamination iron core 3 of the outer circumferential face being arranged on shell holder 2.Impeller (fan) 6 is installed in the periphery of rotor yoke iron 4.In addition, be embedded with thrust plate 7 at the inner bottom part of the cylindrical part 2a of shell holder 2, it is in the end of the side contrary with outlet side of thrust direction pivotal support running shaft 10.
As depicted in figs. 1 and 2, the rotor yoke iron 4 in sintered bearing 20 supporting rotating shaft 10 and the part between thrust plate 7.Sintered bearing 20 is made up of sintering metal (comprising sintered alloy), has porous structure.Containing being soaked with the oiling agent such as lubricant oil and lubricating grease in sintered bearing 20.
Sintered bearing 20 is roughly formed as cylindric, has the bearing hole h being supported to by running shaft 10 and can rotate freely.Bearing hole h is arranged in axis (above-below direction shown in Fig. 1) and runs through sintered bearing 20.
Sintered bearing 20 has clutch shaft bearing portion 21, second bearing portion 22 and is arranged on the intermediate portion 23 between clutch shaft bearing portion 21 and the second bearing portion 22.The inner peripheral surface in clutch shaft bearing portion 21 becomes the clutch shaft bearing face 21a of the outer circumferential face of supporting rotating shaft 10, and the inner peripheral surface of the second bearing portion 22 becomes the second bearing surface 22a of the outer circumferential face of supporting rotating shaft 10.
The internal diameter in clutch shaft bearing portion 21 and the internal diameter of the second bearing portion are formed to be larger than the external diameter of running shaft 10 respectively.In addition, the internal diameter in clutch shaft bearing portion 21 and the internal diameter of the second bearing portion are formed roughly the same size.In the present embodiment, the internal diameter in clutch shaft bearing portion 21 and the internal diameter of the second bearing portion 22 are set to make each bearing surface 21a respectively, and the gap between the outer circumferential face of 22a and running shaft 10 becomes the size of less than 6 μm.In addition, the internal diameter size of intermediate portion 23 be formed than the internal diameter in clutch shaft bearing portion 21 and the internal diameter of the second bearing portion 22 all large.
Running shaft 10 is arranged with the state inserted in the bearing hole h of sintered bearing 20.Further, in sintered bearing 20, the end of the outlet side of clutch shaft bearing portion 21 supporting rotating shaft 10, the end of the side contrary with outlet side of the second bearing portion 22 supporting rotating shaft 10.In addition, in sintered bearing 20, by clutch shaft bearing face 21a and the second bearing surface 22a, running shaft 10 is supported to and can be rotated freely, the inner peripheral surface 23a of intermediate portion 23 does not contact (sliding contact) with the outer circumferential face of running shaft 10.
As shown in Figure 3, the bearing surface of at least one party in clutch shaft bearing face 21a and the second bearing surface 22a is provided with multiple pit d.In the present embodiment, clutch shaft bearing face 21a and the second bearing surface 22a are respectively arranged with multiple pit d.In addition, pit is roughly arranged on each bearing surface 21a, the whole region of 22a, and multiple pit is arranged regularly.The inner peripheral surface 23a of intermediate portion 23 does not arrange pit d.
Each pit d is formed by plastic workings such as shot-peening processing, rolling finishing and embossing processing.The recess that each pit d is formed roughly to be in the shape of a hemispheroid, recess roughly in semiellipsoid shape or roughly in semi-cylindrical recess.In the present embodiment, each pit D-shaped is become minor axis within the scope of 10 ~ 500 μm and major diameter within the scope of 10 ~ 1000 μm roughly in the recess of semiellipsoid shape.In addition, the maximum depth of each pit d is formed in the scope of 1 ~ 50 μm.Again, each pit d is configured to circumferentially (direction orthogonal to the axial direction) extension.
In the present embodiment, each pit d is arranged to and each bearing surface 21a, and the end of the axis of 22a separates certain interval.That is, each pit d does not expose (not being communicated with each end face) on each end face of the axis of each bearing portion 21,22.
