CN100588849C - Transmission component, method of manufacturing the same, and tapered roller bearing - Google Patents
Transmission component, method of manufacturing the same, and tapered roller bearing Download PDFInfo
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- CN100588849C CN100588849C CN200710146996A CN200710146996A CN100588849C CN 100588849 C CN100588849 C CN 100588849C CN 200710146996 A CN200710146996 A CN 200710146996A CN 200710146996 A CN200710146996 A CN 200710146996A CN 100588849 C CN100588849 C CN 100588849C
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Abstract
A transmission component is incorporated into a transmission in which an input shaft, an output shaft, or a gear is rotatably supported by a rolling bearing. The component has a nitriding layer at a surface layer and an austenite grain with a grain size number falling within a range exceeding 10. This provides a transmission component having an increased anti-crack strength, enhanced dimensional stability, and a long fatigue life. A method of manufacturing such a transmission component and a tapered roller bearing are also provided.
Description
The application is to be that February 27, application number in 2004 are 200410008286.4, are entitled as the dividing an application of Chinese invention patent application of " driving parts, make the method and the tapered roller bearing of driving parts " applying date.
Technical field
The present invention relates to have long rolling contact fatigue working life, the cracking resistance of raising or a driving parts of a long-term dimensional changes that reduces, and a method and a tapered roller bearing of constructing this part.
Background technique
For the working life of the part that prolongs a bearing, carry out a heat treatment.Particularly, for example, when quench part, they are heated in having an environment KX gas of further introducing ammonia wherein, be used for the top layer part carburizing-nitrogen to them, that is for example disclosed in Japanese patent application publication No. 8-4774 and 11-101247 is such.This carburizing-nitrogen is handled can the hardened layer part and the contained austenite of the microstructure form of generation, is used to prolong rolling contact fatigue working life.
It is the processing of expansion carbon and nitrogen that above-mentioned carburizing-nitrogen is handled.It requires to keep the high temperature of a long term.Thereby, the cracking resistance that has for example produced an alligatoring structure and almost do not obtained to improve.And, along with keeping more austenite, just having increased the long term dimensional rate of change, this also is the problem during this carburizing-nitrogen is handled.
Provide an alloyed steel of a composition of adjusting by dependence, prevent rolling contact fatigue, can guarantee a working life that prolongs, the cracking resistance of raising is provided and avoids a long term dimensional that increases to change.But, rely on this alloy of design, increased the cost of raw material unfriendly.
The bearing in the future in a transmission device will be used in the environment that at high temperature applies big load.In addition, will require them to use in the transmission device of a minification.Therefore, will require this bearing under the temperature higher, big load, to work than tradition.Therefore, require a bearing to have than hard intensity, than long working life that prevents rolling contact fatigue and bigger anti-resistance to spalling and dimensional stability.
Summary of the invention
A purpose of the present invention provide have a cracking resistance that increases, a driving parts in a dimensional stability that improves and a tired working life that prolongs (or a tapered roller bearing maybe the rolling contact fatigue working life that prolongs when this part is the part of a rolling bearing or a rolling bearing) and a method and a tapered roller bearing of this part of manufacturing.
The invention provides and be combined in and change a driving parts in the transmission device of a rotating speed of an output shaft with respect to a rotating speed of an input shaft by gear meshing.This part has a nitriding layer and has an austenite crystal that drops on above the grain boundary in 10 the scope at a surface layer.
In according to driving parts of the present invention, a little austenite grain size allows to increase significantly cracking resistance, dimensional stability and tired working life (the maybe rolling contact fatigue working life when this part is the part of a rolling bearing or a rolling bearing).For 10 or following austenite grain size number, any to improve tired working life significantly all be impossible, thus this crystallite dimension number greater than 10, and preferably be 11 or more than.Though wishing has further thinner austenite crystal, the crystallite dimension above 13 number normally is difficult to realize.No matter should notice that the austenite structure of driving parts can be in the top layer part of appreciable impact when carburizing-nitrogen the time or than in the inner part of top layer part, this austenite does not change.Thereby top layer part and this inside will be set to all positions of the object that is used for above-mentioned grain boundary scope.
The invention provides another driving parts in the transmission device that is combined in a rotating speed that can change output shaft by a rotating speed of the relative input shaft of gear meshing.This part has the rupture stress value in a nitriding layer of a surface layer and at least 2650 MPas.
The present invention finds can be to surpassing an A
1One temperature of transition point is carried out carburizing-nitrogen, is cooled to and is lower than A then
1One temperature of transition point, be heated above A more subsequently
1One temperature range of transition point and the steel that quenches provide a nitriding layer, and this nitriding layer allows this steel to provide to be not less than a rupture stress value of 2650 MPas, and this value is irrealizable in tradition.Thereby can obtain aspect rupture stress to surpass traditional driving parts, a therefore bigger driving parts aspect intensity.
The invention provides another driving parts in the transmission device that is combined in a rotating speed that can change an output shaft by a rotating speed of the relative input shaft of gear meshing.This part has a nitriding layer and 0.5/1000000th hydrogen content at the most on a top layer.
In according to another driving parts of the present invention, can alleviate because the fragility of the steel that hydrogen causes.Surpass a hydrogen content of 0.5/1000000th if steel has, this steel just has lower cracking resistance so.Such steel is not suitable for standing a supporting structure of one of heavy load very much.Wish to have lower hydrogen content.But hydrogen content drops to and is lower than 0.3/1000000th and requires long heat treatment, and this causes the increase of austenite grain size, thereby has reduced toughness (toughness).Thereby, wish hydrogen content in 0.3/1000000th to 0.5 scope, more preferably in 0.35/1000000th to 0.45 scope.
In measuring above hydrogen content, do not measure diffusible hydrogen and only measure at a predetermined temperature or higher temperature the hydrogen that can not spread from steel release.Even at room temperature, the diffusible hydrogen in a small size sample discharges, spreads, so do not measure diffusible hydrogen from this sample.The hydrogen that can not spread is included among any defective in the steel and only and discharges from this steel under a preset heating temperature or higher temperature.The hydrogen that only measurement can not be spread, but hydrogen content can have sizable variation according to method of measurement.So determine the scope of above-mentioned hydrogen content by the thermal conducting rate.In addition, as hereinafter described, can carry out this measurement by a LECO DH-103 instrument for analyzing hydrogen or similar measuring device.
