A kind of three-shaft linkage mechanical seal ring method for grinding
Technical field
The invention belongs to complicated surface grinding technique field, relate to the grinding of mechanical seal ring, particularly a kind of is the superfine grinding method of the complex surfaces of liquid hybrid type mechanical seal rings that angled straight lines and its inclination angle form along circumferential periodically variable oblique ripple face slightly by flat annular dam facing and radial contour.
Background technology
Mechanical seal is widely used in the slewing of the fluid transfers such as pump, compressor, reactor, agitator, centrifuge and filter or gas.Performance and the life requirements of the mechanical seal of the development that modern industry is produced to being operated at a high speed, under the condition such as high pressure and high temperature are more and more higher.In mechanical seal in early days, two seal faces of laminating are designed and manufacture smoothly as far as possible mutually, and object is to make two effective clearances between seal face as far as possible little to reduce leakage.But the fluid film forming at these two interplanars easily breaks and causes these two seal faces to work in contact condition more, thereby cause larger friction, even breakage of wearing and tearing too early.In order to reduce wearing and tearing and to avoid damaged, people by offer at sealing ring planar end surface deep trouth, shallow slot, radially tapering, radially shoulder, circumferentially the structure such as waviness maintains stable fluid film to avoid two seal faces directly to contact, thereby produced series of new mechanical seal.Wherein most representative is a kind of fluid dynamic and static pressure mating type mechanical seal that the people such as U.S. Lebeck A. O. proposed in the 1980's, in the mechanical seal of this fluid dynamic and static pressure mating type, rotating ring can be also the end face of stationary ring by flat annular dam facing and radial contour for angled straight lines and its inclination angle form along circumferential periodically variable oblique ripple face slightly, while use with another flat sealing ring pairing, circumferentially form corrugated gap on edge, seal interface, radially form convergence gap, its advantage is between two seal interfaces, to have all the time liquid film while ensureing shutdown and operating condition by the hydrostatic pressure effect that radially restrains gap generation, the hydrodynamic effect being produced by circumferential corrugated gap ensures that enough opening forces separate two seal faces, and sealing dam facing strengthens leakage control ability.Result of the test shows that this seal form has larger superiority than the dynamic pressure sealing of grooved faces and the hydrostatic seal of radially offering convergence gap.The mechanical seal of current this fluid dynamic and static pressure mating type successful Application in the high-temperature pump of steam turbine, oil and gas pipes pump, core main pump and petrochemical industry facility.The sealing ring of this seal form is made up as carborundum, silicon nitride, tungsten carbide of high hard material conventionally, the surface figure accuracy of sealing ring dam facing and oblique ripple face requires in 1~2 helium light belt (1 helium light belt is grown 0.29 micron), and surface roughness Ra is in 5 nanometers.Because squint corrugated surface is a kind of Space Free-Form Surface, cannot adopt the processing of traditional method for grinding, and while adopting multi-axis linkage numerical control point contact grinding, abrasion of grinding wheel is fast, shape retention is poor, is difficult to the gratifying surface figure accuracy of acquisition; The computer controlled optical surfacing correction of the flank shape technology such as air bag polishing, MRF, ion beam polishing can realize the high accuracy processing of optical surface, but working (machining) efficiency is low, when processing annular element, exist in various degree edge effect problem, sealing dam facing and oblique ripple face junction are that single order differential is discontinuous, and accurately correction of the flank shape is extremely difficult; While adopting Laser Processing, there is surface roughness problem bigger than normal.
Summary of the invention
The object of the present invention is to provide a kind of three-shaft linkage mechanical seal ring complicated surface method for grinding, can realize by flat annular dam facing and radial contour is that the high surface figure accuracy of complex surfaces of liquid hybrid type mechanical seal rings, the low surface roughness that angled straight lines and its inclination angle form along circumferential periodically variable oblique ripple face slightly processed.