At this, the average microhardness (MHv) of each bearing surface 21a, 22a is if lower than 50, then the wear resistance performance of sintered bearing 20 can be deteriorated, and durability is declined.On the other hand, the average microhardness (MHv) of each bearing surface 21a, 22a if higher than 200, then, when adopting plastic processing method to form each pit d, can cause the surrounding of each pit d to bloat, making size and the precision that cannot obtain regulation.Therefore, preferably the average microhardness (MHv) of each bearing surface 21a, 22a is set in the scope of 50 ~ 200.
In addition, if the area ratio of pit is less than 10%, then the reduction effect of friction factor cannot fully be obtained.On the other hand, if the area ratio of pit is more than 60%, then the slide area of each bearing surface 21a, 22a is not enough, causes resistance toly loadingly becoming insufficient.Therefore, preferably the area ratio of pit is set in the scope of 10 ~ 60%.At this, the area ratio of pit refers to and is formed in each bearing surface 21a, the total projection area of the pit d on 22a is (for being formed in these bearing surfaces 21a, all pit d on 22a, these bearing surfaces 21a will be formed in, the value that the area of contour of each pit d on 22a is carried out adding up to and obtained) relative to the ratio of the gross area of each bearing surface 21a, 22a.
(manufacture method of sintered bearing 20)
Below the manufacture method of sintered bearing 20 is described.
In following manufacture method, as the manufacture method of bearing recessed in the middle of internal diameter, adopt manufacture method disclosed in Japanese Patent Laid-Open 2-8302 publication and Japanese Patent Laid-Open 7-332363 publication.
That is, when manufacturing sintered bearing 20, first metallic lubricant being added to as in the metallic dust of raw material, and carrying out Agitation and mixing.At this, as metallic dust, the mixed-powder of copper powder, bronze powder, brass powder, nickeline powder, iron powder, corronil powder, the iron powder being coated with copper, Stainless Steel Powder or these powder can be used.
In addition, as die lubricant, can use with the powder of the paraffin class oiling agent such as powder or polyethylene of the fatty acid amide such as powder, vinyl bis-stearamides of the metallic soap that is representative such as zine stearate and lithium stearate.According to the purposes of bearing, except metallic dust, the powder that can also to add with graphite, molybdenum disulfide and boron nitride etc. be the solid lubrication composition of representative.
Above-mentioned substance is not limited in as the metallic dust of raw material, solid lubrication composition and die lubricant.
Then, by material powder good for Agitation and mixing under the pressure of about 100 ~ 500MPa, be pressed in mould, form powder compact.
After this, according to the temperature conditions of regulation, powder compact is sintered in the environment of regulation, form sintering body.By sintering powder compact, make adjacent metallic diffusion bond, and metallic is combined and forms the sintering body of Porous.
Described environment is the mixed gas etc. of vacuum environment, reducibility gas environment (ammonolysis craft gas, hydrogen, Endothermic etc.), inert gas environment (nitrogen, argon gas etc.) and these reducibility gas and inert gas, suitably can select according to raw material components.As described sintering temperature, about 600 ~ 1200 DEG C is practical sintering temperature, such as when using bronze (Cu-Sn), the sintering temperature of about 600 ~ 800 DEG C can be adopted, when adopting the material based on iron, can adopt the sintering temperature of about 700 ~ 1200 DEG C, sintering temperature also suitably can be selected according to raw material components.
In addition, can in mould, carry out pressure-sizing (Sizing) (recompression) to sintering body and form recompression body.By carrying out pressure-sizing to sintering body, while raising dimensional accuracy, surface roughness can be improved.
After this, be compressed into the bearing surface 21a of body, 22a forms multiple pit d.When bearing surface 21a, 22a form pit d, can be processed by shot-peening, the plastic working such as rolling finishing and embossing processing forms pit d.Such as, when bearing surface 21a, 22a form pit d, the instrument of plastic working can be used to form pit d.This instrument has axle, retainer and rolling element, and axle has protuberance, and retainer is sleeved on outside axle, and rolling element is kept by retainer, and rolls on the outer circumferential face of axle.By retainer being inserted the inner peripheral surface of bearing hole h, and axle is rotated, make rolling element give prominence to from the outer surface of retainer under the effect of the protuberance of axle or shrink back thus, make bearing surface 21a by outstanding rolling element, 22a produces plastic deformation, can form pit thus.
