RU2332282C1 - Fly hob gear-quill cutting method - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: method involves kinematically linked rotatory movements of the work piece and a cutting hob and its tangential feed. The fly hog is in form of cylindrical worm, consisting of a case and an incomplete loop in form of a tooth. To increase efficiency as well as quality of gear machining, the fly hob is made as an assembly clamped on a disposable carbide blade in form of a trapezium with linear lateral profiled cutting edges, freely installed on pivot, which is pressed into a removable blade, with provision for radial displacement in the groove of the case with screwing screws for pressing the plates to the peripheral surface of the case. The incomplete loop of the tooth is made from a bundle of wires in form of a trapezium with linear lateral profiled cutting edges, overhanging the plate by a preload, and fixed by a pulling rod, passing through an opening in each bundle of wires and joining the removable blade to the rear plank using nuts. On the peripheral surface of the case there is a groove in the form of dovetail, in which the above mentioned plank and wire bundle are put with provision for circular movement.

EFFECT: increased efficiency and quality of gear machining.

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Description

The invention relates to mechanical engineering, to gear processing and can be used when cutting the teeth of a worm cylindrical gear.

There is a method of cutting worm wheels with a combined worm mill - a flapper, consisting of a mounted cylindrical worm with an incomplete turn - a tooth and an eccentric ring entering the worm hole, which, when the cutter is mounted on the spindle of the hobbing machine, provides the formation of a rear angle and a constant tooth outreach [1].

The disadvantage of this method is the low productivity, roughness, machined surface, and not high tool life due to the fact that it is cast and does not allow the use of its body after all regrinding of the tooth, and this increases the cost of the tool, in addition, when grinding the cutter must be removed from the machine and transferred to the grinding machine.

The objective of the invention is to increase the productivity and quality of gear processing by eliminating the backing operation and the introduction of combined gear-cutting.

The problem is solved by the proposed method of milling with a worm milling cutter - a volatile break-in method, in which the engagement of the worm with the worm wheel is reproduced, the worm cutter being used as the worm, and the workpiece used as the worm wheel, including kinematically coupled rotational movements of the workpiece and the worm gear its tangential feed, while using a worm cutter - a fly in the form of a cylindrical worm, consisting of a body and an incomplete turn in de tooth, while the worm milling cutter is made by a national team with mechanical fastening of a non-rotatable carbide plate in the form of a trapezoid with straight side profiling cutting edges freely mounted on a pin that is pressed into an insert knife that can radially move into the groove of the case when screwing in the screws for pressing plates to the peripheral surface of the body, while an incomplete tooth revolution is made of a package of bundles of wire pile in the form of a trapezoid with rectilinear lateral milling cutting edges protruding above the plate by the amount of interference, and secured with a rod passing through the hole in each tuft of pile and connecting the insert knife to the back plate with a nut, a dovetail-shaped groove is made on the peripheral surface of the body, in which with the possibility of circumferential movement, the aforementioned back plate and bundles of wire pile are arranged.

Features zubooglofrezirovaniya worm needle oglofreza - volatile are illustrated by drawings.

In Fig.1 shows a worm acupuncture - fly, working according to the proposed method, end view; figure 2 is a view according to B in figure 1; figure 3 is a view along a in figure 1; figure 4 - section G - G in figure 5 of the element In figure 1; figure 5 is a top view of the element In figure 4; figure 6 is a section D - D in figure 5 of the element In figure 1; Fig.7 - design of a pile of pile of wire from which an incomplete round of tooth is recruited; on Fig - section E - E in Fig.7; figure 9 is a package of bundles of wire pile under load in the working position, located in the cavity between the cut teeth of the processed worm wheel.

The proposed gear-cutting method is used for cutting worm wheels by the rolling method, in which the worm engages with the worm wheel, where the worm cutter is used as the worm and the workpiece is used as the worm wheel. A worm mill - a fly is a cylindrical worm and consists of a housing 1 and an incomplete turn - a tooth 2.

Worm mill - fly made by the national team with mechanical fastening of the non-rotatable carbide cutting insert 3 in the form of a trapezoid with straight lateral profiling cutting edges.

The cutting insert 3 is freely mounted on the pin 4, which is pressed into the hole of the insert knife 5. The insert knife 5 has the ability to radially move into the groove 6 of the housing 1 when the screws 7 are screwed in.

Screws 7, when they are screwed into the housing 1, the plate 3 is pressed against the peripheral surface of the housing 1. The surface of the insert knife 5, on which the cutting plate 3 rests, is cut and sharpened so that a negative rake angle and positive rear angles along the tooth profile are formed.

Worm milling cutter is a part-turn of 2 worms with parameters of the producing helical surface of the worm milling cutter designed for a given cut worm wheel with a step t.

Incomplete turn 2 in addition to the cutting insert 3 contains a bundle of bundles of wire pile 8. The package is made in the form of a trapezoid with straight lateral profiling cutting edges protruding above the insert 3 by the amount of interference i (see figure 2). The bundle of wire bundles 8 is fixed to the housing by known methods.

The proposed method is implemented using the design of the needle cutter, a fly, for which, as an option, an original method for attaching bundles of wire pile, below, has been developed.

First, a pile of pile 9 is made from separate wires connected, for example, by spot welding, as shown in Figs. 7-8. In this bundle, radially arranged wires 9 _P and wires located in the circumferential direction 9 _O are distinguished. Each bundle of pile 9 has an opening 10 and the bottom part in the form of a "dovetail" 11. The bundles of wire pile 9 with the lower part are installed in the groove 12 on the housing 1 and are strung on the rod 13. The rod 13 is rigidly fixed at one end, for example, pressed in the insert knife 5, and on the other end of the threaded thread. On the peripheral surface of the housing, a groove 12 is made in the form of a “dovetail” along the entire length of the incomplete turn.