The present invention adopts following technical scheme to realize:
Adopt a workpiece spindle, a cup emery wheel, a grinding wheel spindle, a swing workbench, a rectilinear movement platform, do crush grinding by cup emery wheel end face.Sealing ring is clamped in workpiece spindle front end center, and workpiece spindle band rotary packing ring does high-precision rotary motion around the axis of rotation of workpiece spindle, and workpiece shaft run-out and end face run-out are 0~0.1 micron, and revolution position error is 0~1 point.Cup emery wheel is arranged on grinding wheel spindle, and this cup emery wheel does high-precision rotary motion around its axis of rotation, and emery wheel shaft run-out and end face run-out are 0~0.1 micron.Workpiece spindle is arranged on the slide carriage of rectilinear movement platform, rectilinear movement platform is arranged on bed piece, grinding wheel spindle is arranged on and swings on workbench, swinging workbench is arranged on bed piece, the axis of rotation of grinding wheel spindle intersects vertically with the axis of oscillation that swings workbench, swing workbench and drive grinding wheel spindle to do high-precision reciprocating swing around the axis of oscillation that swings workbench, swinging position error is 0~20 second.The axis of rotation of workpiece spindle is parallel with the direction of motion of rectilinear movement platform, and the end face of cup emery wheel is towards workpiece spindle.Linear motion platform drives workpiece spindle to do the motion of high accuracy complex line, and positioning precision is 0~20 nanometer.Cup emery wheel diameter is 150~700 millimeters, and cup emery wheel end face width is 2~5 millimeters, and cup emery wheel abrasive material used is 1000# or more fine-grained diamond.In the time that cup emery wheel axis of rotation is parallel with workpiece spindle axis of rotation, the distance that on workpiece spindle axis of rotation, any point has been cup emery wheel axis of rotation and has been swung the plane of workbench axis of oscillation equals 1/2nd of oblique ripple face central diameter, after cup emery wheel axis of rotation and workpiece spindle axis of rotation distance are greater than grinding wheel radius and oblique ripple face inside radius quadratic sum, extract square root, after cup emery wheel axis of rotation and workpiece spindle axis of rotation distance are less than grinding wheel radius and oblique ripple face outer radius quadratic sum, extract square root.The control that can link of the rectilinear motion of the gyration of workpiece spindle, the reciprocally swinging that swings workbench, rectilinear movement platform.Cup emery wheel rotating speed is 50~10000 revs/min, and workpiece spindle rotating speed is 0.1~500 rev/min.
First grinding oblique ripple face, when grinding oblique ripple face, grinding wheel spindle drives the axis of rotation revolution of cup emery wheel around grinding wheel spindle, workpiece spindle band rotary packing ring is around the axis of rotation revolution of workpiece spindle, swinging workbench drives grinding wheel spindle and cup emery wheel around the axis of oscillation reciprocally swinging that swings workbench, rectilinear movement platform drives workpiece spindle to do linear reciprocating motion, need interlock to control the gyration of workpiece spindle, the rectilinear motion that swings the reciprocally swinging of workbench and the platform that moves linearly generates oblique ripple face, when grinding, cup emery wheel is realized by the rectilinear motion of the platform that moves linearly with respect to the feed motion of sealing ring.
When grinding oblique ripple face, if disregard the feed motion that rectilinear movement platform drives workpiece spindle to do, also disregard abrasion of grinding wheel and various error, the linear reciprocating motion of the gyration of workpiece spindle, the reciprocally swinging that swings workbench and rectilinear movement platform will make cup emery wheel and the face of cylinder intersection point that comprises oblique ripple face inner rim all the time on the oblique ripple face inner rim of theoretical perfect form, and make simultaneously cup emery wheel with the face of cylinder intersection point that comprises oblique ripple face neighboring all the time on the oblique ripple face neighboring of theoretical perfect form.
When grinding oblique ripple face, cup emery wheel rotating speed is 100~5000 revs/min, and workpiece spindle rotating speed is 0.1~50 rev/min, utilizes the end face of cup emery wheel to do crush grinding.