Above-mentioned driving parts is preferably a rolling bearing of rotatably support input shaft, output shaft or each gear, and this rolling bearing is a tapered roller bearing.
Above-mentioned driving parts is preferably a rolling bearing of rotatably support input shaft, output shaft or each gear, and this rolling bearing is a needle bearing.
Above-mentioned driving parts is preferably a rolling bearing of rotatably support input shaft, output shaft or each gear, and this rolling bearing is a ball bearing.
The invention provides a method of making the driving parts in the transmission device that is combined in a rotating speed that can change an output shaft by a rotating speed of the relative input shaft of gear meshing.This part is being higher than an A by the part to a bearing
1One temperature carburizing-nitrogen of transition point, this steel is cooled to is lower than A then
1One temperature of transition point, this steel is heated to again is not less than A subsequently
1Transition point and be lower than to a temperature range of the temperature of steel carburizing-nitrogen and to this steel and quench and form.
In making this method of driving parts, after to steel carburizing-nitrogen, this steel is cooled to is lower than A
1One temperature of transition point is finally quenched then.Can obtain a thinner austenite grain size, its result can improve pendulum impact test value, fracture toughness, anti-resistance to spalling, tired working life (or the rolling contact fatigue working life when this part is the part of a rolling bearing or a rolling bearing) etc.
And for example by being cooled to a temperature of austenitic transformation, the austenite crystal border in carburizing-nitrogen can be irrelevant with the situation in the last quenching.In addition, last quenching temperature is lower than carburizing-nitrogen temperature, thereby has compared increase in the quantity that is subjected to carburizing-nitrogen to handle the undissolved carbon body in the top layer that influences with this quantity in carburizing-nitrogen is handled.Thereby the ratio of undissolved carbon body increases, and austenitic ratio has had decline than those ratios in carburizing-nitrogen is handled under the heating-up temperature in the end quenching simultaneously.In addition, from iron-carbon two phasors as can be known, in the zone of carbon body and austenite coexistence, carbon and austenitic concentration in the solid-state solution of carbon descend along with the decline of quenching temperature.
When temperature rises to last quenching temperature,, make austenite crystal thinner owing to kept a large amount of undissolved carbon body that prevents that austenite crystal from increasing.And, have a lower concentration of carbon by the structure that changes from austenite to martensite of quenching, thereby this structure has high toughness from the structure that carburizing-nitrogen temperature is quenched.
In making this method of driving parts, be preferably a temperature range that steel is heated to 790 ℃ to 830 ℃, then it is quenched.
Steel is heated to a temperature that allows austenite crystal to increase hardly again, then steel is quenched.Thereby can obtain thinner austenite grain size.
The invention provides a tapered roller bearing with ring, an outer shroud and tapered roller in one.Interior ring, outer shroud and tapered roller any one has a nitriding layer and has an austenite crystal that drops on the crystallite dimension that surpasses in 10 the scope number at least.
In according to tapered roller bearing of the present invention, provide less austenite grain size interior ring, outer shroud, rolling element any one allows to increase significantly cracking resistance, dimensional stability and rolling contact fatigue working life at least.For 10 or following austenite grain size number, any to improve rolling contact fatigue working life significantly be impossible, thereby crystallite dimension number is greater than 10, preferably be 11 or more than.Though wishing has further thinner austenite crystal, be difficult to realize to surpass 13 crystallite dimension number usually.Should note at an austenite structure of interior ring, outer shroud and the rolling element of the supporting structure of transmission device axis no matter it can be in a top layer that is subjected to appreciable impact when to its carburizing-nitrogen or all is constant than the part of top layer part in inside.Thereby, top layer part and inner all positions that will be set to the object that is used for above-mentioned grain boundary scope.
Interior and outer shroud in this manual can merge with a part of for example one or a housing, or can provide dividually with this part.
Austenite crystal also relates to its small portion of residual after becoming ferritic phase, for example martensite or bainite by the cooling austenitic transformation.Austenite crystal border before quenching is sometimes referred to as " austenite crystal border the preceding ", is different from the austenite crystal of the reservation after the quenching.That is, use " austenite crystal " and the identical content of " austenite crystal border the preceding " expression.
The preceding the austenite crystal border be subjected to a processing, for example a metal phase sample of the part of recent studies on is carried out one corrode processing, can be observed after manifesting a grain boundary.In order to measure this crystallite dimension, mean value (=maximum 8 microns average grain size) by the grain boundary of ASTM (U.S. test and materials association) regulation can be converted to and obtain an average crystal grain diameter, maybe can use method for cutting etc., wherein on a metal phase structure, place a straight line, thereby obtain Mean length between the crossing all points in this straight line and grain boundary at an any direction.
Handle the above-mentioned nitriding layer of formation by following one carburizing that will discuss-nitrogen.This nitriding layer can or can not contain more carbon.
From of the present invention being described in detail below in conjunction with accompanying drawing, it is more obvious that above and other objects of the present invention, feature, aspect and advantage will become.
The accompanying drawing summary
Fig. 1 is a schematic sectional view of a transmission structures, wherein combines the driving parts according to one embodiment of the invention.
Fig. 2 is the schematic sectional view of structure that is used as the deep groove ball bearing of rolling bearing 10A shown in Figure 1 and 10B.
Fig. 3 is the procedure chart that a heat treatment method of the driving parts that is applied in one embodiment of this invention is shown.
Fig. 4 is the procedure chart that an exemplary variations of the heat treatment method that is applied to the driving parts in this embodiment of the present invention is shown.
Fig. 5 A shows a microstructure according to a bearing of the present invention, more specifically is austenite crystal; Fig. 5 B shows a microstructure of the bearing in the background technique, more specifically for austenite crystal.
Fig. 6 A is the austenite crystal boundary graph shown in Fig. 5 A, and Fig. 6 B is the austenite crystal boundary graph shown in Fig. 5 B.
Fig. 7 is a schematic sectional view of a tapered roller bearing structure.
Fig. 8 is a schematic sectional view of a roller bearing structure.
