CN100414129C - Self-aligining roller bearing - Google Patents

Abstract

An outer ring raceway surface (14) formed on the inner peripheral surface of an outer ring (13) has roughness higher than that of inner ring raceways (12a, 12b) of an inner ring (11). Average roughness (Ra) in the axial direction and circumferential direction of the outer ring raceway surface (14) is 0.1 mum <= Ra <= 0.5 mum in the ranges of b1/(B/2) <= 0.9 AND B2(B/2) <= 0.9 and in the measurement length of 0.1 mm to 1.0 mm, with B the width of the outer ring (13), b1 and b2 the distances in the axial direction from both end surfaces of the outer ring (13). Roughness parameter (S) of the outer raceway surface is 0 < S <= 20 mum.

Description

Selfaligning roller bearing

Technical field

Prolong the working life that the present invention relates to be used in the selfaligning roller bearing (self-aligning roller bearing) in general industry machinery, lathe, vibrating sieve, Iron And Steel Industry, motorcycle engine or the like.

Background technique

Selfaligning roller bearing has and can prevent to produce unusual load and improve the radially advantage of bearing capacity, even because when outer shroud or interior ring owing to assemble error or when impulsive load and run-off the straight, the contact condition of rolling element can not change yet.Thus, selfaligning roller bearing is widely used as various rolling bearings (roll neck bearing), vehicle bearing, various industrial bearings in the papermaking equipment or the like.

Explanation in passing, in the clean environment that is formed with oil film satisfactorily, general ball bearing or cylindrical roller bearing can be damaged because surperficial initial type down breaks (the subsurface initiatedfracture).Initial type breaks and shows that the nonmetallic inclusion as starting point has produced fatigue crack from be contained in material under this surface, and broadens gradually.Therefore, can realize that by the turbidity test that improve material prolong the working life of ball bearing and cylindrical roller bearing.

But, different with aforementioned bearings, in some cases, can in selfaligning roller bearing, produce surperficial initial type according to application feature and destroy (the surface initiated failure).The initial type in this surface destroys and shows produced atomic little plastic flow in clean environment on the surface of interior ring, and peels off crackle from producing and diffusing out here thus, causes scaling off.Therefore, the turbidity test of increase material can not prolong the generation appreciable impact to the working life of selfaligning roller bearing.

In selfaligning roller bearing, crooked meeting obviously influence prevents the generation of heat or the prolongation in bearing working life.

Given this, for friction factor between ring and the rolling element and the friction factor between outer shroud and the rolling element in controlling, taked the measure that the surface roughness of the area of contact of bearing and plane of trajectory orbital is controlled.For example, a kind of like this example is disclosed, (surface roughness of interior loop orbit face is 0.1 μ mRa or lower promptly to be set at surface roughness greater than interior loop orbit face by the surface roughness with the outer shroud plane of trajectory orbital, and the surface roughness of outer shroud plane of trajectory orbital is 0.2 μ mRa or higher) come to be controlled to crooked, so that realize prolonging working life (referring to JP-B-57-61933).

As the reason that is used to increase the service life, it is assumed to be, and is making under the situation of roughness greater than the roughness of interior ring of outer shroud, produces to make rolling element crooked to the forward that the bearing outside tilts, and reduces thrust load.In addition, can infer, owing to make rolling element, so the crooked meeting of this negative sense is to producing harmful effect in working life of bearing to the inboard crooked thrust load that increased of negative sense that tilts of bearing.

But, when merely making the roughness of outer shroud plane of trajectory orbital greater than the roughness of interior loop orbit face, in some cases, although it is crooked or increased negative sense and still prolong crooked working life to tend to take place negative sense.Therefore, be difficult to the prolongation generation crucial influence of described crooked control meeting to working life.In addition, when making the roughness of outer shroud plane of trajectory orbital excessive, the ricing of outer shroud plane of trajectory orbital can be greater than the thickness of oil film.Therefore, the lubrication state variation, and can be easy on the contrary the working life of bearing shorten.

In addition, for crooked control or suppress extremely slight slippage, be effective by the surface roughness of outer shroud plane of trajectory orbital being made the approach that surface roughness greater than interior loop orbit face increases frictional force.But according to the position on interior ring and the outer shroud, can there be variation (variation along the circumferential direction) in same bearing on the surface roughness of interior loop orbit face and outer shroud plane of trajectory orbital in the reality.Therefore, in the size of the frictional force that the contacting part office produces between contact segment and outer shroud plane of trajectory orbital and the rolling element between interior loop orbit face and the rolling element, the rotation in the relevant position changes according to bearing in meeting.Thus, be suppressed at as if that slippage and crooked actual effect change in the atomic zonule.

For example, when roughness was measured in the some positions in same bearing, each value of roughness can change.When examining closely according to the roughness scope under the not so good situation of machining status on opportunity, if between interior loop orbit face and outer shroud plane of trajectory orbital, have the part that surface roughness reverses because the roughness scope of the roughness scope of interior loop orbit face and outer shroud plane of trajectory orbital is very approaching or overlapped mutually, the frictional force that the contacting part office produces between rolling element and interior ring and outer shroud can change so, and the rotation of roller can become unstable thus.Therefore, the contacting part office has produced atomic little slippage between interior ring and rolling element, and tends to take place such as peeling off such damaged surfaces or the like.

Therefore, only make that the surface roughness of outer shroud plane of trajectory orbital is not enough greater than the surface roughness of interior loop orbit face.Therefore, must be at roughness distribution and the roughness distribution regulation outer shroud plane of trajectory orbital of interior loop orbit face and the surface roughness ratio between the interior loop orbit face of bearing China and foreign countries loop orbit face.

In addition, in selfaligning roller bearing, by under 200 ℃ or higher temperature internally ring and outer shroud implement high-temperature tempering, make residual austenite composition be reduced to 0% basically, because residual austenite issues estranged separating and causes the size change in the high temperature application feature usually.This high-temperature tempering process can impel residual austenite to decompose, but this technology can produce adverse effect, makes hardness reduce.Therefore, be easy on interior ring to produce such as peeling off such damaged surfaces or the like, and shorten the working life of bearing thus.

On the contrary, if the surface roughness of outer shroud increases, if promptly interior loop orbit face is set to greater than the roughness scope lower limit of outer shroud plane of trajectory orbital on center line in the roughness range limit value on the center line, in can suppressing as previously mentioned so on the ring such as peeling off such damaged surfaces or the like, and can suppress interior ring scission.On the other hand, the frictional force that the contacting part office produces between the relative moderate roller with roughness of the big outer shroud of roughness can increase, and makes the outer shroud driven roller thus.Finally, the tired obviously development of roller surface.

Summary of the invention

The present invention produces in view of aforementioned aspect, and the object of the present invention is to provide a kind of selfaligning roller bearing, can be by suppressing owing to, realize the prolongation in working life such as peeling off scaling off too early that such damaged surfaces or the like causes.

In order to overcome foregoing problems; In the first self-aligning roller bearing in the present invention; Double-row-roller as rolling element along the circumferential direction rollably is arranged between interior ring and the outer shroud; Wherein so that be formed on the roughness of the outer shroud orbital plane on the interior perimeter surface of outer shroud greater than the roughness of the interior loop orbit face on the outer surface that is formed on interior ring; And on axis direction and circumferencial direction; The average roughness Ra of outer shroud orbital plane is set in 0.1 μ m≤Ra≤0.5 μ m; And the roughness parameter S by following formula definition is set in 0＜S≤20 μ m

$S=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{S}_i$

Wherein n is the roughness peak value number that is used to indicate on the roughness curve of roughness of outer shroud plane of trajectory orbital, and Si is the spacing between the adjacent peak value on the roughness curve.

Preferably, the mean roughness of the rolling contact surfaces of described rolling element is set to Ra＜0.1 μ m, and the mean roughness of loop orbit face is set to Ra＜0.15 μ m in described.

Preferably, satisfy inequality R ao/Rai 〉=1.5, wherein Rai is the described interior roughness range limit value of loop orbit face on center line, and Rao be described in the roughness scope lower limit of loop orbit face on center line, and in described rolling element and interior ring and the outer shroud at least the difference of the retained austenite composition γ R between any be set to 3% volume ratio or higher.

Preferably, at b ₁/ (B/2)≤0.9, b ₂/ (B/2)≤0.9 and measured length be in the scope of 0.1mm to 1.0mm, on axial direction and circumferencial direction, the average roughness Ra of described outer shroud plane of trajectory orbital is set in 0.1 μ m≤Ra≤0.5 μ m, wherein B is the width of described outer shroud, b ₁, b ₂Be respectively the distance with two end faces of described outer shroud, and roughness parameter S is set in 0＜S≤20 μ m.

Preferably, described outer shroud plane of trajectory orbital has cross one another machining vestige, and these machining vestiges form by a kind of superfinish (super finishing).

