Applying and reading dimensions on part drawings. Image of holes and elements of the same type Thread depth designation
It's been discussed a lot here. I will repeat in a general sense why it is necessary to show transition lines conditionally: 1. To make the drawing readable. 2. From the transition lines shown conditionally, you can set dimensions that are often not put down on any other view or section. Here is an example. There is a difference? 1. As it is now possible to display in all the listed CAD systems. And here's how to display it. Transition lines are shown conditionally and sizes are shown that, in other modes of displaying transition lines, simply cannot be put down. Why did the controller require this? Yes, just so that the drawings have a familiar look after many years of work in 2D and are well read, especially by the customer who coordinates them.
That's right :) this is nonsense :) in TF you can do it anyway =) there will be no tangible difference in speed, you can even then take any copy to repaint, change holes, delete holes, whatever ... and the array will still remain an array - it will be possible to change the number of copies, the direction, etc., to cut the video or believe it? :) That's right, but what is the task? Translate as SW splines by points into a spline by poles or something, if you think about it, this is also some change in the original geometry - there are no comments about this? :) as I understand it, TF only translates 1 to 1, the rest can already be configured in the TF template before export in DWG - see the figure under the spoiler, or scale it as AC, which, in principle, does not contradict the main methods of working with AutoCAD, and since, in view of the prevalence of AS in the early stages of the peak of the popularity of CAD implementation, this is even more familiar to the age generation: And if to get to the bottom of the possibilities of exporting / importing different CAD systems: 1) how to export only selected lines from a 2D SW drawing to DWG? (from 3D documents more or less SW is adapted, but you still have to small window preview to clean the excess manually). Delete everything that is not needed in advance, and then export-> somehow not modern, not youthful :) 2) And vice versa, how to quickly import selected lines in AutoCAD into SW (for example, for a sketch, or just as a set of lines drawing)? (for TF: selected set desired lines in AC -ctrl + c and then in TF just ctrl + v - that's it)
What detail are we talking about, otherwise this detail may not need to be mirrored, but simply tied differently and it will be just right. A mirror part is the same configuration only created by the machine, you can make the configuration of the part yourself and in some cases it may turn out to be more elegant, it is also easier to edit later.
from 01.01.80
This standard establishes rules for specifying the tolerances of the shape and location of surfaces on the drawings of products in all industries. Terms and definitions of tolerances for the shape and location of surfaces - according to GOST 24642-81. Numerical values of tolerances of the shape and location of surfaces - according to GOST 24643-81. The standard fully complies with ST SEV 368-76.
1. GENERAL REQUIREMENTS
1.1. Tolerances of the shape and location of surfaces are indicated in the drawings by symbols. The type of tolerance of the shape and location of the surfaces must be indicated on the drawing with the signs (graphic symbols) given in the table.|
Tolerance group |
Tolerance type |
|
| Shape tolerance | Straightness tolerance | |
| Flatness tolerance | ||
| roundness tolerance | ||
| Cylindrical tolerance | ||
| Longitudinal section profile tolerance | ||
| Location tolerance | Parallelism tolerance | |
| Perpendicularity tolerance | ||
| Tilt tolerance | ||
| Alignment tolerance | ||
| Symmetry tolerance | ||
| Position tolerance | ||
| Intersection tolerance, axes | ||
| Total shape and location tolerances | Radial runout tolerance Axial runout tolerance Runout tolerance in a given direction | |
| Full radial runout tolerance Full axial runout tolerance | ||
| Tolerance of the shape of a given profile | ||
| Tolerance of the shape of a given surface |
2. APPLICATION OF TOLERANCES
2.1. At symbol data on the tolerances of the shape and location of the surfaces are indicated in a rectangular frame divided into two or more parts (Fig. 1, 2), in which they place: in the first - the tolerance sign according to the table; in the second - the numerical value of the tolerance in millimeters; in the third and subsequent ones - the letter designation of the base (bases) or the letter designation of the surface with which the location tolerance is associated (clauses 3.7; 3.9).Heck. one
Heck. 2
2.2. Frames should be made with solid thin lines. The height of the numbers, letters and signs that fit into the frames must be equal to the font size of the dimensional numbers. The graphic image of the frame is given in mandatory Appendix 1. 2.3. The frame is placed horizontally. In necessary cases, a vertical arrangement of the frame is allowed. It is not allowed to cross the frame with any lines. 2.4. The frame is connected to the element to which the tolerance applies, with a solid thin line ending with an arrow (Fig. 3).
