RU2387522C1 - Facility for milling set-up of screws - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: facility is designed for simultaneous two screws set-up milling of gerotor screw pumps. The pumps have screw surfaces with similar amount of starts, left in one, and right in another direction with a cutting tool in form of a cylinder mill. The mill is designed for processing two work-pieces. In consists of two spindles for simultaneous milling two work-pieces of screws secured in the spindles and arranged parallel. Mechanisms of spindles rotation are made identical. They impart the work pieces with equal matched rotation in mutually opposite directions. The facility also consists of an individual drive of main motion of the cylinder mill performing reciprocal travels relative to cross axis perpendicular to main lengthwise axis passing through centre of the mill coordinated with work-pieces rotation.

EFFECT: upgraded operation characteristics of facility.

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Description

The invention relates to mechanical engineering technology and can be used in the processing of working surfaces of screws with a round screw surface with a large pitch and a small distance between the top and bottom of the screw pumps on turning, grinding machines and machining centers.

There is a method and a device implementing it for processing screws with a round helical surface with a large pitch and a small distance between the apex and trough, in which the helical surface is cut with a cutter installed in the faceplate of the spindle of the lathe, and the axis of the faceplate is relative to the workpiece axis by the cross section eccentricity screw [1]. The cutting faceplate rotates around the offset axis and translates along the axis of the workpiece, kinematically associated with the rotation of the workpiece.

The disadvantages of the known device are: the high complexity of the processing process and low productivity, which is associated with the low resistance of the cutting tool, leading to a decrease in machining accuracy and a quick loss of cutting properties.

A known method and device for processing the screws of gerotor screw pumps, including the rotational movement of the workpiece and the cutting tool and the rectilinear motion of the feed of the cutting tool along the axis of the workpiece, the processing is carried out by the end surface of the cutting tool, the spindle axis of which is located at an acute angle ε to a straight, perpendicular the axis of rotation of the part, while the tool is informed of a rotational planetary movement consistent with the rotation of the workpiece from word of the tool spindle axis around said straight line, moreover, the rotary planetary motion of the cutting tool further accord with the aforementioned straight feed, wherein the treatment is carried out a part of the side surface of the cutting tool, and the angle ε is determined from the formula: ε = arcsin (h / D o) where h is the height of the profile of the screw surface of the part; D _o - the diameter of the forming surface of the tool [2].

The disadvantages of the known device are: the low resistance of the milling mechanical adjustment, leading to a rapid loss of cutting properties due to the rapid blunting of the sharp corners between the end and side cutting surfaces of the mill, and the high complexity of the regrinding process, leading to a decrease in processing accuracy and productivity.

A known method and device for processing screws with a round helical surface with a large pitch and a small distance between the top and bottom of the screw pumps, including the rotational movement of the workpiece and the cutting tool and the linear movement of the longitudinal feed of the cutting tool along the axis of the workpiece, the axis of the spindle of the cutting tool is angled the inclination of the helical line, while a cylindrical cutter is used as a cutting tool, which is additionally informed by oscillatory motion e using a crank head, consisting of a crank, which is informed of a rotation equal to and consistent with the rotation of the workpiece, a connecting rod, which is pivotally connected to the crank at one end, and with a slider performing rectilinear reciprocating movements, and rigidly connecting the connecting rod with a fork in which the said mill is installed with an individual drive of the main movement [3].

The disadvantages of the known method and device are: low accuracy due to the low stiffness of the workpieces and their deflection during unilateral exposure to the cutting tool, which causes beats and vibrations, as well as a decrease in the resistance of the milling setup, leading to a rapid loss of cutting properties, the high complexity of the processing process and the low performance.

The objective of the invention is to expand the technological capabilities of processing open screw surfaces, in particular screws with a round working screw surface with a large pitch and a small distance between the top and bottom of the screw pumps, increasing productivity, accuracy and quality of processing, as well as increasing the durability of tool setup.

The problem is solved using the proposed device for the simultaneous milling of a set of two screws of gerotor screw pumps having screw surfaces with the same number of starts, left on one screw and right on the other directions, with a cutting tool in the form of a cylindrical cutter designed to process two workpieces, containing two spindles for simultaneous processing of two screw blanks fixed on them and mounted parallel to them, spindle drives, the rotation mechanisms of which Full identical to communicate blanks equal coordinated rotary motions in mutually opposite directions, and the individual drive of the main movements of the cylindrical cutter placed, with reciprocating rotary motion about a transverse axis perpendicular to the main longitudinal axis passing through the center of the cutter, coordinated with the rotation of the preforms.

