Bearings are used to support the shaft and are divided into two categories: sliding bearings and rolling bearings. Rolling bearings are widely used in machines due to their low frictional resistance and compact structure. 1. The structure and classification of rolling bearings (GB/T271-1997) According to the direction of load bearing, rolling bearings can be divided into: radial bearings mainly bear radial loads. Such as deep groove ball bearings, tapered roller bearings. Thrust bearings are subject to axial loads. Such as thrust ball bearings. The structure of rolling bearing generally consists of four parts, which is illustrated by the ball bearing shown in Figure 9-39. The inner ring is sleeved on the shaft and rotates with the shaft. The outer ring is installed in the hole of the machine base and is generally fixed or rotated a little. The rolling elements are installed in the raceway between the inner and outer rings. The rolling elements can be made into balls or cones (cylinders, cones or needles). The cage is used to evenly separate the rolling elements, so it is also called an isolation ring. 2. Representation of rolling bearings (GB/T4459.7-1998) Rolling bearings are produced by professional factories, and can be selected according to the model of the bearing when necessary. When it is necessary to represent the rolling bearing, the general drawing method, the characteristic drawing method (all are simplified drawing methods) and the prescribed drawing method can be used according to different occasions. 1. General drawing method When it is not necessary to accurately represent the outline, load characteristics and structural characteristics of the rolling bearing, a rectangular wire frame and an upright cross symbol (line width b) in the center of the wire frame can be used to represent the rolling bearing (Figure 9-40 ), if it is necessary to accurately represent the shape of the rolling bearing, its section outline should be drawn, and an upright cross symbol should be drawn in the center of the outline (Figure 9-41). The bearing type shown is a radial insert ball bearing with an eccentric sleeve. 2. Feature drawing method If the structural characteristics and load characteristics of rolling bearings are more vividly represented, the feature drawing method can be used. At this time, the symbols of its structure and load characteristic elements can be drawn in the rectangular wire frame, as shown in the column of characteristic drawing in Table 9-8. The long thick solid line symbol in the box in the figure represents the rolling axis of the rolling element of the non-aligning bearing (the self-aligning bearing uses a thick circular arc), and the thick thick solid line symbol represents the number and position of the rolling elements (single row drawing). A thick solid line, two columns and two heels). On the view of the projection plane perpendicular to the axis of the rolling element bearing, regardless of the shape (ball, column, needle, etc.) and size of the rolling element, it can be drawn as shown in Figure 9-42. 3. The prescribed drawing method In the product drawings, samples, standards, user manuals and operating instructions of rolling bearings, the prescribed drawing methods shown on the right side of Table 9-8 can be used if necessary. The rolling elements in the figure are not hatched. Each ferrule, etc., can be drawn as hatching lines with the same direction and interval. It is allowed to omit and not draw if it will not cause misunderstanding. The other side of the figure, drawn according to the common drawing method. 3. The code method of rolling bearing (GB\T272-1993) The rolling bearing code is a product symbol that uses letters and numbers to indicate the characteristics of the structure, size, tolerance level, technical requirements and technical performance of the rolling bearing. The rolling bearing code consists of the basic code, the pre-code and the post-code, and its arrangement is as follows: The pre-code and the post-code are the bearings that have changed in structural shape, size, tolerance, technical requirements, etc. Now focus on the basic code. The basic code indicates the basic type, structure and size of the rolling bearing, which is the basis of the rolling bearing code. The basic code of rolling bearings (except needle roller bearings) consists of bearing type code, dimension series code, and inner diameter code. 1. Type code Type code is represented by Arabic numerals or capital Latin letters according to Table 9-9. 2. Dimension series code The dimension series code is represented by numbers, which is composed of the width (height) series code and the diameter series code of the bearing. Commonly used bearing type, dimension series code and combination code consisting of bearing type code and dimension series number are shown in Table 9-103. Inner diameter code The inner diameter code is also represented by numbers. The inner diameter code indicating the nominal inner diameter of the bearing is shown in Table 9-11. Example: spherical roller bearing 23224 2 type code 32 size series code 24 inner diameter code du003d120mn