In addition, can also to the bearing surface 21a formed after pit d, 22a carries out rotation pressure-sizing processing (polishing).By carrying out rotation pressure-sizing processing to bearing surface 21a, 22a, again fine finishing is carried out to the internal diameter of bearing hole h, can not only dimensional accuracy be improved, but also the characteristic of the running-in ability of surface roughness and initial operating stage etc. can be improved.
Then, being compressed into body or implementing the body that is compressed into rotating pressure-sizing processing after pit forms processing after forming processing to pit implements cleaning, the metal fragment produce work in-process and pressure-sizing lubrication wet goods removing.
After this, after cleaning be compressed into impregnation oiling agent in body, complete the manufacture of sintered bearing 20 thus.
(effect of fan motor 1)
Below the effect of fan motor 1 (sintered bearing 20) is described.
By making the coil 3a of the lamination iron core 3 of fan motor 1 be energized, running shaft 10 being rotated, making the impeller 6 of the outlet side being arranged on running shaft 10 rotate thus.
Now, in sintered bearing 20, owing to being arranged on two bearing portions 21, the internal diameter of the intermediate portion 23 between 22 and each bearing portion 21, the internal diameter of 22 is compared and is formed larger size, so the inner peripheral surface 23a of intermediate portion 23 can not come in contact (sliding contact) with running shaft 10.Therefore, compared with linear bearing, the inner peripheral surface of bearing hole h and the contact of running shaft 10 can not only be suppressed, but also the fluid resistance of oiling agent when axle rotates can be reduced, the surface friction drag produced between bearing surface and running shaft 10 can be reduced in thus.
In existing motor, as the method being reduced in the surface friction drag produced between bearing and running shaft, there will be a known the method being carried out supporting rotating shaft by independent two bearings arranged.; in the method; be difficult to suppression two independently bearing generation coaxiality deviation; if the deviation of coaxality is large; running shaft then can be made to pass two bearings; although or can two bearings be passed, because the gap between running shaft and internal diameter slip surface is too small and cause fluid resistance to increase, make the power consumption quantitative change of motor large.Now, the size expanding gap in design must be needed, if and expand the size in gap in design, then concerning the good bearing of the coaxality of coaxality in deviation range, gap between its running shaft and internal diameter slip surface can become excessive, running shaft can be caused to shake, make motor generation noise.At this, coaxality refers to the inclined extent of the reference axis relative to the axis that should be located along the same line with reference axis.
On the other hand, because the clutch shaft bearing portion 21 of sintered bearing 20 and the second bearing portion 22 are formed as one by intermediate portion 23, so can reduce the value of the coaxality of two bearing portions 21,22.By reducing the value of the coaxality of two bearing portions 21,22, two bearing surface 21a can be suppressed further, the contact of 22a and running shaft 10.Especially, owing to clutch shaft bearing portion 21 and the second bearing portion 22 being formed as one in sintered bearing 20, so the coaxality of two bearing portions 21,22 can be controlled below 3 μm.Therefore, in fan motor 1, preferably the coaxality of two bearing portions 21,22 is formed in less than 3 μm.As mentioned above, by by two bearing portions 21, gap (the bearing surface 21a of 22, gap between 22a with running shaft 10) be formed as identical size, when carrying out the batch production of motor 1, the deviation of noise properties and power consumption can be suppressed, the motor of equal quality can be obtained.
In addition, in sintered bearing 20, multiple pit d is provided with being supported to by running shaft 10 at least one bearing surface in the clutch shaft bearing face 21a and the second bearing surface 22a that can rotate freely.Due to bearing surface 21a, the part (scope) being provided with each pit d in 22a can not come in contact with running shaft 10, thus can reduce bearing surface 21a, the slide area in 22a.Thus, not only the contact of bearing surface 21a, 22a and running shaft 10 is inhibited, but also reduces the fluid resistance of oiling agent when axle rotates, so can be reduced in the surface friction drag produced between bearing surface and running shaft 10.Therefore, it is possible to do not reducing bearing surface 21a, when the axial dimension of 22a, reducing the slide area in the inner peripheral surface of bearing hole h, while suppression film strength declines, the surface friction drag produced between bearing surface and running shaft 10 can be reduced in.