In addition, in second kind of selfaligning roller bearing in the present invention, double roller as rolling element along the circumferential direction rollably is arranged between interior ring and the outer shroud, wherein make the roughness of the outer shroud plane of trajectory orbital on the interior perimeter surface be formed on outer shroud greater than the roughness of the interior loop orbit face on the outer surface of ring in being formed on, and on axial direction and circumferencial direction, the average roughness Ra of outer shroud plane of trajectory orbital is set in 0.1 μ m≤Ra≤0.5 μ m, the mean roughness of the rolling contact surfaces of rolling element is set to Ra＜0.1 μ m, and the mean roughness of interior loop orbit face is set to Ra＜0.15 μ m.

Preferably, satisfy inequality R ao/Rai 〉=1.5, wherein Rai is the described interior roughness range limit value of loop orbit face on center line, and Rao be described in the roughness scope lower limit of loop orbit face on center line, and in described rolling element and interior ring and the outer shroud at least the difference of the retained austenite composition γ R between any be set to 3% volume ratio or higher.

Preferably, described outer shroud plane of trajectory orbital has cross one another machining vestige, and these machining vestiges form by a kind of superfinish.

In addition, in the third selfaligning roller bearing in the present invention, double roller as rolling element along the circumferential direction rollably is arranged between interior ring and the outer shroud, wherein make the roughness of the outer shroud plane of trajectory orbital on the interior perimeter surface be formed on outer shroud greater than the roughness of the interior loop orbit face on the outer surface of ring in being formed on, and satisfy inequality R ao/Rai 〉=1.5, wherein Rai is the roughness range limit value of interior loop orbit face on center line, and Rao is the roughness scope lower limit of interior loop orbit face on center line, and in rolling element and interior ring and the outer shroud at least the difference of the retained austenite composition γ R between any be set to 3% volume ratio or higher.

Preferably, described outer shroud plane of trajectory orbital has cross one another machining vestige, and these machining vestiges form by a kind of superfinish.

First kind of selfaligning roller bearing in according to the present invention reduces the localized variation of roughness outside in the gamut that comes in contact with roller on the loop orbit face, and can stably increase the friction factor of outer shroud plane of trajectory orbital and roller.Therefore, can suppress the rotational slip of roller, and can suppress owing to, can realize the prolongation in working life thus such as peeling off scaling off too early that such damaged surfaces or the like causes.

In addition, because the roughness parameter S of outer shroud plane of trajectory orbital is set to 0＜S≤20 μ m, thus can increase the friction factor of contacting part office between the loop orbit face and roller outside, and can suppress the slippage of roller.Therefore, can suppress because such as peeling off scaling off too early that such damaged surfaces or the like causes, and can realize that thus prolong the working life of selfaligning roller bearing.

In addition, second kind of selfaligning roller bearing in according to the present invention, for inhibitory action on interior ring and rolling element and play cause selfaligning roller bearing scale off the effect tangential force, the mean roughness of the rolling contact surfaces of rolling element is set to Ra＜0.1 μ m, the mean roughness on interior loop orbit surface is set to Ra＜0.15 μ m, and the mean roughness of outer shroud plane of trajectory orbital is set to 0.1 μ m≤Ra≤0.5 μ m.Therefore, produce atomic little plastic flow in can being suppressed on the loop orbit face, and can realize the stable prolongation in working life thus.

In addition, the third selfaligning roller bearing in according to the present invention, if be higher than the roughness that orbit ring and residual austenite down improve outer shroud by setting for as the hardness of the roller of rolling element, atomic little slippage in can being suppressed at so on the ring, and the Surface fatigue of ring in can alleviating thus, but roller can become the part that is easy to take place Surface fatigue most.Based on this phenomenon,, can increase the service life by to the easy material requirements that tired roller application opposing Surface fatigue takes place.The surface hardness of raising rolling element and residual austenite down are for very effective such as peeling off such damaged surfaces or the like.

Description of drawings

Fig. 1 is an axial sectional view according to the selfaligning roller bearing of first embodiment of the invention;

Fig. 2 has explained the mode of action according to selfaligning roller bearing of the present invention;

Fig. 3 shows the mean roughness of the test bearing that provides and concerns between working life in table 1;

Fig. 4 shows and works as at b ₁/ (B/2) equal 0.1 to 0.9 and measured length l when equaling under the condition of 0.5mm the roughness of the outer shroud plane of trajectory orbital in the test bearing tested, the test result of acquisition;

Fig. 5 shows the circumferencial direction roughness of test bearing and the relation between the axial direction roughness;

Fig. 6 has explained the roughness parameter S of outer shroud plane of trajectory orbital;

Fig. 7 schematically shows the contact condition between the outer shroud plane of trajectory orbital and roller under the big and less two kinds of situations of this parameter S of the roughness parameter S of loop orbit face outside;

Fig. 8 shows the friction factor test value of contacting part office between the loop orbit face and roller outside;

Fig. 9 schematically shows the lubrication state when the friction factor of contacting part office between outer shroud plane of trajectory orbital and the roller increases;

Figure 10 schematically shows the coarse patterns (a roughness pattern) of outer shroud plane of trajectory orbital;

Figure 11 schematically shows locating of mean roughness on the outer shroud plane of trajectory orbital and roughness parameter;

Figure 12 show in the table 2 working life ratio and roughness parameter between relation;

Figure 13 is an axial sectional view according to the selfaligning roller bearing of second embodiment of the invention;

Figure 14 is the schematic representation of one two cylinder test machine;

Figure 15 is a chart, shows the relation between the size ratio of the surface roughness of driving side test block and tangential force;

Figure 16 is a chart, shows the relation between the size ratio of the surface roughness of slave end test block and tangential force;

Figure 17 example view has explained that rolling element applies in the scope direction of the tangential force that receives from outer shroud in load;

Figure 18 example view has explained that rolling element applies in the scope direction of the tangential force that receives from outer shroud in non-load;

Figure 19 is a chart, shows ratio in working life in the table 3 in the summary mode;

Figure 20 is a schematic general view, shows an axial section shape according to the selfaligning roller bearing of third embodiment of the invention;

Figure 21 shows the range of surface roughness of outer shroud plane of trajectory orbital and interior loop orbit face, and the ratio between the roughness CLV ceiling limit value Rai of the roughness scope lower limit Rao of outer shroud and interior ring; And

Figure 22 shows ratio between the roughness range limit value Rai of the roughness scope lower limit Rao of outer shroud and interior ring and the relation between the working life ratio.

In this article, in aforementioned figures, what reference character 10 referred to is a selfaligning roller bearing, 11,21,31 what refer to is interior ring, what 12a, 12b, 22,32a referred to is interior loop orbit face, and 13,23,33 what refer to is outer shroud, 14,24,34a refers to is the outer shroud plane of trajectory orbital, 15,25,35 what refer to is roller (rolling element), and 16,26,36 what refer to is retainer.

Embodiment

Below with reference to accompanying drawings embodiments of the invention are set forth.In this article, these embodiments only show one embodiment of the present of invention respectively, can not be construed as limited to these embodiments fully.In addition, within the scope of the present invention, can suitably carry out change in design to these embodiments.

Set forth with reference to Fig. 1 to the 12 pair of first embodiment of the present invention below.

Fig. 1 is an axial sectional view according to the selfaligning roller bearing of first embodiment of the invention.In Fig. 1, have in one according to the selfaligning roller bearing 10 of first embodiment of the invention and to encircle 11.Double-row track (also being known as " interior loop orbit face " hereinafter) 12a, 12b are formed on the outer surface of ring 11 in this along the circumferencial direction of interior ring 11.In addition, selfaligning roller bearing 10 has an outer shroud 13.A double integrated spherical track (also being known as " outer shroud plane of trajectory orbital " hereinafter) is formed on the interior perimeter surface of this outer shroud 13 along the circumferencial direction of outer shroud 13.

Interior loop orbit face 12a, 12b and outer shroud plane of trajectory orbital 14 are opposed mutually.A plurality of rollers 15 is set at respectively between interior loop orbit face 12a and the outer shroud plane of trajectory orbital 14 and between interior loop orbit face 12b and the outer shroud plane of trajectory orbital 14.These rollers 15 are maintained in the retainer 16.Circumferential surface sections separately all is made into a similar circular arc, so that have and interior loop orbit face 12a, 12b and outer shroud plane of trajectory orbital 14 radius of curvature much at one.

The surface roughness of outer shroud plane of trajectory orbital 14 is made into to be higher than the surface roughness (being generally 0.05 μ m to 0.15 μ m) of loop orbit face 12a, 12b in (coarse in).Thus, outer shroud plane of trajectory orbital 144 stands to grind when making the rotation axis of grinding stone (grindstone) be parallel to the central axis of outer shroud 13, and is making grinding stone stand superfinish in the axial direction swing of outer shroud 13 subsequently.On axial direction and circumferencial direction, at b ₁/ (B/2)≤0.9, b ₂/ (B/2)≤0.9 and measured length be in the scope of 0.1mm to 1.0mm, average roughness Ra is set to 0.1 μ m≤Ra≤0.5 μ m, wherein B is the width of outer shroud 13, b ₁, b ₂Be respectively and two end faces of outer shroud 13 between distance.

