SU1368150A1 - Method of reconditioning thin-walled gear wheels - Google Patents

Abstract

The invention relates to the processing of metals by pressure and can be used in the restoration of gear wheels (k), preferably with a thin rim. The aim of the invention is the expansion of technological. capabilities due to recovery of a complex configuration, as well as product durability by reducing vibroactivity and increasing the flexibility of recovered K. A compensating layer in the form of a sintered iron-based powder bushing (PV) having cross-linked communicating porosity is performed. 20-25%. The internal diameter of the PT is determined from the volume that compensates for the wear of the wheel material. PV mounted on the mandrel inside and fixed with a stopper. The wheel together with the PV is placed in a separable matrix, placed in a nitrogen-containing medium, heated to 1150-1200 C and held for 5 hours. In the process of saturation of PV with nitrogen, an increase in its size occurs, leading to the distribution of K and the production of permanent connection of PV and K. 1 sludge. (9 (L

Description

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The invention relates to the processing of metals by pressure and can be used in the restoration of gear wheels, preferably with a thin rim.

The aim of the invention is the expansion of technological capabilities by ensuring the restoration of wheels of complex configuration, as well as increasing the durability of products by reducing vibroactivity and increasing; of the restored wheel.

The drawing shows a gear wheel, the moment of restoration.

A wear mandrel is inserted into a thin-walled gear wheel 1 having a bead 3 with a sintered powder bushing installed on it, 4 having a through porosity of 20-25%. Then, a metal sleeve 5 is put on the mandrel 2 from the side of the straight shoulder 3, which is fixed on the mandrel 2 by the stopper 6. In the mandrel 2 there are radial holes 8 connected to the central channel 7 for supplying nitrogen. The shoulder 3 and the metal sleeve 5 are designed to eliminate, increase the length of the sintered powder sleeve 4 when heated.

The reconstructed gear wheel 1 assembled with a mandrel 2, sintered with a powder bushing 4, a metal bushing 5 and a stopper 6 is installed in a split matrix 9, placed in a nitrogen-containing medium, heated to 1150-1200 s and maintained at this temperature B.ch., After This part is cooled, the mandrel 2 and the die 9 are removed, the necessary mechanical and thermal treatment is carried out.

In the process of through-feeding the powder bushing with nitrogen, its size increases by 10–15%, depending on the nitrogen concentration, the porosity of the powder bushing, the holding time and temperature. This effect at high temperature and the exclusion of a change in the internal diameter and length of the powder bushing causes a radial distribution of the gear part. In the process of high-temperature nitriding, a continuous baking of the powder sleeve 4 to the inner surface of the gear wheel 1 with a grip strength of 100-120 MPa is ensured. In addition, by

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The powder layer deposited on the inner surface of the gear ensures a reduction in the vibroactivity of the gear due to the flexibility and damping characteristics.

The outer diameter of the sleeve 4 and the length is designated to correspond to the inner diameter and width of the crown to be restored, respectively. The inner diameter of the sleeve is determined from the volume of the wear-compensating material and is equal to

l d 8n - -f KgrcosoC

where dj is the inner diameter of the sleeve; d is the outer diameter of the sleeve; m - recoverable module

wheels;

 Z is the number of teeth of the wheel to be restored;

L - the size of the gap between the worn surface and the surface of the toothed caliber;

K - coefficient of increase in the volume of the sintered sleeve; c / - profile of the wheel to be restored,

moreover, the radial distribution of the gear ring was dried; it was heated by heating the latter and the sleeve in a nitrogen-containing medium up to 1150-1200 ° C, while eliminating a decrease in the internal diameter and length of the sleeve.

An example of the method. The method of restoring thin-walled gears of complex shape: tested on the experimental area of the Special Design and Technological Equipment Department with the OP INDMASH of the Academy of Sciences of the BSSR when restoring a gear wheel with a mm module. number of teeth, crown width mm, crown thickness mm, crown internal diameter mm, made of steel 12X2H iTA. Restoration was carried out in the following sequence:

for 0.4 mm, the inner diameter of the sleeve dg of the powder material (sleeve porosity 20-25%) was determined.