In addition, in sintered bearing 20, owing to being provided with multiple pit d at bearing surface 21a, 22a, so can store containing the oiling agent be immersed in sintered bearing 20 in each pit d.When running shaft 10 rotates, the oiling agent stored in each pit d attracted to bearing surface 21a, between 22a and running shaft 10.Thus, when running shaft 10 rotates, especially at initial operating stage, the formation of oil film can be made to become easy, bearing surface 21a can be reduced, the friction factor of 22a.
In sintered bearing 20, owing to being provided with multiple pit d at bearing surface 21a, 22a, so bearing surface 21a can be increased, the mean gap between the outer circumferential face of 22a and running shaft 10.Therefore, when running shaft 10 rotates, can reduce and be present in bearing surface 21a, the fluid resistance of the oiling agent between 22a and running shaft 10.
In sintered bearing 20, by making bearing surface 21a, there is plastic deformation and form multiple pit d in 22a.Thereby, it is possible to improve the machining accuracy of each pit d.Especially, because sintered bearing is formed by sintering metallic dust, so have porous structure.Therefore, form each pit d by plastic working, can absorb crushed element by micropore, thus can prevent bearing surface 21a, 22a bloats.
In addition, except plastic working, as the method forming pit, laser beam machining and etching (local etching) processing etc. can be listed, but these methods not only need to use main equipment, and manufacturing procedure can be caused to increase.On the other hand, plastic working is not owing to needing to use main equipment, and manufacturing procedure is few, so can carry out large batch of processing with lower cost.
Especially, in sintered bearing 20, by by bearing surface 21a, the average microhardness (MHv) of 22a is set in the scope of 50 ~ 200, can decline avoiding the durability of sintered bearing, and when avoiding the size of sintered bearing and precision to reduce, form pit at bearing surface.
In addition, in sintered bearing 20, due to the end setting spaced apart of the axis of each pit d and bearing surface 21a, 22a, so hydraulic pressure can be suppressed to escape from the end of the axis of bearing surface 21a, 22a, oily film strength can be suppressed to decline.
As mentioned above, according to sintered bearing 20, due to the fluid resistance of the oiling agent coming in contact between bearing surface and running shaft and reduce when axle rotates can be suppressed, so the surface friction drag produced between bearing surface and running shaft can be reduced in.Therefore, it is possible to obtain following effect in fan motor 1.
The characteristic of the little motor of the driving torques such as fan motor 1 can be improved.That is, in the ordinary course of things, the driving torque of motor is less, and the impact of size on motor characteristic of the surface friction drag produced between bearing surface and running shaft is larger.Along with surface friction drag increases, the rotating speed of motor reduces, and not only can make cannot realize target rotating speed, but also the power consumption of motor can be caused to increase.
On the other hand, in sintered bearing 20, as mentioned above, bearing surface 21a can be reduced in, the surface friction drag produced between 22a and running shaft 10.Therefore, by adopting sintered bearing 20 in fan motor 1, even if when the driving torque of fan motor 1 reduces, the reduction of fan motor 1 rotating speed also can be suppressed, and can reduce power consumption.
In addition, in fan motor 1, bearing surface 21a can be reduced further, the gap between the outer circumferential face of 22a and running shaft 10.That is, in the ordinary course of things, in the motor, along with the gap shrinks between bearing surface and the outer circumferential face of running shaft, the fluid resistance of oiling agent when axle rotates increases, and the surface friction drag produced between bearing surface and running shaft increases.Now, the rotating speed of motor not only can be caused to reduce and make cannot realize target rotating speed, and the power consumption of motor can be caused to increase.