Fig. 9 is a schematic sectional view of a needle bearing structure.
Figure 10 is a schematic sectional view of a self-adjustment roller bearing structure.
Figure 11 wherein uses a tapered roller bearing shown in Figure 7 structural representation as a supporting structure of one in a transmission device.
Figure 12 wherein uses self-adjustment roller bearing shown in Figure 10 as one a structural representation of a supporting structure in the transmission device.
Figure 13 illustrates a sample that is used for a static pressure fracture strength test (measurement rupture stress).
Figure 14 A is a diagrammatic elevation view of a rolling contact fatigue tester in working life, and Figure 14 B is a diagrammatic side view of this rolling contact fatigue tester in working life.
Figure 15 illustrates a sample that is used for a static fracture toughness test.
Embodiment
Hereinafter with reference to accompanying drawing narration embodiments of the invention.
Consult Fig. 1, this transmission device is the transmission device of an engagement, and it mainly comprises rolling bearing 10A to 10F, an input shaft 11, an output shaft 12, a jack shaft 13, gear 14a-14k and a housing 15.
Pass through rolling bearing 10A rotatably support input shaft 11 by housing 15.Outer peripheral portion office at this input shaft 11 is provided with gear 14a, and peripheral part is provided with gear 14b within it.
In the present embodiment, have rolling bearing 10A and 10C for the supporting structure of input shaft 11, the supporting structure for output shaft has rolling bearing 10B and 10C simultaneously.For example rolling bearing 10A and 10B are deep groove ball bearings.For example, rolling bearing 10C is a needle bearing.Supporting structure for gear 14c and 14h to 14k has rolling bearing 10D to 10F.For example, rolling bearing 10D and 10E are needle bearings.Rolling bearing 10F is a needle roller thrust bearing.
Consult Fig. 2, deep groove ball bearing 10A and 10B respectively have the outer shroud 1 (an outer part) that is fixed in housing 15, be fixed in input shaft 11 or output shaft 12 one in ring 2 (parts in), the many balls 3 that between outer shroud 1 and interior ring 2, roll and with many balls 3 each other with a retainer 4 that equidistantly remains on the appropriate location.
Return and consult Fig. 1, the needle bearing 10C that is used as rolling bearing has a retainer and roller structure, and the one retainer keeps many needle roller 3b.In this structure, an outer part of rolling bearing merges mutually with input shaft 11, and its interior part merges mutually with output shaft 12 simultaneously.
The needle bearing that is used as bearing 10D and 10E respectively has a retainer and roller structure, wherein keeps many needle roller 3b by a retainer.In this structure, the outer part of this rolling bearing and gear 14c or 14h to 14k combine, and part and output shaft 12 or jack shaft 13 combine in it simultaneously.The needle roller thrust bearing that is used as rolling bearing 10F has the outer shroud 1c (an outer part) that is fixed in jack shaft 13, be fixed in the gear member that has gear 14h to 14k one in ring 2C (part in), the many needle roller 3c that between outer shroud 1c and interior ring 2c, roll and with many needle roller 3c with mutual one retainer that equidistantly remains on the appropriate location.
Being combined in driving parts (for example at least one of the outer part of rolling bearing 10A to 10F, interior part and rolling element, input shaft 11, output shaft 12, jack shaft 13, gear 14a to 14k, housing 15 etc.) in the above-mentioned transmission device has at a nitriding layer of a surface layer and has and drop on an austenite structure that surpasses the grain boundary in 10 the scope.
Especially when the outer part of each rolling bearing 10A to 10F, interior part and rolling element any one is during according to driving parts of the present invention at least, outer part (outer ring portion of outer shroud 1, output shaft 12 or gear 14c, 14h to 14k), interior part (annular inner portion of an annular inner portion of interior ring 2, input shaft 11, an annular inner portion of output shaft 12 or jack shaft 13) and rolling element (ball 3 or needle roller 3b, 3c) any one comprises the steel that has a nitriding layer and drop on an austenite structure that surpasses the grain boundary in 10 the scope at least.
And, the driving parts (for example, at least one of the outer part of rolling bearing 10A to 10F, interior part and rolling element, input shaft 11, output shaft 12, jack shaft 13, gear 14a to 14k, housing 15 etc.) that is combined in the above-mentioned transmission device has in a nitriding layer of a surface layer and a rupture stress value of 2650 MPas at least.
Especially when the outer part of each rolling bearing 10A to 10F, interior part and rolling element any one is during according to driving parts of the present invention at least, outer part (outer ring portion of outer shroud 1, output shaft 12 or gear 14c, 14h to 14k), interior part (annular inner portion of an annular inner portion of interior ring 2, input shaft 11, an annular inner portion of output shaft 12 or jack shaft 13) and rolling element (ball 3 or needle roller 3b, 3c) any one comprises a rupture stress value that has a nitriding layer and have at least 2650 MPas at least.
And the driving parts (for example at least one of the outer part of rolling bearing 10A to 10F, interior part and rolling element, input shaft 11, output shaft 12, jack shaft 13, gear 14a to 14k, housing 15 etc.) that is combined in above-mentioned transmission device has at a nitriding layer of a surface layer and a hydrogen content of maximum 0.5/1000000th in steel.
Especially when the outer part of each rolling bearing 10A to 10F, interior part and rolling element any one is during according to driving parts of the present invention at least, outer part (outer ring portion of outer shroud 1, output shaft 12 or gear 14c, 14h to 14k), interior part (annular inner portion of an annular inner portion of interior ring 2, input shaft 11, an annular inner portion of output shaft 12 or jack shaft 13) and rolling element (ball 3 or needle roller 3b, 3c) any one comprises the steel that has a nitriding layer and have a hydrogen content of maximum 0.5/1000000th in steel at least.
Below will narrate a speed change job about this transmission device.
When gear 14f did not mesh with gear 14j with gear 14d engagement and gear 14e with gear 14b engagement, gear 14g, the driving force of output shaft 11 passed to output shaft 12 by gear 14a, 14h, 14j and 14e.For example, the transmission device in this state is to be in first grade.
