Hole and shaft clearance tolerance. Great encyclopedia of oil and gas

QUESTIONS FOR PREPARING FOR THE TEST IN ENGINEERING GRAPHICS

IV semester

Types of products [GOST 2.101-68*]

1. What is the product called?

A product is an item or set of items to be manufactured in production.

2. What types of products does the standard establish?

The following types of products are installed:

Detail C is a product made from a material of a homogeneous brand, without the use of assembly operations.

Assembly unit C is a product whose components are subject to interconnection by assembly operations (screwing, welding, riveting, etc.).

Complex- two or more products that are not connected by assembly operations, but are intended to perform interrelated operational functions (for example, a production line of machine tools).

Set- two or more products that are not connected by assembly operations and represent a set of products that have a general operational purpose (for example, a set of tools).

3. What product is called a part?

Part C is a product made from a material of a homogeneous brand, without the use of assembly operations.

4. Which product is called an assembly unit?

An assembly unit C is a product whose components are subject to interconnection by assembly operations (screwing, welding, riveting, etc.).

5. What products can an assembly unit consist of?

From parts and other assembly units

6. How are products divided depending on the presence or absence of components in them?

Without components– a part, with its components – an assembly unit.

7. Which products are classified as purchased or newly developed?

Purchased products are standard, newly developed ones are new products, the drawings of which were prepared by us.

Design documents [GOST 2.102-68]

1. What types of design documents does the standard establish?

Design documents include graphic and text documents that, individually or collectively, determine the composition and structure of the product and contain the necessary data for its development or manufacture, control, acceptance, operation and repair.

GOST 2.102-68 establishes the following types of documents:

detail drawing;

Assembly drawing;

drawing general view;

specification;

• explanatory note.

2. What stages of development of design documents does the standard establish?

Development stage

Technical Proposal

Preliminary design

Technical project

Working design documentation:

a) a prototype (pilot batch) of a product intended

for serial (mass) or single production (except for one-time production)

b) serial (mass) production

3. What design document is called a part drawing? At what stage of development is it mandatory?

Part drawing is a document containing images of the part and other data necessary for its manufacture and control.

4. What design document is called a general view drawing? At what stages of development of design documents can it be performed? At what stage of development is it mandatory?

General drawing type - graphic a document containing images, text, inscriptions and other information necessary to understand the structural design, interaction of components and the principle of operation of the product.

5. What design document is called an assembly drawing? At what stage of development is it performed?

An assembly drawing is a graphic document containing images of an assembly unit and other data necessary for its assembly and control.

6. How does an assembly drawing differ from a general arrangement drawing? What design documents are accepted as the main ones for parts and assembly units?

8. What is the purpose of the specification?

Specification is a text document containing text, divided into columns, that completely defines the composition of an assembly unit, kit or complex. For the types of products listed here, the specification is the main design document.

9. On what formats is the specification performed?

The specification is carried out on A4 sheets according to form 1 (header sheet) and 1a (subsequent sheets). The main inscription (GOST 2.104-68) on the title page is made according to form 2, on subsequent sheets according to form 2a.

10. What sections does the specification consist of?

The specification is filled out from top to bottom and consists of sections:

documentation;

complexes *;

Assembly units;

1. Standard products;

   Other products *;

   materials;

   kits *.

* - canceled (see GOST 2.106-96).

11. In what order are the sections in the specification?

12. In what order are products recorded in the “Standard Products” section of the specification?

Within each category of standards, it is recommended to record by groups of products, combined by their functional purpose (for example, fasteners, bearings, electrical products), within each group C in alphabetical order of product names; within each name C in ascending order of standard designations, and within each standard designation C in ascending order of the main parameters or dimensions of the product.

