A kind of sealing 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 fluid dynamic and static pressure mating type mechanical seal ring complicated surface that constitutes of the circumferential periodically variable oblique ripple face of slight inclination straight line and edge, its inclination angle by flat annular dam facing and radial contour.
Background technology
Mechanical seal is widely used in the slewing of fluid transfers such as pump, compressor, agitated reactor, agitator, centrifuge and filter or gas.The development of modern industry production is increasingly high to the performance and the life requirements that are operated in the mechanical seal under the conditions such as high speed, high pressure and high temperature.In the mechanical seal in early days, two seal faces of fitting mutually are designed and make smoothly as far as possible, and purpose is to make two effective clearances between seal face as far as possible little so that reduce leakage.Yet the fluid film that forms at these two interplanars breaks easily and causes these two seal faces to work in contact condition more, thereby causes bigger friction, wearing and tearing too early even damaged.In order to reduce wearing and tearing and to avoid damaged; People through offer at the sealing ring planar end surface deep trouth, shallow slot, radially tapering, radially shoulder, circumferentially structure such as waviness is kept stable fluid film and is directly contacted to avoid two seal faces, thereby produced a series of novel mechanicals sealings.Wherein most representative is a kind of fluid dynamic and static pressure mating type mechanical seal that 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 also can be that the end face of stationary ring is that slight inclination straight line and its inclination angle constitute along circumferential periodically variable oblique ripple face by flat annular dam facing and radial contour; When using with another flat sealing ring pairing; In the seal interface along circumferentially forming the corrugated gap, radially forming the convergence gap; Its advantage is to have liquid film all the time between two seal interfaces when guaranteeing shutdown and operating condition by the hydrostatic pressure effect that radially restrains the gap generation, and the hydrodynamic effect that is produced by circumferential corrugated gap guarantees that enough opening forces make the separation of two seal faces, and control ability is leaked in the enhancing of sealing dam facing.Result of the test shows that this seal form has bigger superiority than the dynamic pressure sealing of end face fluting with the hydrostatic seal of radially offering the convergence gap.The mechanical seal of present this fluid dynamic and static pressure mating type successful Application in the high-temperature pump of steam turbine, oil and gas pipes pump, nuclear main pump and petrochemical industry facility.The sealing ring of this seal form is processed by high hard material such as carborundum, silicon nitride, tungsten carbide usually; With interior (1 helium light belt is grown 0.29 micron), surface roughness Ra is in 5 nanometers at 1 ~ 2 helium light belt in the surface figure accuracy requirement of sealing ring dam facing and oblique ripple face.Because the squint corrugated surface is a kind of space free curved surface, can't adopt traditional method for grinding processing, and when 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; Computer control optical surface correction of the flank shape technology such as air bag polishing, magnetorheological polishing, ion beam polishing can realize the high-precision processing of optical surface; But working (machining) efficiency is low; Exist the edge effect problem during processing annular element in various degree; Sealing dam facing and oblique ripple face junction are that first order differential is discontinuous, and accurately correction of the flank shape is extremely difficult; There is surface roughness problem bigger than normal when adopting Laser Processing.
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 that by flat annular dam facing and radial contour be the high surface figure accuracy of fluid dynamic and static pressure mating type mechanical seal ring complicated surface, the low surface roughness processing that slight inclination straight line and its inclination angle constitute along circumferential periodically variable oblique ripple face.
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 straight line mobile platform, do crush grinding through the cup emery wheel end face.Sealing ring is clamped in workpiece spindle front end center, and workpiece spindle drives sealing ring and does the 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 the revolution position error is 0 ~ 1 minute.Cup emery wheel is installed on the grinding wheel spindle, and this cup emery wheel is done the 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 installed on the swing workbench, and the swing workbench is installed on the slide carriage of straight line mobile platform, and straight line mobile platform and grinding wheel spindle are installed on the bed piece.The axis of rotation of workpiece spindle is vertical with the axis of oscillation of swing workbench; The axis of rotation of grinding wheel spindle intersects vertically with the axis of oscillation of swing workbench; The axis of rotation of grinding wheel spindle is parallel with the direction of motion of straight line mobile platform, and the end face of cup emery wheel is towards workpiece spindle.The swing workbench drives workpiece spindle and does the high accuracy reciprocally swinging around the axis of oscillation of swing workbench, and the swing position error is 0 ~ 20 second.The straight line mobile platform drives the swing workbench and workpiece spindle is done the high accuracy rectilinear motion, and positioning accuracy is 0 ~ 20 nanometer.The cup emery wheel diameter is 150 ~ 700 millimeters, and cup emery wheel end face width is 2 ~ 5 millimeters, and the used abrasive material of cup emery wheel is 1000# or more fine-grained diamond.When the cup emery wheel axis of rotation is parallel with the workpiece spindle axis of rotation; The distance of a bit being arbitrarily the cup emery wheel axis of rotation and the plane of swing workbench axis of oscillation on the workpiece spindle axis of rotation equals 1/2nd of footpath in the oblique ripple face; Cup emery wheel axis of rotation and workpiece spindle axis of rotation distance are greater than extracting square root after grinding wheel radius and the oblique ripple face inside radius quadratic sum, and cup emery wheel axis of rotation and workpiece spindle axis of rotation distance are less than extracting square root after grinding wheel radius and the oblique ripple face outer radius quadratic sum.The control that can link of the rectilinear motion of reciprocally swinging, the straight line mobile platform of the gyration of workpiece spindle, swing workbench.The cup emery wheel rotating speed is 50 ~ 10000 rev/mins, and the workpiece spindle rotating speed is 0.1 ~ 500 rev/min.
