Development of machining process of "Shaft" part and assembly of worm gear box units

Contents

INTRODUCTION

MAJOR PART

Part Utility and Processability Analysis

designs

Define Production Type

Select Procurement Type and Method

PRACTICAL PART

Process Route and Base Selection

Calculation of machining allowances

Feasibility study and description of the operational process for machining the workpiece

Calculation of cutting modes and time standards

DESIGN PART

Purpose of accessory

Diagram of action of forces on the part in the accessory

Calculation of workpiece clamping force in the accessory

Calculation of part basing error in accessory

Calculation of basic parameters of clamping mechanism

Cutting Tool Calculation

Measuring Tool Calculation

CONCLUSION

BIBLIOGRAPHIC LIST

APPENDIX A

APPENDIX B

Introduction

The course project of the specialist in the discipline "Agricultural Engineering Technology" is a comprehensive practical task, the purpose of which is to acquire practical design skills, technological processes for machining parts of agro-industrial machines, in this case the shaft of the driven worm gear box.

In modern mechanical engineering, there is a wide variety of kinematic schemes of reduction gears, their shapes and structures. A reduction gear is a mechanism consisting of gear or worm gears, made in the form of a separate unit and serving to transfer rotation from the shaft of the engine to the shaft of the working machine.

The theme of my course project is the development of the technological process of mechanical processing of the driven shaft, which is part of a single-stage worm gear, which will allow you to learn and consolidate in practice the knowledge gained earlier in fundamental technical disciplines, as a result of the ability to make the right engineering and technical solutions for a specific task. Also important is the rationale for the selection of the process, equipment and nomenclature of the metal cutting tool.

The course project has a constructive and technological character and consists of text and graphic parts, which can be implemented using modern software products such as: for the text part - MS Office; for graphics - Compass 3E. Therefore, it is assumed the design, critical analysis of the processability of the gear shaft, optimization of methods and modes of its processing, improvement of the equipment, devices and cutting tool used.

Completing all these skills in the course project will allow me to evaluate my knowledge and skills as a specialist and engineer in general.

Main part

Part Utility and Constructability Analysis

Worm reduction gear serves to transfer torque between shafts with crossing axes. Worm mechanisms have the ability to reduce speed (i = 6... 80), self-braking, noiselessness, smooth engagement, and have a relatively small transmission mass per unit of transmitted power. This gearbox is single-stage .

In design, the driven shaft belongs to the class of shafts, is a stepped shaft with two slots for the key. Also, this part has 2 precise journals for bearings. The accuracy of these necks is specified by the tolerance for size (k6), tolerance for deviation of the mold (tolerance for deviation from cylinders), tolerance for mutual arrangement of surfaces (tolerance for deviation from alignment). To prevent the bearing skew after installation, a tolerance is set for deviation from the perpendicular of the end surface against which the bearing rests. The key groove also has a sufficiently high accuracy and roughness (Ra3.2), since the key is a stress concentrator and it is necessary to avoid excessive clearance or interference in this connection. Shaft fabrication material - steel 50 GOST 105088 (carbon structural steel ).

The design of the part is as simple as possible and has no complex elements, and the material steel 50 GOST 105088 is often used for the manufacture of shafts. Moreover, the shaft material is selected by the designer based on the calculation of the worm gear for strength.

The cylindrical surfaces of the shaft, as parts belonging to the class of shafts, are suitably treated with a conventional pass-through cutter, and this design of the part allows this to be done, so in this paragraph the structure can be considered technological. Also, the rigidity of the shaft allows you to obtain the necessary accuracy.

Analysis of structural elements for processability. I believe that all structural elements are quite technological.

The measuring bases of this shaft are the surfaces of the supporting necks, however, their use as technological bases for processing external surfaces is difficult, therefore, in most operations, the surfaces of the center holes at both ends of the workpiece are taken as technological bases. This makes it possible to treat all external surfaces of the shaft on single bases with its installation in centers.

All linear dimensions are measured directly by measuring means. The diameters of the necks, the dimensions of the key slot can also be directly measured using calibers, templates.

Center holes at shaft ends should be used as basing surfaces. This makes it possible to treat all external surfaces of the shaft on single bases with its installation in centers.