Heck. 3
The connecting line can be straight or broken, but the direction of the connecting line segment ending in an arrow must match the direction of the deviation measurement. The connecting line is taken away from the frame, as shown in Fig. 4.
Heck. 4
If necessary, it is allowed: to draw a connecting line from the second (last) part of the frame (Fig. 5 but); end the connecting line with an arrow and from the side of the material of the part (Fig. 5 b).
Heck. five
2.5. If the tolerance refers to the surface or its profile, then the frame is connected to the contour line of the surface or its continuation, while the connecting line should not be a continuation of the dimension line (Fig. 6, 7).
Heck. 6
Heck. 7
2.6. If the tolerance refers to an axis or plane of symmetry, then the connecting line should be a continuation of the dimension line (Fig. 8 but, b). If there is not enough space, the arrow of the dimension line can be combined with the arrow of the connecting line (Fig. 8 in).
Heck. 8
If the size of an element has already been specified once, then it is not indicated on other dimension lines of this element used to symbolize the tolerance of the shape and location. Dimension line without size should be considered as an integral part of the shape or location tolerance symbol (Fig. 9).
Heck. nine
Heck. 10
2.7. If the tolerance refers to the sides of the thread, then the frame is connected to the image in accordance with Fig. 10 but. If the tolerance refers to the axis of the thread, then the frame is connected to the image in accordance with Fig. 10 b. 2.8. If the tolerance refers to a common axis (plane of symmetry) and it is clear from the drawing for which surfaces this axis (plane of symmetry) is common, then the frame is connected to the axis (plane of symmetry) (Fig. 11 but, b).
Heck. eleven
2.9. Before the numerical value of the tolerance, you should indicate: the symbol Æ, if the circular or cylindrical tolerance field is indicated by the diameter (Fig. 12 but); symbol R , if a circular or cylindrical tolerance field is indicated by a radius (Fig. 12 b); symbol T, if the tolerances for symmetry, intersection of axes, the shape of a given profile and a given surface, as well as positional tolerances (for the case when the positional tolerance field is limited by two parallel lines or planes) are indicated in a diametrical expression (Fig. 12 in); symbol T/2 for the same types of tolerances, if they are indicated in radius expression (Fig. 12 G); the word "sphere" and the symbols Æ or R if the tolerance field is spherical (Fig. 12 d).
Heck. 12
2.10. The numerical value of the tolerance of the shape and location of the surfaces indicated in the box (Fig. 13 but), refers to the entire length of the surface. If the tolerance refers to any part of the surface of a given length (or area), then the given length (or area) is indicated next to the tolerance and separated from it by an inclined line (Fig. 13 b, in), which must not touch the frame. If it is necessary to assign a tolerance over the entire length of the surface and at a given length, then the tolerance at a given length is indicated under the tolerance over the entire length (Fig. 13 G).
Heck. 13
(Revised edition, Rev. No. 1). 2.11. If the tolerance must refer to a section located in a certain place of the element, then this section is indicated by a dash-dotted line and is limited in size according to the features. fourteen.
Heck. fourteen
2.12. If it is necessary to set a protruding tolerance field for the location, then after the numerical value of the tolerance indicate the symbol. The contour of the protruding part of the normalized element is limited by a thin solid line, and the length and location of the protruding tolerance field are limited by dimensions (Fig. 15).