Requirements for drawings

1. What surfaces are called mating?

Mating surfaces are surfaces with the help of which the relative position of parts in a product is determined. ( do not correct for connections!!!byPashkin)

2. Which image is called a supplementary view? How is it drawn up in the drawing?

If part of the object cannot be shown in the main views without distorting the shape and size, then an additional view is used. If the main views are depicted in their places, they are not signed; otherwise there should be an inscription like “View A”. The direction of view should be indicated by an arrow indicated by a capital letter. The additional view and the local view are designed in the same way. If additional view is located in a projection connection, then the arrow and inscription above the view are not applied. An additional view can be rotated by adding an O sign to the inscription (the word “rotated” is not written). The local view is usually limited to the cliff line.

3. Which image is called a local species? How is it drawn up in the drawing?

then use an additional form . The image of a separate, limited place of an object is called a local view

4. What is called a remote element? How and in what place do the fields of the drawing form its image?

Callouts are additional separate images (usually enlarged) of any part of an object that requires explanation regarding shape and size.

The extension element is marked on the view, section or section with a closed line (circle or oval) with the designation of the extension element with a letter of the Russian alphabet on the shelf of the leader line.

For the extension element, you should indicate the letter and the image scale in brackets, type: A (2:1).

5. How are sections that are not included in the sections divided? What lines represent these sections in the drawings?

A section is a figure obtained by mentally dissecting an object with a plane. A section differs from a section in that sections depict what is in the section and what is behind the section. Sections depict only what is in the section. Sections that are not part of the section are divided into extended and superimposed. Rules for depicting sections: the contours of the extended section, as well as the section included in the section, are depicted with solid lines, and the contour of the superimposed section - with solid thin lines.

6. How are the sections arranged in the drawings?

The section in construction and location must correspond to the direction indicated by the arrows. It is allowed to place the section anywhere in the drawing field, as well as with a rotation, with the addition of the “rotated” sign.

7. In what cases should an incision be used instead of a section?

8. What simplifications are used to reduce the number of images in a drawing?

The most common conventions and simplifications:

a) if the view, section or section is symmetrical figure, it is allowed to draw only half of the image, limiting it to the center line, or a little more than half. In the second

In this case, the limiting line is the break line.

b) if a part has several identical, evenly spaced elements, then the image of this part can show one or two such elements. For the rest, indicate their location and a mark about their number.

c) if one surface smoothly transitions into another, then the transition line can be omitted or a conventional image can be drawn with a thin line.

d) a slight taper or slope may be depicted with magnification.

e) long objects that have a constant or regularly changing cross-section can be depicted with breaks.

f) for flat parts, only one view can be made, indicating the thickness of the part, indicated by the letter s.

g) to simplify the drawing and reduce the number of views, GOST 2.305-68 allows:

depict a section of a part of an object;

perform complex cuts;

show in section the holes located on a round flange, regardless of whether they fall into the cutting plane or not

9. How is a group drawing drawn up?

10. What dimensions are indicated on the general view drawing, assembly drawing?

The assembly drawing must indicate:

overall dimensions of the product (dimensions that determine the external outline of the product)

installation and connection dimensions (dimensions that determine the dimensions of the elements by which this product is installed at the installation site or connected to another product);

dimensions and other parameters performed or controlled according to this drawing;

other necessary reference dimensions.

Reference dimensions C are dimensions that cannot be made according to this drawing and are indicated for greater ease of use of the drawing. Reference dimensions in the drawing are marked with the sign U*F, and in the technical requirements they write: U*Dimensions for reference F.

Reference dimensions on the assembly drawing include:

dimensions by which limit positions are determined individual elements designs (for example, piston stroke);

dimensions transferred from the drawings of parts and used as installation and connecting dimensions;

overall dimensions transferred from the drawings of parts or being the sum of the dimensions of several parts.

11. What are the rules for marking part numbers on a general view drawing or assembly drawing?

12. How and what lines on an assembly drawing are allowed to depict moving parts of a product, boundary products?

13. How is a product drawing performed when its individual elements are processed together before assembly?

14. When are holes for pins or screws not shown on the part drawing?

15. How is the product located behind a helical spring made without a cut shown in a simplified section?

Thread

1. What parameters characterize any thread?

Helical thread line - a line formed on the lateral surface of a real or imaginary right circular cone or right circular cylinder by a point moving in such a way that the ratio between its axial movement and the corresponding angular movement is constant, but not equal to zero or infinity .