When gear 14g and gear 14d engagement, when gear 14e does not mesh with gear 14j, the driving force of input shaft 11 passes to output shaft 12 by 14a, 14h, 14i, 14c, 14d and 14g.For example, the transmission device in this state is to be in second grade.
When gear 14f and gear 14b engagement, when gear 14e does not mesh with gear 14j, the engagement of gear 14b and 14f is directly connected to output shaft 12 with input shaft 11, thereby the driving force of input shaft 11 directly passes to output shaft 12.For example, the transmission device in this state is in the third gear (top grade).
Below will narrate according to of the present invention about carrying out the heat treatment that one carburizing-nitrogen is handled that comprises on this transmission device.
Fig. 3 shows a heat treatment flow process figure, leads according to this figure and quenches and quench for the second time; Fig. 4 shows a heat treatment flow process figure, is cooled to below A according to this figure material in a Quenching Treatment
1One temperature of transition point, and and then heat and carry out final quenching.This two figure is an exemplary embodiment of the present invention.
Consult Fig. 3, the steel that is used for the part of a bearing be heated to be used for carburizing-nitrogen, be higher than A
1One temperature of transition point (for example 845 ℃).In this temperature, steel is carried out carburizing-nitrogen handle.At a treatment temperature T
1Down, carbon and nitrogen spread in a steel base, thereby carbon can be comprised in the steel fully.Then, at treatment temperature T
1The steel of the part that is used for bearing be subjected to oil quench, be cooled to below A
1One temperature of transition point.Then, steel carries out tempering at 180 ℃.But, can save this tempering.
Then this steel is heated to once more and is not less than A
1One temperature (for example 800 ℃) transition point and that be lower than the temperature of this steel carburizing-nitrogen.Under this temperature, keep this steel to carry out one and handle T2.Then at treatment temperature T
2Make this steel carry out oil quench, be cooled to than A down,
1The temperature that transition point is low.Then, under 180 ℃ to this steel tempering.
Consult Fig. 4, the steel that at first will be used for the part of bearing is heated above A
1Temperature transition point, that be used for carburizing-nitrogen (for example 845 ℃).Under this temperature, this steel is subjected to carburizing-nitrogen and handles.At treatment temperature T
1Down, carbon and nitrogen diffuse into steel base, so that carbon can be comprised in the steel fully.After this, the steel to the part that is used for bearing does not quench, but is cooled to be lower than a temperature of A1 transition point.Then, this steel is heated to once more is not less than the A1 transition point and is lower than a temperature (for example 800 ℃) the temperature of steel carburizing-nitrogen.This steel under this temperature, is handled T2.Then, at treatment temperature T
2Down this steel is carried out oil quench, is cooled to be lower than a temperature of A1 transition point.Then, under 180 ℃, this steel is carried out tempering.
Compare with common or common quenching (carry out carburizing-nitrogen in view of the above, quench immediately then), heat treatment discussed above can provide the rupture strength of raising and the long term dimensional rate of change of reduction, simultaneously to top layer carburizing-nitrogen.This heat treatment also can produce has crystallite dimension less than half of this traditional crystallite dimension or a microstructure of above austenite crystal.Accepted above-mentioned heat treated driving parts and can have long tired working life (perhaps one rolling contact fatigue working life when this part is the part of a rolling bearing or a rolling bearing), a cracking resistance that improves and a long term dimensional rate of change that reduces than length.
It is a nitriding layer of one " carburizing-nitrogen " that two above-mentioned heat treatments allow their carburizing-nitrogen to handle to produce.Owing to be used for material, steel that carburizing-nitrogen handles, have the high concentration of a carbon, so the carbon in the atmosphere that carburizing usually-nitrogen is handled can not easily enter the surface of this steel.For example, for the steel with a high carbon concentration (about 1% weight), a carburized case can have a concentration of carbon higher than this numerical value, perhaps can form a carburized case of not higher than this numerical value concentration of carbon.But the nitrogen concentration in plain carbon steel is low usually to the highest about 0.025% the weight that is not more than, but this depends on the concentration of chromium etc.Therefore, can form a nitriding layer significantly, and irrelevant with the concentration of carbon in the original steel.Will be understood that above-mentioned nitriding layer also can contain more carbon.
Fig. 5 A shows an austenitic crystallite dimension of carrying out a heat treated Bearing Steel shown in Figure 3.As a comparison, Fig. 5 B shows an austenitic crystallite dimension of a Bearing Steel that stands prior heat treatment.Fig. 6 A and 6B schematically show the austenitic crystallite dimension shown in Fig. 5 A and the 5B.In having the structure of austenitic crystallite dimension, traditional austenitic crystal grain diameter is by the determined crystallite dimension of JIS (JIS) numbers 10, and of the present invention, number be 12 by its heat treated austenite grain size, and can see thinner crystal grain.And the average crystal grain diameter of Fig. 5 A is 5.6 microns that are recorded by method for cutting.
Below will be described in a modification situation of the supporting structure that is used for axle in the transmission device.
In structure shown in Figure 1, be deep groove ball bearing as the rolling bearing 10A and the 10B of supporting structure that is used for axle.But, rolling bearing 10A and 10B can be as shown in Figure 7 tapered roller bearing or roller bearing as shown in Figure 8.
When the tapered roller bearing among Fig. 7 and the roller bearing among Fig. 8 separately one outside in the part (outer shroud 1), a part (interior ring 2) and a rolling element (roller 3) any one is according to the driving parts of present embodiment at least the time, any one comprises this of all parts having a nitriding layer and having with a crystallite dimension and number drops on the steel that surpasses the austenite structure in 10 the scope.
And, when tapered roller bearing among Fig. 7 and outer part (outer shroud 1), interior part (interior ring 2) and the rolling element (roller 3) separately of the roller bearing among Fig. 8 any one is a driving parts according to present embodiment at least the time, any one comprises the steel that has a nitriding layer and have a rupture stress value of at least 2650 MPas this of all parts.
And, when tapered roller bearing among Fig. 7 and outer part (outer shroud 1), interior part (interior ring 2) and the rolling element (roller 3) separately of the roller bearing among Fig. 8 any is a driving parts according to present embodiment at least the time, at least one comprises the steel that has a nitriding layer and have a hydrogen content of maximum 0.5/1000000th this of all parts.
