RU2344024C1 - Method of gear and needle shaving - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: method is realised by rolling method, worm is engaged with worm gear, at that worm is worm shaver, and worm gear is processed blank, worm shaver is forcedly rotated, radial feed-motion is communicated to it at free rotation of balnk around its axis. Worm shaver is used in the form of worm, on lateral sides of turns of which wire poil is placed in the form of multiple wires that are rigidly fixed with one end on lateral side of worm turn perpendicular to it. At that diameter of worm shaver is arranged as equal to diameter of conjugated worm, and thickness of turns profile cog - as increased by value of double tension.

EFFECT: higher quality of gear machining, simplification of design and reduction of labour-intensiveness.

6 dwg, 1 ex, 1 tbl

Description

The invention relates to mechanical engineering, to gear processing and can be used in the finishing of the teeth of the worm wheels.

There is a method of finishing machining the teeth of the worm wheels, carried out by a worm shaver, which is a worm, on the top and sides of which a large number of narrow unsightened teeth are applied, while there is no kinematic connection between the shaver and the workpiece - the wheel and the driving element is a shaver; the wheel rotates freely on its axis [1].

The disadvantage of this method is the high complexity and complexity in the manufacture of a worm shaver, with possible errors in the shape and location of the contact spot.

The objective of the invention is to improve the quality of the finishing finishing of the toothwork, simplifying the design and reducing the complexity of manufacturing the tool by using a worm acupuncture with evenly distributed tufts of wire pile on the sides of the worm.

The problem is solved by the proposed method of gearing by rolling, characterized in that they reproduce the engagement of the worm with the worm wheel, and the worm is used as a worm, on the sides of the turns of which a wire pile is placed in the form of a large number of wires rigidly fixed with one end on the side of the turn the worm is perpendicular to it, and as the worm wheel is the workpiece being processed, forced rotational movement and radial feeds are reported iglosheveru worm, and the workpiece is set to be freely rotatable about its axis, the diameter of the worm igloshevera operate equal to the diameter of the conjugate of the worm, and the tooth thickness profile of its turns respectively, increase the amount of double tightness.

Features of gear-worming with a worm and needle-shaver are illustrated by drawings.

Figure 1 shows a diagram of gearing with radial feed, carried out on a gear hobbing machine by a worm needle gear, the axis of which is mounted horizontally, symmetrically to the axis of the workpiece; figure 2 - worm iglovers working on the proposed method, General view; figure 3 is a cross-section aa in figure 2 of turns of a worm iglovever; figure 4 is a view of B in figure 3 on the side of the coil; figure 5 - gear engagement of the worm iglovever with the workpiece, a longitudinal section along the axis of the worm iglovever; in Fig.6 is a section bb In Fig.5, a package of bundles of wire pile, located in the cavity of the worm wheel under load in the working position, and a package of bundles of wire pile, located outside the worm wheel without load in the free position.

The proposed method is intended for finishing finishing gear processing of the worm wheels by needle-shaving, carried out by the running method. The break-in method involves reproducing the engagement of the worm with the worm wheel, where the worm is used as the worm and the billet 1 and the workpiece 2 is used as the worm wheel.

The proposed method includes a forced rotational movement of the V _{And the} tool - the needler 1, its radial feed S _RAD and free rotation V _{SV of the} workpiece 2 about its axis.

Tool - worm iglover 1 is a worm, on the sides of the turns of which a wire pile 3 is applied, the latter consists of a large number of wires rigidly fixed with one end to the side of the turn of the worm and perpendicular to it. The fastening can be carried out, for example, by spot welding (as shown in figure 3, 4) or other known methods.

Finishing the teeth of the worm wheels with the help of worm needle loaders is carried out after finishing gear hobbing.

After fixing on the lateral sides of the turns of the wire pile, the oslover is ground on the same machine and by the same methods as the worm; the diameter of the worm iglover 1 is equal to the diameter of the mating worm, and the thickness of the tooth profile of the turns increased by the value of the double interference i.

In order to increase the service life and obtain a localized contact spot in the middle of the ring gear, the diameter of the needles should be slightly larger than the diameter of the worm mill used before this for finishing. When working with such an acupuncture, the interaxal distance on the machine is accordingly increased and the milling head is additionally rotated by the difference in the elevation angles of both tools.

A worm needle-shaver is less labor-consuming than the well-known traditional worm shaver [1] and is not difficult to manufacture; it is used for processing critical worm gears. When removing small chips, the surface roughness parameter on the tooth profiles decreases and, thus, the antifriction properties of the worm gear are improved.

Acupuncture is performed by the radial feed method by bringing the tool closer to the part until the nominal center distance is reached. The driving element is the worm needle-shaver; the workpiece wheel rotates freely on its axis. There is no kinematic relationship between the oslover and the wheel blank. Radial feed (stepwise) 0.03 ... 0.06 mm / rev table.