Helical thread surface – a surface formed by a curve lying in the same plane with the axis and moving relative to the axis so that each point of the curve moves along the helix of the thread and all possible helical lines of the points of the curve have the same parameters.

Thread projection - a protruding part of the material limited by the helical surface of the thread.

thread groove - the space enclosed between the thread projections.

Thread entry – the beginning of the thread protrusion.

Thread axis – the axis relative to which the helical surface of the thread is formed.

Thread profile – profile of the protrusion and groove of the thread in the plane of the axial section of the thread.

Side thread - part of the helical surface of the thread, located between the top and the bottom of the thread and having a rectilinear profile in the plane of the axial section.

Top of thread - part of the helical surface of the thread connecting adjacent sides of the thread along the top of its protrusion.

Thread root - part of the helical surface of the thread connecting adjacent sides of the thread along the bottom of its groove.

Thread angle – the angle between adjacent sides of the thread in the plane of the axial section.

Outside diameter cylindrical thread - the diameter of an imaginary straight circular cylinder described around the tops of an external cylindrical thread or the valleys of an internal cylindrical thread.

Inner diameter cylindrical thread - the diameter of an imaginary straight circular cylinder inscribed in the recesses of an external cylindrical thread or the tops of an internal thread.

Nominal thread size – diameter, conditionally characterizing the dimensions of the thread and used in its designation.

Thread pitch – the distance to a line parallel to the thread axis, between the midpoints of the nearest sides of the same name of the thread profile, lying in the same plane on one side of the thread axis.

Thread stroke – the distance to a line parallel to the axis of the thread, between any starting point on the flank of the thread and the midpoint obtained

when moving the starting point along a helix at an angle of 360 degrees.

Thread length – the length of the section of the part on which the thread is formed, including the groove and chamfer or thread run-out and chamfer.

Thread run-out – a section in the zone of transition of the thread to the smooth part of the part, where the thread has an incomplete profile.

Falsehood – the size of the threaded part of the part between the end of the rung and the supporting surface.

Undercut – the sum of thread run-out and under-run.

Thread groove - an annular groove made at the end of the thread in order to obtain a full profile thread along the entire length.

Thread chamfer – a conical surface that serves to guide the nut when screwing it in and protect the outer turns of the thread from damage.

Make-up length – length of the section of mutual overlap of external and internal threads in the axial direction.

2. How are threads classified according to purpose?

Mounting threads – threads intended for connecting parts. Running threads – threads with the help of which rotational motion is converted into reciprocating

3. List the mounting threads?

Metric conical and cylindrical; pipe conical and cylindrical; conical inch; round.

4. How to depict a thread on a rod when projecting it onto a plane

a) parallel to the axis of the rod:

A continuous thin line along the inner diameter of the thread is drawn along the entire length of the thread without running off.

An arc is drawn along the inner diameter of the thread, approximately 3/4 of the circle and open anywhere; except center lines

5. How to depict a thread in a hole when projecting it onto a plane

a) parallel to the axis of the rod:

A continuous thin line along the outer diameter of the thread is drawn along the entire length of the thread without running off.

b) perpendicular to the axis of the rod:

An arc is drawn along the outer diameter of the thread, approximately 3/4 of the circle and open anywhere; except center lines

6. At what distance is it allowed to draw a solid thin line from the main line when depicting a thread?

At a distance of at least 0.8mm from the main one and no more than the thread pitch.

7. How are threads depicted on a rod and in a hole?

On the rod – solid main lines along the outer diameter of the thread and solid thin lines along the inner diameter.

In the hole – solid main lines along the inner diameter of the thread and solid thin lines along the outer diameter.

8. How is the end of a blind threaded hole shown in the drawings?

The bottom of the hole has the shape of a cone with an angle at the apex close to 120 degrees (the angle is not indicated in the drawing). This cone is formed by the cutting part of the drill when drilling a hole for a thread. The drilling depth is calculated and applied only taking into account the cylindrical part of the socket

9. How are threads with a non-standard profile depicted and designated?

Shows all thread parameters, with all necessary dimensions. The drawing also indicates additional data: the number of starts, the direction of the thread, etc., with the addition of the word “thread”.