Heck. 15
2.13. Inscriptions supplementing the data given in the tolerance frame should be applied above the frame below it or as shown in Fig. 16.
Heck. 16
(Revised edition, Rev. No. 1). 2.14. If for one element it is necessary to set two different types of tolerance, then it is allowed to combine the frames and arrange them according to the features. 17 (upper designation). If for the surface it is required to indicate simultaneously the symbol of the tolerance of the shape or location and its letter designation used to normalize another tolerance, then the frames with both symbols can be placed side by side on the connecting line (Fig. 17, lower designation). 2.15. Repeating the same or different types tolerances, denoted by the same sign, having the same numerical values \u200b\u200band referring to the same bases, it is allowed to indicate once in a frame from which one connecting line departs, which then branches to all normalized elements (Fig. 18).
Heck. 17
Heck. eighteen
2.16. The tolerances of the shape and location of symmetrically located elements on symmetrical parts are indicated once.
3. DESIGNATION OF BASES
3.1. The bases are indicated by a blackened triangle, which is connected with a connecting line to the frame. When making drawings with the help of computer output devices, the triangle denoting the base is allowed not to be blackened. The triangle denoting the base must be equilateral, with a height approximately equal to the font size of the dimension numbers. 3.2. If the base is a surface or its profile, then the base of the triangle is placed on the contour line of the surface (Fig. 19 but) or on its continuation (Fig. 19 b). In this case, the connecting line should not be a continuation of the dimension line.
Heck. 19
3.3. If the base is an axis or a plane of symmetry, then the triangle is placed at the end of the dimension line (Fig. 18). In case of lack of space, the arrow of the dimension line can be replaced with a triangle denoting the base (Fig. 20).
Heck. twenty
If the base is a common axis (Fig. 21 but) or a plane of symmetry (Fig. 21 b) and it is clear from the drawing for which surfaces the axis (plane of symmetry) is common, then the triangle is placed on the axis.
Heck. 21
(Revised edition, Rev. No. 1). 3.4. If the base is the axis of the center holes, then next to the designation of the base axis, the inscription "Axis of centers" is made (Fig. 22). It is allowed to designate the base axis of the center holes in accordance with Fig. 23.
Heck. 22
Heck. 23
3.5. If the base is a certain part of the element, then it is indicated by a dash-dotted line and limited in size in accordance with the features. 24. If the base is a certain place of the element, then it must be determined by the dimensions according to the features. 25.
Heck. 24
Heck. 25
3.6. If there is no need to select one of the surfaces as a base, then the triangle is replaced by an arrow (Fig. 26 b). 3.7. If the connection of the frame with the base or other surface to which the location deviation relates is difficult, the surface is indicated by a capital letter that fits into the third part of the frame. The same letter is inscribed in a frame, which is connected to the designated surface by a line, instilled with a triangle, if the base is designated (Fig. 27 but), or an arrow if the indicated surface is not a base (Fig. 27 b). In this case, the letter should be placed parallel to the main inscription.
Heck. 26
Heck. 27
3.8. If the size of an element has already been specified once, then it is not indicated on other dimension lines of this element used to symbolize the base. A dimension line without a dimension should be considered as an integral part of the base designation (Fig. 28).
Heck. 28
3.9. If two or more elements form a combined base and their sequence does not matter (for example, they have a common axis or plane of symmetry), then each element is designated independently and all letters are entered in a row in the third part of the frame (Fig. 25, 29). 3.10. If it is necessary to set the location tolerance relative to the set of bases, then the letter designations of the bases are indicated in independent parts (third and further) of the frame. In this case, the bases are written in descending order of the number of degrees of freedom they deprive (Fig. 30).
Heck. 29
Heck. thirty
4. INDICATION OF NOMINAL LOCATION
4.1. The linear and angular dimensions that determine the nominal location and (or) the nominal shape of the elements limited by the tolerance, when assigning a positional tolerance, tilt tolerance, tolerance of the shape of a given surface or a given profile, are indicated in the drawings without maximum deviations and enclosed in rectangular frames (Fig. 31 ).
