handbook of die design 2nd edition phần 9

Máy giặt máy giặt Finger Finger được sử dụng trong các trường hợp tải tĩnh như những tác dụng bởi chủng tộc bi. Trong ứng dụng như máy giặt ngón tay được sử dụng để giảm độ rung và tiếng ồn. Tải tuần hoàn không được khuyến cáo cho loại máy giặt mùa xuân (Hình 13-4). | SPRING WASHERS 575 SPRING WASHERS FIGURE 13-4 Typical finger spring washer. From Design Handbook 1987. Reprinted with permission from Associated Spring Barnes Group Inc. Dallas TX. and the deflection f is tied to a formula n2S D d 2 f 48EtN2 13-8 13-2-1 Finger Washers Finger washers are used in static load cases such as those exerted by ball-bearing races. In such an application finger washers are utilized to reduce vibration and noise. Cyclic loading is not recommended for this type of spring washer Fig. 13-4 . Finger washers combine the equality of distribution of loading of wave washers with the flexibility of curved washers. Stresses deflection and other calculations for this type of washer should be calculated considering fingers to be cantilever springs. Actual samples of the calculated values should be produced and tested prior to use. Finger washers usually do not retain any favorable residual stresses and they are usually supplied in their stress-relieved condition. Operating stresses from Tables 13-3 and 13-4 may be used for finger washers as well. TABLE 13-3 Maximum Recommended Operating Stress Levels for Special Spring Washers in Static Applications Percent of tensile strength Material Stress-relieved With favorable residual stresses Steels alloy steels Nonferrous alloys and austenitic steel 80 100 80 Finger washers are not generally supplied with favorable residual stresses. Source Design Handbook 1987. Reprinted with permission from Associated Spring Barnes Group Inc. Dallas TX. Downloaded from Digital Engineering Library @ McGraw-Hill Copyright 2004 The McGraw-Hill Companies. All rights reserved. Any Use is subject to the Terms of Use as given at the website. SPRING WASHERS 576 CHAPTER THIRTEEN TABLE 13-4 Load Tolerances for Special Spring Washers Stock thickness Washer type in mm Load percentage Curved 15 Wave 33 25 20 .