Acceptance allowances are shown in the table.

Tolerance (mm) on the thickness of the tooth blanks - worm wheels Module mm For tooth gearing Module mm For tooth gearing Up to 2 0.1 St. 6 ”8 0.20-0.25 St. 2 to 4 0.1-0.15 ”8” 10 0.25-0.30 ”4” 6 0.15-0.20 ”10” 14 0.30-0.40

When worm wheel blanks are acupunctured, errors in the shape and location of the contact spot are possible. An oversized overshoe provides a limited contact spot in the middle of the gear ring. As the iglover regrinds to the nominal diameter, the contact lengthens and is located along the entire length of the tooth. When using an oslover with an underestimated diameter after sharpening, the contact spot is located at the ends of the tooth of the worm wheel blank, which is unacceptable. When the contact spot is located on the head or tooth leg of the wheel billet, there is a difference in the angles of the needle and billet profile due to improper sharpening of the needle and incorrect manufacture of profiles.

Example. After finishing gear hobbing, billets of worm wheels having 29 teeth, m = 3 mm, made of: steel hub 45, crown made of bronze А9Ж3А, gear-braided with radial feed on the gear-milling machine mod. 53A20V with a worm-mounted acupuncture. A steel spring wire with a diameter of 0.5 ... 1.0 mm from 65G steel was used as a pile.

To carry out the finishing treatment with an aclover, 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 l is the free length of the wire element; 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 - density of the wire pile is in the range of 0.7 ... 0.9.

The hardness and tensile strength of the material of the workpiece - bronze Br A9Zh3A is 110 ... 180 HB, 55 kgf / mm ² = 550 MPa, GOST 1628-72, respectively; the hardness and tensile strength of the material of the wire elements of the pile made of steel 65G, respectively, are 220 HB, 71 kgf / mm ² = 710 MPa GOST 2500-71. Since the workpiece material in hardness and tensile strength is approximately 1.5 ... 2 times lower than these parameters of the tool material, an interference fit of i = 0.7 ... 1.0 mm was taken for stripping; ... 2.0 mm. In each case, the optimum interference fit is selected by experimental processing and should average i = 0.7 ... 2.5 mm.

In the process of processing the depression of the worm wheel blanks, the tufts of tufts enter the spacer between the teeth and, sagging due to interference i, are pressed against the blank. The magnitude of the force acting on the machined lateral surface of the tooth will be affected by the length l of the wire element. The main force impact on the surface being machined is carried out by the first wire elements in the direction of rotation having 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.

Processing by the proposed method with the help of a worm acupuncture showed that the force of pressing the beam to the workpiece surface was 200 ... 600 N per 10 mm of the width of the working surface of the tool. For treatment with an acupuncture, it is necessary to comply with the condition: p / σ _in = 1.5 ... 2.0, where p is the pressure during gearing, MPa; σ _in - the tensile strength of the material of the workpiece, MPa.

The choice of the corresponding pressure p depends on the physicomechanical properties of the material of the wire pile, on the stiffness and density of the latter, and also on the interference fit i [2].

The modes of operation of the tool can be recommended as follows. The peripheral speed for finishing processing is 2 ... 5 m / s. The longitudinal feed is determined by the formula S = L _protr n (mm / min), where n is the tool speed, min ^-1 ; the value of L _protrusion (mm) depends on the interference and the diameter of the tool and is determined empirically or by calculation.

When finishing the metals with the proposed method, the hardness of the treated surface does not increase, as a result, the quality of processing, the roughness of the processed surface are improved, and the processing productivity and durability of the tool are increased, its installation and dismantling are simplified.

The maximum roughness value achieved during processing by the proposed method using an oslover is R _a = 0.8 μm, a reduction of the initial roughness by a factor of 2.5 is possible.

The gear hatching of the worm wheels of the proposed method improves the quality and accuracy of the final finish of the teeth, reduces its cost due to the cheaper manufacturing tool.

Information sources

1. 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 - prototype.

2. Gavrilenko I. G. The method of combining preliminary and final needle-milling stripping of cylindrical parts // Automation and modern technology. - 1992. - No. 9. - S.27-30.

Claims (1)

A method of gear hornbing by rolling, characterized in that the worm engages with the worm wheel, and the worm is used as a worm, on the sides of the turns of which a wire pile is placed in the form of a large number of wires rigidly fixed with one end face on the side of the worm turn perpendicular to and, as a worm wheel, the workpiece being processed, a forced rotational movement and radial feed to the worm gear are reported, and the workpiece is installed vayut freely rotatable about its axis, the diameter of the worm igloshevera operate equal to the diameter of the conjugate of the worm, and the tooth thickness profile of its turns respectively, increase the amount of double tightness.

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