10. How is a threaded connection depicted in section on a plane parallel to its axis?

Hatching on the section is applied to a solid main line corresponding to the internal diameter in the hole or the external diameter on the rod. In this case, a solid thin line in the hole shows outside diameter, and on the rod - internal.

11. How are special threads depicted with a standard profile?

Considering the connections of machine parts in pairs, we notice that they are very diverse in nature in different pairs. In some cases, one of the parts of a pair remains motionless in relation to the other part of the same pair during operation of the machine; in other cases, it makes one or another movement (for example, rotational, translational, etc.) relative to another part paired with it.

Two parts that make up a pair similar to one of those just discussed are called conjugate.

Female and Male Parts. When two parts are mated, one of them seems to cover the other, therefore the first of these parts (in relation to the other) is called female, and the second is called male.

The shapes of the mating parts are very diverse and their names, which exactly correspond to reality, are in many cases cumbersome and inconvenient for pronunciation and for recording. Therefore, in all cases, it was agreed that the female part (the surface of this part involved in a given interface) should be called a hole, and the male part (the surface involved in a given interface) a shaft.

Concept of landing. If, when processing the mating parts (both or one of them) or when assembling the machine, the required nature of their mating had not been taken into account, then it is obvious that the machine assembled from such parts would not be suitable for work.

In other words, an indispensable condition for the satisfactory operation of any machine is right choice and the implementation of the nature of the interfaces of its parts, or, as they say, landings.

Fit is the nature or type of mating (or connection) of two parts inserted into one another, ensuring, to one degree or another, the strength of their connection or the freedom of their relative movement.

Landings fixed and movable. Landings in which the strength of the connection of mating parts must be ensured are called fixed ones.

Connections of this nature are obtained if, before assembling the mating parts, the diameter of the shaft is slightly larger than the diameter of the hole, and therefore, after assembling the parts, a stressed state arises between them.

Landings for free movement, or (briefly) movable, are those that provide for constant relative movement of the mating parts during their operation. The possibility of relative movement of these parts is obtained if the diameter of the hole is slightly larger than the diameter of the shaft.

Modern mechanical engineering is unthinkable without the interchangeability of parts. Interchangeability is the property of parts manufactured with a given precision to ensure the possibility of assembling (or replacing during repair) mating parts into an assembly, and assemblies into a product, subject to compliance with the requirements presented to them technical requirements. Parts are interchangeable only if their size, shape, physical properties material and other quantitative and quality characteristics are within specified limits.
Not only parts, but also components and mechanisms as a whole can be interchangeable. First of all, these should be those parts and assemblies on which reliability, durability and others depend. performance products. Spare parts must also meet this requirement.
Interchangeability in ship repair has great importance and provides a significant economic effect, since the availability of ready-made spare parts and assemblies that can be easily, without adjustment, put in place to replace failed ones, makes repairs much easier and simpler.
To ensure wide interchangeability of parts in mechanical engineering, State standards. Standardized parts are manufactured according to the dimensions and shape established by GOST, regardless of the industry in which they are used. Examples of such standardized parts include fasteners, pipes, etc.
Technological operations in any production when manufacturing parts are performed in a certain order. The purpose of these operations is to give the workpiece such shapes and sizes that, according to the drawing (or specification), it should have ready product. During processing, a certain layer of metal is removed from the surface of the workpiece. The difference in the dimensions of the workpiece before and after processing is called processing allowance. The layer of metal to be removed (allowance) can be removed from the surface not immediately, but gradually, using different kinds processing, or, as they say, various operations. Allowances that are sequentially removed during various processing operations are called operational allowances. The total allowance size is the sum of the allowances for each operation.
With any method of processing parts (manually or on a machine), there are some deviations from the dimensions specified in the drawing and deviations from the specified geometric shape. These include: ovality and versatility, barrel-shaped and corseted shape, distortion of geometric axes, etc. For flat surfaces, deviations from the geometric shape are non-straightness and non-flatness.
The main causes of machining errors are: inaccuracy and wear of the machines and devices on which the part is processed; inaccuracy of the control and measuring instrument; inaccuracy of the base surfaces of the processed parts; errors when installing parts and when installing tools; errors made during measurements; heating of parts during processing; violations technological process allowed by the worker.
The main calculated size, which is indicated in the drawing, is called nominal; actual dimensions obtained by direct measurement are called actual. If only nominal dimensions are indicated on the drawing, this means that the degree of accuracy has not been established, and therefore small free deviations from the dimensions according to the drawing are accepted for processing.
When designing a part, permissible maximum dimensions are always assigned, which ensure reliable performance and interchangeability of parts.
The largest and the smallest maximum dimensions are called those between which the actual size may lie. Thus, the actual size may be larger or smaller than the nominal size. The difference between the largest and smallest maximum dimensions is called tolerance (Fig. 87).