Oblique ripple face machines rear grinding sealing dam facing, when grinding sealing dam facing, swing workbench and be locked in the cup emery wheel axis of rotation position parallel with workpiece spindle axis of rotation, workpiece spindle band rotary packing ring is around the axis of rotation constant speed revolution of workpiece spindle, grinding wheel spindle drives the axis of rotation constant speed revolution of cup emery wheel around grinding wheel spindle, rectilinear movement platform drives workpiece spindle to do feed motion, cup emery wheel rotating speed is 1000~10000 revs/min, workpiece spindle rotating speed is 10~500 revs/min, utilize the end face of cup emery wheel to do crush grinding, until be ground to final size.
Owing to adopting end face width to only have the end face of the cup emery wheel of 2~5 millimeters to carry out crush grinding, the Grinding Contact district of cup emery wheel and workpiece extends through neighboring from the inner rim of surface to be machined always, do not need feed motion radially just can realize the grinding of oblique ripple face or dam facing, therefore do not exist while adopting multi-axis linkage numerical control point to contact grinding and need to do complicated track planning problem.
Because the maximum at the radial contour inclination angle of sealing ring oblique ripple face only has hundreds of microradian, when grinding sealing ring oblique ripple face, the angle of cup emery wheel axis of rotation and workpiece spindle axis of rotation is minimum, in hundreds of microradian, two axial lines is parallel substantially, and when therefore grinding oblique ripple face is with sealing dam facing, contact arc length, contact area, the entrance angle of cup emery wheel and sealing ring are almost constant, and it is constant that grinding force keeps, machining state is stable, is conducive to ensure machining accuracy.
Owing to adopting end face width to only have the end face of 2~5 millimeters of cup emery wheels to carry out crush grinding, when grinding, cup emery wheel is that line contacts with sealing ring, on abrasive wheel end face, cutting speed, cutting depth and the cutting path length of active grain is everywhere basically identical, therefore abrasive wheel end face wearing and tearing are everywhere uniform, when grinding, the geometry of cup emery wheel end face remains unchanged, and does not have the accurate correction of the flank shape difficult problem of emery wheel.
Because abrasion of grinding wheel only shows as the uniform loss of cup emery wheel end face, cup emery wheel wearing and tearing only exert an influence to cup emery wheel end face and the distance that swings workbench axis of oscillation, can carry out effective compensation to abrasion of grinding wheel by the rectilinear motion of rectilinear movement platform.
Effect of the present invention and benefit are to be that angled straight lines and its inclination angle form along circumferential periodically variable oblique ripple face slightly complex surfaces of liquid hybrid type mechanical seal rings carries out high surface figure accuracy and low surface roughness is processed to the annular dam facing by flat and radial contour.
Brief description of the drawings
Fig. 1 is the present invention's sealing ring complicated surface schematic diagram to be processed.
Fig. 2 is Principle of Grinding and Cutting figure of the present invention.
In figure: 1 sealing ring; 2 oblique ripple faces; 3 dam facings; 4 rectilinear movement platforms; 5 workpiece spindles; 6 cup emery wheels; 7 grinding wheel spindles; 8 swing workbench.
Detailed description of the invention
Describe the specific embodiment of the present invention in detail below in conjunction with technical scheme and accompanying drawing.
As shown in Figure 1, the annular dam facing that the end face of sealing ring to be processed is served as reasons flat and radial contour are the complex surfaces of liquid hybrid type mechanical seal rings that angled straight lines and its inclination angle form along circumferential periodically variable oblique ripple face slightly, its internal diameter be 160 millimeters, external diameter be 200 millimeters, sealing dam facing external diameter be 170 millimeters, oblique ripple face radial profile inclination angle between 0~0.0006 radian along circumferentially cyclically-varying, ripple quantity is 9, and material is pressureless sintering carborundum.
As shown in Figure 2, adopt the workpiece spindle of a high accuracy air bearings support, a cup emery wheel, a high accuracy air bearings support grinding wheel spindle, a high-precision hydraulic to swing workbench and a high-precision hydraulic rectilinear movement platform, do crush grinding by cup emery wheel end face.
