Shaft Manufacturing Process Design - Heading

Purpose. Operating condition and design description.

The detail considered in this project "Shaft Hkhosi" is a part of the turning screw cutter of fashion. MK6046. It is located in the speed box of the machine and is designed to transmit torque. The shaft can transmit a small torque, since its transmission to the lever is carried out using a segment key, which can withstand small loads; this is also indicated by a shaft diameter of 22 mm. It operates under the condition of thermal mode, low loads, oil medium.

On the left side, the shaft is oriented in the housing by means of the following structural elements: the bushing 4 pressed into the housing 3 orients the shaft in space, and the screw 7 through the washer 5 by means of a threaded connection fixes the shaft in the axial direction. Lever (2) is fixed by end face of shaft degree and bushing (4).

On the right side the shaft is connected through bushing 6 to another shaft (directly connected to speed change handle) by means of segment key.

2. Analysis of assembly specifications.

An analysis of the assembly specification is carried out for the mass production type. The processability of the structure is divided into operational, repair and production.

The following technical requirements apply to the general assembly of the speed box of machine MK6046:

1. Easy access to various speed box assemblies. This technical requirement must be fulfilled to facilitate visual control over the technical condition of the parts and units of the speed box, the possibility of repairing or replacing individual units of the mechanism and be ensured by the presence of a convenient plane of the housing connector, the presence of additional working space to facilitate access to the units.

2. Sufficient heat exchange with the environment - necessary to prevent overheating of parts and assemblies during operation. It is provided by increase of internal space of speed box, presence of sufficient amount of lubricating liquid. Quality and quantity of lubricant are monitored.

3. Ensuring high accuracy performance. Increasing accuracy increases the accuracy of the machine. Control over fulfillment of this technical requirement consists in control of technical requirements at the stage of manufacturing of parts of the mechanism, assembly of parts into assemblies, and at the stage of general assembly - control of accurate performance indicators of the speed box.

4. Provision of high reliability of speed box units operation. With high reliability of operation, the probability of failure of any of the mechanism units is reduced. This requirement will increase the service life of the mechanism, increase the performance of the speed box. Ensuring the reliability of the speed box is expressed in ensuring the reliability of its units and parts, which must be provided by the design of the part itself.

5. Minimum number of part names. This requirement is necessary in order to simplify the design of the speed box as much as possible, while providing the operating parameters specified by the designer, facilitating and reducing the assembly process .

6. Maximum use of standard parts. It makes it possible to simplify the assembly process, reduce the volume of manufactured parts.

7. Minimum number of fastener sizes. Needed to facilitate the product assembly process, reduces the range of products used for assembly.

8. Prevents incorrect part orientation. In case of incorrect orientation of the part during assembly, incorrect operation of the mechanism occurs, which leads to increased wear of parts and assemblies, reduced service life of the product, violation of accuracy characteristics of the mechanism, and ultimately - failure. The method of control of this technical requirement is methods of control over the quality of assembly of parts into units, and then control over assembly of units into a mechanism .

9. Providing easy disassembly. Necessary for ease of work on replacement, repair or diagnostics of structural elements.

10. Quality is ensured by prevention and timely detection of product scrap at all stages of the production process. Preventive control is aimed at checking components, semi-finished products, checking assembly equipment and accessories, as well as at systematic verification of the correct process of assembly.

At assembly of a wave of HHy the following technical requirements are imposed on an axis:

- provision of required force of bushing (4) pressing into housing (3);

- free movement of lever (2) is required;

- ensure transmission of the required torque to the lever from the speed change handle;

- ensure correct orientation during assembly of lever 2 and shaft 1 by means of segment key;

- when assembling the lever and shaft, the segment key must be tilted, which will facilitate the assembling process;

-Use the minimum amount of snap-in used to assemble a subassembly-simplifies the assembly technique of the subassembly. Set when the product assembly process is developed;

- providing convenience of assembly disassembly. It is necessary for simplification and acceleration of replacement, repair of parts of the unit;

- ensuring the assembly quality of the assembly. Quality assurance of assembly is carried out by means of control over the performed technical requirements.

During assembly, check:

- availability of necessary parts in assembled joints - inspection;

- correctness of mating parts and assemblies position - inspection;

- gaps in assembled conjugations - probe;

- accuracy of mutual arrangement of conjugated parts (for radial and axial run-out, etc.) - are performed in control devices;

- tightness of connection in special accessories and density of parts surfaces abutment on paint during assembly;

- tightening of threaded connections;

- dimensions specified in assembly drawings;

- fulfillment of special requirements;

- appearance of assembled articles (absence of damages of parts, contaminants and other defects that may occur during assembly).