On the other hand, in sintered bearing 20, as mentioned above, can reduce and be present in bearing surface 21a, the fluid resistance of the oiling agent between 22a and running shaft 10.Therefore, by adopting sintered bearing 20 in fan motor 1, even if when gap shrinks between bearing surface 21a, 22a and the outer circumferential face of running shaft 10, the reduction of the rotating speed of fan motor 1 also can be suppressed.In addition, the increase of the power consumption of fan motor 1 can also be suppressed.And, due to bearing surface 21a can be reduced, gap between the outer circumferential face of 22a and running shaft 10, so running shaft 10 can be suppressed at bearing surface 21a, shake in gap between the outer circumferential face of 22a and running shaft 10, while the value of coaxality reducing above-mentioned two bearing portions 21,22, the noise of motor can be reduced.
In general, in the motor that fan motor etc. drives with underload, if the gap between bearing surface and the outer circumferential face of running shaft is greater than 6 μm, then running shaft may be made to shake in this gap, thus make noise become large.On the other hand, if the gap between bearing surface and the outer circumferential face of running shaft is arranged on less than 6 μm, then the fluid resistance of oiling agent when axle rotates increases, and the surface friction drag produced between bearing surface and running shaft can be caused to increase.On the other hand in, by adopting sintered bearing 20 in fan motor 1, then can be reduced in bearing surface 21a, the surface friction drag occurred between 22a and running shaft 10, so the gap between bearing surface 21a, 22a and the outer circumferential face of running shaft 10 can be arranged on less than 6 μm.Therefore, in fan motor 1, in order to reduce noise, preferably the gap between bearing surface 21a, 22a and the outer circumferential face of running shaft 10 is arranged on less than 6 μm.
Further, in fan motor 1, more full-bodied oiling agent can be used.That is, in the ordinary course of things, in the motor, along with the viscosity of used oiling agent increases, the fluid resistance being present in the oiling agent between bearing surface and running shaft can increase.Now, the rotating speed of motor not only can be caused to reduce and make cannot realize target rotating speed, and the power consumption of motor can be caused to increase.
On the other hand, in sintered bearing 20, as mentioned above, can reduce and be present in bearing surface 21a, the fluid resistance of the oiling agent between 22a and running shaft 10.Therefore, by adopting sintered bearing 20 in fan motor 1, even if use full-bodied oiling agent, the reduction of motor speed also can be suppressed.In addition, the increase of the power consumption of motor can also be suppressed.Further, due to full-bodied oiling agent can be used, so can while the wear resistance performance improving bearing, oiling agent is suppressed at high temperature to evaporate, can suppress aging, and can lubricant leakage be suppressed, thus the working life of motor can be extended.Especially, by using full-bodied oiling agent, the oily film strength generated at internal diameter slip surface can be improved, and the noise of motor can be reduced.
In general, in the motor that driving torque is little, in order to reduce the fluid resistance of oiling agent, use 32mm
2the oiling agent of/below s.On the other hand, by adopting sintered bearing 20 in fan motor 1, the fluid resistance of oiling agent can be reduced, so in the current value range of the regulation of motor, 70mm can be brought up to by maximum for the viscosity of oiling agent used
2/ s.On the other hand, if the viscosity of oiling agent is reduced to lower than 10mm
2/ s, then can cause the evaporation characteristic of oiling agent to decline.Therefore, in fan motor 1, preferably the viscosity of oiling agent is set in 10 ~ 70mm
2in the scope of/s.At this, viscosity (mm
2/ s) viscosity when referring to 40 DEG C.
In addition, in fan motor 1, the serviceability temperature scope from low temperature to high temperature can be expanded.That is, in the ordinary course of things, in the motor, along with serviceability temperature declines, the viscosity of oiling agent can increase considerably, thus the fluid resistance of the oiling agent be present between bearing surface and running shaft can be caused to increase.Now, the rotating speed of motor not only can be caused to reduce and make cannot realize target rotating speed, and the power consumption of motor can be caused to increase.Especially in the motor of low torque, in the worst occasion, the situation of poor starting (being in the state that cannot start) may be there is.On the contrary, along with the serviceability temperature of motor raises, the viscosity of oiling agent can significantly reduce, thus causes the oily film strength produced at the internal diameter slip surface of bearing to decline.Now, the wear resistance performance of bearing can be caused to decline, make motor easily produce noise.In addition, due to oiling agent easily evaporate, aging and leak, so can cause decline the working life of motor.