By this way, if on axial direction and circumferencial direction, at b ₁/ (B/2)≤0.9, b ₂/ (B/2)≤0.9 and measured length be in the scope of 0.1mm to 1.0mm, the average roughness Ra of outer shroud plane of trajectory orbital 14 is set to 0.1 μ m≤Ra≤0.5 μ m, the variation of local roughness degree can reduce in the whole surface that comes in contact with roller 15 on the loop orbit face 14 so outside, and stably improves the friction factor of outer shroud plane of trajectory orbital 14 and roller 15.Finally, can be by suppressing owing to realize the prolongation in working life such as peeling off scaling off too early that such damaged surfaces or the like causes.

In addition, in the aforementioned embodiment, because outer shroud plane of trajectory orbital 14 stands to grind when making the rotation axis of grinding stone be parallel to the central axis of outer shroud 13, and making grinding stone in the axial direction swing of outer shroud 13, stand superfinish subsequently, so form the grinding vestige of similar mesh pattern outside on the loop orbit face 14, as shown in Fig. 2 (c).That is to say, form cross one another machining vestige on the loop orbit face 14 outside by superfinish.Therefore, because the described outer shroud plane of trajectory orbital that is made into can reduce the variation of roughness, so can more effectively prolong the working life of described selfaligning roller bearing.Here, the θ among Fig. 2 (c) is the angle of cut of machining vestige along the circumferential direction.If the angle of cut of described machining vestige and plane of trajectory orbital circumferencial direction be set at 90 the degree to 150 the degree within, so can be so that roughness is approaching more mutually on circumferencial direction and axial direction.

As the Ginding process of described outer shroud plane of trajectory orbital, have usually and when the rotation axis that keeps grinding stone is parallel to the central axis of outer shroud, carry out abrasive method (being known as " straight line grinding " hereinafter) and by utilizing diameter to carry out abrasive method (being known as " grinding of cup-shaped grinding stone " hereinafter) greater than the cup-shaped grinding stone of outer ring width.Grind according to the straight line among both, the grinding vestige that is formed on the described outer shroud plane of trajectory orbital can produce a straight-line pattern that is parallel to the circumferencial direction of this outer shroud, as shown in Fig. 2 (a).Therefore, when when the axial direction of described outer shroud is measured the roughness of this outer shroud plane of trajectory orbital, measured load can be greater than the situation of measuring roughness along the circumferencial direction of described outer shroud.But, because the frictional force of generation is along the circumferencial direction effect of outer shroud when described roller rolls on the loop orbit face outside, so compare with the roughness that when measuring the roughness of outer shroud plane of trajectory orbital along the circumferencial direction of described outer shroud, detects, when the roughness that detects when the axial direction of outer shroud is measured described roughness can produce a small amount of influence to the increase of friction factor.In addition, when the average roughness Ra that determines when the axial direction along described outer shroud was big, this roughness had the effect that increases friction factor.But, when average roughness Ra is excessive, to compare with the thickness of oil film, the ricing on the described outer shroud plane of trajectory orbital can become greatly, and makes thus and the lubrication state variation be easy to shorten working life.

On the contrary, because carrying out described cup-shaped grinding stone when making the rotation axis of cup-shaped grinding stone perpendicular to the central axis of outer shroud grinds, so can on described outer shroud plane of trajectory orbital, form the grinding vestige that is similar to curve pattern, wherein said curve pattern with the center of outer shroud as the summit, as shown in Fig. 2 (b).Therefore; when when the axial direction of described outer shroud is measured the roughness of this outer shroud plane of trajectory orbital; grind vestige outside on the end of loop orbit face from axial direction and circumferencial direction run-off the straight; and thus in the situation of measuring described roughness along the circumferencial direction of described outer shroud, it is big that average roughness Ra becomes.In addition, under the situation that described cup-shaped grinding stone grinds, intersect mutually owing near the end of described outer shroud plane of trajectory orbital, grind vestige, friction factor can obviously increase, but near the core of described outer shroud plane of trajectory orbital, the grinding vestige becomes and almost is parallel to the axial direction of described outer shroud.Thus, when when the circumferencial direction of described outer shroud is measured described roughness, average roughness Ra can become greatly, but when when the axial direction of described outer shroud is measured described roughness, average roughness Ra can not become so greatly.Compare with described straight line grinding, described cup-shaped grinding stone grinds and can suppress rotational slip by the circumferencial direction increase friction factor along described outer shroud, but, when utilizing the external loop orbit face of described cup-shaped grinding stone to grind, near the friction factor the core of described outer shroud plane of trajectory orbital can become less than near the friction factor the end.Therefore, friction factor changes according to the position on the described outer shroud plane of trajectory orbital, and the rolling of described roller can become unstable.

On the contrary, be similar to present embodiment, if described outer shroud plane of trajectory orbital stands to grind when the rotation axis that keeps grinding stone is parallel to the central axis of this outer shroud, and making grinding stone in the axial direction swing of described outer shroud, stand superfinish subsequently, on described outer shroud plane of trajectory orbital, can form the grinding vestige that is similar to mesh pattern so, as shown in Fig. 2 (c), and the variation of the roughness of the outer shroud plane of trajectory orbital of making thus can reduce.Finally, can more effectively prolong the working life of described selfaligning roller bearing.

In order to check aforementioned effect, the present inventor has carried out life test to described selfaligning roller bearing under such test condition: revolution: 1500min ^-1Test load: 45217N; Lubrication state: RO68.In addition, before carrying out life test, the present inventor measures the average roughness Ra of described outer shroud plane of trajectory orbital for 1 to 3 time at following condition determination.In this article, described life test ends at 26.3 ratio in working life.

Condition determination 1: measured length: l=15mm; Measure direction: the outer ring axis direction; Measure the position: whole outer shroud plane of trajectory orbital

Condition determination 2: measured length: l=0.5mm; Measure direction: the outer ring axis direction; Measure position: b ₁/ (B/2)=0.7

Condition determination 3: measured length: l=0.5mm; Measure direction: the outer shroud circumferencial direction; Measure position: b ₁/ (B/2)=0.4

The test result of aforementioned life test and the measurement result of mean roughness provide in table 1.

[table 1]

*) → those bearings that expression test is not taking place to interrupt under the exfoliate condition

(A): the schematic representation of rough form

(B): condition determination 1

Measured length: 1=15mm,

Measure direction: the outer ring axis direction,

Measure the position: whole outer shroud plane of trajectory orbital

(C): condition determination 2

Measured length l=0.5mm,

Measure direction: the outer ring axis direction,

Measure position: b ₁/ (B/2)=0.7

(D): condition determination 3

Measured length: l=0.5mm,

Measure direction: the outer shroud circumferencial direction,

Measure position: b ₁/ (B/2)=0.4

EMB: embodiment

C.E: comparative examples

In table 1, TB1 to TB7 and TB20 to TB23 show wherein the outer shroud plane of trajectory orbital respectively and utilize the test bearing that method is handled shown in Fig. 2 (c), TB8 to TB13 shows the test bearing that outer shroud plane of trajectory orbital wherein utilizes the straight line Ginding process shown in Fig. 2 (a) to handle respectively, and TB14 to TB19 shows the test bearing that outer shroud plane of trajectory orbital wherein utilizes the cup-shaped grinding stone Ginding process shown in Fig. 2 (b) to handle respectively.In this article, used the selfaligning roller bearing (model is 22211, and external diameter is 100mm, and internal diameter is 55mm, and width is 25mm) made by Nippon Seiko K.K. as test bearing.

As shown in table 1, be under the situation that condition determination 1 time tests the mean roughness of described outer shroud plane of trajectory orbital, test bearing TB1 to TB19 has shown average roughness value much at one, but compare with the ratio in working life of TB1 to TB7, the ratio in working life of test bearing TB8 to TB19 (being set to the ratio in working life that obtains under 1 the condition in the working life of hypothesis test bearing TB11) is shown as a less value.In addition, be under the situation that condition determination 2 times tests the mean roughness of described outer shroud plane of trajectory orbital, test bearing TB1 to TB13 has shown average roughness value much at one, but compare with the ratio in working life of TB1 to TB7, the ratio in working life of test bearing TB8 to TB13 is shown as a less value.In addition, be under the situation that condition determination 3 times tests the mean roughness of described outer shroud plane of trajectory orbital, test bearing TB1 to TB7 and TB14 to TB19 have shown average roughness value much at one, but compare with the ratio in working life of TB1 to TB7, the ratio in working life of test bearing TB14 to TB19 is shown as a less value.Can find that from aforementioned content the test bearing TB1 to TB7 among the test bearing TB1 to TB19 can provide working life than the selfaligning roller bearing of test bearing TB8 to TB19 length.