Rice. 87. Graphic representation of shaft and hole tolerances.

Deviations from the nominal size within the tolerance can be upper and lower. The upper deviation is the difference between the largest limit and nominal sizes. The lower deviation is the difference between the smallest limit and nominal sizes. The actual deviation (size deviation) is the difference between the actual and nominal sizes. Deviation can be positive or negative.
A positive deviation is indicated by a sign (+) and occurs when the actual size of the part is larger than the nominal size. A negative deviation is indicated by a (-) sign and occurs when the actual size is less than the nominal size. Deviations are indicated decimal and are placed next to the nominal size: upper deviation above, below below. A positive deviation number is preceded by a (+) sign, and a negative deviation number is preceded by a (-) sign. If the upper and lower deviations are equal, one is entered total number with plus and minus signs (±). For example, the designation 60 0.05 0.02 shows that the nominal size of the part is 60 mm, and the upper positive deviation is 0.05 mm, and lower deviation(also positive) is 0.02 mm. Therefore, the largest limiting size of the part will be 60 + 0.05 = 60.05 mm, and the smallest limiting size will be 60 + 0.02 = 60.02 mm. Thus, the tolerance is 60.05-60.02 = 0.03 mm. The designation indicates that the part size can range from 40.15 mm to 39.90 mm. The difference between the dimensions 40.15-39.90 = 0.25 mm is the tolerance. The tighter the tolerance, the more accurately the part must be manufactured.
When assembling various mechanisms, their parts are mated in different ways. The nature of the mating of two parts is called a fit. Landings can be carried out with a gap or with an interference fit. For example, if the shaft has a diameter smaller than the diameter of the sleeve hole, then when these parts are connected, a gap will form between the surfaces of the sleeve and the shaft, called a gap, and the mating of the parts will be movable. If the diameter of the shaft is slightly larger than the diameter of the sleeve hole, then these parts can be connected only when the sleeve is heated to a certain temperature. After the sleeve cools down, an interference will form in such a connection, and the connection will be motionless.
In Fig. 88 shows a graphical representation of the clearance and interference. Thus, the clearance is the positive difference between the diameters of the hole and the shaft, and the interference is the negative difference between the diameters of the hole and the shaft. Since the shaft and hole diameters may vary various sizes within tolerance, the gaps or tensions in the connection can also be different. If you take the largest hole size and the smallest shaft size, then the gap between them will be the largest. If the shaft size is largest and the hole size is smallest, then the gap will be the smallest.

Rice. 88. Graphic representation of clearance and interference.

Depending on the size of the gap or interference, the nature of the fit also changes, i.e., the degree of mobility of the mating parts relative to each other. Currently, the standard establishes 16 types of landings: six fixed, four transitional and six movable. Transitional landings can be with clearance and interference, depending on the dimensions of the shaft and hole, within tolerance. Fixed landings provide guaranteed interference, movable - guaranteed clearance.
The names and designations of plantings are given in table. 1. The nature of the fit is chosen depending on the operating conditions of the part.