Heck. 31
5. DESIGNATION OF DEPENDENT TOLERANCES
5.1. Dependent shape and location tolerances denote symbol, which is placed: after the numerical value of the tolerance, if dependent tolerance associated with the actual dimensions of the element in question (Fig. 32 but); after letter designation bases (Fig. 32 b) or without a letter designation in the third part of the frame (Fig. 32 G), if the dependent tolerance is related to the actual dimensions of the base element; after the numerical value of the tolerance and the letter designation of the base (Fig. 32 in) or without a letter designation (Fig. 32 d), if the dependent tolerance is related to the actual dimensions of the element under consideration and the base element. 5.2. If a location or shape tolerance is not specified as dependent, then it is considered independent.
Heck. 32
ATTACHMENT 1
Mandatory
SHAPE AND DIMENSIONS OF SIGNS
APPENDIX 2
Reference
EXAMPLES OF INSTRUCTIONS ON THE DRAWINGS OF TOLERANCES FOR THE FORM AND LOCATION OF SURFACES
|
Tolerance type |
Indication of shape and location tolerances by symbol |
Explanation |
| 1. Straightness tolerance | The straightness tolerance of the generatrix of the cone is 0.01 mm. | |
|
|
Hole axis straightness tolerance Æ 0.08 mm (dependent tolerance). | |
|
|
The surface straightness tolerance is 0.25 mm over the entire length and 0.1 mm over a length of 100 mm. | |
|
|
Surface straightness tolerance in the transverse direction 0.06 mm, in the longitudinal direction 0.1 mm. | |
| 2. Flatness tolerance |
|
Surface flatness tolerance 0.1 mm. |
|
|
The surface flatness tolerance is 0.1 mm over an area of 100 ´ 100 mm. | |
|
|
The flatness tolerance of the surfaces relative to the common adjacent plane is 0.1 mm. | |
|
|
The flatness tolerance of each surface is 0.01 mm. | |
| 3. Roundness tolerance |
|
Shaft roundness tolerance 0.02 mm. |
| Cone roundness tolerance 0.02 mm. | ||
| 4. Cylindrical tolerance |
|
Shaft cylindricity tolerance 0.04 mm. |
|
|
Shaft cylindricity tolerance 0.01 mm over a length of 50 mm. Shaft roundness tolerance 0.004 mm. | |
| 5. Tolerance of the profile of the longitudinal section |
|
Shaft roundness tolerance 0.01 mm. The tolerance of the profile of the longitudinal section of the shaft is 0.016 mm. |
|
|
The tolerance of the profile of the longitudinal section of the shaft is 0.1 mm. | |
| 6. Parallelism tolerance |
|
Tolerance of surface parallelism with respect to surface BUT 0.02 mm. |
|
|
Tolerance of parallelism of the common adjacent plane of surfaces relative to the surface BUT 0.1 mm. | |
|
|
Tolerance of parallelism of each surface relative to the surface BUT 0.1 mm. | |
|
|
The tolerance of parallelism of the axis of the hole relative to the base is 0.05 mm. | |
|
|
The tolerance of parallelism of the axes of the holes in the common plane is 0.1 mm. Tolerance of misalignment of the axes of the holes is 0.2 mm. Base - hole axis BUT. | |
|
|
Tolerance of parallelism of the hole axis with respect to the hole axis BUT 00.2 mm. | |
| 7. Perpendicular tolerance |
|
Surface Perpendicularity Tolerance BUT 0.02 mm. |
|
|
Tolerance of perpendicularity of the hole axis relative to the hole axis BUT 0.06 mm. | |
|
|
Perpendicularity tolerance of the protrusion axis relative to the surface BUT Æ 0.02 mm. | |
| Tolerance of perpendicularity of the OSB ledge relative to the base 0, l mm. | ||
|
|
Tolerance of perpendicularity of the projection axis in the transverse direction 0.2 mm, in the longitudinal direction 0.1 mm. Base - base | |
|
|
Tolerance of perpendicularity of the hole axis relative to the surface Æ 0.1 mm (dependent tolerance). | |
| 8. Tilt tolerance |
|
Tolerance of slope of the surface relative to the surface BUT 0.08 mm. |
|
|
Tolerance of inclination of the hole axis relative to the surface BUT 0.08 mm. | |
| 9. Alignment tolerance |
|
Hole alignment tolerance relative to hole Æ 0.08 mm. |
|
|
The tolerance of the alignment of two holes relative to their common axis is Æ 0.01 mm (dependent tolerance). | |
| 10. Symmetry tolerance |
|
Groove symmetry tolerance T 0.05 mm. Base - plane of symmetry of surfaces BUT |
|
|