Sealing ring is clamped in workpiece spindle front end center, and workpiece spindle band rotary packing ring does high-precision rotary motion around the axis of rotation of workpiece spindle, and workpiece shaft run-out and end face run-out are less than 0.05 micron, and revolution position error is less than 0.5 point.Cup emery wheel is arranged on grinding wheel spindle, and this cup emery wheel does high-precision rotary motion around its axis of rotation, and emery wheel shaft run-out and end face run-out are less than 0.05 micron.
Workpiece spindle is arranged on the slide carriage of rectilinear movement platform, rectilinear movement platform is arranged on bed piece, grinding wheel spindle is arranged on and swings on workbench, swinging workbench is arranged on bed piece, the axis of rotation of grinding wheel spindle intersects vertically with the axis of oscillation that swings workbench, swing workbench and drive grinding wheel spindle to do high-precision reciprocating swing around the axis of oscillation that swings workbench, the swing position error that swings workbench is less than 8 seconds.The axis of rotation of workpiece spindle is parallel with the direction of motion of rectilinear movement platform, and the end face of cup emery wheel is towards workpiece spindle.Linear motion platform drives workpiece spindle to do high accuracy rectilinear motion, and positioning precision is less than 20 nanometers.Cup emery wheel diameter is 350 millimeters, and the face width of cup emery wheel end face is 3 millimeters, and cup emery wheel abrasive material used is 1000# diamond.In the time that cup emery wheel axis of rotation is parallel with workpiece spindle axis of rotation, the distance that on workpiece spindle axis of rotation, any point has been cup emery wheel axis of rotation and has been swung the plane of workbench axis of oscillation equals 92.5 millimeters, and cup emery wheel axis of rotation and workpiece spindle axis of rotation are apart from being 197 millimeters.Cup emery wheel rotating speed is 50~5000 revs/min, and workpiece spindle rotating speed is 0.1~500 rev/min.
First grinding oblique ripple face, when grinding oblique ripple face, workpiece spindle band rotary packing ring is around the axis of rotation revolution of workpiece spindle, grinding wheel spindle drives the axis of rotation revolution of cup emery wheel around grinding wheel spindle, swinging workbench drives grinding wheel spindle and cup emery wheel around the axis of oscillation reciprocally swinging that swings workbench, rectilinear movement platform band swings workbench and moving grinding wheel spindle does rectilinear motion, need interlock to control the gyration of workpiece spindle, the rectilinear motion that swings the reciprocally swinging of workbench and the platform that moves linearly generates oblique ripple face, when grinding, cup emery wheel is realized by the rectilinear motion of the platform that moves linearly with respect to the feed motion of sealing ring.
When grinding oblique ripple face, if disregard the feed motion that rectilinear movement platform drives workpiece spindle to do, also disregard abrasion of grinding wheel and various error, the rectilinear motion of the gyration of workpiece spindle, the reciprocally swinging that swings workbench and rectilinear movement platform will make cup emery wheel and the face of cylinder intersection point that comprises oblique ripple face inner rim all the time on the oblique ripple face inner rim of theoretical perfect form, and make simultaneously cup emery wheel with the face of cylinder intersection point that comprises oblique ripple face neighboring all the time on the oblique ripple face neighboring of theoretical perfect form.When grinding oblique ripple face, cup emery wheel rotating speed is 500 revs/min, and workpiece spindle rotating speed is 1 rev/min, and feed speed is 0.5 micro-m/min, utilizes the end face of cup emery wheel to do crush grinding.
Oblique ripple face machines rear grinding sealing dam facing, when grinding sealing dam facing, swing workbench and be locked in the cup emery wheel axis of rotation position parallel with workpiece spindle axis of rotation, workpiece spindle band rotary packing ring is around the axis of rotation revolution of workpiece spindle, grinding wheel spindle drives the axis of rotation revolution of cup emery wheel around grinding wheel spindle, rectilinear movement platform drives workpiece spindle to do feed motion, cup emery wheel rotating speed is 2000 revs/min, workpiece spindle rotating speed is 50 revs/min, utilize the end face of cup emery wheel to do crush grinding, feed speed is 1 micro-m/min, micro-feed motion resolution ratio is 0.1 micron, until be ground to final size.