解题，将解题步骤写的更详细一点，所关联的知识点也要详细讲解，解题步骤要非常详细，计算过程也要详细---**Chapter Title:** 第四章 螺纹连接和螺旋传动 **Question Number:** 71. **Question Stem:** 图示螺栓连接中采用 2 个 M20 ($d_1$=17.3 mm) 的螺栓, 其许用拉应力$[\sigma]$=160 MPa, 被连接件接合面间的摩擦系数 $f=0.2$, 若考虑摩擦传力的可靠性系数 $K_s$=1.2, 试计算该连接允许传递的静载荷 $F_Q$。 **Question Translation:** The bolted connection shown in the figure uses 2 M20 bolts ($d_1$=17.3 mm), their allowable tensile stress $[\sigma]$=160 MPa, the friction coefficient between the contact surfaces of the connected parts is $f=0.2$. If the reliability coefficient for friction transmission is considered to be $K_s$=1.2, calculate the allowable static load $F_Q$ that this connection can transmit. **Given Information:** * Number of bolts: 2 * Bolt type: M20 * Minor diameter of thread: $d_1 = 17.3$ mm * Allowable tensile stress: $[\sigma] = 160$ MPa * Friction coefficient: $f = 0.2$ * Reliability coefficient for friction transmission: $K_s = 1.2$ **Diagram Description:** * **Type:** Sectional view of a bolted connection assembly. * **Main Elements:** * Two bolts shown in section view, oriented vertically. Each bolt consists of a head (top), a shank passing through multiple connected parts, and a nut and washer(s) at the bottom. * Multiple connected parts (plates or blocks) are shown clamped together by the bolts. These parts are shown in section with diagonal hatching patterns. There appear to be two outer parts (hatched diagonally upwards to the right) and one inner part (hatched diagonally downwards to the right). * The inner part is shown being subjected to a horizontal force $F_Q$ from the left, indicated by an arrow pointing to the right from the label $F_Q$. * The outer parts are shown resisting this force with horizontal forces of magnitude $\frac{F_Q}{2}$ each, indicated by arrows pointing to the left from the labels $\frac{F_Q}{2}$. These forces are applied to the right-hand surfaces of the outer parts. * The connection relies on the friction between the connected parts' surfaces to transmit the load $F_Q$. * Centerlines are shown vertically through the bolts and horizontally through the connection. * **Relative Position:** The bolts pass through holes in the stacked connected parts, clamping them together. The inner part is positioned between the two outer parts in the horizontal direction of the applied load. **Options:** No options (A, B, C, D) are present in the provided image. **Other Relevant Text:** None.