By between test bearing TB20 and test bearing TB22, comparing, test bearing TB20 demonstrates the average roughness value (being approximately 0.1 μ m) much at one with test bearing TB22, and the ratio in working life of test bearing TB22 is shown as a value littler than test bearing TB20.Based on this,, can shorten the working life of selfaligning roller bearing so if obviously the mean roughness of outer shroud plane of trajectory orbital becomes less than 0.1 μ m.

By between test bearing TB21 and test bearing TB23, comparing, test bearing TB21 demonstrates the average roughness value (being approximately 0.5 μ m) much at one with test bearing TB23, and the ratio in working life of test bearing TB23 is shown as a value littler than test bearing TB21.Based on this,, can shorten the working life of selfaligning roller bearing so if obviously the mean roughness of outer shroud plane of trajectory orbital becomes above 0.5 μ m.

Fig. 3 shows the relation between mean roughness and the working life ratio in test bearing TB1 to TB23.In Fig. 3, (a) show relation between mean roughness when condition determination 2 times is measured the roughness of described outer shroud plane of trajectory orbital and working life ratio, and (b) show the relation between mean roughness when condition determination 3 times is measured the roughness of described outer shroud plane of trajectory orbital and working life ratio.

As shown in Figure 3, can understand that test bearing TB1 to TB7, TB20 among the test bearing TB1 to TB23 and TB21 are at b ₁/ (B/2)=0.7 and b ₁Mean roughness in/(B/2)=0.4 scope is positioned at the scope of 0.1 μ m to 0.5 μ m, and test bearing TB8 to TB19, TB22 and TB223 are at b ₁/ (B/2)=0.7 and b ₁Mean roughness in/(B/2)=0.4 scope is positioned at outside the scope of 0.1 μ m to 0.5 μ m.In this article, in described roughness mensuration process, range of measurement is set at b ₁/ (B/2)=0.7 and b ₁/ (B/2)=0.4 reason is, is applied near position corresponding to b of largest face pressure when described selfaligning roller bearing receives radial load ₁/ (B/2)=0.4, and when interior ring and roller receive thrust load and torque load (the moment load) and run-off the straight, be applied near position of largest face pressure corresponding to b ₁/ (B/2)=0.7.

When at b ₁/ (B/2)=0.1 to 0.9 and the condition of measured length l=0.5mm under when the outer shroud plane of trajectory orbital roughness among the test bearing TB1 measured institute to obtain measurement result shown in Figure 4.In Fig. 4, ◆ what refer to is the roughness of the axial direction of described outer shroud, is the roughness of the circumferencial direction of described outer shroud and ■ refers to.

As shown in Figure 4, obviously, when at 0.1≤b ₁When the roughness of external loop orbit face was measured under/(B/2)≤0.9 condition determination, on axial direction and circumferencial direction, the average roughness Ra of described outer shroud plane of trajectory orbital was positioned at the scope of 0.1 μ m≤Ra≤0.5 μ m.

Fig. 5 shows roughness on the circumferencial direction of test bearing TB1 to TB23 and the relation between the roughness on the axial direction.As shown in Figure 5, test bearing TB1 to TB7, TB20 among the test bearing TB1 to TB23 and the mean roughness of TB21 on axial direction and circumferencial direction all are positioned at the scope of 0.1 μ m to 0.5 μ m, but test bearing TB8 to TB19, TB22 and the TB23 mean roughness on axial direction and circumferencial direction all is not positioned at the scope of 0.1 μ m to 0.5 μ m.

Utilize aforementioned content, if, at b ₁/ (B/2)≤0.9, b ₁/ (B/2)≤0.9 and measured length be in the scope of 0.1mm to 1.0mm, the average roughness Ra of outer shroud plane of trajectory orbital on axial direction and circumferencial direction is set in the scope of 0.1 μ m to 0.5 μ m, can obtain such selfaligning roller bearing so, promptly can be by suppressing owing to realize the prolongation in working life such as peeling off scaling off too early that such damaged surfaces or the like causes.More preferably, if the average roughness Ra of the outer shroud plane of trajectory orbital on axial direction and circumferencial direction is set in the scope of 0.2 μ m to 0.4 μ m, as providing in the table 1, can further prolong the working life of described selfaligning roller bearing so.

In addition, the present inventor studies the prolongation in working life of described selfaligning roller bearing in earnest.Thus, the present inventor finds, if increase the friction factor of contacting part office between the loop orbit face and roller outside by the roughness that improves the outer shroud plane of trajectory orbital in order to suppress roller to rotate slippage, can prolong by suppressing to peel off the working life of realizing described selfaligning roller bearing so, but owing to be not enough by the value that merely increases as the average roughness Ra of roughness curve amplitude (vertically) parameter of outer shroud plane of trajectory orbital only, so importantly reduce the ricing interval of spacing (laterally) parameter as roughness curve.

Say that more specifically as shown in Figure 6, roughness parameter S so defines

$S=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{S}_i\&CenterDot;\&CenterDot;\&CenterDot;\left(1\right)$

Wherein l is the measured length of roughness curve C of the roughness of the described outer shroud plane of trajectory orbital of indication, and n is the number of the roughness peak value on the roughness curve C, and Si is the interval between the adjacent peak value on the roughness curve C.If this roughness parameter S is set to 0＜S≤20 μ m, the friction factor of contacting part office can increase between loop orbit face and the roller so outside, and can suppress the slippage of roller thus.Therefore, can suppress because such as peeling off scaling off too early that such damaged surfaces or the like causes, thereby prolong the working life that can realize described selfaligning roller bearing.

Contact condition under the situation that the roughness parameter S that Fig. 7 schematically shows in described outer shroud plane of trajectory orbital is big and this parameter S is less between described outer shroud plane of trajectory orbital and the roller.As shown in Figure 7, under the less situation of the roughness parameter S of described outer shroud plane of trajectory orbital, the roughness peak value number of this outer shroud plane of trajectory orbital that contacts with roller is greater than the bigger situation of roughness parameter S.Therefore, the friction factor of contacting part office increases between described outer shroud plane of trajectory orbital and roller, and has suppressed the slippage of roller.

Figure 8 illustrates the practical measurement result of the friction factor of contacting part office between hour described outer shroud plane of trajectory orbital and the roller of as the roughness parameter S of described outer shroud plane of trajectory orbital big and this parameter S.As shown in Figure 8, under the situation that average roughness Ra equates basically, if roughness parameter S is less, the friction factor of contacting part office can become big between described outer shroud plane of trajectory orbital and roller so.Here, the friction factor ratio among Fig. 8 is to have the relative value that derives when the friction factor of roughness parameter S is 1 greatly when hypothesis.

Fig. 9 schematically shows under the situation that increases the friction factor of contacting part office between described outer shroud plane of trajectory orbital and the roller by the mean roughness S that increases described outer shroud plane of trajectory orbital and the lubrication state under the situation that increases the friction factor of contacting part office between described outer shroud plane of trajectory orbital and the roller by the roughness parameter S that reduces described outer shroud plane of trajectory orbital.As shown in Figure 9, when increasing the friction factor of contacting part office between described outer shroud plane of trajectory orbital and the roller by the average roughness Ra that increases described outer shroud plane of trajectory orbital, the lubrication state variation, and shorten the working life of described selfaligning roller bearing thus.On the contrary, when increasing the friction factor of contacting part office between described outer shroud plane of trajectory orbital and the roller by the roughness parameter S that reduces described outer shroud plane of trajectory orbital, although the friction factor of contacting part office increases between described outer shroud plane of trajectory orbital and roller, coarse ricing with respect to oil slick thickness (oil film parameter) can not change.Therefore, will never shorten because of the lubrication state variation working life of described selfaligning roller bearing.

In order to check aforementioned effect, the present inventor has carried out life test to described selfaligning roller bearing under such condition determination: revolution: 1500min ^-1Test load: 45217N; Lubrication state: VG68, (model is 22211 to adopt the selfaligning roller bearing of being made by Nippon Seiko K.K. simultaneously, external diameter is 100mm, internal diameter is 55mm, width is 25mm) as test bearing, and before carrying out life test, also determined the average roughness Ra and the roughness parameter S of outer shroud plane of trajectory orbital.

The test result of aforementioned life test and the measurement result of average roughness Ra and roughness parameter S provide in table 2.