, 0 -. | 66i 4j, 5, 4, 8 11 4 О7Го7939-3, Т4

mm

(for calculation, 1); on a mandrel with a diameter of 44 mm, having an axial (S12 mm) and radial ($ 0.8mm) hole, put a sleeve sintered from the above powder (pori

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20-25%), lubricating the interface with graphite grease; Insert the mandrel with the sleeve into the restored gear and lock it; the restored gear wheel together with the mandrel was placed in a separable matrix, installed in a furnace with a nitrogen-containing medium, heated

to 1150-1200 C, kept at this temperature for 5 h and cooled; removing the mandrel from the cavity of the hub attached to the wheel, accompanying it with light strokes with the mandrel rotating; Mechanical and chemical heat treatment of the gears was carried out (after hardening, surface hardness HRC 58-63).

The evaluation of the vibroactivity of the reconstructed gears was carried out on the SI stand 3 of the INMASH Academy of Sciences of the BSSR. Studies have shown that the overall level of vibration accelerations generated by the engagement with restored gears is 1.5-2.5 dB lower than the vibration accelerations arising in conjunction with the new gears.

Thus, the proposed restoration method allows not only to restore the working profile: a worn-out thin-walled wheel, but also makes it possible to increase durability by reducing vibroactivity and increasing compliance.

Formula a and 3 o b ete n i

The method of restoring a thin-walled gear, by

cottages with compression on the outer surface of the gear profile by preliminary execution and placement of a compensating layer on the inner side

wheels, characterized in that, in order to expand technological capabilities by providing restoration of wheels of complex configuration, as well as increasing product durability by reducing vibroactivity and increasing the flexibility of the wheel to be restored, the compensating layer is in the form of a sintered iron-based powder sleeve with a through connected porosity, the outer diameter and the length of the sleeve being corresponding to the inner diameter and width of the crown to be restored, and the inner diameter Sleeve djj selected from ratios of

5n d

d

2il - -. At 4 K-TG.

where C1 is the outer diameter of the sleeve; t, Z is the modulus and the number of teeth of the restored crown; a is the maximum size of the gap between the worn surface and the surface of the toothed caliber;

K - coefficient of increase in the volume of the sintered sleeve; c / is the angle of the profile of the wheel being repaired, and the crown is distributed on a mandrel with an outer diameter equal to the inner diameter of the hub at 40

roar up to 1150-1200 ° C in a nitrogen atmosphere by zavolivanii sleeve in length.

at

Groove

Claims (1)

Claim A method of restoring a thin-walled gear wheel, by distributing it with compression on the outer surface of the gear profile by pre-executing and placing the compensating layer on the inside of the wheel, characterized in that, in order to expand technological capabilities by ensuring the restoration of wheels of complex configuration, as well as increase durability products by reducing vibration activity and increasing the flexibility of the restored wheels, the compensating layer is made in the form of sintered powder th sleeve based on iron with through communicating porosity, and the outer diameter and length of the sleeve correspond to the inner diameter and width of the restored crown, and the inner diameter of the sleeve d _{9H is} selected from the ratio J _=? , ld ". _ 4_ι5_πτΖ_Λ_ at 4 K - 7G · cos ⁰ '''where d _H is the outer diameter of the sleeve; m, Z - the module and the number of teeth of the restored crown; d is the maximum gap between the worn surface and the surface of the toothed caliber; K is the coefficient of increase in the volume of the sintered sleeve; U is the angle of the profile of the restored wheel, and the distribution of the crown is carried out on a mandrel with an outer diameter equal to the inner diameter of the sleeve when heated to 1150–1200 ° C in a nitrogen medium when the sleeve is anevoluted along the length. Compiled by V. Grigoriev Editor G. Gerber 'Tehred L · Oliynyk Corrector M. Demchik Order 152/14 Draw 920 Subscription VNIIIPI of the USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and printing company, Uzhhorod, st. Project, 4