Double row tapered roller automobile wheel hub bearing plastic cage is generally used for rolling element (tapered roller) guidance, because it has the characteristics of small mass, high machining accuracy, high coincidence with the contact surface of the roller, and low noise during operation. , At present, many double-row tapered roller automobile wheel hub bearing products at home and abroad use plastic cages. In use, it bears various alternating loads and impact loads, and is easy to wear and break, so it is particularly important to design and calculate the structural strength of the plastic cage. 1 The value range of the main parameters of the double-row tapered roller automobile wheel hub bearing The structure of the double-row tapered roller automobile wheel hub bearing is shown in Figure 1, and the value ranges of its main parameters are: 4 ~ 11 mm; L is 1.5 ~2.5 D; Z is 15 to 25; 1. ≤ coffee ≤ 2. ; 10. ≤ ≤ 20. . Design and Calculation of Cage Structural Parameters The cage structure and main parameters of the double-row tapered roller automobile wheel bearing are shown in Figure 2, and the parameters are deduced as follows. 2.1 Selection of cage beam thickness S Since S is the weakest link of the entire cage, especially Fig. 1 Double row tapered roller automobile wheel hub bearing Fig. 2 Structure and size of cage The mold parting structure of the cage, so s must be guaranteed not to be less than the limit value that meets the strength of the cage. After repeated design, test and use of multiple products, it can be seen that the empirical value of S is S u003d 0.3 D. Generally, in the specific design, the calculated value S is determined by the formula, and then the value of s is appropriately adjusted according to the bearing capacity. The upper bearing is a bearing with a small bearing capacity, and the cage is appropriately increased by S, the purpose is to improve the strength of the cage; for a bearing with a large bearing capacity, the outer dimension of the cage is larger, and can be appropriately reduced on the premise that the strength meets the use. S, Table 1 is the reference value range and preferred value of S for different size segments. 2.2 R. R l and cb determine the cage pressure slope angle 0. Selected as 2O ¨, the calculation formula of the arc radius is R u003d 1.03 D / 2 R l u003d 1. O3 D l/2 where the coefficient is 1. O3 is an empirical value, and the value is related to the radial clearance of the roller in the window hole, which can be adjusted in the specific design. Figure 3 is a cross-sectional analysis diagram of the small end face of the roller, in which c is related to the number z of the cage window L... . Fig. 3 Cross-section of the small end face of the roller Fig. 2.3 Determination of Dh The calculation formula of the parting dimension D of the cage die is Dhu003dD-2tan0 (0.35/+It1/cos0) The dimension of the parting line of the die is selected is 0.35/place (0.35 is the empirical value), see Figure 4. The actual guiding effect of the cage on the roller in the 0.35/size segment is very small. The coefficient can be adjusted in the specific design to improve the guiding effect, but the precondition is to ensure that the cage is divided into the mold. The strength of the mold structure meets the requirements for use. 2.4 Representation of the structural strength of the cage As shown in Figure 4, if the external dimensions of the cage are similar, the change of the cross-sectional area (day) of the cage has a greater impact on the structural strength of the cage. The cross-sectional area (f, h), c and s are all parameters that characterize the structural strength of the cage. Attention should be paid to the design. In addition, Z can be adjusted when the design strength of the cage satisfies a certain radial tensile strength. , to meet the cage size requirements of the sealed space. 2.5 hours. The calculation formula of the thickness h of the small end section of the cage for f l and fc2 is hu003d(O.35/ +It1/cos0)tan0 In general, when h≥1 mm, the strength of the cage is relatively reliable. If h is too small in the design, it is necessary to verify the reliability of its structural strength. As shown in Figure 4, z. For the values u200bu200bof and z, please refer to Table 2, and also refer to Section 2.4. Table 2 Selection of ld and nlllD reference value l I reference value l exceeds 4 6 lJ 01.2 2.02.46 8 1.41.6 2.4 ~ 2.68 11 lJ 62.0 2.63.02 .6 the centre line of the cage. AC. . Deterministic use of AC and 0 (one coffee), 0. , R, D and D. and other known conditions, the two special points A sum on the center line of the cage can be determined (Fig. 2). The radial dimension of the point A sum can be used as a graph method, or it can be directly substituted into the empirical formula, that is, dAu003d dl+ 0 ．4 D dBu003d d2+ 0.4 After the special point A and D are determined, the center line sum of the cage can be determined. When 0 is found, it can be used as a graph method, or the difference value of (d - d ) can be directly used to maintain The frame window hole length z is substituted into the empirical formula 0u003darcsin[(dBdA)/l] After the center line of the cage is determined, according to the obtained R , R . , S, 0. and other parameters, the cage frame is large and the opening size of the small head is AC. And AC (where AC is the theoretical value, only for mold processing reference) can be determined... . In this paper, the structural design of the plastic cage for double-row tapered roller automobile wheel hub bearing is discussed, the design principle and calculation method of the cage are discussed, and the value range of the main parameters of the double-row tapered roller automobile wheel hub bearing is specified. The products have achieved good results after years of use.