Background technique
Wind energy resources, as a kind of clean renewable energy sources, extensively exists in the whole world, and aboundresources is inexhaustible, the environmental protection of using.Therefore wind energy power has safe, clean feature, can be the mankind energy supply steady in a long-term is provided.At present, Main Developed Countries, developing country, the important means of all having challenged with the reply new century energy development wind energy power technology as state basic policy.
Transmitted chains is the core of wind power generating set, and main shaft bearing is to support the critical component that Transmitted chains runs well, and main shaft bearing performance directly determines the reliability of running of wind generating set, and the design of main shaft bearing is the important component part of Transmitted chains design.It is strong that selfaligning roller bearing has bearing capacity, manufacture simple, the feature that assembly process process is good, at present, commercial off-the-shelf megawatt-level wind unit adopts biserial spheric roller bearing form more, and two row roller specifications are identical, but, because wind-powered electricity generation unit is horizontal axis unit, in unit running process, the thrust that wind wheel is subject to is very big, and this thrust load is all born by main shaft bearing.Design feature due to double-row self-aligning roller bearing itself, be in the wind when receiving thrust, the roller stand under load of lower wind direction side is much larger than upwind side, according to on-the-spot test, the stressed difference of two row rollers is at least more than 3 times, front and back two row roller discontinuity equalizations, the wearing and tearing of rear row roller and raceway thereof are comparatively serious, had a strong impact on the working life of unit.
Summary of the invention
The present invention, in order to overcome the shortcoming of above-mentioned technical problem, provides a kind of unequal wind driven generator principal shaft selfaligning roller bearing of two rollers and design method thereof being applied on megawatt-level wind unit.
Wind driven generator principal shaft selfaligning roller bearing of the present invention, wind-driven generator comprise accept wind energy wind wheel, for the main shaft of transferring power and the bearing support that is arranged on main shaft, form, bearing support forms the selfaligning roller bearing that has comprised carrying effect, and selfaligning roller bearing comprises bearing outer ring, bearing inner race and two row rollers; It is characterized in that: on selfaligning roller bearing, the length of a row roller of close wind wheel side is less than the length of another row roller.Main shaft is for being delivered to the rotation of wind wheel the input end of gear-box, and selfaligning roller bearing is arranged on bearing support and forms above, guarantees that main shaft can freely rotate.Due to the selfaligning roller bearing effect that is not only stressed, be also subject to the powerful thrust that produced by wind wheel, cause the row roller away from wind wheel end very easily to wear and tear; Therefore the roller length away from wind wheel side is designed to be greater than the length of another row roller, can effectively increases the wear-resisting property of whole selfaligning roller bearing, increase the service life.
Wind driven generator principal shaft selfaligning roller bearing of the present invention, what on described bearing inner race, arrange does not match raceway width not etc. with two row rollers, and the raceway width matching with large size roller is greater than the raceway width matching with small size roller.The size of two row rollers is unequal, is easy to process the raceway adapting with roller length.
Wind driven generator principal shaft selfaligning roller bearing of the present invention, is provided with oil groove on described bearing outer ring, a side of oil groove deflection small size roller.Oil groove is arranged on the bearing outer ring between two row rollers.
Wind driven generator principal shaft selfaligning roller bearing of the present invention, described bearing support forms and also comprises bearing (ball) cover, bearing support, seal ring and sealing bracing ring; Bearing seat is in the periphery of selfaligning roller bearing, and bearing (ball) cover, seal ring and sealing bracing ring are positioned at the both sides of selfaligning roller bearing.
The design method of wind driven generator principal shaft selfaligning roller bearing of the present invention, wind-driven generator comprises wind wheel, play the gear-box of accelerating function and for connecting the main shaft of wind wheel and gear-box, selfaligning roller bearing is arranged on main shaft, and the roller length near wind wheel side on selfaligning roller bearing is less than the roller length near gear box side; It is characterized in that, design bearing method comprises the following steps: a. sets up system of coordinates, take the intersection point of wind wheel and the main shaft two-dimensional coordinate system in initial point is set up vertical plane, and this system of coordinates is the rest frame of not rotating with wind wheel; B. calculate stressed at true origin place of main shaft, establish
for the active force being produced by the suffered thrust of wind wheel,
active force for the gravity by wind wheel and spindle unit produces, calculates according to formula
size;
(1)
Wherein,
For thrust coefficient,
For atmospheric density,
For wind speed; Thrust coefficient
Be averaged wind speed respective value, wind speed according to thrust coefficient curve
Desirable annual mean wind speed is simplified calculating; C. calculate self-aligning roller bearing stressed,If thrust and pressure that self-aligning roller bearing center is suffered are respectively
With
, the active force that gear-box produces main shaft at vertical direction is
; By
=
,
=
+
Calculate the suffered thrust of self-aligning roller bearing and pressure; D. self-aligning roller bearing design, what establish close wind wheel one side is front row roller, length is
; Near gear-box one side be rear row roller, length is
; The contact stress of front row roller and rear row roller and raceway is respectively
With
;If proportionality coefficient
=
/
; Calculate according to following steps
,
Size: d-1. calculates the contact stress of roller and raceway, when
,
Get in the situation of concrete numerical value, according to bearing inner race diameter, bearing outer diameter, bearing width, the thrust of self-aligning roller bearing
And pressure
, calculate contact stress
With
; D-2. take off limit value, get one group of forward and backward row roller length value
With
, calculate the contact stress of forward and backward row roller and raceway according to the computational methods in steps d-1
,
, adjust
With
Size, make
>
, record
=
/
In
Value; D-3. capping value, gets one group of forward and backward row roller length value
With
, calculate the contact stress of forward and backward row roller and raceway according to the computational methods in steps d-1
,
, adjust
With
Size, make
>
, record
=
/
In
Value; D-4. get
=(
+
)/2, according to
=
/
, calculate
With
Value, calculate the contact stress of forward and backward row roller and raceway according to the computational methods in steps d-1
,
; If
<
, get
=(
+
)/2; If
>
, get
=(
+
), the like; D-5. in steps d-4, proportionality coefficient
=
/
Time, calculate corresponding contact stress and whether meet |
-
| <3
/ 100 and |
-
| <3
/ 100, record satisfies condition
Value, according to
With
Value is determined bearing roller size, designs satisfactory bearing.