The final fastening of the wire pile 9 on the body is carried out by tightening the bundles with a nut 14, screwed onto the threaded end of the rod 13, on which the back plate 15 is pre-installed. When tightening the nut 14, the tufts of the wire pile are circumferentially moved and sealed, as well as they are rigidly connected to the body.

After the general assembly, it is necessary to grind the needle part of the coil along the profile, taking into account the interference fit i, before gearing.

Example. 29 teeth were milled, m = 3 of a worm wheel made of: hub made of steel 45, crown made of bronze A9ZhZA, on a gear hobbing machine mod. 53A20 B according to the proposed method, a worm needle-mill, equipped with a VK4 carbide cutting insert used for roughing, and a bundle of wire pile bundles for final finishing. These transitions were made at the same time due to the design features of the worm acupuncture - volatiles.

According to the traditional standard technological process, rough gear hobbing was first carried out, and then the final finishing of the worm wheel on a shaving machine, for example, mod. 5B702 B, on which sheving was finally made.

Processing by the proposed method was carried out by the tangential feed method [2]. During operation, the machined wheel engages with a single-entry worm, therefore, we perform needle milling with a feed of 0.9 ... 0.15 mm / rev table, cutting speed of 12 ... 18 m / min. The ability to adjust the cutting insert in the housing in height allows you to get a uniform quality of engagement of the worm wheels. Finishing the teeth is carried out simultaneously after rough gear hobbing, using bundles of wire pile, which are installed behind the cutting plate in the form of an incomplete turn 2. The following allowances for finishing gear cutting are recommended, see table No. 1.

1. The allowances (mm) for the thickness of the tooth of the worm wheels

Module mm For gear cutting Up to 2 0.35 St. 2 to 4 0.35 ... 0.55 "4" 6 0.55 ... 0.80 "6" 8 0.80 ... 1.00 "8" 10 1.00 ... 1.30 "10" 14 1.00 ... 1.50

As a pile, a steel spring wire with a diameter of 0.5 ... 1.0 mm from 65G steel is used. To carry out the finishing treatment, it is necessary that the hardness and tensile strength of the material of the wire elements of the pile be 1.5 ... 2 times higher than these parameters of the material of the workpiece, the ratio l / I, where I is the smallest inertia radius of the cross section of the wire elements, was in the range of 50 ... 100, and the coefficient K _{p the} density of the wire pile in the range of 0.7 ... 0.9; the tightness should be - i = 0.7 ... 1.5 mm.

In the process of processing the depression of the workpiece of the worm wheel, the tufts of pile 9o are placed between the teeth (see Fig. 9) and are pressed against the workpiece with an interference fit. Due to the fact that the tufts of pile 9 _{O of the} circumferential direction work at their two ends, the length l _O will affect the force on the machined side surfaces of the teeth. The main force acting on the surface being machined is carried out by the first 9 _O wire elements with the largest free length l and deflection f. The wire elements adjacent to them elastically compress them, slightly increasing the concentrated total effect on the treated surfaces.

Tests of a flying worm needle-cutter showed that the force of pressing the beam against the workpiece’s work surface is 200 ... 600 N per 10 mm of the width of the tool’s working surface, and the tangential component of the cutting force is 150 ... 550 N.

For processing by the proposed method, it is necessary to observe the conditions: p / σ _in = 1.5 ... 2.0, where p is the pressure during acupuncture, MPa;

σ _in - the tensile strength of the material of the workpiece, MPa.

The choice of the appropriate pressure p depends on the physicomechanical properties of the material of the wire pile, on the rigidity and density of the latter, as well as on the interference fit i [3].

The proposed method of gear-cutting with a worm needle-mill-worm increases the productivity by combining roughing and finishing operations with a carbide plate and bundles of wire pile, reduces the number of operations and the number of jobs, eliminates the backing operation due to the use of a non-rotatable carbide plate with mechanical fastening, and also improves the quality and accuracy of tooth treatment by introducing a combined needle-milling tooth treatment.

Information sources

1. A.S. USSR No. 107509, IPC B23F 21/18. Worm milling cutter - fly for cutting worm wheels. I.S. Sakhno. Application 7102/455163, 07/05/1955 - prototype.

2. Reference technologist-machine builder. In 2 volumes of T. 1. Ed. A.G. Kosilova and R.K. Meshcheryakova. - 4th ed., Revised. and add. - M.: Mechanical Engineering. 1986. S. 371-372.

3. Gaprilenko I.G. A method of combining preliminary and final needle-milling stripping of cylindrical parts // Automation and modern technology. - 1992. - No. 9. - P.27-30.

Claims (1)

A method of milling a worm milling cutter with a volatile break-in method, in which the engagement of the worm with the worm wheel is reproduced, wherein the worm cutter is used as a worm, and the workpiece is used as a worm wheel, including kinematically coupled rotational movements of the workpiece and the worm cutter and its tangential feed in this case, a flying worm milling cutter in the form of a cylindrical worm consisting of a housing and a partial turn in the form of a tooth, characterized in that the worm milling cutter the cloud was made by the national team with mechanical fastening of a non-turning trapezoidal carbide plate with rectilinear lateral profiling cutting edges freely mounted on a pin that is pressed into an insert knife that can radially move into the groove of the case when the screws are screwed in to tighten the plate to the peripheral surface of the case, an incomplete tooth revolution is made of a bundle of wire tufts in the form of a trapezoid with straight lateral profiling cutting edges falling over the plate by the amount of interference, and secured with a rod passing through the hole in each bundle of the pile and connecting the insert knife to the back plate using a nut, a dovetail-shaped groove is made on the peripheral surface of the body, in which it can be moved around have the above named back plate and tufts of wire pile.

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