Gear Manufacturing Process

Contents

Contents

Introduction

1 Part Assignment and Design

2 Part Constructability Analysis

3 Definition of production type

4 Basic Process Analysis

5 Procurement Selection

6 Adopted Routing Process

7 Calculation of processing allowances

8 Calculation of cutting modes

8.1 Calculation of cutting modes by analytical method

8.2 Calculation of cutting modes by standards

9 Calculation of time norms

10 Refinement of production type

11 Calculation of operation accuracy

12 Economic justification of the adopted version of the process

13 Calculation and design of machine tool

13.1 Purpose and arrangement of the accessory

13.2 Selection and calculation of accessory drive

13.3 Calculation of the device for strength

13.4 Calculation of the accessory for accuracy

Conclusion

List of sources used

Appendix A Set of documents (38 sheets)

Appendix B Specification (3 sheets)

Introduction

Scientific and technological progress in mechanical engineering largely determines the development and improvement of the entire national economy of the country. The most important conditions for accelerating scientific and technological progress are increasing labor productivity, improving the efficiency of public production and improving the quality of products.

The improvement of technological methods of manufacturing machines is of paramount importance. The quality of the machine, reliability, durability and cost-effectiveness of operation depend not only on the perfection of its design, but also on production technology. Application of advanced high-performance machining methods ensuring high accuracy and quality of machine parts surfaces, methods of strengthening working surfaces, which increase the service life of parts and the machine as a whole, efficient use of modern automatic and flow lines, software-controlled machines, electronic and computing machines and other new technologies, the application of progressive forms of organization and economics of production processes - all this is aimed at solving the main tasks: increasing production efficiency and product quality. In the course project, the following are being developed: the technological process of machining a given part, special equipment and feasibility studies, as well as a number of issues directly related to it. The course project is divided into graphic part, explanatory note and technical documentation

Part Assignment and Design

Part "Drive gear" 5462402017 enters the central gear box

drive bridge of 546P self-propelled fastener.

Self-propelled scraper is designed for layer-by-layer soil development

of the first and second categories, their transportation and filling of the layer of the specified thickness

dams to erect structures or dumps.

It is allowed to use scrapers for the development of soils of the third and fourth

vert of categories with mandatory preliminary loosening.

The soil is collected by a scraper using a tractor pusher, wallpaper

equipped with a special pushing device or a dotted dump

bulldozer.

Drive axle consists of central reduction gear, wheel gears of pla-

non-rack type and crankcase of the bridge with trunnions and semi-axles.

Single-stage central reduction gear with a pair of bevel gears with

spiral teeth and interwheel conical differential. Conducted

main gear is attached by rivets to RH differential cup.

During operation at considerable loads in the main gear

large forces arise that push the driven gear off the

drive, disrupting correct engagement.

To ensure correct engagement of gear teeth of the main gear

output in the gear box there is a limiter of driven gear deformation -

nor. The gears of the main gear during assembly are pre-selected

(mating). In case of failure of one of the gears, both are subject to replacement

gears in the set.

The differential of the drive axle is conical, with four satellites and two axle gears is installed on two conical roller bearings, which are adjusted by two nuts. Joint processing of hours

a neck that ensures the exact location of the crosses in them requires, in the case of

necessity, replacement of cups complete.

To provide abundant supply of lubricant to differential parts to the le-

oil traps are welded to the howl cup. Gears, differential and bearings

main gear is lubricated with oil sprayed from oil bath

drive bridge crankcase.

Two pins are pressed into bosses located inside crankcase cavity.

ft, on which the gearbox of the main gear rests. Pins unload bol-

you, connecting the gear box with the drive axle case, from the action of the reactor

of a quiet moment.

Gears and bearings of wheel gear are lubricated with oil,

wheel hub loosened from oil bath.

Maintenance of the drive bridge during operation is as follows:

timely elimination of leaks, replacement of oil in cavities of main and wheel

transmission, check and tightening of threaded connections, check and performance of adjustment

Lyrevok.

Adjustment of bearings and engagement of gears of the main gear

the ductor should be carried out together, operations to adjust each pair

bearings (drive gear and differential) are made separately.

Driving gear serves to transmit torque from cardan

shaft to power take-off gear box, which drives semi-axles.

A part has a large number of cylindrical surfaces that

refer to simple. Complex surfaces are splined, threaded and

toothed surfaces. High requirements are placed on the surfaces G, G and I, on which bearings are installed.

