Sliding bearing formula electricity main shaft
Technical field
The invention belongs to mechanical manufacturing field, be specifically related to a kind of architecture advances of high-speed and precise electric main shaft.
Background technology
With high cutting speed, high feed speed, high manufacturing accuracy is that the High-speed machining of principal character is one of four big advanced manufacturing technologies in the present age, is to make manufacturing technology produce the new and high technology that revolutionary character for the second time leaps continue Numeric Control Technology after.It not only has high productivity ratio, and can improve the machining accuracy and the surface quality of part significantly.The high-speed and precise electric main shaft is as the Core Feature parts in the High-speed NC Machining lathe, and the height of its performance directly has influence on the overall development level of high-speed processing machine tool.
The high-speed and precise electric main shaft is a kind of high-tech product that directly depends on the height electromechanical integration of technology such as bearing technology, accurate manufacturing and assembling.Its characteristics are, the function and the machine tool chief axis function of motor combined together from structure, have saved complicated middle transmission link, have speed-regulating range width, rotary inertia little, can quick start and stop, be easy to realize advantages such as stepless speed regulation and accurate control.Along with the modern times equipment, manufacturing industry is to the develop rapidly of high-speed, high accuracy, high efficiency direction, performance requirement to the machine tool chief axis unit is more and more higher, and electric main shaft just progressively replaces traditional belt driven type mechanical main shaft, becomes the main flow structure of modern machine main shaft.
The bearing of high-speed and precise electric main shaft comprises magnetic suspension bearing, air bearing, rolling bearing and liquid sliding bearing etc.Wherein, magnetic suspension bearing rotating speed height, it is little to wear and tear, but since its control system complexity, the cost height, and its practicality as machine tool chief axis is restricted.Air bearing has the rotating speed height, and it is little to wear and tear, advantage of high precision, but, can only be used for the small-power main shaft of small cutting force processing because its rigidity is little, and bearing capacity is limited.Rolling bearing is the main support structure of present machine tool chief axis, have the speed height, simple in structure, can produce in batches, can integral replacing when keeping in repair etc. advantage, but there are two intrinsic deficiencies: the one, because rolling bearing is a high-frequency rotary work under contact condition, there are fretting wear and fatigue wear inevitably, service life is shorter, after work a period of time, must take main shaft apart and keep in repair; And because the maintenance of main shaft and matching requirements maintenance personal's technological level is very high, maintenance or replacing main shaft need spend more time and cost, have reduced the production operation efficiency of lathe.The 2nd, because rolling bearing is to rely on the rigidity contact of limited rolling element that bearing capacity is provided, the local stress that raceway and ball touch inside and outside bearing is very high, and the local stress that does not touch is less, is certainly existing in a circumferential direction to be out of shape uneven phenomenon.Therefore adopt rolling bearing not to be suitable for machining accuracy and surface smoothness are required very high occasion, as precision grinder, fine boring machine etc. as the machine tool chief axis that supports.
Liquid sliding bearing is because the effect that bearing capacity is strong, lubricant medium has damping vibration attenuation and " homogenizing " error, therefore adopt liquid sliding bearing as the machine tool chief axis good rigidly, the rotating accuracy height that support, be very suitable for spindle unit as precision machine tool such as precision grinder and fine boring machine.But liquid sliding bearing exists shortcomings such as liquid medium frictional dissipation height, bearing temperature rise height, thereby causes adopting liquid sliding bearing lower as the working speed of the machine tool chief axis that supports.Simultaneously, be connected for interference owing to adopt between front and back bearings and the main shaft housing of main shaft of liquid sliding bearing, usually cause two kinds of rough sledding to occur: if the stator that bearing is installed motor is again installed by 1 elder generation, because motor stator cylindrical radial dimension is greater than the brearing bore size, motor stator can not directly be packed between the two bearings, can only place the rear portion of the main shaft outside the two bearings, becomes motor postposition formula main shaft, cause the main shaft axial dimension excessive, make the rigidity variation of front-end of spindle; 2 if pack motor stator between the two bearings into, the housing rear portion of again rear bearing being packed into behind the housing of must earlier motor stator being packed into during installation, when motor stator needs repairing replacing, the rear bearing that must be connected with the housing interference takes out earlier, could take out motor stator, because motor stator is connected the structure that no longer splits that is generally " cover is dead " with the interference of housing, implement very difficulty of dismounting.
The employing liquid sliding bearing owing to there is above-mentioned defective, causes it to fail at present fully to be used on lathe as the electric main shaft that supports, and fails to realize the production in enormous quantities of sliding bearing formula electricity main shaft as the Elementary Function parts.
Summary of the invention
Technical problem to be solved by this invention is the defective that overcomes above-mentioned prior art, a kind of rational in infrastructure, good, main shaft good rigidly of assembling maintenance process is provided, can realizes the sliding bearing formula electricity main shaft of high speed, precise treatment.
