SU1696073A1 - Method for final forming of tooth profiles - Google Patents

Abstract

The invention relates to the processing of gear profiles and can be used in the production of gears of medium and large modules and chain sprockets. The goal is to improve the accuracy of the finished gear profile. This is achieved by first preliminarily engaging the partially formed teeth of the workpiece with the teeth of the knurling mounted on the axles rotatably. At the same time, the workpiece is heated, the rotation is shared with it, and the speed of its rotation is coordinated with the speed of rotation of the knurling units, heated. The final formation of the teeth is carried out with the radially moving knurlers, and the calibration of the workpiece is carried out by the rolling-in method, forming a rigid connection between the knurling machines and the workpiece. Heating with pre-engagement is carried out to 600-1100 ° C. This eliminates slippage and improves performance. 1 Cp. F.-ly, 1 tab. - fe

Description

The invention relates to the processing of gear profiles using plastic deformation and can be used in the manufacture of gears of medium and large modules and chain sprockets.

The aim of the invention is to improve the accuracy of the finished gear profile by eliminating slippage during processing.

The method is carried out as follows.

The partly formed teeth are pre-engaged with

the teeth of the knurling wheels mounted on the axles with the possibility of rotation and associated with the reference wheel. The workpiece is then reported to rotate at the speed of the knurlers, with the result that the workpiece is preheated. After the acceleration of the knurlers, turn on the heating of the workpiece using a sector inductor, then finally form the tooth profile, radially displacing the knurlers. The process is completed by calibration, which is performed by rolling the knurlers along the formed gear profile with a constant center distance, forming a rigid bond.

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knuckles and blanks, for example, by incorporating a sleeve embedded in this connection.

Obviously, preheating should be as large as possible and limited only by the strength of the tooth or 1 max.

1100 ° C, since it improves productivity by reducing the time to warm up to t, max. This makes it possible to determine the preheating temperature by the strength of the tooth, which is sufficient to absorb the inertial forces that occur when accelerating the knurlers to the working speed.

According to known specifications for asterisks with a pitch of 1 15875; 19.05; 25.4 mm, the number of revolutions of the knurls can be taken on average equal to PM 261 / min. For steel 45, the yield strengths for t 600 ° С from 8 kg / mm2, for t 1100 ° С or 4-6 kg / mm2.

The data are given in the table.

According to the table, the billet can be heated to 600 ° C at a tooth pitch of 15.875, 19.05 and up to 1100 ° C at a pitch of 25.4 mm. When determining the minimum initial temperature (600 ° C) to start acceleration of the asterisks, it is also taken into account that when the difference is 500-600 ° C, the flow resistance changes 2.5 times, and when the difference 600-1100 ° C - 20-70% . Such stability of the properties after 600 ° C is very beneficial for the stability of the knurling machines and the accuracy of the part obtained during the spent knurling process, since it stabilizes the elastic deformations of the blanks and increases the accuracy of the sprockets.

Example. A blank, for example a chain transfer sprocket with a pitch I of 12 mm, a number of Z 41 teeth and a thickness of 6–3 mm, is milled in a stack on a hobbing machine in a single pass. Then the stack of blanks is fed to the rolling mill, and one by one is automatically fed and fixed to the head of the product, then the non-driven knurlers are inserted into the hollows of the teeth of the workpiece to a depth of 4-6 mm to ensure continuity of the engagement. The process of introducing the rolls into the engagement is carried out, for example, by slowly rotating the workpiece when the spindles approach each other before the teeth of the knurling teeth get into the cavities of the tooth of the workpiece. After deepening to a predetermined depth

the workpiece begins to rotate with a working speed of p 15-90 rpm, and with the help of a sector HDTV inductor its crown is heated to 800–1000 ° C, after which the working feed of calipers with knurls turns on, which form a tooth on the workpiece with its broadening and formation cross section with the help of flanges to the specified parameters. The process ends with the calibration of the ring gear, which

made by the same knurlers when stopping the movement of the calipers, on rigid stops.

Rolling over the proposed batch of said chain sprocket gears allows obtaining an accuracy of

class 2 GOST.

Claims (2)

1. A method of finishing the formation of gear profiles, in which partial pre-engagement is carried out the formed teeth of the workpiece with the teeth of the knurlers mounted on the axes with the possibility of rotation, the subsequent heating of the workpiece, the final formation of the teeth when radially moving the knurlers and calibrating the workpiece with rotating knurls, characterized in that, in order to increase the accuracy of the finished gear profile by eliminating slippage and productivity by using hot blanks, with preliminary engagement, the workpiece is additionally heated, with rotation and matching, the speed of its rotation with the speed of rotation of the knurlers, and the calibration is carried out by the method of running in, forming a rigid connection between the knurlers and the workpiece. 2. A method according to claim 1, characterized in that, in order to increase productivity, the preform is heated up to the temperature t 600-1100 ° C.