*) → what indicate is those bearings that test is not taking place to interrupt under the exfoliate condition

(A): the schematic representation of rough form

(B): A locates

(C): B locates

(D): C locates

(E): the mean value of the A that locates, B, C

EMB: embodiment

C.E: comparative examples

In table 2, test bearing TB31 to TB37 and TB45, TB46 indicate respectively is test bearing with coarse patterns shown in Figure 10 (b) of wherein outer shroud plane of trajectory orbital (the outer shroud plane of trajectory orbital in this selfaligning roller bearing is ground when the rotation axis that keeps grinding stone is parallel to the central axis of outer shroud, stands superfinish subsequently when making grinding stone along the axial direction swing of outer shroud).Have again, test bearing TB38 to TB44 indicates respectively is test bearing with coarse patterns shown in Figure 10 (a) of wherein outer shroud plane of trajectory orbital (the outer shroud plane of trajectory orbital in this selfaligning roller bearing is ground when the rotation axis that keeps grinding stone is parallel to the central axis of outer shroud, stands superfinish subsequently when making grinding stone along the axial direction swing of outer shroud).In addition, average roughness Ra in the table 2 and roughness parameter S are corresponding to the value that goes out in position determination shown in Figure 11.Here, in Figure 11, locating is applied in the position of largest face pressure when A and C are considered to when interior ring and roller owing to apply thrust load and torque load run-off the straight, and the B that locates is considered to be applied in the position of largest face pressure when bearing stands pure radial load.In addition, a relative value of the derivation when the value in the hypothesis comparative examples 5 is 1 of the ratio utilization in working life in the table 2 represents that wherein working life is the shortest in comparative examples 5.Described life test working life ratio be to stop in 15.0 o'clock.

Figure 12 illustrates the relation between roughness parameter S and the working life ratio.As shown in Figure 12, be positioned at the scope of 0.25 μ m to 0.40 μ m in the average roughness Ra of embodiment 1 to 9 and comparative examples 1 to 7 China and foreign countries' loop orbit face, but be shorter than embodiment 1 to 9 working life of comparative examples 1 to 7.This be because the roughness parameter S of outer shroud plane of trajectory orbital described in the embodiment 1 to 9 be 20 μ m but in comparative examples 1 roughness parameter S surpassed 20 μ m.

As previously mentioned, owing to be set to 0＜S≤20 μ m,, and can suppress the slippage of roller so the friction factor of contacting part office can increase between described outer shroud plane of trajectory orbital and roller by the roughness parameter S of formula (1) definition.Therefore, can be by suppressing owing to, realize that prolong the working life of described selfaligning roller bearing such as peeling off scaling off too early that such damaged surfaces or the like causes.If the value of Ra is in the scope of 0.1 μ m to 0.5 μ m and the value of S is 20 μ m or littler, can obtain gratifying outer shroud roughness result so.More preferably, if the value of S is set to 15 μ m or littler, as providing in the table 2, can further prolong the working life of described selfaligning roller bearing so.In addition, desirablely be, for outside between loop orbit face and the roller contacting part office stably obtain high coefficient of friction, the average roughness Ra on circumferencial direction and axial direction should be set to Ra=0.25 μ m to 0.4 μ m.In addition, passed judgment on from smallest particles size of grinding stone or the like, the lower limit of S can be considered to approximate greatly 0.01 μ m.

Next, set forth with reference to Figure 13 to the 19 pair of second embodiment of the present invention hereinafter.

Figure 13 is an axial sectional view according to the selfaligning roller bearing of second embodiment of the invention.In Figure 13, in selfaligning roller bearing according to second embodiment of the invention, as the double convex surface roller 25 of rolling element along the circumferential direction via a retainer 26 rollably be arranged on have double-row track 22 (also being known as " interior loop orbit face " hereinafter) interior ring 21 and have between the outer shroud 23 of double integrated spherical track 24 (also being known as " outer shroud plane of trajectory orbital " hereinafter).Between the double-row track 22 on the interior ring 21, be provided with a guide ring 27, and the race way diameter on the interior ring 21 is set to along axial direction at the middle part greater than two ends.

The present inventor studies the prolongation in working life of described selfaligning roller bearing in earnest.Finally, the present inventor finds, aforementioned selfaligning roller bearing is peculiar to break not is directly to take place crooked by rolling element and cause, but is caused by the tangential force that acts between inner and outer rings and the rolling element.Therefore, the present inventor finds that breaking is caused by the institute that scales off that originates in atomic little plastic flow, wherein said plastic flow as a starting point and tangential force that ought be bigger as the time spent result from described on the surface of ring.Atomic little plastic flow results near surface in tangential force as the time spent.Therefore, not only promote to peel off crackle, and made and to expose the maximum shear stress position from the teeth outwards, increased the value of shearing stress thus.In other words, described tangential force is to having huge adverse effect in working life of bearing.

In addition, the present inventor also finds, there is a direction (identical) with rotating direction, tangential force can have a negative impact to working life in the direction, an and direction (opposite) with rotating direction, tangential force is very little to working life influence in the direction, and makes the time spent crackle when tangential force along the mode identical with rotating direction and be easy to occur and broaden (in slow circumferential speed side).

Therefore, for prolong the working life of realizing selfaligning roller bearing, importantly suppress to act on as the tangential force on the interior ring of main damaged portion along rotating direction.Therefore, the present inventor has finished the present invention, is conceived to optimize the roughness balance between inner and outer rings and the rolling element, as a kind of measure that is used to suppress described tangential force.

Specifically, the tangential force that acts on the described interior ring can increase in these cases: (A) surface pressure is very big; (B) roughness of the rolling contact surfaces of rolling element and interior loop orbit face is very big; And (C) in the ring and rolling element between slippage (circumferential speed there are differences) very big.

Surface pressure depends primarily on application feature in (A).Therefore, for the tangential force of inhibitory action on interior ring, the roughness that can consider rolling contact surfaces by suppressing described rolling element and interior loop orbit face is as the measure that is used for (B), perhaps by the rotating speed that reduces described rolling element make described rolling element suppress near a kind of pure rolling state in slippage between ring and the rolling element as the measure that is used for (C).

At first, will at length set forth below the important implication of the numerical value in (B).

For the influence of the surface roughness of studying interior ring in the described selfaligning roller bearing and rolling element to tangential force, when adopting two cylinder test machines shown in Figure 14, by determining described tangential force by means of the torque meter mensuration friction torque that is assemblied on the back shaft.Condition determination is set to the largest face pressure P _Max=3.2Gpa, slip rate are 10%, and lubricant oil is RO68.

As the mensuration and the result of calculation of the circumferential speed of the circumferential speed of the interior ring in the described selfaligning roller bearing and rolling element, the circumferential speed of rolling element has surpassed the circumferential speed of interior ring.Therefore, a test block (test piece) that is used to simulate described rolling element is assembled in driving side, and one be used to simulate described in the test block of ring be assembled in slave end, and the rotating speed of slave end test block is minimized by gear train (gear ratio is 10: 9).Thus, the revolution of driving side test block is set to 500min ^-1, and the revolution of slave end test block is set to 450min ^-1

Figure 15 show surface roughness at the driving side test block that is used to simulate rolling element change be kept for simultaneously simulating in the surface roughness of slave end test block of ring under RaF=0.1 μ m place keeps constant situation, utilize described two cylinder test machines acquisition to acting on the result of study of two tangential force difference in size on the test block.In Figure 15, the size ratio when described tangential force is 1 as the tangential force that obtains when hypothesis under the average surface roughness RaD=0.05 of driving side test block μ m provides.

In addition, the surface roughness that Figure 16 shows the slave end test block of ring in being used to simulate changes the surface roughness of the driving side test block that is kept for simulating rolling element simultaneously under RaD=0.05 μ m place keeps constant situation, utilize described two cylinder test machines acquisition to acting on the result of study of two tangential force magnitude difference on the test block.In Figure 16, the size ratio when described tangential force is 1 as the tangential force that obtains when hypothesis under the average surface roughness RaF=0.1 of slave end test block μ m provides.

Use the material of high-carbon-chromium bearing steel (SUJ2) here, as each test block of described driving side and slave end.Under 830 to 850 ℃, this steel is carried out Quenching Treatment, and under 160 to 240 ℃, this steel is carried out temper subsequently.Finally, along with the surface roughness increase is many more, at the driving side test block that is used for simulating described rolling element be used to simulate the slave end test block tangential force of encircling in described and all can increase more, but when the average surface roughness of driving side test block increases to average surface roughness above RaD 〉=0.1 μ m and slave end test block when increasing to above RaF 〉=0.15 μ m, described tangential force is tending towards quick increase.

Therefore, inhibitory action in described, encircle and rolling element on tangential force aspect effectively, the mean roughness of interior loop orbit face should be set to Ra＜0.15 μ m, and the mean roughness of the rolling contact surfaces of rolling element should be set to Ra＜0.1 μ m.In this case, the result of the life test of Miao Shuing is passed judgment on from behind, the mean roughness of loop orbit face should be set to Ra＜0.1 μ m in preferably described, and the mean roughness of the rolling contact surfaces of described rolling element should be set to Ra＜0.05 μ m.As the lower limit that causes owing to the restriction on making, the mean roughness of described interior loop orbit face is Ra＞0.001 μ m, and the mean roughness of the rolling contact surfaces of described rolling element is Ra＞0.001 μ m.