For solving the problems of the technologies described above, the technical solution adopted in the present invention is: it comprises main shaft, motor stator, rotor, fore bearing, rear bearing, housing, fore bearing, rear bearing is supported on the main shaft two ends, it is characterized in that described fore bearing and rear bearing are sliding bearing, preceding floating ring is set between fore bearing and main shaft, the back floating ring is set between rear bearing and the main shaft, preceding floating ring, be full of between the inner ring surface of back floating ring and the main shaft periphery lubricant medium is arranged, between the outer ring surface of preceding floating ring and the bearing shell of fore bearing, be full of between the outer ring surface of back floating ring and the bearing shell of rear bearing lubricant medium is arranged, motor stator and rotor place between fore bearing and the rear bearing, and the cable of motor stator passes the outside by the hole on the housing.
As a further improvement on the present invention, described housing is combined by front-end bearing pedestal and rear bearing block, and both are fastenedly connected by securing member.
Described fore bearing places the front end of front-end bearing pedestal, and the flange location of making axial location by this bearing front end setting, motor stator places the rear end of front-end bearing pedestal, rear bearing places rear bearing block, and the flange location of making axial location that is provided with by this bearing rear end, be provided with the motor stator locating ring in the motor stator rear end, this motor stator locating ring is fastening by securing member and motor stator and front-end bearing pedestal, the front end of floating ring is provided with a flange of making axial limiting before described, the rear end of back floating ring is provided with the flange of making axial limiting, front end at front-end bearing pedestal is provided with drive end bearing bracket, floating ring thrust adjusting pad before being provided with between drive end bearing bracket and the fore bearing, outside the floating ring flange excircle, drive end bearing bracket and preceding floating ring thrust adjusting pad were anchored on the front-end bearing pedestal before floating ring thrust adjusting pad was sheathed on before described; Floating ring rear end, described back is provided with retainer ring, between rear bearing and retainer ring, be provided with back floating ring thrust adjusting pad, described back floating ring thrust adjusting pad is sheathed on outside the floating ring flange excircle of back, be provided with the main shaft thrust ring in the retainer ring rear end, described main shaft thrust ring is fixed on the main shaft by locking nut, be provided with the rear end cap that is fastenedly connected with rear bearing block in the rear end of rear bearing block, be provided with the adjusting pad of main shaft thrust ring between rear end cap and the retainer ring, the adjusting pad of described main shaft thrust ring is sheathed on outside the excircle of main shaft thrust ring.
Sliding bearing formula electricity main shaft of the present invention, adopt the sliding supported condition main shaft, and between sliding bearing and main shaft, floating ring is set, form floating ring formula sliding bearing, during main axis rotation, between the inner ring surface of floating ring and the main shaft periphery, all be full of between the outer ring surface of floating ring and the bearing bush lubricant medium arranged, floating ring rotates under the drive of the lubricant medium that main shaft drives.The absolute rotary speed of main shaft is a main shaft with respect to the rotary speed of annulus and the annulus rotary speed sum with respect to bearing shell, therefore under same absolute speed conditions, the speed of the inside and outside oil film of floating ring formula sliding bearing is starkly lower than the speed of the oil film in the traditional sliding bearing that does not adopt floating ring.Because speed reduces to cause frictional dissipation to reduce, temperature rise reduces naturally.In other words, under same temperature condition, adopt floating ring formula main shaft can realize higher working speed, realize the main shaft high speed.And, because traditional single sliding bearing has become the combined bearing of being made up of floating ring and sliding bearing, can split installation, made things convenient for the assembly and disassembly of bearing and main shaft and motor stator.
The present invention can make housing the split-type structure, is divided into dismountable forward and backward bearing block, and the rotor that can realize motor more easily places the electric main axle structure between two sliding bearings, makes installation, location and the dismounting of motor stator easy to maintenance.
Description of drawings
Fig. 1 is a structural representation of the present invention.
