Detail main view from the top side dimensioning. Arrangement of views in the drawing. Terms and Definitions

Building views begins with a mental choice of the position of the part in front of the projection planes. Then choose the number of types necessary and sufficient to identify the shape of the part, as well as the method of their construction.

The choice of the position of the part in the system of projection planes depends on its working position, manufacturing method in production, and shape. For example, if a part is made on a lathe, then in the drawing its axis of rotation should be horizontal.

Drawing views can be performed in various ways. Let's take a look at some of them.

Construction of views based on the sequential drawing of geometric bodies that make up the shape of an object. In order to complete the drawing in this way, it is necessary to mentally divide the part into its constituent simple geometric bodies, finding out how they are located relative to each other. Then you need to select the main view of the part and the number of images that make it possible to understand its shape and sequentially depict one geometric body after another until the shape of the object is fully displayed. It is necessary to observe the dimensions of the form and correctly orient its elements relative to each other (Table 8).

The construction of views on the basis of element-by-element drawing of geometric bodies that make up the shape of an object is carried out using the methods of removal and increment.

When drawing a geometric body using the removal technique in the drawing, the shape of the workpiece is successively changed by removing volumes similar to the techniques for processing it by turning, drilling, milling, etc.

When drawing a geometric body using the increment technique, the volumes of the product elements complement each other, as it were, increment.

8. Element-wise drawing of geometric bodies that make up the shape of an object

Construction of views using a constant direct drawing (external coordination method). A constant straight line of a drawing is a line that is drawn from the center of coordinates (point O) down to the right at an angle of 45 ° (Fig. 86).

The object is mentally placed in a system of projection planes. The axes of the projection planes are taken as the coordinate axes. The projection communication between the top view and the left view is carried out using projection communication lines, which are drawn up to the intersection with a constant straight line of the drawing and are built at an angle of 90 ° to each other.

The constant straight line of the drawing, as a rule, is used in cases when it is necessary to build a third type of part from two given views (see Fig. 86). Having re-drawn two types of parts, they build a constant straight line of the drawing and draw lines of projection communication parallel to the OX axis until they intersect with the constant straight line of the drawing, and then parallel to the OZ axis.

The considered construction method is called the external coordination method, since the object is fixed in space relative to the axes of the projection planes, which are located outside the depicted object.

(If the projection axes are not shown in the drawing and it is necessary to perform a third view of the part, then you can build a constant line of the drawing anywhere on the right side of the top view.)

Build views using internal object coordination. Internal coordination consists in the mental introduction of additional coordinate axes tied to the projected object.

Rice. 86. Construction of the third projection on two given using a constant straight drawing

Rice. 87. Building views by means of internal coordination of an object

The rules for the depiction of objects (products, structures and their constituent elements) in the drawings of all industries and construction are established by GOST 2.305 - 68.

Images of objects should be performed using the method of rectangular (orthogonal) projection onto a plane. In this case, the object is placed between the observer and the corresponding projection plane. Attention should be paid to the difference between the image and the projection of an object. Not every image is a projection of an object. There is a one-to-one point correspondence between the object and its projection, which consists in the fact that each point of the object corresponds to a certain point on the projection and vice versa.
When constructing images of objects, the standard allows the use of conventions and simplifications, as a result of which the indicated correspondence is violated. Therefore, the figures resulting from the projection of an object are called not projections, but images. The faces of a hollow cube are taken as the main projection planes, into which an object is mentally placed and projected onto the inner surfaces of the faces. The faces are aligned with the plane, as shown in Fig. 1.

Rice. 1 Types

The image on the frontal plane is taken as the main one in the drawing. The object is positioned relative to the frontal plane of the projections so that the image on it gives the most complete picture of the shape and size of the object. Images in the drawing, depending on their content, are divided into views, sections, sections.
View - the image of the visible part of the object's surface facing the observer. To reduce the number of images, it is allowed to show the necessary invisible parts of the surface in views using dashed lines. However, it should be borne in mind that the presence of a large number of dashed lines makes it difficult to read the drawing, so their use should be limited.

The types are divided into basic, local and additional.
Main types- images obtained on the main projection planes - cube faces (Fig. 1):

1 - front view (main view);

2 - top view;

3 - left side view;

4 - right side view;

5 - bottom view;

6 is a rear view.

The names of the views in the drawings are not labeled if they are located as shown in Fig. 1, i.e. in projection communication. If the views from above, to the left and to the right are not in projection connection with the main image, then they are marked on the drawing with an inscription of type "A". The direction of gaze is indicated by an arrow denoted by a capital letter of the Russian alphabet.

When there is no image on which the direction of gaze can be shown, the name of the species is inscribed.

A local view is an image of a separate limited area of ​​the surface of an object on one of the main projection planes. The local view can be placed on any free place of the drawing, marking it with an inscription of the type "A", and an arrow indicating the direction of gaze should be placed at the associated image of the object, with the corresponding letter designation (Fig. 2).

Rice. 2. Complementary and local views.

The local view can be limited by the cliff line, as small as possible, or not limited (Fig. 2).

Additional types- images obtained on planes not parallel to the main projection planes. They are used in cases where any part of the object cannot be shown in the main views without distorting the shape and size. The additional view is marked on the drawing with an inscription of type "A" (Fig. 2), and an arrow with the corresponding letter designation (arrow A, Fig. 2) is placed in the object associated with the additional view of the image (arrow A, Fig. 2), indicating the direction of gaze.

When the additional view is located in direct projection connection with the corresponding image, the arrow and the inscription above the view are not applied (Fig. 2). The secondary view can be rotated while maintaining the position taken for this item in the main image. In this case, the sign "rotated" is added to the inscription "A" (Fig. 2).