The essence of the proposed device for simultaneous processing of a set of two screws of screw pumps is illustrated by drawings.

Figure 1 shows a diagram of the simultaneous processing of a set of two screws with a round screw surface with a large pitch and a small distance between the top and the bottom of the screw pump with a cylindrical cutter using the proposed device, which shows the initial position of the tool and workpieces in cross section, the angle of inclination of the axis of the tool to a straight line perpendicular to a plane passing through the axis of the workpieces is equal to zero; figure 2 - shows the same, but the angle of inclination of the axis of the tool to a straight line perpendicular to the plane passing through the axis of the workpieces is equal to the maximum value; figure 3 - the relative position of the tool and workpieces, General view. 1-3, the indices

“ ^/ ” And “ ^// ” denote the left and right workpieces.

The proposed device is designed to handle a set of two screws

1 ^/ and 1 ^// with right and left directions and the same number of entries with a round screw surface with a large pitch and a small distance between the top and bottom of the screw pumps with a highly productive tool - a cylindrical mill 2.

The surface formation of the screws is carried out by the rolling method with the coordinated movement of the cutting tool 2 and the workpieces 1 ^/ and 1 ^// , while the tool 2 is informed of a complex planetary movement, which consists of rotation relative to its own longitudinal axis with the speed of the main cutting movement V _AND and rotational motion relative to the transverse axis perpendicular to the main longitudinal axis and passing through the central point C, with speed S _AND .

The composition of the proposed device includes two spindles with drives (not shown), in which the workpieces 1 ^/ and 1 ^// are fixed and to which rotational movements around their main central longitudinal axis of rotation _OZ ^/ and _OZ ^{// are} reported with a circular feed speed S _Z. To obtain a helical generatrix along the length of the workpieces 1 ^/ and 1 ^{// the} tool 2, which is fixed in the tool spindle and which is driven by an individual drive (not shown), report a linear motion along the axis of the workpieces

1 ^/ and 1 ^// with the longitudinal axial feed rate S _О equal to the step t of the machined screws per revolution of the workpieces.

The axis of the spindle of the tool 2 is located at an angle α _V ^/ = α _V ^{// of the} inclination of the helical line of the machined screws.

The cylindrical milling cutter 2 is additionally informed with a rotational motion S _AND , realized by means of an additional individual drive (not shown), kinematically connected with the rotation S _{3 of the} workpieces. The cutter 2 rotates S _And until it is embedded in the workpiece to the full height of the profile h of the machined screws and the angle of inclination α _And reaches the maximum value. Point A of the start of processing will occupy the position of point K of the end of the introduction, while points A and K will be diametrically opposed (see figure 2). After passing the point K, the cylindrical cutter 2 will change the reciprocating movement S _And the opposite and the angle of inclination α _And will begin to decrease to zero and will reach zero when the workpiece rotates 360 ° relative to the initial point A.

The movements of the circular feeds and axial feeds are coordinated with each other using the kinematic chains of the device (not shown).

Thus, when the tool rolls around the surface of the screws, eccentric screw surfaces are formed with the profile height h determined by the distance between the points of the tool cutting edge that are the most distant and the closest to the workpiece axes, and the helical surface of the workpieces is formed by milling with a cylindrical mill.

The proposed device is intended for processing a set consisting of two blanks of screws with a right and left direction and the same number of approaches with a round screw surface with a large pitch and a small distance between the top and the bottom. For the formation of a helical surface, the cutting tool is informed of the linear motion of the axial feed along the axis of the screws in the direction of approach of the turns, the feed amount being chosen equal to the pitch of the screws per revolution of the workpiece.

The proposed device allows you to fully use the advantages of multi-blade processing when cutting the working surfaces of the screws of screw pumps. The principle of separation of the removed allowance into the tooth of the tool is realized and the division and crushing of chips is facilitated. The device provides adjustment of the angle of inclination of the cutting edge of the tool relative to the work surface.

The advantage of the proposed device for processing screw pump screws is the high productivity of the process, which is associated with the high resistance of the multi-tooth tool and the ability to achieve high cutting speeds, as well as the complete processing of two workpieces with one tool at once.

