RU2334595C1 - Device for orbital pin milling of screws - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: device includes front and back orbital stocks and milling cutter. Front stock carries outer and inner eccentric shells, the inner shell holding a spindle with a blank, rotating independently around orbital axis. Internal eccentric shell with 'e' eccentricity has separate orbital rotation drive against central axis. Threaded disc milling cutter is mounted on miller head spindle with separate drive on a transverse rest and can be separately driven by manual transverse feed drive. The device features milling pin cutter mounted on pin cutter head spindle with separate electric drive and can be separately driven by manual transverse feed drive in opposite direction to the threaded disc milling cutter which is intended to function as a mobile support holder loaded by blank clamping force equal to cutting force exerted by the threaded disc milling cutter. Lengthwise movement of transverse rest is kinematically connected to orbital rotation of a blank on the condition of a distance covered by a rest with threaded disc cutter and milling pin cutter per one turn of orbital axis equal to the processed spiral surface pitch.

EFFECT: extended technological possibilities for processing of screws of tough materials.

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Description

The invention relates to mechanical engineering, to the field of machine tool engineering and mechanical engineering technology, can be used for high-speed milling of screw surfaces of precision screws from hard materials in combination with needle milling.

A known method of thread milling, implemented by a device for planetary milling of eccentric with eccentricity "e" screws, containing front and rear headstock and mill [1].

The known device has a significant drawback. For its implementation, special expensive tools and equipment are required, which increases the cost of workpieces. At the same time, narrow technological capabilities (only for parts with a short threaded surface) limit the scope, in addition, the unilateral action of the cutting force in the transverse plane causes longitudinal deflection of a long non-rigid workpiece, which reduces the quality and productivity of processing.

The objective of the invention is to expand the technological capabilities of high-speed milling of helical surfaces of precision screws from difficult to machine materials, which allows to increase tool life, productivity and quality of processing by additional communication of the planetary motion blanks, as well as to reduce the longitudinal deflection of a long non-rigid screw blanks by installing an additional tool in a diametrically opposite place form of acupuncture.

The problem is solved using the proposed device for planetary milling of screws with an eccentricity "e", containing the front and rear headstock and cutter, while the headstock is made planetary, while the front headstock contains eccentrically installed outer and inner sleeves, the last of which contains a spindle with the workpiece, independently rotating relative to its planetary axis, while the inner sleeve with an eccentricity "e" has an individual planetary rotation drive relative to the central si, the milling cutter is made in the form of a threaded disk and mounted on the spindle of the milling head with an individual electric drive on the transverse support with the possibility of independent manual drive of the transverse feed, and the device is equipped with a needle cutter mounted on the spindle of the milling head with an individual electric drive with the possibility of independent manual drive of the transverse feed diametrically opposite relatively disk threaded milling cutter, designed to perform the function of a movable lunette and loaded with a force p Izhimei to the workpiece, cutting equal force developed by the threaded disc cutter, wherein the longitudinal movement of the cross slide is kinematically linked with the planetary rotation of the workpiece from the condition that movement of the caliper with the disk cutter and threaded iglofrezoy per revolution of the planetary screw axis step machined surface.

Design features of the device are illustrated by drawings.

Figure 1 shows a diagram of the processing of a screw blank using the proposed device for combined needle-milling processing of screws with the installation of the blank in the lathe chuck with planetary movement of the spindle and pressing the rear center, which also performs planetary movements, top view; figure 2, 3, 4 - section bB in figure 1 of the front headstock of a lathe with planetary movement of the spindle, which shows the relative position of the spindle, the inner and outer eccentric sleeves; figure 5 is a cross section aa in figure 1, which shows the relative position of the tools and the workpiece; in Fig.6 is a cross-section BB in Fig.1, a device for attaching a threaded disk mill on the spindle of the milling head with an individual electric drive mounted on a transverse support; in Fig.7 - the device for attaching the needle cutter on the spindle of the needle-head with an individual electric drive mounted on a transverse support; on Fig is a diagram of the processing of the subsequent section of the screw and the relative position of the workpiece and tools when the workpiece is rotated half a turn relative to the central axis, top view; figure 9 - the relative position of the workpiece and tools when the workpiece is rotated half a turn relative to the planetary axis, top view.