Hole symmetry tolerance T 0.05 mm (tolerance dependent). Base - the plane of symmetry of the surface A. | |
|
|
Tolerance of symmetry of the OSB hole relative to common plane groove symmetry AB T 0.2 mm and relative to the common plane of symmetry of the grooves VG T 0.1 mm. | |
| 11. Position tolerance |
|
Positional tolerance of the hole axis Æ 9.06 mm. |
|
|
Positional tolerance of the hole axes Æ 0.2 mm (dependent tolerance). | |
|
|
Positional tolerance of axes of 4 holes Æ 0.1 mm (dependent tolerance). Base - hole axis BUT(tolerance dependent). | |
|
|
Positional tolerance of 4 holes Æ 0.1 mm (dependent tolerance). | |
|
|
Positional tolerance 3 threaded holesÆ 0.1 mm (tolerance dependent) in the area located outside the part and protruding 30 mm from the surface. | |
| 12. Tolerance of intersection of axes |
|
Hole intersection tolerance T 0.06mm |
| 13. Radial runout tolerance |
|
Tolerance of radial runout of the shaft relative to the axis of the cone 0.01 mm. |
|
|
The tolerance of the radial runout of the surface relative to the common axis of the surface BUT And B 0.1 mm | |
|
|
Tolerance of radial runout of a surface area relative to the axis of the hole BUT 0.2mm | |
|
|
Run-out tolerance of hole 0.01 mm First base - surface L. The second base is the axis of the surface B. The tolerance of the end runout relative to the same bases is 0.016 mm. | |
| 14. Axial runout tolerance |
|
End runout tolerance at a diameter of 20 mm relative to the surface axis BUT 0.1 mm |
| 15. Runout tolerance in a given direction |
|
Cone run-out tolerance relative to the hole axis BUT in the direction perpendicular to the generatrix of the cone 0.01 mm. |
| 16. Tolerance of full radial runout |
|
Tolerance of total radial runout relative to a common axis is superficial BUT And B 0.1 mm. |
| 17. Full axial runout tolerance |
|
Tolerance of full face runout of the surface relative to the axis of the surface is 0.1 mm. |
| 18. Tolerance of the shape of a given profile |
|
Tolerance of the shape of a given profile T 0.04 mm. |
| 19. Tolerance of the shape of a given surface |
|
Tolerance of the shape of a given surface relative to surfaces A, B, C, T 0.1 mm. |
| 20. Total parallelism and flatness tolerance |
|
The total tolerance of parallelism and flatness of the surface relative to the base is 0.1 mm. |
| 21. Total tolerance of perpendicularity and flatness |
|
The total tolerance of perpendicularity and flatness of the surface relative to the base is 0.02 mm. |
| 22. Total tilt and flatness tolerance |
|
The total tolerance of the slope and flatness of the surface relative to the base is 0.05 mi |
In the previously released documentation, the tolerances for alignment, symmetry, displacement of the axes from the nominal location (positional tolerance), indicated respectively by signs 
or text in the specification should be understood as tolerances in radius terms. 2. Indication of tolerances for the shape and location of surfaces in text documents or in the technical requirements of the drawing, by analogy with the text, an explanation should be given to the symbols for the shape and location tolerances given in this appendix. In this case, the surfaces to which the tolerances of the shape and location belong, or which are taken as the base, should be indicated by letters or their design names should be carried out. It is allowed instead of the words "tolerance dependent" to indicate the sign and instead of indications before the numerical value of the symbols Æ ; R; T; T/2 writing in text, for example, "0.1 mm axis position tolerance in diametric terms" or "0.12 mm symmetry tolerance in radial terms". 3. In the newly developed documentation, the entry in the technical requirements for tolerances of ovality, cone shape, barrel shape and saddle shape should be, for example, the following: “Tolerance of ovality of the surface BUT 0.2 mm (semi-difference in diameter). In the technical documentation developed before 01/01/80, the limiting values of ovality, cone shape, barrel shape and saddle shape are defined as the difference between the largest and smallest diameters. (Revised edition, Rev. No. 1).