When roller bearing outer part (outer shroud 1), interior part (interior ring 2) and the rolling element (roller 3) separately of the tapered roller bearing of Fig. 7 and Fig. 8 any is a driving parts according to present embodiment at least the time, any is formed this of all parts by the method as shown in Fig. 3 and 4.
Tapered roller bearing shown in Figure 7 has the many tapered rollers (awl roller) 3 that kept by retainer 4 between outer shroud 1 and interior ring 2.The summit that this tapered roller bearing is designed to a circular cone of the raceway face of outer shroud 1 and interior ring 2 and roller 3 converge on the bearing axis a bit.Therefore, from the raceway face of outer shroud 1 and interior ring 2 make a concerted effort roller 3 pressed in a big ring of ring 2, guide and rolling roller 3 along raceway simultaneously.
Roller bearing shown in Figure 8 has the many cylindrical rollers 3 that kept by retainer 4 between outer shroud 1 and interior ring 2.
Needle bearing shown in Figure 9 has the many needle rollers 3 that kept by retainer 4 between outer shroud 1 and annular inner portion (not shown).Needle roller 3 has a diameter of maximum 5 millimeters usually and is a length of 3 to 10 times of diameters.
Self-adjustment roller bearing shown in Figure 10 has many barrel-type roller 3 between outer shroud 1 and interior ring 2, these rollers are configured to two row and are held frame 4 maintain.These barrel-type roller 3 that are configured to two row have the ability of the self-adjustment of the inclination etc. that can handle axle.
Consult Figure 11, its be provided with one 21 of many gear 24a to 24d by housing 15 by tapered roller bearing 10A (or 10B) rotatably support.
Consult Figure 12, its be provided with one 31 of many gear 34a to 34d by housing 15 by self-adjustment roller bearing 10A rotatably support.
Be combined in driving parts (for example, many gear 24a to 24d as shown in figure 11, axle 21, the outer part of tapered roller bearing 10A and 10B, interior part and rolling element, at least one of housing 15 grades in the transmission device shown in Figure 11 or 12; Or many gear 34a to 34d as shown in figure 12, axle 31, the outer part of self-adjustment roller bearing 10A, interior part and rolling element, at least one of housing 15 grades) have at a nitriding layer of a surface layer and have an austenite structure that drops on the crystallite dimension that surpasses in 10 the scope number.
Be combined in driving parts (for example, many gear 24a to 24d as shown in figure 11, axle 21, the outer part of tapered roller bearing 10A and 10B, interior part and rolling element, at least one of housing 15 grades in the transmission device shown in Figure 11 or 12; Or many gear 34a to 34d as shown in figure 12, axle 31, the outer part of self-adjustment roller bearing 10A, interior part and rolling element, at least one of housing 15 grades) have in a nitriding layer of a surface layer and a rupture stress value of at least 2650 MPas.
Be combined in driving parts (for example, many gear 24a to 24d as shown in figure 11, axle 21, the outer part of tapered roller bearing 10A and 10B, interior part and rolling element, at least one of housing 15 grades in the transmission device shown in Figure 11 or 12; Or many gear 34a to 34d as shown in figure 12, axle 31, the outer part of self-adjustment roller bearing 10A, interior part and rolling element, at least one of housing 15 grades) have at a nitriding layer of a surface layer and a hydrogen content of 0.5/1000000th at the most.
In structure shown in Figure 1, be a needle bearing as the roller bearing 10C of supporting structure that is used for axle.But rolling bearing 10C can be deep groove ball bearing as shown in Figure 2, tapered roller bearing shown in Figure 7, roller bearing shown in Figure 8, needle bearing (structure with ring in an outer shroud or) or self-adjustment roller bearing shown in Figure 10 shown in Figure 9.
In above embodiment, mainly narrated the transmission device of engagement.But the present invention is not limited to the transmission device of this type.The present invention also can be applicable to the transmission device of other type, for example a slip-mesh gear or a synchronous-mesh gear.
To narrate the present invention with way of example now.
Example 1
Use JIS-SUJ2 (carbon of 1% weight, the silicon of 0.25% weight, the manganese of 0.4% weight, the chromium of 1.5% weight) to be used for example 1 of the present invention.Respectively pass through the step production of the following stated at the sample shown in the table 1.
Table 1
| Sample | A | B | C | D | E | F | Traditional carburizing nitrogen product | Common quenching product |
| Quench for the second time | 780 1) | 800 | 815 | 830 | 850 | 870 |
| Temperature (℃) | ||||||||
| Hydrogen content (1,000,000/) | 0.37 | 0.40 | 0.38 | 0.42 | 0.40 | 0.72 | 0.38 | |
| Crystallite dimension number (JIS) | 12 | 11.5 | 11 | 10 | 10 | 10 | 10 | |
| The pendulum impact test value (burnt/centimetre 2) | 6.65 | 6.40 | 6.30 | 6.20 | 6.30 | 5.33 | 6.70 | |
| Rupture stress value (MPa) | 2840 | 2780 | 2650 | 2650 | 2700 | 2330 | 2770 | |
| Rolling contact fatigue ratio in working life (L 10) | 5.4 | 4.2 | 3.5 | 2.9 | 2.8 | 3.1 | 1 |
1) owing to inadequate quenching, so do not estimate specifically.
Sample A-D: example of the present invention
In an atmosphere of a mixture of KX gas and ammonia, keep carrying out in 150 minutes carburizing-nitrogen down at 850 ℃.Press the heat treatment figure of Fig. 3, lead quenching, and quench by being heated to the second time that the temperature from a temperature range of 780 ℃ to 830 ℃ that is lower than carburizing-nitrogen temperature carries out subsequently from 850 ℃ one carburizings-nitrogen temperature.Because the quenching of Sample A is insufficient, so test does not have 780 ℃ the Sample A of quenching temperature for the second time.
Sample E and F: example of the present invention
These samples carry out the second time in the temperature from 850 ℃ to 870 ℃ that is equal to or higher than carburizing-nitrogen temperature of 850 ℃ then and quench by carrying out carburizing-nitrogen with the same steps as of Sample A-D of the present invention.
