RU1814605C - Method of reconditioning workpieces - Google Patents

Abstract

Use: mechanical assembly production. SUMMARY OF THE INVENTION: when creating a layer of hardening material between the contacting surfaces of repair and restored parts, gaps and surfaces in the area of welds in the joints prevent hardening adhesive material from entering them. Welding of repair parts in the joints to the parts being restored is performed after filling the gaps between the repair and the parts being restored with adhesive hardening material and pressing them to the parts being restored. In the process of welding the joints of the repair parts to the parts being restored, additional cooling of the repair parts in the weld zone is applied . As coolers use clamping elements of clamping devices. 3 ill.

Description

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The invention relates to mechanical assembly, to methods for restoring worn parts of machines, in which repair parts are installed on worn and damaged work surfaces and fixed by welding. In particular, the invention relates to methods for restoring worn necks of crankshafts of automotive and other reciprocating engines, as well as reciprocating compressors and vacuum pumps, in which repair parts made, for example, in the form of half rings (sectors) are mounted and secured to the necks. The invention is intended for use in repair facilities, restoring the necks of various shafts and other parts.

The aim of the invention is to improve the quality of recovery and simplify the process.

In FIG. 1 shows a cross section of the shaft neck and shows the location of the adhesive layer in the gap between the repair and reconditioned surfaces; in FIG. 2 is a section AA in FIG. 1; in FIG. 3 - an example of the protection of the welding zones of repair parts when applying glue.

In FIG. 1-3, the following designations are adopted: 1 - shaft journal; 2 - a layer of adhesive material between the repair part and the restored; 3 and 5 - repair parts made in the form of incomplete half rings; 4 and 6 - clamping elements of the clamping device; 7 and 8 - welding seams connecting repair parts at the joints with each other and connecting them to the shaft journal; 9 - a device that protects the weld zone from glue when applied to a repair part; I is the size of the zone on the neck of the shaft, which is protected from glue penetration during its application; m - zone size on

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a repair part that is protected from adhesive during application; s - clearance at the junction of repair parts.

The proposed method includes the following operations:

1. Processing of worn and damaged surfaces of parts 1 for additional repair parts 3 and 5 (half rings, plates, sectors of the sleeve and

etc.).

2. Cleaning surfaces of repair and restored parts before applying glue.

3. Protection of surfaces in the places of welding from glue, for example, by installing devices 9 (Fig. 2), tapes, plates in the form of stencils or by applying glue in the welding zones, visually focusing on the structural elements of the surfaces of the parts;

4. Application of a thin layer of glue 2 on specified areas;

5. Removal of protective devices from the surfaces of parts 3,5 and 1. Glue can be applied both to both surfaces in contact with the connection, and only to one of them.

6. Installation of repair parts 3 and 5 on the surface of the restored part 1.

7. Orientation of the joints of the repair parts and alignment of the gaps s in the joints.

8. Preloading repair parts 3 and 6 to the surface to be repaired 1. To clamp the repair part to the reconditioned one, devices are used, the clamping elements 4 and 5 of which ensure the removal of heat from the welding zone and reduction of the heat affected zones within specified limits during the welding process. The hold-down elements can be sleepy. Supplied with additional devices for supplying a cooling medium. In the process of pressing repair parts to the surfaces of the parts being restored, by the action of forces P, micro- and macro-irregularities, areas of the parts' non-adherence, voids are filled with adhesive and the excess glue is forced out of the gaps.

The joints of the repair parts 3 and 5 are welded by electric arc welding. Seams 7 and 8 simultaneously connect repair parts to each other and attach them to the restored one. Adhesive is polymerized. According to the invention, the bond strength of the repair parts to be restored is determined by the combined action of the adhesive joint 2 and the welds 7 and 8.

Example. Implementation of the method using the example of restoration of the main journals of crankshafts of automobile engines ZMZ-53.

Crankshafts of ZMZ-53 engines are made of ductile iron.

The diameter of the main necks is 70 mm, and the connecting rod 60 mm. The main and connecting rod journals are equipped with oil supply channels.

