Gap adjustable magnetic suspension electric spindle
The technical field is as follows:
the invention relates to the technical field of electric spindles, in particular to a gap-adjustable magnetic suspension electric spindle which is used for high-end numerical control machine tools with different cutting forms.
Background art:
in the current manufacturing of the active magnetic suspension electric spindle, the radial clearance of a single electric spindle is fixed, the radial clearance can be controlled within a certain range, ultra-precision machining is adopted, and the requirement on machining equipment is high. In addition, the size of the radial clearance directly influences the use of the radial clearance, for example, for a grinding machine tool, because the rigidity requirement is not high, the adjustment range of a controller is facilitated when some clearances work, so that the instability probability is reduced, for a milling and turning machine tool, the rigidity requirement is high, and the method for reducing the clearance is an effective method for improving the rigidity.
The invention content is as follows:
the radial clearance between the rotating shaft of the magnetic suspension electric spindle and the inner diameter of the magnetic bearing is difficult to control under common manufacturing conditions, the clearance-adjustable magnetic suspension electric spindle adopts an adjustable precise coupling piece structure, so that the radial clearance is adjustable and stable, and after the clearance-adjustable magnetic suspension electric spindle structure is adopted, the requirements of different cutting forms are met, and besides, the electric spindle with high quality and high requirements can be produced under common metal processing conditions.
In order to solve the technical problems, the magnetic bearing of the invention adopts a small-angle magnetic conduction taper sleeve structure which is provided with an inner taper hole, and the rotating shaft of the electric spindle adopts a small-angle taper shaft structure which is provided with a taper part, and different coupling positions are taken in the axial direction to change the radial gap.
The invention adopts the following steps:
(1) a magnetic bearing bracket (a tightening disc, a bracket turntable and a tightening screw) is constructed, so that the magnetic bearing can be fixed and the axial adjustment can be carried out;
(2) the electric spindle outer sleeve is provided with an adjusting thread which can enable the support turntable and the locking disc to be axially adjusted;
(3) and a support turntable and a locking disc are constructed, and the magnetic bearing support and the magnetic bearing can be axially positioned and locked through a waist hole structure.
The invention is realized by the following technical scheme:
a gap-adjustable magnetic suspension electric spindle comprises a rotating shaft and a magnetic bearing, wherein the rotating shaft is arranged in the electric spindle, the magnetic bearing is sleeved outside the rotating shaft, the rotating shaft is provided with a taper part, and an inner ring of the magnetic bearing is provided with an inner taper hole in clearance fit with the taper part.
In order to realize adjustable clearance, the invention designs a special adjusting mechanism which comprises a tightening disc, a bracket turntable, tightening screws, locking screws and locking discs, wherein the tightening disc and the bracket turntable are respectively pressed and mounted at two ends of a magnetic bearing, a plurality of tightening screws are uniformly arranged along the outer circumference of the bracket turntable, each tightening screw sequentially penetrates through the bracket turntable, the magnetic bearing and the tightening disc and is in threaded connection with the tightening disc, the locking disc is packaged at one end of the bracket turntable, and the locking disc is fixed with the bracket turntable through a plurality of locking screws.
In order to axially adjust the support turntable and the locking disc, the inner wall of the outer sleeve of the electric spindle is provided with a threaded part in threaded connection with the outer walls of the support turntable and the locking disc.
Further, in order to avoid the support carousel, locking dish to carry out the axial adjustment after, tighten up the screw rod and can't with tighten up the dish and align, in order to realize accurate locking, tighten up evenly set up on the dish 2 group with the corresponding screw hole of support carousel, 8 screw holes of every group are equallyd divide, deflect 11.5 degrees between two sets of screw holes, evenly set up 16 waist type holes of equallying divide on the support carousel.
In a preferred embodiment of the invention, after a plurality of experiments, we find that the taper K of the taper part is preferably 1/150, and the adjustment range of the gap delta between the inner ring of the magnetic bearing and the taper part is 0-0.0667 mm.
The invention has the beneficial effects that:
(1) the structure is simple, firm and stable;
(2) the adjustment is convenient, and no influence is caused on other mechanisms;
(3) the adjustable range of the clearance is 0-0.0667mm, and the working precision of a common processing machine tool is met;
(4) the demand is wide, and the magnetic suspension system is a good news for magnetic suspension research and magnetic suspension product developers.