The proposed device is designed for roughing and semi-finishing of screws 1 with eccentric screw surfaces having an eccentricity "e", a disk threaded mill 2 in combination with a needle mill 3. The operation of the device for needle cutting of screws, such as oil pump screws operating in the oil industry, includes a message the workpiece of the screw 1 of an independent rotational movement with a speed V _З that determines the cutting speed, and assigned depending on the cutting properties of the tool. This independent rotational movement V _{З of the} workpiece is carried out relative to the planetary axis О _П , offset from the central axis О _{Ц of the} workpiece by the eccentricity value "e".

In addition, a planetary rotational movement V _P relative to the central axis O _C is kinematically connected with the longitudinal feed S _{PR of} tools 2 and 3. This means that when the planetary axis O _p rotates about the central axis O _C by one revolution, the transverse support 4 with tools 2 and 3 will move in the longitudinal direction by the step size “t” of the machined screw surface.

The device provides for simultaneous rough machining with milling to carry out finishing with needle milling. To this end, in a diametrically opposite place relative to the disk threaded cutter 2 on the transverse support 4, a head 5 with a needle cutter 3 is installed, having an individual electric drive. The head 6, on the spindle of which the cutter 2 is fixed, also includes an individual electric drive.

The head 5 with needle cutter 3 has an independent transverse feed drive similar to the transverse feed drive of a threaded disk cutter 2, and plays the role of a movable lunette, which is loaded with a clamp force P _AND to the workpiece equal to the cutting force P _U developed by the thread mill.

The work of the proposed device for planetary acupuncture of screws is performed in the following sequence.

The workpiece of the screw 1, for example, smooth round rolling, is installed and fixed in a chuck 7 equipped with cams 8, and is pressed by the rear center 9. The chuck 7 is mounted on the spindle 10 of the front planetary headstock 11 of the lathe. The planetary headstock 11 of the lathe is characterized by the placental movement of the spindle 10, which is installed in the inner 12 and outer 13 eccentric sleeves [2]. As can be seen in FIGS. 2-4, two eccentric sleeves 12 and 13 and a spindle 10 are located in the body of the grinding headstock 11, and the rotation of the inner sleeve 12 provides planetary movement V _P , and the outer sleeve 13 serves to set the required eccentricity e. Figure 3 shows the layout of the spindle 10 with the workpiece when the eccentricity is maximum and equal to "2E". 4, the axis of the spindle 10 coincides with the axis of the outer sleeve 13. The alignment of the axis of the spindle 10 with the axis of the outer sleeve 13 is used to process conventional shafts with coaxial surfaces,

Pinole 14 with center 9 is located in the tailstock 15 of the machine and has the ability to make planetary motion V _P , similar to the spindle of the front headstock and synchronous with it.

After fixing the screw blank to the rear, the needle cutter 3 is brought in using the handwheel 16, which is mounted on the screw 17 of the cross support 4 of the machine, creating a certain interference force P _{AND of the} needle cutter on the workpiece. Next, the handwheel 18, which is mounted on the screw 19, connected with the upper movable plate 20, is fed to the workpiece threaded cutter 2. The threaded cutter 2 is mounted on the spindle of the head 6, which is mounted on the upper movable plate 20. On the dial (not shown), the handwheel 18 is installed depth of cut, as with traditional thread milling, and longitudinal feed S _{PR is} turned on.

The proposed device allows you to abandon the wide low-performance threaded cutters that are used in traditional thread cutting and profiling, reduce power loads and improve accuracy and productivity.