Grinding oblique ripple face at first; During grinding oblique ripple face; Grinding wheel spindle drives the axis of rotation revolution of cup emery wheel around grinding wheel spindle; Workpiece spindle drives the axis of rotation revolution of sealing ring around workpiece spindle, and swing workbench drive workpiece spindle and sealing ring are around the axis of oscillation reciprocally swinging of swing workbench, and the straight line mobile platform drives the swing workbench and workpiece spindle is done linear reciprocating motion.Need the gyration of interlock control workpiece spindle, the reciprocally swinging of swing workbench and the rectilinear motion of straight line mobile platform to generate the oblique ripple face.Cup emery wheel is realized by the rectilinear motion of straight line mobile platform with respect to the feed motion of sealing ring during grinding.
During grinding oblique ripple face; If disregard the feed motion that straight line mobile platform drive swing workbench and workpiece spindle are done; Also disregard abrasion of grinding wheel and various error; The rectilinear motion of reciprocally swinging and the straight line mobile platform of the gyration of workpiece spindle, swing workbench 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 cup emery wheel and the face of cylinder intersection point that comprises oblique ripple face neighboring simultaneously all the time on the oblique ripple face neighboring of theoretical perfect form.During grinding oblique ripple face, the cup emery wheel rotating speed is 100 ~ 5000 rev/mins, and the workpiece spindle rotating speed is 0.1 ~ 50 rev/min, utilizes the end face of cup emery wheel to do crush grinding.
The oblique ripple face machines back grinding sealing dam facing; The swing workbench is locked in the cup emery wheel axis of rotation position parallel with the workpiece spindle axis of rotation during grinding sealing dam facing; Workpiece spindle drives the axis of rotation constant speed revolution of sealing ring around workpiece spindle, and grinding wheel spindle drives the axis of rotation constant speed revolution of cup emery wheel around grinding wheel spindle, and the straight line mobile platform drives cup emery wheel and does feed motion; The cup emery wheel rotating speed is 1000 ~ 10000 rev/mins; The workpiece spindle rotating speed is 10 ~ 500 rev/mins, utilizes the end face of cup emery wheel to do crush grinding, till being ground to final size.
Owing to adopt the end face width to have only the end face of 2 ~ 5 millimeters cup emery wheel to carry out crush grinding; The Grinding Contact district of cup emery wheel and workpiece extends through the neighboring from the inner rim of surface to be machined always; Do not need radially feed motion just can realize the grinding of oblique ripple face or dam facing, therefore do not exist when adopting multi-axis linkage numerical control point to contact grinding and need not do the complicated track planning problem.
Because the maximum at the radial contour inclination angle of sealing ring oblique ripple face has only the hundreds of microradian, during grinding sealing ring oblique ripple face, the angle of cup emery wheel axis of rotation and workpiece spindle axis of rotation is minimum; In the hundreds of microradian; Two axial lines is parallel substantially, thus grinding oblique ripple face and sealing during dam facing cup emery wheel almost constant with contact arc length, contact area, the entrance angle of sealing ring, the grinding force maintenance is constant; Machining state is stable, helps guaranteeing machining accuracy.
Owing to adopt the end face width to have only the end face of 2 ~ 5 millimeters cup emery wheels to carry out crush grinding; Cup emery wheel is that line contacts with sealing ring during grinding; Everywhere cutting speed, cutting depth and the cutting path length basically identical of effective abrasive particle on the abrasive wheel end face; Therefore abrasive wheel end face wearing and tearing everywhere are that the geometry of cup emery wheel end face remains unchanged during grinding, does not have the accurate correction of the flank shape difficult problem of emery wheel uniformly.
Because abrasion of grinding wheel only shows as the uniform loss of cup emery wheel end face; The cup emery wheel wearing and tearing only exert an influence to the distance of cup emery wheel end face with swing workbench axis of oscillation, can abrasion of grinding wheel effectively be compensated through the rectilinear motion of straight line mobile platform.
Effect of the present invention and benefit are can be to being that fluid dynamic and static pressure mating type mechanical seal ring complicated surface that slight inclination straight line and its inclination angle constitute along circumferential periodically variable oblique ripple face carries out high surface figure accuracy and low surface roughness is processed by flat annular dam facing and radial contour.
Description of drawings
Fig. 1 is the present invention's sealing ring complicated surface sketch map to be processed.
Fig. 2 is Principle of Grinding and Cutting figure of the present invention.
Among the figure: 1 sealing ring; 2 oblique ripple faces; 3 dam facings; 4 swing workbench; 5 straight line mobile platforms; 6 workpiece spindles; 7 cup emery wheels; 8 grinding wheel spindles.