Computational methods of the present invention, can utilize finite element algorithm to calculate the contact stress of roller and raceway, utilize interpolation to determine the scaling factor of two row rollers, design the roller of two row's different sizes, before and after making, the suffered contact stress of two row rollers is equal as far as possible, the difference of contact stress
less contact stress 3% with interior think meet design requirement.Steps d adopts interpolation to calculate, and gets larger roller scaling factor
less roller scaling factor
, before and after making there is the state that size is contrary in two row roller contact stress, gets
with
average
; Again relatively at scaling factor
two row roller contact stress states before and after lower bearing; If
lower with
the contact stress state of lower two row rollers is identical, gets
with
average be scaling factor
otherwise, get
with
average be scaling factor
, by that analogy, until the difference of bearing front and back two row roller contact stress is in
less contact stress 3%.
The invention has the beneficial effects as follows: wind driven generator principal shaft selfaligning roller bearing of the present invention, according to the stressed unequal feature of the forward and backward row roller of bearing, selfaligning roller bearing is designed to little, the rear row roller of front row roller large, can effectively reduce the contact stress of roller and raceway, avoid in the past due to the stressed large and phenomenon of serious wear of rear row roller; Reduce rate of fault, improved bearing working life.The little side of oil groove deflection roller dimension, and the width of raceway and the size of roller are directly proportional.The design method of wind driven generator principal shaft selfaligning roller bearing of the present invention, by the qualitative and quantitative analysis to selfaligning roller bearing stressing conditions, adopt finite element and difference arithmetic to calculate rational front and rear row roller length, and by the difference of two row roller contact stress be controlled at less contact stress 3% in, make the working life of two row rollers basically identical, effectively improved bearing working life.
Accompanying drawing explanation
Fig. 1 is the structural representation of selfaligning roller bearing for existing wind driven generator principal shaft;
Fig. 2 is the structural representation of selfaligning roller bearing of the present invention;
Fig. 3 is structural representation and the force analysis figure of wind turbine transmission chain of the present invention;
Fig. 4 is the force analysis figure of selfaligning roller bearing in the present invention;
Fig. 5 is the structural representation that bottom bracket of the present invention forms.
In figure: 1 bearing outer ring, 2 front row rollers, 3 rear row rollers, 4 bearing inner races, 5 bearing outer rings, 6 front row rollers, 7 rear row rollers, 8 bearing inner races, 9 wind wheels, 10 main shafts, 11 bearing supports form, 12 gear-boxes, 13 bearing (ball) covers, 14 bearing supports, 15 selfaligning roller bearings, 16 seal rings, 17 sealing bracing rings, 18 locknuts.
Embodiment
Below in conjunction with accompanying drawing and embodiment, the invention will be further described.
As shown in Figure 1, provided the structural representation of selfaligning roller bearing for existing wind driven generator principal shaft, it comprises bearing outer ring 1, bearing inner race 4, front row roller 2, rear row roller 3; The diameter dimension of front row roller 2 and rear row roller 3 equates.In the process of using, because the thrust that wind wheel is subject to is very big, this thrust load is all born by the selfaligning roller bearing on main shaft, makes the roller stand under load of lower wind direction side much larger than upwind side.The stressed difference of general two row rollers (2,3) is at least more than 3 times, front and back two row roller discontinuity equalizations, and the wearing and tearing of rear row roller 3 and raceway thereof are comparatively serious, had a strong impact on the working life of unit.