Example. The left screw H41.1016.01.001 of the screw pump EVN5-25-1500 was processed, which had the following dimensions: total length - 1282 mm, length of the screw part - 1208 mm, cross-section diameter of the screw - D = 27 ^-0.05 mm, eccentricity e = 1.65 mm, 2e = 3.3 mm, pitch t = 28 ^{± 0.01} mm, roughness R _a = 3.2 μm; single-helical screw surface, left direction; material - steel 18HGT GOST 4543-74, hardness HB 207-228, weight - 5.8 kg. Billet from round high-quality rolled metal in accordance with GOST 2590-71 with a diameter of 32 mm.

Processing was carried out on a modernized mod screw-cutting lathe. 16K20, with a planetary front headstock (described above) and a planetary tailstock, as well as a transverse caliper on which the milling (front) and needle-milling (rear) heads are mounted, respectively, with a threaded semicircular convex milling cutter Р6М5 GOST 9305-69 and needle needle with a pile of wire with a diameter of 1.5 mm, installed in front and behind the workpiece. Cutting speed i.e. mill rotation speed (mill 2262-0057 GOST 9305-69, diameter 80 mm, diameter hole 27 mm, width 10 mm, number of teeth 10) V _Ф = 30 m / min; n _Ф = 120 rpm, workpiece speed V _З = 17 m / min (0.283 m / s), n _З = 200 r / min, planetary speed of the workpiece - V _П = 0.8 m / min (0.0133 m / s), n _П = 77.2 rpm, longitudinal feed S _PR = 0.4 mm / rev. A lubricating-cooling liquid (coolant) was supplied to the treatment zones. The required roughness and accuracy of the helical surface was achieved after T _m = 39.2 min (against T _m ^bases = 76.5 min according to the basic version with the traditional separate rough and semi-finished turning of screws on a turning machine model 1K62, equipped with a swirl head, on AO Livhydromash).

Thus, to ensure the required quality and dimensional accuracy of processing, the main time was required is almost 2 times less than with separate roughing and semi-turning.

The control was carried out by an indicator bracket with an indicator ICh 10 B cells. 1 GOST 577-68. The cumulative error between any non-adjacent steps was not more than 0.1 mm, the clearance when controlling the straightedge of the protrusions forming in diameter was not more than 0.07 mm, which is permissible according to the technical specifications.

The proposed device for processing screw screw surfaces expands technological capabilities through the use of planetary high-speed milling, improves the quality and increases processing productivity due to combined milling and needle-milling, and also reduces the longitudinal deflection of a long non-rigid workpiece by installing an additional support equipped with a needle-mill, due to the installation of the latter increases wear resistance and durability of the processed surfaces.

Information sources

1. Patent WO 95/26845, B23C 3/32, 1995.

2. Reference technologist-machine builder. In 2 vols. T.1 / Ed. V.M.Kovana. - 2nd ed., Rev. and add. - M.: GNTIML, 1963. S.359-360, Fig. 210 - prototype.

3. Loskutov VV Metal Grinding: A Textbook for Secondary Vocational Schools. - 7th ed., Revised. and add. - M.: Mechanical Engineering, 1985, S. 94-95.

Claims (1)

A device for planetary milling of screws with an eccentricity “e”, comprising a front and rear headstock and a milling cutter, characterized in that the headstock is planetary, while the front headstock contains eccentrically mounted outer and inner sleeves, the last of which contains a spindle with a workpiece, independently rotating relative to its planetary axis, while the inner sleeve with an eccentricity "e" has an individual planetary rotation drive relative to the central axis, the cutter is made in the form of a disk thread It is mounted on a spindle of a milling head with an individual electric drive on the cross support with the possibility of an independent manual drive of a transverse feed, and the device is equipped with a needle mill mounted on a spindle of a milling head with an individual electric drive with the possibility of an independent manual drive of a transverse feed diametrically opposite to a disk threaded cutter, designed for performing the function of a movable lunette and loaded with a clamping force to the workpiece, equal to the cutting force, VIVA threaded disk cutter, the longitudinal movement of the cross slide is kinematically linked with the planetary rotation of the workpiece from the condition that movement of the caliper with the disk cutter and threaded iglofrezoy per revolution of the planetary screw axis step machined surface.

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