tailieunhanh - Dimensioning and Tolerancing Part 8

Tham khảo tài liệu 'dimensioning and tolerancing part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | DIMENSIONING AND TOLERANCING ASME I FIG. 5-20 e pattern-locating tolerance -zone cylinder 4 zones basically related to each other and basically located to the datums feature-relating tolerance zone cylinder 4 zones basically related to each other and oriented to the datums 0 A B 0 A B H Feature axes must simultaneously lie within both tolerance zone cylinders 10 from datum B from datum c One possible displacement of actual feature pattern. FIG. 5-20 HOLE PATTERNS OF FIG. 5-19 WITH SECONDARY DATUMS IN FEATURE-RELATING SEGMENTS OF COMPOSITE FEATURE CONTROL FRAMES CONTD Tolerance Zones for Four-Hole Pattern 105 ASME DIMENSIONING AND TOLERANCING FIG. 5-20 HOLE PATTERNS OF FIG. 5-19 WITH SECONDARY DATUMS IN FEATURE-RELATING SEGMENTS OF COMPOSITE FEATURE CONTROL FRAMES CONTD Tolerance Zones for Six-Hole Pattern 0 A B cj 0 A B to datum plane A and therefore parallel to each othei. In certain instances portions of the smaller zones may fall beyond the peripheries of the larger tolerance zones. However these portions of the smaller tolerance zones are not usable because the axes of the features must not violate the boundaries of the larger tolerance zones. The axes of the holes must lie within the larger tolerance zones and within the smaller tolerance zones. The axes of the actual holes may vary obliquely out of perpendicularity only within the confines of the respective smaller positional tolerance zones FRTZF . Figure 5-19 e repeats the heretofore-described relationships for the four-hole pattern and Fig. 5-19 f for the six-hole pattern of features shown in Fig. 5-19. NOTE The zones in Figs. 5-19 and 5-20 are shown as they exist at MMC of the features. The large zones would increase in size by the amount the features depart from MMC as would the smaller zones the two zones are not cumulative. Primary and Secondary Datums Repeated In Lower Segment. Figure 5-20 repeats the hole patterns of Fig. 5-19. In Fig. 5-20