The part is subject to high requirements for accuracy and roughness.

stand. Check is performed for radial and end run-out of L, G and I surfaces, as well as slits. Requirements for non-variability must be met

diameter in transverse and longitudinal sections of surfaces G, G and I. Side

the sides of the splines must be straight and parallel to each other.

Only part of the part must be cemented before it can be cemented.

cementation site D. It can be protected from cementation by a thin layer of copper

or isolate with special coatings. Annealing of the surface is also allowed

tD. The toothed rim is allowed to phosphote, which will increase its heat resistance, corrosion resistance, wear resistance and hardness. It is allowed to cut two pairs of splines in width by 0.03 mm. From the point of view of mechanical processing, it is better to use more modern equipment, which will reduce the number of operations and increase productivity.

The driving gear is one of the most important parts in the self-propelled fastener. It is subjected to heavy loads. Because of what it is necessary to

This steel is prone to internal oxidation during gas cementation, which reduces the hardness of the cement layer and the endurance limit. However, this material is cheaper than, for example, chromium nickel steels.

After cementation, the part is subjected to heat treatment, which includes:

self hardening and low vacation. During hardening the workpiece is heated to temperature -

ratura 950... 1880 ° C followed by cooling in air or heating to

temperature 2850 ° C followed by cooling in oil. At low vacation

the workpiece is heated to 200 ° C with subsequent cooling

in water or oil. After heat treatment the workpiece material acquires mechanical properties given in Table 1.2 Hardness

material, after heat treatment, 156... 159 HV.

"Drive gear" blank is obtained by stamping from material

25HGT. This material relates to structural alloy steels. This steel is prone to internal oxidation during gas cementation, which reduces the hardness of the cement layer and the endurance limit. However, this material is cheaper than, for example, chromium nickel steels.

Chemical composition and mechanical properties of 25ChT steel are given in Tables 1.1 and 1.2, respectively.

Part Constructability Analysis

The part is a driving gear, made of structural alloyed steel, and undergoes thermal treatment. From the point of view of machining, the part is generally non-technological, since the operation of cutting splines and teeth with removal of chips is carried out by low-productivity methods by schlickefreasing and tooth cutting, respectively (as can be seen from the process, these operations take a long time and, therefore, reduce productivity). The part design provides a workpiece whose shape and dimensions will approximate that of the part. Holes are non-technological, since a special device must be designed to drill them. If all of these factors are taken into account when designing a part, processability can be greatly improved. For quantitative evaluation of workability of the part GOST 14.20273 provides a number of quantitative indicators of workability of the part.

We define the average accuracy of processing:

Define Production Type

In this section we define the preliminary production type by annual production and mass of parts.

Based on the annual production volume of parts N = 1600 pcs and the mass of the part m = 11 kg, we choose the serial type of production [1, Table 3].

We round the calculated number of shifts to the accepted integer, then we determine the number of parts in the batch necessary to load the equipment at the main operations during the whole number of shifts:

Procurement Selection

The billet of the part "Driving gear" is obtained by stamping on a horizontal forging machine (MCC).

The stamping process consists in shaping the workpiece and

dimensions by filling the die. stamping includes technological transitions, landing, piercing, extrusion, knocking out and section of forging from bar.

The advantage of stamping on GKM - high productivity and eco -

nomic use of metal.

Calculation of processing allowances

The allowance calculation is performed on two surfaces:

- for surface treatment with diameter of 45 mm;

- for treatment of end surfaces on the length of 306 mm.

Calculation of allowances is carried out by drawing up tables in which we sequentially record the technological route of external surface processing and all values of allowance elements. The workpiece is a stamping of the degree of complexity C2, the group of steels M2, the accuracy class T4, weighing 18.2 kg.

The process route for processing a surface with a diameter of 45 consists of the following operations:

1. Draft Turn

2. Finishing turn

3. Preliminary grinding

4. Final grinding

We select the values of the height of micro-irregularities and the depth of the surface defective layer [3] and put them in Table 7.1.

We determine the value of total spatial deviation, mcm:

Diagram of graphical arrangement of allowances and tolerances for surface treatment with length of 306 mm is given in Figure 7.2.

surface treatment 306 mm long

We assign allowances to all other machined surfaces as per GOST 7505-

Calculation of cutting modes

8.1 Calculation of cutting modes by analytical method

Operation 005 - Milling Centered.

Mill-centered machine of MP71M model.

Transition 1: Mill Endcaps

Initial data: cutting tool - two end cutters with hard alloy plates T15K6, cutter diameter, cutting depth, milling width, number of cutter teeth.

Set cutting modes can be performed on this machine.