Currently, two tolerance systems are accepted in mechanical engineering: the hole system (denoted SA) and the shaft system (denoted SV). In the hole system, the size of the hole with certain limiting dimensions is taken as the basis, and the fit is carried out only by changing the size of the shaft. The hole system is shown schematically in Fig. 89, a. In this system the nominal mating size is smallest size holes, and hole deviations are only positive.
In the shaft system, the size of the shaft with certain maximum dimensions is taken as the basis, and the fit is carried out by changing the size of the hole (Fig. 89, b). In this system, the nominal mating size is the largest shaft size, and shaft deflections are only negative.

When sketches are taken of single, unrelated parts, the main attention when drawing dimensions is drawn to the connection with their manufacturing technology.

The parts from which machines and their individual components are assembled are interconnected. Therefore, when putting dimensions on sketches of such parts, it is necessary to take into account not only the technology of their manufacture, but also design features, as well as the position of this part in the product.

Two or more parts, movably or immovably connected to each other, are called mating. The surfaces or dimensions along which parts are mated are also called mating surfaces.

Conjugate dimensions determine the relative position of two or more parts in a product. They provide the ability to assemble and disassemble, as well as the required interchangeability. Interchangeability refers to the possibility of replacing some parts during assembly or repair with others made according to the same drawings without additional adjustment.

Other unrelated dimensions and surfaces do not directly affect the nature of the connection of parts; they are determined by the strength of the part, its weight, size, etc.

The mating surfaces and their dimensions can be male or female. The surface of the outer part is called the female one, the inner surface is called the male surface.

The size common to the male and female surfaces is called nominal. The nature of the connection is determined by the difference between the female and male dimensions. Parts are mated mainly along cylindrical, conical, spherical or flat surfaces.

3.3.1 Cylindrical mates are the most common. They are used in rotational and converter motion mechanisms - in shaft supports, when installing bushings in housings, in connections of pulleys and gears with shafts or axles.

Such connections can be movable or fixed. If the nominal dimensions of the mating surfaces are the same, then on the assembly drawing they are depicted as one line and the nominal size is indicated (Ø 30 in accordance with Figure 3.6).

Figure 3.6 – Designation of nominal diameter

mating surfaces

If the female dimension is larger than the male one, then the difference between the indicated dimensions forms a gap, which is shown on the assembly drawing (Ø 40 and Ø 42 in accordance with Figure 3.6).

A peculiarity of the constructive implementation of assembly connections on a cylindrical surface is that it is advisable to pair two parts only along one coaxial surface (the pairing of parts along two concentric surfaces is difficult), while the end contact of the parts is also allowed on no more than one plane.

Figure 3.6 shows the installation of the seat in the valve body. The contact of the two parts occurs along a plane and a cylindrical surface Ø 30, which ensures the centering of the saddle axis. The nature of the pairing of parts depends on the operating conditions of the product. The more precise the pairing, the more difficult and expensive its production. Therefore, where operating conditions do not require great precision in manufacturing, the parts can be connected to each other with a gap. Nominal sizes the sketches of the corresponding parts must provide this gap.

In the connection of the spindle with the flywheel, it is necessary to provide a gap “c” in accordance with Figure A1, option a), ensuring the possibility of tightly pressing the spindle to the flywheel along the contact plane by tightening the nut. The size of this gap depends on the thread run-out at the end of the spindle, because It is impossible to screw the nut onto an imperfectly cut part of the thread.

When fastening flanges, the alignment of the holes for fastening bolts or screws is ensured by the identical coordination of their centers on the sketches of the mating parts. Parts connected by threads must have the same type and size of thread. The working length of bolts, studs and screws is also a related dimension.

3.3.2 By mating parts along a conical surface, three types of connections can be made - tight (sealed), movable and fixed.

Tight or sealed are used in pipeline fittings (plug valves), in valve devices of various regulators, pumps, etc.

An example of movable conical joints is the support of spindles of metal-cutting machines in plain bearings.

Fixed conical connections are used when landing shanks cutting tools, in couplings, when installing conical pins, etc.