Traditional carburizing-nitrogen sample: comparative example
In an atmosphere of a mixture of KX gas and ammonia, keep carrying out in 150 minutes carburizing-nitrogen down at 850 ℃.Quench continuously and do not carry out the second time and quench from carburizing-nitrogen temperature.
Common quenching sample: comparative example
Do not have carburizing-nitrogen, quench, and do not carry out the second time and quench by being heated to 850 ℃.
To above all samples, having carried out following test has: (1) measures hydrogen content, and (2) measure crystallite dimension, (3) pendulum impact test, and (4) measure rupture stress and the test of (5) rolling contact fatigue.Their result has been shown in table 1.
To narrate their measurement and test method now.
(1) measures hydrogen content
Analyze being used for of making the DH-103 instrument for analyzing hydrogen of content of the hydrogen that can not spread of a steel with LECO company and determine hydrogen content, do not measure diffusible hydrogen content.The technical specification of LECO DH-103 instrument for analyzing hydrogen is as follows:
Analyst coverage: 1,000,000/0.01-50.00
Analysis precision: ± hundred 0.1/10000th or ± 3%H (higher)
Sensitivity for analysis: 0.01/1000000th
Detecting method: thermoelectric conductance
Sample weight size: 10 milligrams-35 gram (maximums: 12 millimeters (diameter) * 100 millimeter (length))
Furnace scope: 50 ℃-1100 ℃
Reagent: anhydrone (Mg (ClO
4)
2), carbon-dioxide absorbent and NaOH
Carrying gas: nitrogen, dosage gas (hydrogen)
(two gases have a pressure of the pressure (2.8 Kilogram Force Per Square Centimeter) of at least 99.99% a purity and 40 pounds/square inch).
In this step of narrative analysis roughly.Keep a sample and this sample and sample thief are put into instrument for analyzing hydrogen together by a special-purpose sample collector.Wherein diffusible hydrogen is introduced a thermoelectric conductance detector by nitrogen carrying gas.In this example, do not measure the hydrogen of diffusion.Then, from sample collector, take out this sample, and in a resistance heater, it is heated, and indiffusible hydrogen is introduced thermoelectric conductance detector by nitrogen carrying gas.Measure the thermal conducting rate by thermoelectric conductance detector, be used for determining indiffusible hydrogen content.
(2) measure crystallite dimension
The method of the austenitic crystallite dimension of test in steel according to JIS G 0551 regulation is measured this crystallite dimension.
(3) pendulum impact test
According to steel carried out the pendulum impact test method carry out the pendulum type bump test by JIS Z 2242 regulation.Here an employed test specimen is the U notch test specimen (No. 3 test specimens of JIS) by JIS Z 2202 regulations.
Should note: the absorption ENERGY E that a pendulum impact test value is removed by sectional area (0.8 square centimeter), a numerical value as described below.
Absorb ENERGY E=WgK (cos β-cos α)
Pendulum weight W=25.438 kilogram
Gravity quickens the g=9.80665 meter per second
2
From the rotatingshaft center of pendulum to center of gravity apart from K=0.6569 rice
Angle [alpha]=146 that pendulum rises °
The upper and lower motion angle β of pendulum
(4) measure rupture stress
Figure 13 shows a test specimen that is used to measure rupture stress.Used the general testing machine of Amslek.Apply a load along the direction P among this figure.Then, will use following Stress calculation formula for the measured load of a fracturing load and convert a stress to about a bent beam.Should note: used test specimen is not limited to test specimen shown in Figure 13, can be to have difform any test specimen.
Suppose that the fiber stress (fibek stkess) on the convex surfaces of as shown in figure 13 test specimen is σ
1Be σ at a recessed lip-deep fiber stress
2, (JSME mechanical engineer handbook, the A4-intensity of material A4-40) is determined σ by following formula so
1And σ
2In the formula: N represents to comprise the axial force of a section of the axis of ring specimen, and A represents a section area, e
1Represent an outer radius, e
2Represent an inside radius, and k is a section modulus of bent beam.
σ
1＝(N/A+{M/(Aρ
0)}[1+e
1/{k(ρ
0+e
1)}]
σ
2＝(N/A+{M/(Aρ
0)}[1-e
2/{k(ρ
0-e
2)}]
k＝-(1/A)∫A{η/(ρ
0+η)}dA
(5) rolling contact fatigue test
In Figure 14 A and 14B, show rolling contact fatigue tester in working life with its reduced form.Test conditions about a rolling contact fatigue test in working life has been shown in table 2.With reference to Figure 14 A and 14B, a test specimen 221 that stands rolling contact fatigue test in working life is driven by a live axle 211, thereby rotates, and contacts with all balls 213 simultaneously.Ball 213 is by the ball of a deflector roll 212 guiding, (3/4) inch that rolls.Ball 213 applies a big surface pressure on test specimen 221, test specimen 221 also applies a big surface pressure on ball 213 simultaneously.
Will be in the result that will narrate above-mentioned measurement and test.
(1) hydrogen content
It in the steel is a sizable hydrogen content of 0.72/1000000th that table 1 shows that the traditional carburizing-nitrogen sample that does not have additional treatments has.Think that a reason is contained ammonia (NH in the atmosphere that carburizing-nitrogen is handled
3) be decomposed and then hydrogen enter in the steel.Aspect in addition, the hydrogen content in the steel of sample B-F reduces to 0.37/1000000th to 0.42, and this almost is half of hydrogen content of traditional sample.This hydrogen content in the steel be substantially equal to quench usually hydrogen content of sample.
The above-mentioned decline of the hydrogen content in the steel can alleviate because the degree of brittleness of the caused steel of hydrogen in solid-state solution.In other words, by reducing hydrogen content, improved pendulum impact test value and the rupture stress value of sample B-F of the present invention significantly.
(2) crystallite dimension
Consulting table 1, about crystallite dimension, the sample that carries out quenching for the second time in a temperature that is lower than the quenching temperature (the main quenching) that carburizing-nitrogen handles, is that sample B-D has significantly tiny austenite crystal, and promptly crystallite dimension number is 11-12.Sample E and F and traditional carburizing-nitrogen sample and usually the quenching sample have in the crystallite dimension number 10 austenite crystal, this means the crystallite dimension of the crystallite dimension of sample E and F greater than sample B-D.