Thread is made cutting tool with the removal of a layer of material, knurling - by extruding screw protrusions, casting, pressing, stamping, depending on the material (metal, plastic, glass) and other conditions.
Due to the device of a thread-cutting tool (for example, a tap, Fig. 8.14; dies, Fig. 8.15) or when the cutter is retracted, when moving from a surface area with a full profile thread (sections l) to a smooth one, a section is formed on which the thread seems to come off no (sections l1), a thread runaway is formed (Fig. 8.16). If the thread is made to a certain surface that does not allow the tool to be brought all the way to it, then a thread undercut is formed (Fig. 8.16.6, c). Runaway plus undercut form a thread undercut. If it is required to make a thread of a full profile, without a run-off, then a groove is made to output the thread-forming tool, the diameter of which is for external thread should be slightly less than the inner diameter of the thread (Fig. 8.16, d), and for an internal thread - slightly larger than the outer diameter of the thread (Fig. 8.17). At the beginning of the thread, as a rule, a conical chamfer is made, which protects the extreme turns from damage and serves as a guide when connecting threaded parts (see Fig. 8.16). Chamfering is performed before threading. The sizes of chamfers, runs, undercuts and grooves are standardized, see GOST 10549-80 * and 27148-86 (ST SEV 214-86). Fastener products. Thread outlet. Run away, undercuts and grooves. Dimensions.
Building an accurate image of the threads is time-consuming, so it is used in rare cases. According to GOST 2.311 - 68 * (ST SEV 284-76), in the drawings the thread is depicted conditionally, regardless of the thread profile: on the rod - with solid main lines along the outer diameter of the thread and solid thin lines - along the inner, for the entire length of the thread, including the chamfer ( Fig. 8.18, a). On images obtained by projecting onto a plane perpendicular to the axis of the rod, an arc is drawn along the inner diameter of the thread with a solid thin line equal to 3/4 of the circle and open anywhere. On the images of the thread in the hole, solid main and solid thin lines seem to change places (Fig. 8.18.6).
A solid thin line is applied at a distance of at least 0.8 mm from the main line (Fig. 8.18), but not more than the thread pitch. Hatching in the sections is brought to the line of the outer diameter of the thread on the rod (Fig. 8.18, d) and to the line of the inner diameter in a hole (Fig. 8.18.6). Chamfers on a threaded rod and in a threaded hole, which do not have a special design purpose, are not depicted in projection onto a plane perpendicular to the axis of the rod or hole (Fig. 8.18). The thread boundary on the rod and in the hole is drawn at the end of the complete thread profile (before the start of the run-off) with the main line (or dashed if the thread is shown as invisible, Fig. 8.19), bringing it to the lines of the outer diameter of the thread. If necessary, the thread run-off is depicted with thin lines , held approximately at an angle of 30 ° to the axis (Fig. 8.18, a, b).