On the other hand, in sintered bearing 20, as mentioned above, can reduce and be present in bearing surface 21a, the fluid resistance of the oiling agent between 22a and running shaft 10.Therefore, by adopting sintered bearing 20 in fan motor 1, even if the viscosity of oiling agent improves because of low temperature, the reduction of motor speed also can be suppressed.In addition, the increase of the power consumption of motor can also be suppressed.At this, when the oiling agent adopting viscosity identical with existing bearing, while the hot properties maintaining motor, the low-temperature characteristics of motor can be improved.On the other hand, when the oiling agent adopting the existing bearing of ratio of viscosities high, while the low-temperature characteristics maintaining motor, the hot properties of motor can be improved.
Sintered bearing 20 is such as adapted at using in the fan motor of refrigerator.That is, in recent years, in order to defrost in refrigerator, the defrost control improving temperature is regularly carried out.Therefore, when fan motor is used for refrigerator, if the viscosity of oiling agent is too high, the situation of motor generation poor starting may be caused.On the other hand, if the viscosity of oiling agent is too low, then, when carrying out defrost control, oiling agent easily evaporates, aging and leakage, can cause decline the working life of motor.On the other hand, by using the fan motor 1 that can use in larger temperature range in refrigerator, can, while preventing motor generation poor starting, suppress decline the working life of motor.
(variation)
Above embodiments of the present invention are illustrated.Above-mentioned mode of execution can carry out various change.
Such as, in the above-described embodiment, on clutch shaft bearing face 21a and the second bearing surface 22a, multiple pit d is provided with respectively.But, also only at two bearing surface 21a, the clutch shaft bearing face 21a in 22a can arrange multiple pit d, and also only at two bearing surface 21a, the second bearing surface 22a in 22a can arrange multiple pit d.Especially, by only at two bearing surface 21a, the second bearing surface 22a in 22a arranges multiple pit d, while the film strength of the clutch shaft bearing face 21a preventing the outlet side of heavier loads declines, the friction factor of the second bearing surface 22a of the lighter side contrary with outlet side of load can be reduced.
In addition, in the above-described embodiment, the shape, the size that are formed in the shape of the pit d on the 21a of clutch shaft bearing face, size and maximum depth and the pit d be formed on the second bearing surface 22a are identical with maximum depth.But, also the shape of the pit d be formed on the 21a of clutch shaft bearing face, size and at least one in maximum depth can be arranged to different from the pit d be formed on the second bearing surface 22a.Such as, in the clutch shaft bearing face 21a of the outlet side of heavier loads, reduce at least one in the size of pit d and maximum depth, in the second bearing surface 22a of the lighter side contrary with outlet side of load, increase at least one in the size of pit d and maximum depth.
In addition, also can make two bearing surface 21a, the pit d in 22a to arrange scope and density etc. different from each other.Such as, in the clutch shaft bearing face 21a of the outlet side of heavier loads, reduce the scope that arranges and the density of pit d, and increase the scope that arranges and the density of pit d in the second bearing surface 22a of the lighter side contrary with outlet side of load.At this, density refers to the quantity (following identical) of the pit of per unit area.
Again, in the above-described embodiment, multiple pit d is arranged on each bearing surface 21a, the roughly whole region of 22a.But, also can the region not forming pit d be set in the local of each bearing surface 21a, 22a.Such as, arranged the region not forming pit d, can suppress each bearing surface 21a by least one end in two ends of the axis at each bearing surface 21a, 22a, the film strength of 22a declines.
Further, in the above-described embodiment, the shape of each pit d is roughly formed as semiellipsoid shape (shape on projection plane is elliptical shape).But the shape on the projection plane of each pit d also can be formed as circular, fan-shaped, triangle, quadrilateral or rhombus.
In addition, in the above-described embodiment, be arranged on each bearing surface 21a, shape, the size of multiple pit d of 22a are identical with maximum depth.But, be arranged on each bearing surface 21a, in multiple pit d of 22a, also can mixing and shape, pit d that size is different with at least one in maximum depth are set.