(3) pendulum impact test value
The pendulum impact test value that table 1 shows traditional carburizing-nitrogen sample is 5.33 Jiao/square centimeters, and this test value of sample B-F of the present invention is higher, from 6.20 to 6.65 Jiao/square centimeters.From this also as can be known the lower quenching temperature second time caused a higher pendulum impact test value.Usually the sample that quenches has the higher pendulum impact test value of 6.70 Jiao/square centimeters.
(4) measurement of rupture stress value
Rupture stress is corresponding to anti-resistance to spalling.The rupture stress of traditional as known from Table 1 carburizing-nitrogen sample is 2330 MPas.Aspect in addition, the rupture stress of sample B-F is improved to 2650 to 2840 MPas.The rupture stress that common quenching sample has 2770 MPas, this is in the scope of the rupture stress of sample B-F.And think that the decline of hydrogen content is very beneficial for improving the cracking resistance of sample B-F and dwindling of austenite grain size.
(5) rolling contact fatigue test
According to table 1, the sample that quenches has short rolling contact fatigue (L in working life usually
10), this is owing to there is not a nitriding layer on the top layer.Compare, the rolling contact fatigue of traditional carburizing-nitrogen sample is 3.1 double-lengths of sample of quenching usually working life.The rolling contact fatigue working life of sample B-D and traditional carburizing-nitrogen sample have relatively had significant improvement.Sample E has almost identical with traditional carburizing-nitrogen sample rolling contact fatigue working life with F.
In a word, at the hydrogen content that can reduce to the F according to sample B of the present invention in the steel.Thereby, the rupture stress and the pendulum impact test value that can be improved to the F in sample B.Except these rupture stress values and pendulum impact test value, hope should improve rolling contact fatigue working life.This only realizes to D having the crystallite dimension number sample B at least about 11 thinner crystal grain.Sample B to F corresponding to according to example of the present invention, still, thus the scope that the present invention more wants be corresponding to be lower than carry out quenching for the second time under the temperature of temperature that steel applies carburizing-nitrogen and have more the compact grained sample B to D.
Example 2
Narrate example 2 of the present invention now
On following Sample A, B and C, carry out a series of tests.Usually being used in material Sample A-C, that will heat-treat is JIS-SUJ2 (chromium of the manganese of the silicon of the carbon of 1% weight, 0.25% weight, 0.4% weight, 1.5% weight).Each handles Sample A-C through the following step.
Sample A-comparative example: only common quenching (not having carburizing-nitrogen)
Sample B-comparative example: direct quenching behind carburizing-nitrogen (traditional carburizing-nitrogen and quenching).Keep carrying out in 150 minutes carburizing-nitrogen down at 845 ℃.The atmosphere that carburizing-nitrogen is handled is a mixture of KX gas and ammonia.
Sample C-example of the present invention: one bearing material is handled according to heat treatment figure shown in Figure 2.Keeping carrying out carburizing-nitrogen in 150 minutes down at 845 ℃ handles.The atmosphere that carburizing-nitrogen is handled is a mixture of KX gas and ammonia.Last quenching temperature is 800 ℃.
(1) rolling contact fatigue working life
In table 2 and Fig. 7, illustrated and be used for the rolling contact fatigue test conditions and the testing apparatus in working life.Table 3 shows the result of rolling contact fatigue test in working life.
Table 2
| | φ | 12 * L22 cylindrical specimen |
| The test specimen number | 10 | |
| |
3/4 inch (19.05 millimeters) | |
| Pressure of contact surface | 5.88 gpa |
| Loading velocity | 46240 cycle-indexes/minute |
| Lubricant oil | Turbine VG68-self-contained lubrication |
Table 3 test result
According to table 3, carburizing-nitrogen sample B (comparative example) has rolling contact fatigue working life for 3.1 double-lengths of the Sample A (comparative example) of only quenching usually (L10 working life: a damage is arranged in 10 test specimens), handles the effect that has obtained extending working life by carburizing-nitrogen as can be known.Compare, sample C of the present invention has the working life that prolongs for 5.4 double-lengths 1.74 double-lengths of sample B and that be Sample A.And think and obtained this improvement mainly due to thinner microstructure.
(2) pendulum impact test
By using a U notch test specimen to carry out pendulum impact test by above-mentioned JIS Z 2242 regulations.Table 4 shows this test result.
Table 4
| Sample | The pendulum impact test value (burnt/centimetre 2) | Relative shock test value |
| A | 6.7 | 1.0 |
| B | 5.3 | 0.8 |
| C | 6.7 | 1.0 |
The sample C of an example of the present invention has obtained a pendulum impact test value identical with the Sample A of only quenching usually (comparative example) and that be higher than carburizing-nitrogen sample B (comparative example).
(3) static fracture toughness test
Use test specimen shown in Figure 15 to carry out static fracture toughness test.In this test specimen, made about 1 millimeter one and split in advance, apply then and can produce a static load of bikini bending, and determine a fracturing load then.Utilize following formula to calculate fracture toughness value (K
ICValue).This test result has been shown in the table 5.
K
IC＝(PL√a/BW
2){5.8-9.2(a/w)+43.6(a/w)
2
-75.3(a/w)
3+77.5(a/w)
4}
Table 5
Because the cracking of introducing has the degree of depth than nitriding layer depth in advance, Sample A and the about 1.2 times high fracture toughness value (K of B (comparative example) have been obtained being for Sample A and B (comparative example)
IC)
(4) static pressure fracture strength test (measurement of rupture stress)
Use the static pressure rupture strength test specimen shown in above-mentioned Figure 13.Apply a load along the direction P among this figure, carry out as a described static pressure fracture strength test just now.Table 6 shows test result.
Table 6 test result
| Sample | Test number (TN) | Static rupture strength (kgf) | Static relatively rupture |
| A | |||
| 3 | 4200 | 1.00 | |
| |
3 | 3500 | 0.84 |
| |
3 | 4300 | 1.03 |
Carburizing-nitrogen sample B (comparative example) has a numerical value of a static pressure rupture strength more smaller than the Sample A (comparative example) of only carrying out common quenching.Compare, the sample C of an example of the present invention has more much higher and a little more than a static pressure rupture strength value of Sample A than sample B.