Each label is represented among the figure:
1, drive end bearing bracket 2, preceding floating ring thrust adjusting pad
3, preceding floating ring 31, flange
4, fore bearing 41, flange
5, housing 51, front-end bearing pedestal
52, rear bearing block 6, main shaft
7, motor stator 8, rotor
9, motor stator locating ring 11, rear bearing
111, flange 12, back floating ring
121, flange 13, back floating ring thrust adjusting pad
14, retainer ring 15, main shaft thrust ring
16, the adjusting pad of locking nut 17, main shaft thrust ring
18, rear end cap 19, cable
The specific embodiment
As shown in Figure 1, sliding bearing formula electricity main shaft of the present invention, comprise main shaft 6, motor stator 7, rotor 8, fore bearing 4, rear bearing 11, housing 5, fore bearing 4, rear bearing 11 are supported on main shaft 6 two ends, fore bearing 4 and rear bearing 11 are sliding bearing, floating ring 3 before between fore bearing 4 and main shaft 6, being provided with, back floating ring 12 is set between rear bearing 11 and the main shaft 6, form floating ring formula sliding bearing, motor stator 7 and rotor 8 place between fore bearing 4 and the rear bearing 11, and the cable 19 of motor stator 7 passes the outside from housing 5.Before between the inner ring surface and main shaft 6 peripheries of floating ring 3, back floating ring 12, between the bearing shell of the outer ring surface of preceding floating ring 3 and fore bearing 4, all be full of between the bearing shell of the outer ring surface of back floating ring 12 and rear bearing 11 lubricant medium arranged, main shaft 6 rotations, drive the liquid medium rotation between main shaft 6 and preceding floating ring 3, the back floating ring 12, floating ring 3,12 rotations of back floating ring before liquid medium drives, the liquid medium rotation before preceding floating ring 3, back floating ring 12 drive between floating ring 3, back floating ring 12 and fore bearing 4, the rear bearing 11.Form relative rotary motion between main shaft 6 and preceding floating ring 3, the back floating ring 12.The absolute rotary speed of main shaft 6 is main shafts 6 with respect to the rotary speed of preceding floating ring 3, back floating ring 12 and preceding floating ring 3, the back floating ring 12 rotary speed sum with respect to fore bearing 4, rear bearing 11 bearing shells, therefore under same absolute speed conditions, the speed of the inside and outside oil film of floating ring formula sliding bearing is starkly lower than the speed of the oil film in the traditional sliding bearing that does not adopt floating ring.Because speed reduces to cause frictional dissipation to reduce, temperature rise reduces naturally.In other words, under same temperature condition, adopt floating ring formula main shaft can realize higher working speed.Housing 5 of the present invention is combined by front-end bearing pedestal 51 and rear bearing block 52, and both are fastenedly connected by securing member.Rear bearing block 52 is connected for interference with rear bearing 11, if desired with motor stator 8 when housing 5 takes out, can be earlier rear bearing block 52 and rear bearing 11 whole taking-ups, can split installation easily, if solved integral housing exist the motor stator dress not advance or be loaded into after be difficult to split out and motor stator places main shaft rear portion outside the two bearings can cause the problem of the excessive and front-end of spindle rigidity variation of main shaft axial dimension.Fore bearing 4 places the front end of front-end bearing pedestal 51, and 41 location of the flange of making axial location by this bearing front end setting, motor stator 7 places the rear end of front-end bearing pedestal 51, rear bearing 11 places rear bearing block 52, and the flange of making axial location 111 location that are provided with by this bearing rear end, be provided with motor stator locating ring 9 in the motor stator rear end, this motor stator locating ring 9 is fastening by securing member and motor stator 7 and front-end bearing pedestal 51, motor stator 7 is played the axial location effect, prevent that simultaneously motor stator 7 under the electromagnetic torque effect of circumferencial direction twist motion taking place.Before the front end of floating ring 3 be provided with a flange 31 of making axial limiting, the rear end of back floating ring 12 is provided with the flange 121 of making axial limiting, flange 31,121 limits preceding floating ring 3, the axially-movable of floating ring 12 afterwards respectively.Front end at front-end bearing pedestal 51 is provided with drive end bearing bracket 1, floating ring thrust adjusting pad 2 before being provided with between drive end bearing bracket 1 and the fore bearing 4, outside flange 31 excircles of floating ring, drive end bearing bracket 1 and preceding floating ring thrust adjusting pad 2 were anchored on the front-end bearing pedestal 51 before preceding floating ring thrust adjusting pad 2 was sheathed on; Back floating ring 12 rear ends are provided with retainer ring 14, between rear bearing 11 and retainer ring 14, be provided with back floating ring thrust adjusting pad 13, back floating ring thrust adjusting pad 13 is sheathed on outside flange 121 excircles of back floating ring, be provided with main shaft thrust ring 15 in retainer ring 14 rear ends, main shaft thrust ring 15 is fixed on the main shaft 6 by locking nut 16, during installation, because main shaft 6 adopts main shaft thrust ring 15 as the shaft shoulder, before rotor 8 parts on shaft such as grade were installed, rotor 8 can be inserted in from main shaft 6 rear ends easily.Be provided with the rear end cap 18 that is fastenedly connected with rear bearing block 52 in the rear end of rear bearing block 52, be provided with the adjusting pad 17 of main shaft thrust ring between rear end cap 18 and the retainer ring 14, the adjusting pad 17 of this main shaft thrust ring is sheathed on outside the excircle of main shaft thrust ring 15.The thickness of the adjusting pad 17 of floating ring thrust adjusting pad 2, back floating ring thrust adjusting pad 13 and main shaft thrust ring before can changing by grinding, before being respectively floating ring 3 do axial limiting flange 31, back floating ring 12 makes the flange 121 of axial limiting and the left and right sides of main shaft thrust ring 15 provides suitable gap.