In the above-described embodiment, multiple pit d is arranged on each bearing surface 21a regularly, on 22a.But multiple pit d also can be arranged on each bearing surface 21a brokenly, on 22a.
In the above-described embodiment, each pit d is arranged in the mode circumferentially extended.But each pit d also can be arranged according to the mode axially extended, and also can arrange according to the mode extended along the direction relative to axial and circumferential inclination predetermined angular.
In addition, in the above-described embodiment, after implementing pressure-sizing (recompression) to sintering body, be compressed into the bearing surface 21a of body, 22a forms multiple pit d.But, also after the multiple pit d of the upper formation of the bearing surface 21a of sintering body, 22a, then pressure-sizing (recompression) can be implemented.
In the above-described embodiment, show example sintered bearing 20 being applied to fan motor 1, but as described below, sintered bearing 20 of many uses, be wherein particluarly suitable for using in the motor of High Rotation Speed.
(household electrical appliances are used)
Minor diameter stepping motor, refrigerator fan, microwave oven fan, electric fan, ventilating fan, air conditioner, blower, vacuum cleaner, juice blender, food processor, vibrating motor, ODD axle motor, the HDD axle motor of the cooling fan of electronic computer, television set, DV, projector, LED illumination etc., DLP colour wheel motor, digital camera and DV etc.
(vehicle-mounted)
The motor of the air-breathing exhaust gear of storage battery cooling fan, temperature adjustment sheet fan, car inner sensor fan, sound equipment and navigator cooling fan, blower, idle call actuator, washery pump, wing mirror, door closer, seat back recliner, seat slide device, motorized window, rain brush, starter, ETC and EGR etc., EPS (electric steering), EPB (electronic control Parking Brake) etc.
(OA equipment is used)
Polygon mirror scanner motor, stepping motor etc.
Claims (6)
1. a sintered bearing, by mould to metallic dust carry out press-powder shaping after sinter and formed, there is the bearing hole being supported to by running shaft and can rotate freely, and containing being soaked with oiling agent, the feature of described sintered bearing is,
There is clutch shaft bearing portion, the second bearing portion and intermediate portion,
Described clutch shaft bearing portion has the clutch shaft bearing face supporting described running shaft,
Described second bearing portion has the second bearing surface supporting described running shaft,
Described intermediate portion is arranged between described clutch shaft bearing portion and described second bearing portion,
The internal diameter of described intermediate portion be formed as than the internal diameter in described clutch shaft bearing portion and the internal diameter of described second bearing portion all large,
The bearing surface of at least one party in described clutch shaft bearing face and described second bearing surface is formed with multiple pit.
2. sintered bearing as claimed in claim 1, it is characterized in that, described multiple pit is formed by plastic working.
3. sintered bearing as described in claim 1 or 2, is characterized in that, the end setting spaced apart of the axis of described pit and described bearing surface.
4. the sintered bearing as described in any one in claims 1 to 3, is characterized in that, the gap be provided with between the bearing surface of described multiple pit and the outer circumferential face of described running shaft is set as less than 6 μm.
5. the sintered bearing as described in any one in Claims 1-4, is characterized in that, is provided with the average microhardness (MHv) of the bearing surface of described multiple pit in the scope of 50 ~ 200.
6. the sintered bearing as described in any one in claim 1 to 5, is characterized in that, described sintered bearing is applied to fan motor.
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| CN201410074753.7A CN104895926B (en) | 2014-03-03 | 2014-03-03 | Sintered bearing |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410074753.7A CN104895926B (en) | 2014-03-03 | 2014-03-03 | Sintered bearing |
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| CN104895926A true CN104895926A (en) | 2015-09-09 |
| CN104895926B CN104895926B (en) | 2020-10-09 |
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| CN201410074753.7A Active CN104895926B (en) | 2014-03-03 | 2014-03-03 | Sintered bearing |
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Cited By (1)
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| CN110150982A (en) * | 2017-04-25 | 2019-08-23 | 吕一让 | Spout filter screen and manufacturing method thereof |
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| CN104895926B (en) | 2020-10-09 |
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