Basic, local and additional views are used to depict the shape of the outer surfaces of the object. Their successful combination allows you to avoid dashed lines or reduce their number to a minimum.

(SITELINK-S35) back (/ SITELINK)

In drawing the image of the visible part of the object's surface facing the observer is called a view. The names of the species depend on the side from which the object is viewed during projection (Fig. 12).

The original in the drawing is front view , which is also called main view ... If you look at the object from the left, at right angles to the profile plane of the projections, you get left view... When looking at an object from above, projections perpendicular to the horizontal plane are obtained view from above.

The directions in which one looks at the part, one or another kind, are indicated in Fig. 11 by arrows with inscriptions. Each view occupies a strictly defined place in the drawing in relation to the main view. Left view located to the right of the main view and at the same level with it, view from above- under the main guise. This rule cannot be violated by placing views in arbitrary places without special designation.

Knowing the rule of arrangement of species, one can represent the shape of an object by its flat images. To do this, you need to compare all the views given in the drawing and recreate the volumetric shape of the object in your imagination. In addition to front, top and left views, views can be used to depict the subject. right, bottom, back- they are all called basic. However, the number of views in the drawing should be the smallest, but sufficient to fully reveal the shape and size of the object.

To understand the drawings, you need to know well how the views are located on them.

By the kind is called the image of the visible part of the object's surface facing the observer.

The names of the species depend on which side the object is viewed from. The gaze directions are shown in Fig. 3, and arrows with inscriptions.

The original is front view also called main view.

If you look at the object on the left, at right angles to the original position of the part, you get left view.

When looking at an object from above, perpendicular to the horizontal plane, one gets view from above.

And what should you call the view if you look at the detail from below? Left view? Right view? Bottom view? (Choose the correct answer).

Each type has a strictly defined place in the drawing. The left view is located to the right of the main view and on the same level with it, the top view is under the main view (Fig. 3, b). You cannot break this rule by placing views in arbitrary places.

Knowing the rule of arrangement of species, one can imagine the shape of an object by its flat images. To do this, you need to compare all the views given in the drawing and recreate the volumetric shape of the object in your imagination.

Answer the questions?

1. What is called a view in drawing?

2. What is the original image in the drawing?

3. Write down the names of the species you know.

4. What is the name given to the species?

5. How are the views located in the drawing?

6. Is arbitrary arrangement of views acceptable?

7. How to represent the volumetric shape of an object using flat images?

Tasks for § 1

Exercise 1

(Exercises that are answered at the end of the book are marked with a *.)

A. In fig. 4, a drawing is given containing three views. Each type is marked with a number. What is the name of each of the types given in Fig. 4, huh? Write down their names in your workbook.

B. Of the four pictorial images of various parts shown in fig. 4.6, only one is a depiction of the part shown in fig. 4, a. Write down the number of this visual image in a notebook.

B. Which direction of gaze indicated by the arrow with the letter in fig. 4, b, corresponds to the main view, left view, top view, shown in Fig. 4, a. Write the answer in a notebook in the following form: Direction B corresponds to the main view.

Exercise 2

A. What are the names of the species shown in Fig. 5, b-d? Write down their names in a notebook. B. Of the three drawings in fig. 5, b-d, only one part shows a detail corresponding to the pictorial image in Fig. 5, a. Which? Write down his number in a notebook.

B. Which direction of gaze indicated by the arrows with letters in fig. 5, a, corresponds to the main view, top view, left view? An example of recording an answer: Direction ... corresponds to the main view.

Exercise # 3

Find their drawings by visual images of objects (fig. 6). Write in a notebook which visual image, indicated by a letter, corresponds to a drawing indicated by a number.

Digital designation	Species name
A

A view is an image of the visible part of the surface of an object facing the observer.

To reduce the number of images, it is allowed in the views to show with dashed lines the invisible parts of the object's surface (Fig. 372). GOST 3453-59 establishes six names of the main species obtained on six main planes (Fig. 371, c).

1 is a front view (also called a main view); 2 - top view; 3 - left side view; 4 - right side view; 5 - bottom view; 6 is a rear view. If the views from the top, left, right, bottom, back are displaced relative to the main view (image), then they should be marked in the drawing with the inscriptions "View A", "View B", etc. with a line below (Fig. 373). The direction of looking at the object in the corresponding projection should be indicated by an arrow with the corresponding letter.

In cases where the listed views are separated from the main image by other images or are not located on the same sheet with it, the direction of view should also be indicated with the corresponding letter, and the corresponding inscription should be placed above the view. There are cases that any part of the object is depicted on the main planes of projections with a distortion of its shape and size. To avoid this, an additional view should be made by projecting this part onto a plane that is not parallel to any of the main projection planes, and this plane should be parallel to the projected part (Fig. 374, a - c).

The additional view is marked on the drawing with a signature, for example, "View B", and the object associated with the additional view of the image should have an arrow indicating the direction of view, with the corresponding letter designation. It is allowed not to make signatures and directions with an arrow in cases similar to that shown in figure 374, c.

The location of the additional view shown in (374, a and b) is preferred. An additional view is allowed to be rotated, but with the preservation, as a rule, of the position adopted for a given object in the main view (image).

In this case, the rotation must be added to the inscription (Fig. 375). The image of a separate narrowly limited area on the surface of an object is called a local view (Fig. 376, a and b); it can be limited by the break line (Fig. 376, a) or not limited (Fig. 376, b). The local species should be marked in the same way as the supplementary species. If there is a need for an inscription indicating the name of the depicted element, it should be done by type. (see View D - flange in figure 376 b.)