The specific embodiment
Be described in detail the specific embodiment of the present invention below in conjunction with technical scheme and accompanying drawing.
Shown in accompanying drawing 1; Annular dam facing that the end face of sealing ring to be processed is served as reasons flat and radial contour are the fluid dynamic and static pressure mating type mechanical seal ring complicated surface that slight inclination straight line and its inclination angle constitute along circumferential periodically variable oblique ripple face; Its internal diameter be 160 millimeters, external diameter be 200 millimeters, sealing dam facing external diameter be 170 millimeters, oblique ripple face diameter to the outline line inclination angle between 0 ~ 0.0006 radian along circumferentially cyclically-varying; Ripple quantity is 9, and material is a pressureless sintering carborundum.
Shown in accompanying drawing 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 swing workbench and a high-precision hydraulic straight line mobile platform, do crush grinding through the cup emery wheel end face.
Sealing ring is clamped in workpiece spindle front end center, and workpiece spindle drives sealing ring and does the 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 the revolution position error was less than 0.5 minute.Cup emery wheel is installed on the grinding wheel spindle, and this cup emery wheel is done the 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 installed on the swing workbench, and the swing workbench is installed on the slide carriage of straight line travelling table, and straight line mobile platform and grinding wheel spindle are installed on the bed piece.The axis of rotation of workpiece spindle is vertical with the axis of oscillation of swing workbench; The axis of rotation of grinding wheel spindle intersects vertically with the axis of oscillation of swing workbench; The axis of rotation of grinding wheel spindle is parallel with the direction of motion of straight line mobile platform, and the end face of cup emery wheel is towards workpiece spindle.The swing workbench drives workpiece spindle and does the high accuracy reciprocally swinging around the axis of oscillation of swing workbench, and the swing position error is 0 ~ 8 second.The straight line mobile platform drives the swing workbench and workpiece spindle is done the high accuracy rectilinear motion, and positioning accuracy is 0 ~ 20 nanometer.The cup emery wheel diameter is 350 millimeters, and the face width of cup emery wheel end face is 3 millimeters, and the used abrasive material of cup emery wheel is the 1000# diamond.When the cup emery wheel axis of rotation is parallel with the workpiece spindle axis of rotation; The distance of a bit being the cup emery wheel axis of rotation and the plane of swing workbench axis of oscillation on the workpiece spindle axis of rotation arbitrarily equals 92.5 millimeters, and cup emery wheel axis of rotation and workpiece spindle axis of rotation distance equal 197 millimeters.The control that can link of the rectilinear motion of reciprocally swinging and the straight line mobile platform of the gyration of workpiece spindle, swing workbench.The cup emery wheel rotating speed is 50 ~ 10000 rev/mins, and the workpiece spindle rotating speed is 0.1 ~ 500 rev/min.
Grinding oblique ripple face at first; During grinding oblique ripple face; Workpiece spindle drives the axis of rotation revolution of sealing ring around workpiece spindle; Grinding wheel spindle drives the axis of rotation revolution of cup emery wheel around grinding wheel spindle, and swing workbench drive workpiece spindle and sealing ring are around the axis of oscillation reciprocally swinging of swing workbench, and the straight line mobile platform drives the swing workbench and workpiece spindle is done linear reciprocating motion.Need the gyration of interlock control workpiece spindle, the reciprocally swinging of swing workbench and the linear reciprocating motion of straight line mobile platform to generate the oblique ripple face.Cup emery wheel is realized by the rectilinear motion of straight line mobile platform with respect to the feed motion of sealing ring during grinding.
During grinding oblique ripple face; If disregard the feed motion that straight line mobile platform drive swing workbench and workpiece spindle are done; Also disregard abrasion of grinding wheel and various error; The rectilinear motion of reciprocally swinging and the straight line mobile platform of the gyration of workpiece spindle, swing workbench 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 cup emery wheel and the face of cylinder intersection point that comprises oblique ripple face neighboring simultaneously all the time on the oblique ripple face neighboring of theoretical perfect form.During grinding oblique ripple face, the cup emery wheel rotating speed is 500 rev/mins, and the workpiece spindle rotating speed is 1 rev/min, and feed speed is 0.5 micron/minute, utilizes the end face of cup emery wheel to do crush grinding.
The oblique ripple face machines back grinding sealing dam facing, and the swing workbench is locked in the cup emery wheel axis of rotation position parallel with the workpiece spindle axis of rotation during grinding sealing dam facing, and workpiece spindle drives the axis of rotation revolution of sealing ring around workpiece spindle; Grinding wheel spindle drives the axis of rotation revolution of cup emery wheel around grinding wheel spindle; The straight line mobile platform drives cup emery wheel and does feed motion, and the cup emery wheel rotating speed is 2000 rev/mins, and the workpiece spindle rotating speed is 50 rev/mins; Utilize the end face of cup emery wheel to do crush grinding; Feed speed is 1 micron/minute, and little feed motion resolution ratio is 0.1 micron, till being ground to final size.