There are no specific requirements for the part, therefore additional technological operations are not required;

From the conditions of the course design, the workpiece can be obtained by stamping on hammers or a crank hot stamping press (KGShP). It should be said that stamping on CGWP gives higher surface accuracy and roughness, smaller stamping slopes and greater Kim, but the final method will be determined after calculation.

2.3 Feasibility study and description of the operational process of part workpiece machining

Cutting tool is used with replaceable non-turning plates. The use of polyhedral hard-alloy nonwintering plates provides:

+ 2025% greater resistance compared to napkin cutters;

+ increase of cutting modes by simplicity of recovery of cutting properties of plates;

+ reduction of tool costs by 2-3 times, loss of tungsten and cobalt by 44.5 times, auxiliary time for changing and turning cutters;

+ simplification of tooling;

+ reduction of abrasives consumption.

In view of the above process route and calculation of machining allowances, the shaft manufacturing process will be as follows:

005 Milling Centering.

Equipment: milling-centered semi-automatic mode. MP76M.

Machine tool: clamp with prismatic mounting elements equipped with pneumatic drive.

Pos. 1-Mill. Mill the end faces on both sides of the workpiece.

Cutting tool: 2 end cutters, 01.2.0200.00000 T15K6 TU 203587482.

auxiliary tool 62220116 Mandrel GOST2653885.

Pos. 2 - centered. Drill 2 center holes.

Cutting tool - 2 center drills R6M5 GOST 1495275, auxiliary tool mandrel 60390008 GOST 268272.

010 Turning. Sharpen the surface on the right side of the shaft.

Equipment: NC mode lathe. 1A616 FZ.

Machine Tool: Designed Tool

Cutting tools: 1) PDINR2020K15 Contour cutter with hard alloy plate (GOST 2425680) TU 203589282; 2) 03521261801 Groove cutter with hard alloy plate (GOST 2425680) OST 2I10784.

Auxiliary tool 191711044 Tool holder TU 2024553981.

015 Turning. Sharpen the surface on the right side of the shaft.

Equipment: NC mode lathe. 1A616 FZ.

Machine Tool: Designed Tool

Cutting tools: 1) PDINR2020K15 Contour cutter with hard alloy plate (GOST 2425680) TU 203589282;

Auxiliary tool 191711044 Tool holder TU 2024553981.

020, 025 Key-milling. Mill the keyway.

Equipment: DF-96 key-milling machine.

Machine tool: Two prism clamping device GOST1219566 equipped with pneumatic drive

Cutting tool: 22340205 Key cutter GOST 1646380.

Auxiliary tool: 130690 collet cartridge GOST 2653985.

030 Grinding. Grind the journals for the bearing with diameter Ø40k6.

Equipment: circular grinding machine mod.3M151.

Machine tool: drive cartridge.

Cutting tool: grinding wheel PP 400 × 40 × 127 33A 40N CM2 5 K5 35m/s A 1kl. GOST 242483. auxiliary tool: Mandrel GOST232376.

A significant part of the equipment consists of universal machines equipped with both special and universal adjustment (UNP) and universal assembly (USP) devices, which allows to reduce labor intensity and reduce the cost of production.

Conclusion

In the course of this work, an analysis of the Shaft part was carried out, the initial workpiece was selected and its drawing was made, the technological process of manufacturing the Shaft part was compiled, and an accessory for processing the workpiece at the turning operation was designed. The development of all these points makes it possible to ensure in the medium-term production of products of the required quality, reduce labor intensity, and quickly solve problems encountered during production. A properly constructed and resolved dimension chain guarantees that when assembled using the incomplete interchangeability method, all products will be assembled, with the exception of a small number of products that fall into the scrap percentage. The rational choice of the method of obtaining the initial procurement made production more economical. Calculation of allowances reduces the cost of machining, since it is more accurate and the calculated allowance is less than the allowance selected according to the table.

The process using new equipment and advanced equipment reduces the labor input of the product. The development of technical documentation, such as drawings of a part, workpiece, accessory, cutting tool, measuring tool, and the preparation of process maps allows you to qualitatively organize production.