(5) long term dimensional rate of change
Table 7 shows the speed of the long term dimensional variation that records under the condition of 130 ℃ (maintenance temperature) and 500 hours (retention time), and surface hardness and contained austenitic amount (from 0.1 millimeter depths, surface) are arranged.
Table 7
| Sample | Test number (TN) | Surface hardness (HKC) | γ (%) is contained in institute | Dimensional changes speed (* 10 -5) | Relative dimensional changes speed *) |
| |
3 3 3 | 62.5 63.6 60.0 | 9.0 28.0 11.3 | 18 35 22 | 1.0 1.9 1.2 |
*: less is superior
With the dimensional changes speed ratio with a large amount of contained austenitic sample B, the sample C of an example of the present invention has a lower dimensional changes speed.
(6) test in the working life under the lubricating condition of polluting
Use ball bearing 6206 to estimate in the rolling contact fatigue working life that has under the contaminated lubricating condition common, that be mixed in pollutant wherein of a predetermined quantity.
Table 8 shows test conditions and table 9 shows test result.
Table 8
| Load | Thousand Ns of Fk=6.86 |
| Pressure of contact surface | P max=3.2 gpa |
| Rotating speed | 2000 rev/mins |
| Oiling agent | Turbine 56-bath lubrication |
| Amount of pollutant | 0.4 restrain/1000 milliliters |
| Pollutant | Particle size: 100-180 micron, hardness: Hv800 |
Table 9
| Sample | L 10Working life (hour) | Opposing L 10 |
| A | 20.0 | 1.0 |
| B | 50.2 | 2.5 |
| C | 74.0 | 3.7 |
The sample B (comparative example) of carrying out carburizing-nitrogen has a working life of 2.5 double-lengths that are about Sample A, and sample C of the present invention has the working life of 3.7 double-lengths that are about Sample A.
Though the sample C of the present invention relatively sample B of example has more a spot of contained austenite, sample C has long working life, and this is because the influence of nitrogen that enters and thinner microstructure.
Therefore from result discussed above sample C of the present invention as can be known, be used as a bearing parts a supporting structure the transmission device, that handled by heat treatment method of the present invention and can realize three purposes simultaneously: the rolling contact fatigue working life of the prolongation that is difficult to realize by traditional carburizing-nitrogen, the long term dimensional rate of change of improved cracking resistance and reduction.
Should notice that in this specification austenite crystal is meant the austenitic crystal grain of phase transformation during heating treatment, and the micro-crystal grain of the reservation after austenite becomes martensite by the cooling transformation.
In method and tapered roller bearing according to driving parts of the present invention and this driving parts of manufacturing, form a nitriding layer, in addition, can access former irrealizable one superior rupture stress value.Therefore, improved cracking resistance etc. in the present invention.In addition, can dwindle the size of transmission device.
Though at length narrated and shown the present invention, only should be expressly understood with illustrative ground and exemplarily rather than restrictively narrate the present invention that the principle and scope of the present invention are only by the definition of term of appended claims.For example, needle bearing can be a perfect form (full type) roller bearing or a shell mould roller bearing.
Claims (4)
1. driving parts, it is combined in the transmission device of a rotating speed that can change an output shaft (12) by a rotating speed of the relative input shaft of the engagement of gear (14a to 14k) (11), described driving parts has a hydrogen content that can not spread of a nitriding layer and maximum 0.5/1000000th on the top layer, the crystallite dimension of the austenite crystal of described driving parts number drops on and to surpass in 10 the scope
Wherein, constituent part is so to form: be higher than an A
1One temperature of transition point is to steel carburizing-nitrogen, be cooled to this steel and be lower than A then
1The temperature of transition point, this steel is heated to again is not less than A subsequently
1Transition point and being lower than to a temperature range of the described temperature of steel carburizing-nitrogen and to this steel quenches.
2. driving parts as claimed in claim 1 is characterized in that: the form with the rolling bearing of the described input shaft of rotatably support, described output shaft or each described gear provides described driving parts, and described rolling bearing is a tapered roller bearing.
3. driving parts as claimed in claim 1 is characterized in that: the form with the rolling bearing of the described input shaft of rotatably support, described output shaft or each described gear provides described driving parts, and described rolling bearing is a needle bearing.
4. driving parts as claimed in claim 1 is characterized in that: the form with the rolling bearing of the described input shaft of rotatably support, described output shaft or each described gear provides described driving parts, and described rolling bearing is a ball bearing.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003053748 | 2003-02-28 | ||
| JP2003053748 | 2003-02-28 | ||
| JP2004024096 | 2004-01-30 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2004100082864A Division CN100412395C (en) | 2003-02-28 | 2004-02-27 | Driving parts, method for producing driving parts and tapered rooler bearing |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101109413A CN101109413A (en) | 2008-01-23 |
| CN100588849C true CN100588849C (en) | 2010-02-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2007101469971A Expired - Lifetime CN101109414B (en) | 2003-02-28 | 2004-02-27 | Transmission component, method of manufacturing the same, and tapered roller bearing |
| CN200710146996A Expired - Lifetime CN100588849C (en) | 2003-02-28 | 2004-02-27 | Transmission component, method of manufacturing the same, and tapered roller bearing |
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Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2280865A (en) * | 1993-08-13 | 1995-02-15 | Mono Pumps Ltd | Flexible drive shaft |
| US6224688B1 (en) * | 1997-08-18 | 2001-05-01 | Nsk Ltd. | Rolling bearing |
| DE19922792A1 (en) * | 1999-05-18 | 2000-11-23 | Gkn Sinter Metals Holding Gmbh | Geared pump rotor assembly e.g. for lubricating oil on internal combustion engine, comprises planet gears in outer ring round star-shaped rotor |
| JP2001032900A (en) * | 1999-07-23 | 2001-02-06 | Nsk Ltd | Toroidal type continuously variable transmission |
-
2004
- 2004-02-27 CN CN2007101469971A patent/CN101109414B/en not_active Expired - Lifetime
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| CN101109414B (en) | 2010-11-24 |
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