The thread, shown as invisible, is depicted by dashed lines of the same thickness along the outer and inner diameters (Fig. 8.19). The length of the thread is the length of the section of the part on which the thread is formed, including the run-off and chamfer. Usually, the drawings indicate only the length l of the thread with a full profile (Fig. 8.20, a). If there is a groove, external (see Fig. 8.16, d) or internal (see Fig. 8.17), then its width is also included in the thread length. 8.20, b, c. The undercut of the thread, made to the stop, is depicted as shown in fig. 8.21, a, b. Options "c" and "d" are acceptable.
In the drawings, according to which the thread is not performed (on the assembly drawings), it is allowed to depict the end of a blind hole according to fig. 8.22 On sections threaded connection in the image on a plane parallel to its axis, only that part of the thread that is not covered by the thread of the rod is shown in the hole (Fig. 8.23).
There are threads: general purpose and special designed for use on certain types of products; fastening, intended, as a rule, for a fixed detachable connection constituent parts products, and running gear - to transmit movement. Right-hand threads are predominantly used, LH is added to the designation of left-hand threads. In the designations of multi-start threads, the stroke is indicated, and in brackets - the pitch and its value
A blind threaded hole is made in the following order: first, a hole of diameter d1 threaded, then lead-in chamfer S x45º (Fig. 8, but) and finally sliced internal thread d(Fig. 8, b). The bottom of the threaded hole has a conical shape, and the angle at the top of the cone φ depends on sharpening drills but. When designing, φ = 120º is assumed (nominal sharpening angle of drills). It is quite obvious that the depth of the thread should be more length screw-in threaded end of the fastener. There is also some distance between the end of the thread and the bottom of the hole. but called "undercut".
From fig. 9, the approach to sizing blind threaded holes becomes clear: thread depth h defined as the difference in draw length L threaded part and total thickness H attracted parts (may
be one, or maybe several), plus a small margin of thread k, usually taken equal to 2-3 steps R carving
h = L – H + k,
where k = (2…3) R.
Rice. 8. Sequence of execution of blind threaded holes
Rice. 9. Assembly screw fixing
Drawbar length L fastener is indicated in its symbol. For example: "Bolt M6x20.46 GOST 7798-70" - its tightening length L= 20 mm. Total thickness of attracted parts H calculated from drawing general view(to this amount should be added the thickness of the washer placed under the head of the fastener). thread pitch R also indicated in the symbol of the fastener. For example: "Screw M12x1.25x40.58 GOST 11738-72" - its thread has a fine pitch R= 1.25 mm. If the step is not specified, then by default it is the main (large). Lead-in leg S usually taken equal to the thread pitch R. Depth N threaded holes more value h on the size of the undercut but:
N = h + a.
Some difference in the calculation of the dimensions of the threaded hole for the stud is that the screwed threaded end of the stud does not depend on its clamping length and the thickness of the parts being attracted. For the GOST 22032-76 studs presented in the task, the screwed “stud” end is equal to the thread diameter d, that's why
h = d + k.
The measurements obtained should be rounded up to the nearest whole number.
The final image of a blind threaded hole with required dimensions shown in fig. 10. The diameter of the threaded hole and the angle of sharpening the drill are not indicated in the drawing.
Rice. 10. Image of a blind threaded hole in the drawing
The reference tables show the values of all calculated values (thread hole diameters, undercuts, washer thicknesses, etc.).
Necessary remark: the use of a short undercut must be justified. For example, if the part at the location of the threaded hole in it is not thick enough, and through hole under the thread can break the tightness of the hydraulic or pneumatic system, then the designer has to “squeeze”, incl. shortening the undercut.
PARTS TO BE MACHINED TOGETHER
In the manufacture of machines, some surfaces of parts are processed not individually, but together with the surfaces of counter parts. The drawings of such products have features. Not claiming to full review options, consider two varieties of such details found in assignments on the topic.