мин по базовому варианту при последовательном нарезании двух винтов резцовой головкой на токарном станке модели 16К20). Полученное снижение основного времени составило ΔT_o=24,4 мин.Example. The left screw H41.1016.01.001 and the right screw H41.1016.01.002 of the screw pump EVN5-25-1500 were processed, which had the following dimensions: total length - 1282 mm, length of the screw part - 1208 mm, diameter d of the screw cross section - --27 _-0.05 mm, outer diameter of the workpiece D = 30.3 mm, profile height h = 3.3 mm, pitch t = 28 ± 0.01 mm; single-screw surfaces, left and right; material - steel 18HGT GOST 4543-74, hardness HB 207-228, weight 5.8 kg. Processing was carried out on a modernized lathe mod. 16K20 using the proposed device, providing control of the angle of inclination of the tool spindle relative to the axis of rolling. Tool - end mill GOST 17026-71, outer diameter - 25 mm, number of teeth z = 4, material - high-speed steel Р6М5 GOST 19265-73, tool spindle tilt angle - 15 ° 18 '. The frequency of rotation of the tool spindle is 250 rpm, the tool feed S _И = 2.16 rpm, the circular feed of workpieces S _З = 2 rpm, the tool feed along the axes of the workpieces per part revolution S _О = 28 mm / rev. The main processing time for two screws simultaneously was T _o = 24.3 min (against

min according to the basic version when sequentially cutting two screws with a cutter head on a model lathe 16K20). The resulting decrease in the main time was ΔT _o = 24.4 min.

During processing, favorable cutting conditions, the absence of vibrations, the minimum uniform wear of the cutting part of the tool, and the convenience of controlling the processing process were noted.

Thanks to the use of the proposed device, the quality of the machined surface is improved due to a more uniform distribution of the removed allowance on the cutter tooth and the dimensional accuracy of the cutting part of the tool is maintained due to its high resistance. The proposed device allows to intensify the cutting process and achieve high accuracy.

The proposed device allows to reduce the values of the axial component of the cutting force and thereby the cutting power, and also to improve the quality of processing by ensuring equal conditions for cutting two workpieces with a mill. In addition, equal cutting conditions (temperature, pressure, force, etc.) during processing by the proposed device eliminate vibrations and increase tool life.

Information sources

1. Screw pumps. D.F. Baldenko, M.G. Bidman, V.L. Kalishevsky, etc. - M .: Mashinostroenie, 1982. - S.122-123, Fig. 73.

2. RF patent 2209129, IPC ⁷ В23С 3/00, B23G 1/32. A method of processing screws for gerotor screw pumps. Klevtsov I.P., Brusov S.I., Tarapanov A.S., Kharlamov G.A. Application 2001135579/02; 12/21/2001; 07/27/2003. Bull. No. 21.

3. RF patent 2306199, IPC B23C 3/00, B23G 1/32. A method of milling screws with a round helical surface. Stepanov Yu.S., Kirichek A.V., Tarapanov A.S., Kharlamov G.A., Borodin M.V., Afanasyev B.I., Fomin D.S., Brusov S.I. Application 2006101248/02; 01/16/2006; 09/20/2007. Bull. No. 26.

4. RF patent 2306200, IPC B23C 3/00, B23G 1/32. A device for milling screws with a round helical surface. Stepanov Yu.S., Kirichek A.V., Tarapanov A.S., Kharlamov G.A., Borodin M.V., Afanasyev B.I., Fomin D.S., Brusov S.I. Application 2006101225/02; 01/16/2006; 09/20/2007. Bull. No. 26.

Claims (1)

Device for simultaneous milling of a set of two screws of gerotor screw pumps having screw surfaces with the same number of entries, left on one screw and right in the other direction, with a cutting tool in the form of a cylindrical cutter designed to process two workpieces, containing two spindles for simultaneous processing two screw blanks fixed on them and installed in parallel, spindle drives, the rotation mechanisms of which are made identical with the possibility of communicating the workpiece cam of equal coordinated rotational movements in mutually opposite directions, and an individual drive of the main movement of the cylindrical cutter, placed with the possibility of a reciprocating motion relative to the transverse axis perpendicular to the main longitudinal axis passing through the center of the cutter, consistent with the rotation of the workpieces.

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