Next, be used for the measure of the tangential force of inhibitory action on interior ring and rolling member as another, to reduce by rotating speed described rolling element make described rolling element approach the pure rolling state suppress described in (C) in the approach of slippage between ring and the rolling element set forth.

As the specific process of the rotating speed that is used to suppress described rolling element, the present inventor pays close attention to and makes the surface roughness of outer shroud plane of trajectory orbital become big solution route.The example view of this approach schematically shows in Figure 17 and 18 respectively.

Figure 17 and 18 shows respectively in load and applies the direction that scope and non-load apply the tangential force that rolling element described in the scope receives from outer shroud.Usually, apply in the scope in load, it is faster than the rotational speed of this rolling element (revolution speed) that the rotating speed of described rolling element becomes.Therefore, as shown in Figure 17, the tangential force that acts between described outer shroud and the rolling element is done work along the direction of the rotating speed that suppresses described rolling element.

On the contrary, apply in the zone in non-load, the rotating speed of described rolling element becomes slower than rotational speed.Therefore, as shown in Figure 18, the tangential force that acts between described outer shroud and the rolling element is done work along the direction of the rotating speed that strengthens described rolling element.In other words, shown in the result of two cylinders test in Figure 15 and 16, when the surface roughness of outer shroud plane of trajectory orbital increases, the tangential force that acts between described outer shroud and the rolling element can be increased, and thus, can suppress by the rotation of controlling described rolling element described in the ring and rolling element between slippage.

Especially, the load of breaking in meeting applies in the scope, and described rolling element is along suppressing rotating speed and suppressing because the direction of the tangential force that speed difference (slippage) causes between interior ring and the rolling element receives tangential force from described outer shroud.Finally, break, can increase the service life by stoping described interior environment-development life.

Passed judgment on from the result of the test of two cylinders shown in Figure 15 and 16, can think, if the mean roughness of this outer shroud plane of trajectory orbital is set at the scope of Ra 〉=0.1 μ m as the mean roughness of outer shroud plane of trajectory orbital, like this can be effective to the prolongation in working life, the tangential force that acts on so between outer shroud and the rolling element can increase, and can suppress rotating speed.If the mean roughness of described outer shroud plane of trajectory orbital increases, can suppress described interior environment-development life so and break, but can on described outer shroud, act on bigger tangential force naturally.Therefore, excessive if the mean roughness of described outer shroud plane of trajectory orbital is set to, this moment, this outer shroud will be damaged so.As hereinafter described, the Ra if the mean roughness of described outer shroud plane of trajectory orbital becomes＞0.5 μ m, can shorten so opposite working life owing to described outer shroud breaks.

Therefore, if be set at 0.1 μ m≤Ra≤0.5 μ m by mean roughness with the outer shroud plane of trajectory orbital, make the tangential force that acts between outer shroud and the rolling element increase, reach and can not cause described outer shroud that exfoliate degree takes place, the rotating speed that can suppress described rolling element so, and can inhibitory action in described, encircle and rolling element on tangential force, thereby prolong the working life that can realize described selfaligning roller bearing.

In order to check effect of the present invention, the present inventor has carried out following test.In these trials, having adopted model is 22211 selfaligning roller bearing.Use high-carbon-chromium bearing steel (SUJ2) as described inner and outer rings and rolling element, and carried out the aforementioned hot processing.Used the selfaligning roller bearing that all satisfies following condition as embodiments of the invention: the average roughness Ra of the rolling contact surfaces of rolling element＜0.1 μ m, the average roughness Ra of interior loop orbit face＜0.15 μ m, and the mean roughness 0.1 μ m≤Ra≤0.5 μ m of outer shroud plane of trajectory orbital, simultaneously, adopted the selfaligning roller bearing that one of do not satisfy at least in aforementioned mean roughness example as a comparison.Then, carried out the life-span contrast test.

Test condition is as described below:

Revolution: 1500min ^-1

Test load: 45217N

Lubrication state: RO68

Test result provides in table 3.Utilize working life when the ratio of hypothesis acquisition when the value in the working life the shortest comparative examples is 1 and indicate.Figure 19 is a chart, based on the result in the table 3, shows the working life of embodiments of the invention and comparative examples in the summary mode.

[table 3]

	(A) (μm)	(B) (μm)	(C) (μm)	Working life ratio	Remarks
						EMB 1	0.164	0.8	0.012	15.4
EMB 2	0.153	0.083	0.026	13.3
						EMB 3	0.144	0.115	0.039	11
EMB 4	0.147	0.116	0.04	12.7
						EMB 5	0.163	0.094	0.033	14.2
EMB 6	0.152	0.143	0.095	9.6	I.R, the R.E → roughness upper limit
						EMB 7	0.488	0.097	0.03	18	O.R → roughness the upper limit
EMB
	8	0.102	0.092	0.047	10.9	O.R → roughness lower limit
C.E 1							0.089	0.166	0.108	1	O.R, I.R, R.E → exceed roughness scope
	C.E 2	0.082	0.161	0.035	2.8	O.R, I.R → exceed roughness scope
C.E 3							0.093	0.117	0.035	4.5	O.R → the be lower than lower limit of roughness
	C.E 4	0.556	0.109	0.03	5.5	O.R → the be higher than upper limit of roughness

Annotate) (A): the mean roughness of outer shroud (O.R)

(B): the mean roughness of interior ring (I.R)

(C): the mean roughness of rolling element (R.E)

C.E: comparative examples

As shown in table 3, resemble comparative examples 2, be suppressed within Ra＜0.1 μ m iff mean roughness the rolling contact surfaces of described rolling element, prolong effect the working life that can obtain so approximately to compare than three times of length in the example 1, and wherein the roughness of outer shroud, interior ring and rolling element has all exceeded scope of the present invention in comparative examples 1.In addition, resemble comparative examples 3 and 4,, can obtain approximately to compare working life so than five times of example 1 length if the mean roughness of loop orbit face is suppressed within Ra＜0.15 μ m in described.On the contrary, resemble the embodiment 1 to 8 among the present invention, obviously, if not only the mean roughness of the rolling contact surfaces of described rolling element and the mean roughness of interior loop orbit face are suppressed at respectively within Ra＜0.1 μ m and the Ra＜0.15 μ m, and 0.1 μ m≤Ra≤0.5 μ m within the mean roughness of outer shroud plane of trajectory orbital is set in, can obtain comparison so than 1 long ten times or more working life of example.

In other words, these results show, the rolling contact surfaces by reducing described rolling element and the surface roughness of interior loop orbit face come inhibitory action in described, encircle and rolling element between tangential force, can increase the service life, and the surface roughness by increasing described outer shroud plane of trajectory orbital come load apply the rotation that suppresses described rolling element in the scope and further reduce act on described in tangential force on the ring, working life can be than ten times or more of the bearing prolongations that exceeds the scope of the invention.

But, resemble the comparative examples 4 in the table 3, if it is excessive that the mean roughness of described outer shroud plane of trajectory orbital is set to, such as Ra＞0.5 μ m, but though, prolong effect working life so can't obtain bearing so owing to suppressed interior environment-development raw cook shape and peel off and impelled outer shroud to scale off on the contrary.Therefore, the mean roughness of described outer shroud plane of trajectory orbital must be suppressed within Ra≤0.5 μ m.

Next, set forth with reference to Figure 20 to the 22 pair of third embodiment of the present invention.

Figure 20 is a longitudinal sectional view, shows a selfaligning roller bearing according to third embodiment of the invention.In Figure 20, according to the selfaligning roller bearing of third embodiment of the invention by an interior ring with double-row track 32a (also being known as " interior loop orbit face " hereinafter) 31, one have double integrated spherical track 34a (also being known as " outer shroud plane of trajectory orbital " hereinafter) outer shroud 33, a plurality ofly constitute with double form roller 35 and retainer 36 that is used for rollably maintaining roller 35 between interior loop orbit face 32a and outer shroud plane of trajectory orbital 34a.

In interior loop orbit face 32a and outer shroud plane of trajectory orbital 34a, the diameter d 3 at middle part, d4 are set to diameter d 1, the d2 greater than two ends.Example illustrated in the shape of retainer 36 is not limited to, but can use other pattern.But two end face 36a are opposed mutually via two ends and the gap S broad ways of interior loop orbit face 32a.

The present inventor recognizes, under situation about making for the purpose of the rolling of stablizing described roller and with the surface roughness of described outer shroud plane of trajectory orbital greater than the surface roughness of interior loop orbit face, by reducing in the bearing operation process that the contacting part office produces between described roller and interior ring and described roller and outer shroud change in friction force suppresses since aspect the atomic little slippage on surface of contact that change in friction force produces effectively, not only should the outer shroud plane of trajectory orbital be made with regard to mean roughness more coarse than interior loop orbit face, and should consider described in the variation of surface roughness of loop orbit face and outer shroud plane of trajectory orbital.In addition, the present inventor recognizes, because by the relation between the surface roughness of optimizing described interior loop orbit face and outer shroud plane of trajectory orbital at described variation, the part that stands maximum Surface fatigue can be transferred on the rolling element from inner and outer rings, by selecting anti-heat treatment requirements of peeling off and roller material, can realize the prolongation in working life.