3. Constructability analysis.

The assembly consists of a small number of elements: 9 parts and assemblies. A feature of the design is the ability to assemble the product as a whole from pre-assembled assembly units, which ensures ease of assembly and disassembly, improves serviceability. Assembly is done manually. The assembly does not require a special tool. The assembly uses unified standard parts, which reduces the cost of the assembly and increases processability. Assembly bases are combined with installation and measuring bases. Lead-in chamfers are provided at the ends of the mating surfaces, which facilitates the assembly process. The assembly is repairable as it is easily disassembled and subsequently assembled. In a given type of production, the product meets the basic requirements of processability.

Section B. Part Manufacturing Process Design.

1. Purpose of the part in the unit, analysis of technical requirements, identification of technological tasks arising during manufacturing.

The detail "A wave of HHy of an axis" represents a rotation body type detail, is a part of the mechanism of switching of a box of speeds of the MK6046 lathe and is intended for switching of frequency of rotation of a spindle.

This part is intended for:

- transmission of torque from the handle for changing the rotation ranges to the spear, which controls the shift levers of the gear wheel blocks.

2. Analyze the shape of a part.

Part material: Steel 45 GOST1050-74

Maximum overall dimensions of the part: ǿ22 mm, L = 4260.76 mm

Weight 1.34 kg

The part is a stepped shaft and has the following structural features:

To the left of the shaft, the section ǿ18f7 32 mm long with Ra 1.25 (Taken as the base of E). Inside this section, metric thread M87H is cut to a length of 22 mm with preliminary drilling of the hole to a depth of 24 mm, there is also a center hole ǿ10 mm x 60˚ with Ra2.5

On the left end there is a flange with a width of mm to a depth of 3 mm (view B)

and chamfer 1kh30˚.

Further at distance of 32 mm from the left face there is a flute ǿ in mm and width of mm with Ra2.5 and radiuses of rounding off of R0.4 (the Look G). It has a rigid radial run-out requirement of 0.04 mm diameter relative to base D.

The ends inside the groove can be manufactured with an inclination in the interval 0˚5˚.

The next section of the shaft ǿ mm with Ra1.25 has a slot for the segment key at a distance of 18 mm (section A-A). The segment key cannot transmit large torques, therefore, the shaft does not carry large power loads. This section of the shaft has a restriction on radial run-out in the size of 0.03, relative to the base D represented by the axis of the part.

Then there is a groove ǿ17.5 mm and a width of 3 mm.

Further, the shaft portion is ǿ22 mm by a length of 50 mm, the shaft portion is ǿ mm by a length of 218 mm,

Then ǿ22kh50mm,

The groove ǿ17.5 mm and width 3 mm passes into the shaft section ǿ mm for a length of 27 mm and with Ra1.25, on which the second slot for the segment key is located (section B-B).

ǿ has a radial run-out limit of 0.03, relative to base G.

3. Part processability analysis.

The processability of the part structures processed by cutting depends on: the processability of the part shape; rational selection of procurement, including its material; availability of convenient and reliable bases for installation of blanks.

We will analyze the processability of this part from the point of view of procurement, machining and control.

When you select a workpiece for a given part, you first assign a method for obtaining it. The main thing when selecting a workpiece is to ensure a given quality of the finished part at its minimum cost, as well as a decrease in the amount of subsequently cut material. Workpiece production processes are determined by material process properties, part structural shapes and dimensions, and release program.

The structure of the shaft, which is simple, but has differences in diameters, allows the use of hot-rolled rolled stock as a workpiece, the use of other methods for producing the workpiece is economically impractical, since it is expensive.

We will evaluate the workability of the part from the point of view of machining. First of all, we evaluate the convenience of basing the part.

The part is not rigid, since it has a large length of 426 mm and a relatively small diameter of 22 mm, as a result of which there are problems of basing and fixing, additional fastening elements are required to prevent deformation of the part during processing under the influence of cutting forces. (for example, a lunet).

Now we will evaluate the convenience of machining individual surfaces. All surfaces are machined in one or more passes with a standard or special tool. During machining, turning, milling, grinding are used.

The outer cylindrical surfaces and ends, chamfers 1kh30˚ are pierced on a CNC machine with straight passing, trimmed thrust cutters, and then ground..

The 10b12x3-width projection is milled by an end cutter, 2 slots for the segment key are milled by an end slot cutter on a vertical milling machine.

The drilling and cutting of the M87H thread is performed by a spiral drill and a throttle on the lathe, respectively.

Flutes a look and a look E are carried out by standard grooving tools on the lathe.

In general terms, from the point of view of machining, the part can be called technological, especially for turning and grinding, but when milling there is a need for special devices, which increases the cost.

The workability of the part should be evaluated from the control point of view. You can control this part in standard ways, since the shaft does not have particularly difficult controlled surfaces that require special devices and devices. In addition to control of deviation from symmetry of key slot and M87N thread.

In the manufacture of a part, in most cases, special methods for obtaining a workpiece, special tooling for machining, special control methods are not required, but in some cases they are required, so the part cannot be called completely technological