Pin connections
If in an assembly two parts are joined along a common plane and there is a need to accurately fix their relative position, then the parts are connected with pins. Pins allow not only to fix parts, but also to easily restore their previous position after disassembly for repair purposes. For example, in the assembly of two body parts 1 And 2 (see Fig. 11) it is necessary to ensure the alignment of the bores Ø48 and Ø40 for bearing units. Flanges are pressed with bolts 3 , and the alignment of the bores adjusted once is provided by two pins 6 . A pin is a precise cylindrical or conical rod; The pin hole is also very precise, with a surface roughness of at least Ra 0.8. It is obvious that the complete coincidence of the pin hole, the halves of which are located in different parts, is easiest to do if the two parts are first set in the required position, fastened with bolts and a hole for the pin is made in one pass of the tool in both flanges at once. This is called co-processing. But such an approach must be specified in project documentation so that the technologist takes it into account when forming technological process assembly manufacturing. The indication of the joint processing of holes for the pin is performed in the design documentation in the following way.
On the ASSEMBLY drawing, the dimensions of the holes for the pin, the dimensions of their location, and the roughness of the hole processing are specified. The named dimensions are marked with "*", and in the technical requirements of the drawing an entry is made: "All dimensions for reference, except those marked with *". This means that the dimensions by which holes are made on the assembled unit are executive and they are subject to control. And on the drawings of DETAILS, holes for the pin are not shown (and therefore are not performed).
Connector bores
In some machines, bored holes for bearings are located simultaneously in two parts with the plane of their connector located along the axis of the bearing (most often found in gearbox designs - the “body-cover” connection). Bearing bores are precise surfaces with a roughness of at least Ra 2.5, they are made by joint processing, and this is specified in the drawings as follows (see Fig. 12 and 13).
On the drawings of EACH of the two parts, the numerical values of the dimensions of the surfaces processed together are indicated in square brackets. In the technical requirements of the drawing, an entry is made: “Processing by dimensions in square brackets should be carried out together with det. No. ... ". The number refers to the designation of the drawing of the counterpart.
Rice. 11. Setting the hole for the pin on the drawing
Rice. 12. Boring with a connector. Assembly drawing
Rice. 13. Specifying a boring with a socket on the drawings of parts
CONCLUSION
After reading the process of creating a part drawing described above, a doubt may arise: do professional designers really work out every small detail so carefully? I can assure you - that's right! It's just that when making drawings of simple and typical parts, all this is done in the designer's head instantly, but in complex products - only this way, step by step.
REFERENCES
1. GOST 2.102-68 ESKD. Types and completeness of design documents. M. : IPK Standards Publishing House, 2004.
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3. GOST 2.109-73 ESKD. Basic requirements for drawings. M. : IPK Standards Publishing House, 2004.
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5. GOST 2.118-73 ESKD. Technical Proposal. M. : IPK Standards Publishing House, 2004.
6. GOST 2.119-73 ESKD. Preliminary design. M. : IPK Standards Publishing House, 2004.
7. GOST 2.120-73 ESKD. Technical project. M. : IPK Standards Publishing House, 2004.
8. GOST 2.305-68 ESKD. Images - views, cuts, sections. M. : IPK Standards Publishing House, 2004.
9. Levitsky V. S. Engineering drawing: textbook. for universities / V. S. Levitsky. M. : Vyssh. school, 1994.
10. Mechanical engineering drawing / G. P. Vyatkin [and others]. M. : Mashinostroenie, 1985.
11. Reference guide to drawing / V. I. Bogdanov. [and etc.]. M. :
Engineering, 1989.
12. Kauzov A. M. Execution of drawings of parts: reference materials
/ A. M. Kauzov. Yekaterinburg: USTU-UPI, 2009.
APPS
Attachment 1
Task on topic 3106 and an example of its execution
Task number 26
An example of the execution of task No. 26
Annex 2
Common Mistakes students when performing detailing