We choose the thickness of the repair half ring on the restored necks equal to 2.0 mm, the gap at the joints s equal to 5 ± 0.5 mm, and the size m 6 ± 1 mm. 5 Repair half rings are made of sheet steel 45 with a thickness of 3 mm. Semirings are thermally processed and they have a hardness in the range of 40 ... 48 L

Openings for oil channels in repair half rings are made taking into account the location of the joints of repair half rings in the zones of least loading or wear,

The inner surface of the repair 5 half rings is machined on lathes according to the fine boring regimes. Acetone can be used as a solvent for degreasing surfaces. The adhesive used was 0 epoxy compound K-153 with hardener polyethylene polyamine. To weld the joints of repair half rings, semi-automatic arc welding in carbon dioxide and welding wire 5 Sv-08G2S (GOST 2246-70) 0 1.2 mm are used.

Welding of the joints of repair half rings to the necks is performed according to the following mode:

Welding current, A 130 ... 150 0 Open circuit voltage of the power source, V 28.,. 21

The voltage during welding, B 20 ... 23 The recovery process is carried out as follows.

5 Install the crankshaft on the tilt stand. intended for assembling necks with repair half rings and welding joints to necks.

They cleanse and degrease the necks. They clean and degrease the inner surface of repair half rings. Protective devices 9 are installed on the ends of the repair half rings and a thin layer of glue 2 is applied on the inner surface,

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excluding areas adjacent to joints. Remove from the repair half rings of the device.

Install repair half rings 3 and 4 on the necks 1, orient and align the gaps s in the joints, Press the repair half rings to the necks with a force of P 8000 ... 20,000 N. Weld the joints to the necks and simultaneously weld them together. After welding the first joint 7, they proceed to welding the opposite joint 8. After welding the joints, the shutter speed necessary for curing the adhesive is produced, and the crankshafts are sent for machining the necks to the specified dimensions.

Technical appraisal and economic advantages of the proposed method:

1. In general, the method improves the quality of the restored parts and their reliability. It makes it possible to reduce the requirements for the quality of processing and the fit of repair parts with renewable ones and, therefore, to simplify the technological process of restoration.

2. The method creates the following additional (private) advantages:

1) provides the possibility, provided that the repair parts are isolated from the adhesive restored by the layer, to supply electric current to the welding zone through the restored component;

2) practically the gases formed during glue heating during the welding process do not affect the stability of electric arc burning and the quality of the weld;

3) the penetration depth of the restored and repair parts is increased, the reliability of the welded joint is increased;

4) when restoring the necks of the shrinkage metal shafts in the welds and the heat-affected zone during cooling, provides additional compression of the repair parts to the restored ones and improves the quality of the adhesive joint;

5) the shrinkage of the seams and the heat-affected zone on the shaft necks during cooling is accompanied by an additional displacement of the uncured adhesive from the gap, therefore, overvoltage in the repair

details x causing the formation of welding cracks in the heat affected zones;

5) the glue in the gaps ensures the production of tight (sealed) joints, 5 increase of the landing strength with reduced requirements to the quality of processing of repair and restored parts;

7) the adhesive layer eliminates the possibility of wear of micro- and macro-irregularities of the contacting surfaces and weakening of the fit under operating conditions, there is an increase in the corrosion resistance of the surfaces of the parts in their joints;

5 8) it is possible to increase the strength of the joint of repair and reconditioned parts due to the combined action of the adhesive and welding joint;

0 9) the failures of the restored parts as a result of the destruction of the adhesive joint during operation are excluded. The adhesive layer after the destruction of the adhesive joint plays a positive role as a laying, and the necessary strength for the connection of the parts is ensured by welding seams.

Claims (1)

Formula from gaining A method of restoring parts, including machining worn surfaces for repair parts, installing them and pressing the heat-retaining elements to the surface to be restored, welding the joints 5 repair parts with their additional cooling in the weld zone by clamping elements and machining to a predetermined size, characterized in that that, in order to improve the quality of recovery 0 and to simplify the process technology, before pressing between the mating surfaces of the repair and restored parts, with the exception of the weld areas, a layer of glue is placed, and the repair parts 5 are additionally welded to the part being restored in welds. Editor L. Volkova Compiled by Z. Dagis Tehred M. Morgenthal Fig. $ Proofreader I. Schull