The conical interface consists of a conical surface of the male part (plug), called the outer cone, and a surface of the female part (body), called the inner cone, in accordance with Figure 3.7.

The following main elements are distinguished in conical mates:

a) the base of the cone (usually one of the flat ends of the conical surface is taken, perpendicular to the axis of the cone);

b) design section - a section of the cone perpendicular to the axis, located at a certain distance from the base of the cone;

c) base distance – the distance of the design section to the base of the cone;

d) taper k – ratio of the difference in diameters of two cross sections cone to the distance between them. GOST 8953-81 establishes normal tapers for conical connections general purpose. Therefore, the taper obtained by calculation must be corrected according to the corresponding tables.

To ensure the tightness of the connection between the plug and the body, it is necessary that the tapers of the mating conical surfaces coincide. The conical surfaces of both parts are specified by the height of the cone, the diameter in the plane of the base and the taper. Thus, the conical surface on the sketch of a plug is specified by the height of the cone L , diameter D and taper k , and in the sketch of the body - height l , diameter d and taper k in accordance with Figure 3.7.

3.3.3 When pairing via spherical surface Only movable joints are obtained, which are used in valve structures, hinges, self-aligning supports, ball joints of pipelines, etc.

The mating of spherical and conical surfaces can be carried out as shown in Figure 3.8.

Figure 3.7 – Conical connection between the plug and the valve body

Figure 3.8 – Conjugation of spherical and conical surfaces

3.3.4 Flat or groove mates usually consist of two parallel or inclined planes, where two interconnected planes of one part (groove) cover two planes of another part in accordance with Figure A1, option b).

If the product contains parts that are processed together, then the assembly drawing provides all the necessary data for joint processing in accordance with Figure A1, option b). On the sketches of the parts of this product, no indications regarding joint processing during assembly are made.

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The mating parts formed during the assembly of products, depending on the number of degrees of freedom, as already noted, will have different properties and can be fixed or movable. In turn, depending on the relative sizes of the parts forming the interface, the latter may have varying degrees of immobility or mobility. These degrees, as is known, are characterized by the magnitude of interference or clearances maintained during the assembly of mating parts, or, in other words, by the magnitude and sign of design and manufacturing deviations in the dimensions of mating parts.

Mating parts are characterized by the amount of gap or tension between the mating surfaces. Due to differences in the material and heating temperature of the parts, the gap size does not remain constant when the thermal state of the engine changes.

In most cases, parts are connected using bolts and studs. There are bolts of ordinary and critical threaded connections.

The mating of parts assembled with the wedge must ensure smooth, uniform movement without jumps with minimal clearances. This is achieved by regulation and scraping. Mechanical restoration wedges are performed on special devices, ensuring the installation of the wedge at the desired angle. Grinding can be done on a rotary magnetic table.

Matings of parts that do not require great accuracy should be made according to the 4th and 5th accuracy classes. Wherever possible, grade 5 should be taken.

Mating parts that do not require great accuracy should be manufactured according to the 4th and 5th accuracy classes. Wherever possible, grade 5 should be used.

The mating parts formed during the assembly of products, depending on the number of degrees of freedom, as already noted, will have different properties and can be fixed or movable. The degree of its immobility or mobility depends on the relative sizes of the parts that form the interface.

The mating parts of the supports must fit tightly; through gaps in joints are not allowed. Filling cracks or voids between working surfaces with wedges is prohibited.

The mating of threaded parts according to the average diameter corresponds in its type to the tightness of the fit.

The mating parts of the supports must fit tightly; through gaps in joints are not allowed. Filling cracks or voids between working surfaces with wedges is prohibited. The bolts connecting the individual parts of the supports must fit tightly into the hole and be securely tightened. The thread of the bolts should not protrude more than 400 mm above the nuts. Bolts located at a height of less than 3 m from ground level must be cored. Washers should be placed under the bolt head and under the nut. The holes in the traverses for the fastening parts of the insulator strings must be drilled exactly to the diameter of the bolts.

After mating the parts, turning them relative to each other is not allowed.