8.2 Calculation of cutting modes by standards

Operation 010 - NC Lathe

Lathe with NC model 16K20T1.

Operation content: sharpen surfaces with diameter 40 mm, diameter 71.5 mm, diameter 76.5 mm, chamfer 0.87 30 °, surface with diameter 74 mm, sharpen chamfer 0.87 30 °, surfaces with diameter 76.5 mm, diameter 94 mm, chamfer 15 ° 45, surface with diameter 153 mm.

Initial data: cutting tool - pass-through cutter equipped with hard alloy plates T15K6. Depth of cutting.

Calculation of time standards

We calculate the time standards for those operations for which the cutting modes are calculated in Section 8. Calculation is performed according to the procedure [3].

In the average production, the rate of piece-costing time, min:

Refinement of production type

Based on the calculated time standards, we will refine the type of production.

The calculated number of machines required for each operation is determined by the formula:

Calculation of operation accuracy

The calculation is made according to the procedure and formulas from the source [1] for a surface with a diameter of mm obtained at turning operation 020:

Economic justification of the adopted version of the process

In the course design, two versions of the process are compared: basic and designed. The base case is the factory process plan.

The calculated costs and process costs are calculated for all changing process operations.

The specified costs for the two compared process versions are calculated according to the formula:

Calculation and design of machine tool

13.1 Purpose and arrangement of the accessory

At vertical drilling operation for drilling and countersinking of holes

thium with a diameter of 6.2 mm is used special machine tool -

conductor for drilling holes. The conductor consists of a housing, on which

plaques are welded. Two prisms are installed on the plates, and are attached with screws and pins. The fixture clamping mechanism consists of a clamp 8 in which a stud is screwed. Spring is fitted on pin for precise fixation of part. Eccentric holds down the grip. A plunger is also provided for fixing an angle of 90 °. A strut with a hinged conductor bushing and a bar is welded to the housing. Thanks to the shutoff screw, the conductor sleeve can be turned off to allow countersink of the part.

The part is installed in prisms and clamped by a grip. The hole is drilled, the part is squeezed and rotated by 90 °. A plunger is inserted into the newly drilled hole and the part is clamped. After drilling of the second hole, the conductor bushing is folded and the hole is sequentially countersunk at 1 45 ° on four sides. The part is pressed and removed. The following part is treated in the same way.

13.2 Selection and calculation of accessory drive

In the process of drilling the holes, the workpiece to be processed is under the influence of the torque of the axial force P0. The feed force and the clamp force act in one direction to press the blank. Under the action of the cutting torque M, the part tends to rotate about the axis. This is counteracted by the friction moment Mtp generated by the clamping axial force

Conclusion

As a result of the development of this course project, a complete study of the technological process of obtaining the part in medium-term production conditions was carried out. The most important stage of technology design is the purpose of the route processing process, the selection of equipment, cutting tools and machine tools. The following changes have been made to the basic process:

- applied one milling centering operation;

- two locksmith operations were removed;

- use in the last turning operation with NC a leash cartridge with end knives;

- abandoned the use of operations: shot blasting and phosphotting;

- based on the type of production, the turning and hydrocopying operations were replaced with turning operations with NC;

As a result of economic calculations, the economic effect of the accepted technological process was determined in relation to the basic one, which amounted to 5678400 rubles.

List of sources used

1. Methodological guidelines on course design for students of specialty T.03.01 - "Technology, equipment and automation of mechanical engineering." - Mogilev: BRU, 2004. – 48 pages.

2. Kosilova A.G., Meshcheryakov R.K. Handbook of the technologist - mechanical engineer. In 2 tons T 1. - M.: Engineering, 1973. – 694 pages.

3. Gorbatsevich A.F., Shkred V.A. Course design in mechanical engineering technology. - Mn.: The highest school, 1979. – 255 pages.

4. Kosilova A.G., Meshcheryakov R.K. Handbook of the technologist - mechanical engineer. In 2 vol. T 2. - M.: Engineering, 1973. – 568 pages.

5. Baranovsky Yu.V. Metal cutting modes. - M.: Engineering, 1972. – 407 pages.

6. Babuk V.V. Diploma design in mechanical engineering technology.

- Mn.: The highest school, 1979. – 463 pages.

7. Gorokhov V.A. Design of technological equipment. - Mn.: "Berwita," 1997. – 343 pages.

8. Pashkevich M.F. Technological tooling. Methodological guidelines and tasks for control work in the discipline "Technological tooling for students - absentees in the specialty T03.01.00 -" Technology, equipment and automation of mechanical engineering. "" - Mogilev: MMI, 1999.