Description of the drawings:
FIG. 1 is a schematic view of a rotating shaft of the present invention in cooperation with a magnetic bearing;
FIG. 2 is a schematic structural diagram of an adjusting mechanism of the present invention;
FIG. 3 is a schematic structural view of the take-up reel of the present invention;
fig. 4 is a schematic structural diagram of the rack turntable of the present invention.
The specific implementation mode is as follows:
the following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings, will make the advantages and features of the invention more readily understood by those skilled in the art, and thus will more clearly and distinctly define the scope of the invention. The directional terms used in the present invention, such as "up", "down", "front", "back", "left", "right", "top", "bottom", etc., refer to the directions of the attached drawings. Accordingly, the directional terms used are used for explanation and understanding of the present invention, and are not used for limiting the present invention.
As shown in fig. 1, the gap-adjustable magnetic levitation electric spindle includes a rotating shaft 1 disposed in the electric spindle and a magnetic bearing 2 sleeved outside the rotating shaft 1, wherein the rotating shaft 1 has a taper portion, the magnetic bearing inner ring has an inner taper hole in clearance fit with the taper portion, δ is a gap between the magnetic bearing inner ring and the taper portion, Δ L is an axial displacement of the magnetic bearing, K is a taper, and Δ δ ═ Δ L × K; example (c): when Δ L is 5mm, Δ δ is 0.033 mm. Usually, the range of delta L is 10mm, and the range of clearance adjustment reaches 0-0.0667mm, so that the precision requirement on processing equipment is low, and the method can be realized by a common machine tool.
The adjusting mechanism shown in fig. 2 comprises a tightening disc 4, a bracket turntable 5, a tightening screw 6, a locking screw 8 and a locking disc 7, the tightening discs 4 and the support turnplate 5 are respectively pressed at the left end and the right end of the magnetic bearing 2, a plurality of tightening screws 6 are uniformly arranged along the outer circumference of the support turnplate 5, each tightening screw 6 sequentially penetrates through the support turnplate 5, the magnetic bearing 2 and the tightening disc 4 and is in threaded connection with the tightening disc 4, the support turnplate 5 and the tightening screws 6 form an installation support of the magnetic bearing 2, the magnetic bearing 2 is installed in the electric spindle outer sleeve 3, locking dish 7 encapsulates at 5 right-hand members of support carousel, and locking dish 7 is fixed mutually through a plurality of locking screws 8 between 5 with the support carousel, realizes the fixed of whole installing support, and 3 inner walls of electricity main shaft overcoat have with support carousel 5 and 7 outer wall threaded connection's of locking dish screw thread portion.
As for the tightening disc 4 shown in fig. 3, 2 groups of circular threaded holes 10 corresponding to the tightening screws are uniformly formed in the tightening disc 4, each group of 8 threaded holes 10 form an 8-equal-division structure, and the central included angle of each group of threaded holes 10 is 11.25 degrees; as shown in fig. 4, the bracket rotating disc 5 is uniformly provided with 16 waist-shaped holes 9 corresponding to the threaded holes 10 to form 16 equal-division structures, and an included angle of each equal-division structure is 22.5 degrees, that is, no matter the tightening disc rotates to any angle, the tightening screw rod can pass through the waist-shaped hole 9 and enter the threaded hole 10.
During machining, the rotating shaft 1 is machined into a part 1 by an external grinding machine at the corresponding position of the magnetic bearing 2: 150 (adjusting head and tail frames to 1: 150 groove positions on a common cylindrical grinder), and the axial length is more than the axial length of the magnetic bearing plus 10 mm; processing an inner ring of the magnetic bearing 2 into a magnetic bearing by an internal grinding machine 1: 150 (adjusting head and tail frames to 1: 150 scribed lines on a common internal circular grinder); processing a magnetic bearing bracket component (a tightening disc, a tightening screw rod and a bracket turntable); processing a locking disc and a locking screw; and (5) assembling according to the drawing.
During adjustment, firstly 8 tightening screws 6 are screwed down, the axial displacement delta L is adjusted according to the required gap variable delta, and then the tightening screws 6 penetrate through waist-shaped holes 9 on the support turntable 5 and are connected and screwed with threaded holes 10 on the tightening disc 4, so that gap adjustment is realized.
In addition, in the description of the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "disposed," "provided," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.