As shown in Figure 2, provided the structural representation of selfaligning roller bearing of the present invention, it comprises bearing outer ring 5, front row roller 6, rear row roller 7 and bearing inner race 8; Fig. 3 and Fig. 5 have provided respectively wind turbine transmission chain and bearing support forms 11 structural representation, and the Transmitted chains of wind-powered electricity generation unit comprises wind wheel 9, main shaft 10, bearing support composition 11 and gear-box 12; Bearing support forms 11 and comprises bearing (ball) cover 13, bearing support 14, selfaligning roller bearing 15, seal ring 16, sealing bracing ring 17, locknut 18.In the Transmitted chains of wind-powered electricity generation unit, wind wheel 9 is for receiving wind energy and driving main shaft 10 to rotate, and main shaft 10 is input to the rotation of wind wheel 9 input end of gear-box 12, and gear-box 12 is step-up gear.Bearing support forms 11 on the main shaft 10 between wind wheel 9 and gear-box 12, and bearing support forms the location that the selfaligning roller bearing 15 on 11 is realized main shaft, guarantees that main shaft 10 freely rotates.Front row roller 6 is the row roller near wind wheel 9 one sides, and rear row roller 7 is the roller away from wind wheel 9 one sides, and the length of rear row roller 7 is greater than the length of front row roller 6.Like this, even if the active force that rear row roller 7 bears is larger, also can guarantee that front and rear row roller (6,7) equates with the contact stress of raceway or it is equal to approach, the transition of row roller 7 after while having avoided two row roller sizes to equate, cross quick-wearing, effectively extended the working life of selfaligning roller bearing 15.
Bearing support 14 is positioned at the periphery of selfaligning roller bearing 15, realizes the fixation to selfaligning roller bearing 15; Bearing (ball) cover 13, seal ring 16 and sealing bracing ring 17 are arranged at the both sides of selfaligning roller bearing 15, realize the effective location to selfaligning roller bearing 15.The phase place effect that locknut 18 is realized sealing bracing ring 17.
Because rear row roller 7 and raceway area of contact are large, can reduce the contact stress between roller and raceway, reduced rate of fault, improve bearing working life.Oil groove on bearing outer ring 5 is not in centre, but row roller 6 one sides before deflection.Bearing inner race 8 left-right asymmetries, the raceway of front row roller 6 correspondences is narrow.Meanwhile, the bearing of design should have assembly process process, guarantees that bearing and bearing support are easy to assembling.
By the Design of length of rear row roller 7, be to be only greater than the length of front-seat 6 rollers or far from being enough, because without quantitative analysis, how must do not go out the contact stress of front row roller 6, rear row roller 7 and track, equate, approach or differ greatly.Provide the design method of this wind driven generator principal shaft selfaligning roller bearing below, so that the contact stress that obtains front row roller 6, rear row roller 7 and raceway on long terms selfaligning roller bearing about equally.It comprises the following steps:
A. set up system of coordinates, take the intersection point of wind wheel and the main shaft two-dimensional coordinate system in initial point is set up vertical plane, this system of coordinates is the rest frame of not rotating with wind wheel; The initial point of system of coordinates is power in Fig. 3
with power
intersection point;
B. calculate stressed at true origin place of main shaft, establish
for the active force being produced by the suffered thrust of wind wheel,
active force for the gravity by wind wheel and spindle unit produces, calculates according to formula (1)
size;
Wherein,
for thrust coefficient,
for air density,
for wind speed; Thrust coefficient
according to thrust coefficient curve, be averaged wind speed respective value, wind speed
desirable annual mean wind speed is simplified calculating;
C. calculate selfaligning roller bearing stressed, establish the suffered thrust in selfaligning roller bearing center and pressure and be respectively
with
, as shown in Figure 4, the active force that gear-box produces main shaft at vertical direction is
; By
=
,
=
+
calculate the suffered thrust of selfaligning roller bearing and pressure;
D. selfaligning roller bearing design, what establish close wind wheel one side is front row roller, length is
; Near gear-box one side be rear row roller, length is
; The contact stress of front row roller and rear row roller and raceway is respectively
with
; If scaling factor
=
/
; According to following steps, calculate
,
size:
D-1. calculate the contact stress of roller and raceway, when
,
get in the situation of concrete numerical value, according to bearing inner race diameter, bearing outer diameter, bearing width, the thrust of selfaligning roller bearing
and pressure
, calculate contact stress
with
; In the process of calculating, can adopt finite element algorithm;
D-2. take off limit value, get one group of forward and backward row roller length value
with
, according to the computational methods in steps d-1, calculate the contact stress of forward and backward row roller and raceway
,
, adjust
with
size, make
>
, record
=
/
in
value;
D-3. capping value, gets one group of forward and backward row roller length value
with
, according to the computational methods in steps d-1, calculate the contact stress of forward and backward row roller and raceway
,
, adjust
with
size, make
<
, record
=
/
in
value;
D-4. get
=(
+
)/2, according to
=
/
, calculate
with
value, according to the computational methods in steps d-1, calculate the contact stress of forward and backward row roller and raceway
,
; If
<
, get
=(
+
)/2; If
>
, get
=(
+
), the like;
D-5. in steps d-4, scaling factor
=
/
time, calculate corresponding contact stress and whether meet |
-
| <3
/ 100 and |
-
| <3
/ 100, record satisfies condition
value, according to
with
value is determined bearing roller size, designs satisfactory bearing.