Especially, the present invention has a kind of unique construction aspect following, promptly internally the surface roughness of loop orbit face 32a and outer shroud plane of trajectory orbital 34a is adjusted (roughness range limit value Rai 〉=1.5 of loop orbit face on center line in the roughness scope lower limit Rao/ of outer shroud plane of trajectory orbital on center line), and should be adjusted (γ R (rolling element)-γ R (orbit ring) 〉=3%) to the difference of the retained austenite composition between rolling element 35 and the orbit ring 31,33.

To only partly set forth below the structure of uniqueness, to other the structure part, such as interior ring 31, outer shroud 33, roller 35 and retainer 36 or the like, elaboration will be omitted.But within the scope of the present invention, these structure parts can change in design suitably.

Here, in the present invention, two different parts on interior ring 31 and outer shroud 33 circumference or more multi-section position internal loop orbit face 32a and the mean roughness of outer shroud plane of trajectory orbital 34a on center line are measured respectively, then, go out standard deviation based on mean value calculation, and will work as the roughness that goes out ± obtain during 3 σ at mean value calculation subsequently as " roughness scope " of the present invention.

In the roughness scope of interior loop orbit face 32a and outer shroud plane of trajectory orbital 34a, the roughness range limit value of interior loop orbit face 32a is set to Rai, and the roughness scope lower limit of outer shroud plane of trajectory orbital 34a is set to Rao.Pass between roughness scope, Rao and the Rai ties up among Figure 21 and schematically shows.

In the present invention, if come the roughness scope lower limit Rao of external loop orbit face 34a and the roughness range limit value Rai of interior loop orbit face 32a to examine closely according to the roughness scope, roughness difference between outer shroud plane of trajectory orbital 34a and the interior loop orbit face 32a reduces usually, that is the difference of the frictional force between frictional force between outer shroud 33 and the roller 35 and interior ring 31 and the roller 35 and, thus by making the influence of the coarse generation of outer shroud plane of trajectory orbital 34a reach minimum state.

In addition, change under the very large situation in roughness, although the roughness average of outer shroud plane of trajectory orbital 34a is greater than the roughness average of interior loop orbit face 32a, but when Rao compares with Rai, two values are almost equal (when the comparative examples among Figure 20 a), supposing as the case may be perhaps that Rai becomes more coarse than Rao (the comparative examples b among Figure 20).In this case, accounting for main is that the frictional force between outer shroud 31 and the roller 35 should be greater than the frictional force between interior ring 31 and the roller 35, yet, according to specific part, phenomenon still can appear reversing, and the frictional force in making between ring 31 and the roller 35 becomes bigger.Thus, in the turning course of roller 35, frictional force can change significantly.Finally, it is unstable that the rotation/rotation (revolution) of roller 35 becomes, and the contacting part office produces atomic little slippage between interior ring 31 and roller 35 thus, and is easy to thus cause producing such as peeling off such Surface fatigue.

On the contrary, in the present invention, be set to 1.5 or when higher at the ratio of the roughness scope lower limit Rao of the roughness range limit value Rai of interior loop orbit face 32a and outer shroud plane of trajectory orbital 34a, change in the roughness of bearing inside by not only considering mean roughness but also considering, can keep the state of the roughness of outer shroud plane of trajectory orbital 34a always greater than the roughness of interior loop orbit face 32a.As shown in Figure 21, adopted ratio R ao/Rai=2.5 in the present embodiment.

Therefore, the frictional force between roller 35 and the orbit ring 31,33 can not change in the operation process of bearing significantly.Therefore, be not easy to occur in the slippage in the tiny area, and in can suppressing thus ring on 31 such as peeling off such damaged surfaces or the like.

Be used as at normally used steel SUJ2 under the situation of material of roller 35, if replacing high-temperature tempering handles, temper after in 160 to 220 ℃ low temperature range, quenching, different with the heat treatment of orbit ring 31,33, hardness can be set to Hv 700 or higher, and can impel residual austenite composition γ R to remain in the scope of 3 to 12% volume ratios.Utilize this structure, described roller is difficult for peeling off very much.

In addition, under the situation of having used the roller of making by SUJ2, if used by martensite and handled (the marstressing) carbonitriding processing (carbonitriding process) for example, so since the solid-state dispersion of nitrogen (solid-dissolved) in basic material, improve residual austenite composition γ R, and can utilize the nitrogen of solid-state dispersion to suppress the generation of peeling off better.In addition, if residual austenite composition remains on 3% or more, the hardness of ring 31, outer shroud 33 in the hardness of rolling element 35 can be higher than inevitably so, and this thus processing is more effective for peeling off damage.Desirable is that nonhomogeneous hardness should be set to Hv 30 or higher (little Vickers hardness (the micro Vickers hardness)).

In order to check effect of the present invention, the corresponding bearing in embodiment 1 to 12 and the comparative examples 1 to 7 has been carried out life test, and will the embodiment who wherein assesses based on the L10 life-span working life have been set forth.Test result provides in table 4.

Here, test condition is as described below:

" test condition "

Revolution: 25 seconds ^-1(1500rpm)

Test load: 45217N

Lubrication state: self-contained lubrication oil (VG68)

Bearing specification: selfaligning roller bearing (model 22211)

As the material of interior ring, outer shroud and roller, used SUJ2 (high-carbon-chromium bearing steel) respectively.In addition, as described below respectively internally ring, outer shroud and roller heat-treat:

＜interior ring and outer shroud 〉

830 to 850 ℃ of Quenching Treatment

220 to 240 ℃ * 2 hours temper

＜roller 〉

1. 830 to 850 ℃ of Quenching Treatment

160 to 260 ℃ * 2 hours temper

2. 820 to 840 ℃ of carbonitridings are handled and Quenching Treatment subsequently

160 to 200 ℃ * 2 hours temper

Loop orbit face and the roughness of outer shroud plane of trajectory orbital, the hardness of described rolling element and residual austenite composition provide in table 4 in described.

As for the roughness of loop orbit face in described and outer shroud plane of trajectory orbital, at three positions the roughness on the center line is measured, calculate the roughness scope based on standard deviation subsequently, and then calculate Rao and Rai.

[table 4]

	(A)	(B)	(C)	(D)	(E)	(F)	(G)
								EMB1	180	0.293	0.044	0.065	0.036	0.249	0.101
EMB2	180	0.300	0.053	0.055	0.021	0.247	0.076
								EMB3	180	0.352	0.053	0.078	0.042	0.299	0.12
EMB4	180	0.239	0.048	0.052	0.023	0.191	0.075
								EMB5	180	0.239	0.044	0.063	0.023	0.195	0.086
EMB6	180	0.273	0.123	0.065	0.024	0.15	0.089
								EMB7	180	0.193	0.039	0.081	0.021	0.154	0.102
EMB8	180	0.367	0.048	0.071	0.025	0.319	0.096
								EMB9	180	0.385	0.055	0.074	0.033	0.33	0.107
EMB10	200	0.296	0.044	0.081	0.036	0.252	0.117
								EMB11	220	0.293	0.052	0.092	0.039	0.241	0.131
EMB12	180	0.392	0.033	0.065	0.017	0.359	0.082
								C.E1	260	0.239	0.048	0.052	0.023	0.191	0.075
C.E2	240	0.239	0.044	0.063	0.023	0.195	0.086
								C.E3	180	0.044	0.016	0.126	0.032	0.028	0.158
C.E4	180	0.312	0.046	0.149	0.032	0.266	0.181
								C.E5	180	0.231	0.042	0.15	0.032	0.189	0.182
C.E6	180	0.092	0.016	0.048	0.021	0.076	0.069
								C.E7	180	0.123	0.024	0.115	0.023	0.099	0.138

	Rao/Rai	(H)	(I)	ΔHv	(J )	(K )	ΔγR	(L)
									EMB1	2.47	793	676	117	9	0	9.1	2.2
EMB2	3.25	785	673	112	9	1	7.6	2.1
									EMB3	2.49	785	670	115	8	0	8.1	2.1
EMB4	2.55	790	667	123	8	1	6.6	2
									EMB5	2.27	763	670	93	8	1	6.8	1.9
EMB6	1.69	777	661	116	8	1	7.3	1.8
									EMB7	1.51	795	666	129	9	0	8.8	1.7
EMB8	3.32	793	688	105	9	0	8.9	2.1
									EMB9	3.08	788	690	98	9	1	7.5	2
EMB10	2.15	710	678	32	5	0	5.3	1.6
									EMB11	1.84	708	678	30	3	0	3	1.5
EMB12	4.38	793	679	114	7	0	7	1.7
									C.E1	2.55	687	683	4	0	0	0	1.2
C.E2	2.27	695	676	19	2	0	2	1.2
									C.E3	0.18	785	688	97	9	1	7.6	1
C.E4	1.47	792	680	112	9	0	9.3	1.3
									C.E5	1.04	793	682	111	8	0	7.5	1.2
C.E6	1.10	768	675	93	8	0	7.5	1.1
									C.E7	0.72	783	688	95	6	0	6.4	1.1

Annotate) (A): roller annealing in process (temper) (℃)

(B): the average roughness value on the outer shroud center line

(C): outer shroud 3 σ

(D): the average roughness value on the interior ring center line

(E): interior ring 3 σ

(F): the lower limit Rai of outer shroud roughness scope

(G): the CLV ceiling limit value Rao of interior ring roughness scope

(H): the hardness of rolling element

(I): the hardness of interior ring

(J): the retained austenite composition (percent by volume) in the rolling element

(K): the material austenite composition (percent by volume) in the interior ring

(L): L10 ratio in working life

EMB: embodiment

C.E: comparative examples

In addition, Figure 22 shows the relation between ratio R ao/Rai and the working life ratio, simultaneously described in the heat-treat condition of ring, outer shroud and roller remain unchanged.What " ratio in working life " referred to is a ratio that draws when be 1 working life that hypothesis calculates under aforementioned test condition.

According to table 4, the value of Rao/Rai is in 0.18 to 2.55 the scope in comparative examples 1 to 7, and the value of Rao/Rai is in 1.51 to 4.38 the scope in embodiment 1 to 12.In addition, γ R (rolling element) in comparative examples 1 to 7-γ R (orbit ring) is in 0 to the 9.3% percent by volume scope, and γ R (rolling element)-γ R (orbit ring) is in 3 to the 9.1% percent by volume scopes in embodiment 1 to 12.

Thus, L10 ratio in working life is in 1 to 1.3 the scope in comparative examples 1 to 7, and L10 ratio in working life is in 1.5 to 2.2 the scope in embodiment 1 to 12, and finds that working life is shorter.

Under the situation that ring in described and the relation between the roughness of outer shroud are verified, obvious, as shown in Figure 22,, prolong effect working life and become fairly obvious, as among the embodiment 1 to 12 when the value of aforementioned Rao/Rai is 1.5 or when higher.

The value of Rao/Rai less than 1.5 situation under, resemble comparative examples 3 to 7, it is not enough that the frictional force size between outer shroud and the roller becomes, and cause the rolling of roller to seem unstable thus.Finally, contacting part office that can be between roller and orbit ring produces slippage, cause peeling off, and reduction of service life thus.On the contrary, the value of Rao/Rai greater than 1.5 situation under, resemble embodiment 1 to 12, will never on interior ring, cause such as peeling off such damaged surfaces or the like, and be prolonged working life thus.

Therefore, in the present invention, the value of Rao/Rai is set to 1.5 or higher.In addition, too much if the value of Rao/Rai is set resembling among the embodiment 12, effect will reach capacity so.Therefore, the value of the desirable Rao/Rai of being should be set and be equal to, or greater than 2.0, but is equal to or less than 3.5.

Especially, very coarse if the surface roughness of described outer shroud plane of trajectory orbital is set to, and can't form enough oil films, be easy to so produce such as peeling off such damaged surfaces or the like.Therefore, desirable is that the absolute value of the mean roughness of described outer shroud plane of trajectory orbital should be set to 0.4 μ mRa.

In addition, in table 4, in an embodiment of the present invention, the hardness of described rolling element is set to the hardness greater than described outer shroud and interior ring, the difference of the retained austenite composition of described rolling element is set to 3% or higher, and the value of Rao/Rai is set to 1.5 or higher.Therefore, even transfer to the material requirements that also can resist damaged surfaces on these rollers, so can obtain longer bearing working life because described roller can satisfy fatigue.

The solid-state dispersion of nitrogen in addition, resembles embodiment 12, using under the situation of carbonitriding processing, owing to can improve residual austenite composition, and can keep hardness higher to described roller.Therefore, especially strengthened and prolonged effect working life.

In comparative examples 1 and 2, the value of Rao/Rai is set to 1.5 or higher, but by handling as in orbit ring, roller being carried out high-temperature tempering, and because residual austenite composition is almost 0%, so not there are differences aspect the retained austenite composition between described orbit ring and rolling element, the hardness of described orbit ring and rolling element is set at equal basically.In this case, as previously mentioned,, be transferred on the roller from interior ring so the position of Surface fatigue takes place, but meeting produces damaged surfaces and then causes peeling off on roller because the surface roughness of described outer shroud plane of trajectory orbital is bigger.Therefore, can shorten the working life of bearing.

The present invention is elaborated at this with reference to specific embodiment.But,, obviously can under the condition that does not break away from the spirit and scope of the invention, carry out multiple modification and improvement for those skilled persons in the art.

In addition, the present invention can be implemented when combination utilizes each embodiment.For example, selfaligning roller bearing among the present invention structure that can combine by the part with first embodiment's a part and second embodiment and/or the 3rd embodiment forms, and perhaps can combine to construct by the part with second embodiment's a part and the 3rd embodiment forms.

As specific example, in the selfaligning roller bearing in first embodiment, the mean roughness of the rolling contact surfaces of rolling element can be set to Ra＜0.1 μ m, the mean roughness of interior loop orbit face can be set to Ra＜0.15 μ m, and can the roughness lower limit Rao on center line is set at and satisfies inequality R ao/Rai 〉=1.5 at roughness range limit value Rai on the center line and outer shroud plane of trajectory orbital with interior loop orbit face, the difference of retained austenite composition γ R can be set to 3% volume ratio or higher between rolling element and the orbit ring.In addition, in the selfaligning roller bearing in first embodiment or second embodiment, roughness scope lower limit Rao on center line can be set to and satisfies inequality R ao/Rai 〉=1.5 interior loop orbit face at roughness range limit value Rai on the center line and outer shroud plane of trajectory orbital, and the difference of retained austenite composition γ R can be set to 3% volume ratio or higher between rolling element and the orbit ring.In addition, in the selfaligning roller bearing in second embodiment or the 3rd embodiment, the outer shroud plane of trajectory orbital can stand to grind when making the rotation axis of grinding stone be parallel to the central axis of outer shroud, and is making grinding stone stand superfinish in the axial direction swing (swing) of outer shroud subsequently.

Claims (6)

1. selfaligning roller bearing between ring and the outer shroud, is characterized in that in wherein along the circumferential direction rollably being arranged in as the double roller of rolling element,

Make the outer shroud plane of trajectory orbital on the interior perimeter surface be formed on described outer shroud roughness greater than be formed on described in the roughness of interior loop orbit face on the outer surface of ring, and

On axial direction and circumferencial direction, the average roughness Ra of described outer shroud plane of trajectory orbital is set in 0.1 μ m≤Ra≤0.5 μ m, be set in 0＜S≤20 μ m by the roughness parameter S of following formula definition,

$S=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{S}_i$

Wherein n is the roughness peak value number that is used to indicate on the roughness curve of roughness of described outer shroud plane of trajectory orbital, and Si is the spacing between the adjacent peak value on the roughness curve.

2. selfaligning roller bearing according to claim 1 is characterized in that, the mean roughness of the rolling contact surfaces of described rolling element is set to Ra＜0.1 μ m, and the mean roughness of loop orbit face is set to Ra＜0.15 μ m in described.

3. selfaligning roller bearing according to claim 1, it is characterized in that, satisfy inequality R ao/Rai 〉=1.5, wherein Rai is the described interior roughness range limit value of loop orbit face on center line, and Rao is the roughness scope lower limit of described outer shroud plane of trajectory orbital on center line, and in described rolling element and interior ring and the outer shroud at least the difference of the retained austenite composition γ R between any be set to 3% volume ratio or higher.

4. selfaligning roller bearing according to claim 2, it is characterized in that, satisfy inequality R ao/Rai 〉=1.5, wherein Rai is the described interior roughness range limit value of loop orbit face on center line, and Rao is the roughness scope lower limit of described outer shroud plane of trajectory orbital on center line, and in described rolling element and interior ring and the outer shroud at least the difference of the retained austenite composition γ R between any be set to 3% volume ratio or higher.

5. selfaligning roller bearing according to claim 1 is characterized in that, at b ₁/ (B/2)≤0.9, b ₂/ (B/2)≤0.9 and measured length be in the scope of 0.1mm to 1.0mm, on axial direction and circumferencial direction, the average roughness Ra of described outer shroud plane of trajectory orbital is set in 0.1 μ m≤Ra≤0.5 μ m, wherein B is the width of described outer shroud, b ₁, b ₂Be respectively the distance with two end faces of described outer shroud, and roughness parameter S is set in 0＜S≤20 μ m.

6. selfaligning roller bearing according to claim 1 is characterized in that, described outer shroud plane of trajectory orbital has cross one another machining vestige, and these machining vestiges form by a kind of superfinish.

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