OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 6 No. 1 2024 Fig. 3. A fragment of a half-open shed of a loom where Ln is the dimension of the lever; Hn is the full stroke of the heddle shaft corresponding to its number; μ1 is the angle determining the position of the lever relative to the vertical axis. After determining the required dimensions of the lever system, the synthesis of the cam mechanism becomes possible. The synthesis of the mechanism begins with determining the main parameters and the law of motion for the roller center [10–12, 24–39, 45, 46]. It was necessary to determine the law for the roller center motion because we were only given a table of radius vector values. We considered power-law, straight-line, simple harmonic, double harmonic and cycloidal laws of motion. There is no need to dwell on this in more detail, as it is well described in [10–12, 19, 24–28, 35–38, 45, 46]. The law of motion of the roller center along the cycloid was found to be the most acceptable for the case under consideration. For the synthesis of the cam mechanism, the following calculated data were used: minimum cam radius rmin = 124.5, maximum cam radius rmax = 152.5; roller radius R = 75 mm; phase angles: heddle lifting φ1 = 70°, delay in the upper position – φ2 = 110°, lowering of the heddle – φ3 = 70°, delay in the lower position is φ4 = 110°; the interaxial distance is O1O2 = 151 mm. The coeffi cients for the cycloid calculations are taken from [10–12, 19, 24–28, 35–38, 45, 46]: 1 max 3 max 2 2 1 3 2 2 ; k S k S π π ϕ ϕ = ⋅ = ⋅ . The calculation of acceleration analogues was performed using the formula: ( ) 1 1 1 1 2 1 3 1 2 1 2 3 3 1 2 3 2 sin 0 0 2 sin 0 360 k if if a k if if π ϕ ϕ ϕ φ ϕ ϕ ϕ ϕ ϕ π ϕ ϕ ϕ ϕ ϕ ϕ ϕ φ ϕ ϕ ϕ æ ö÷ ç ÷ ⋅ ⋅ £ £ ç ÷ ç ÷ çè ø £ £ + = æ ö÷ ç ÷ ⋅ ⋅ + £ £ + + ç ÷ ç ÷ çè ø + + £ , (13) To determine the speed of the roller center, we integrated accelerations from 0° to 360° of cam rotation. 0 ( ) ( ) ( ) V a d ϕ ϕ ϕ ϕ =ò , (14) To determine the motion of the roller center, we integrated the speeds from 0° to the 360° cam rotation. 0 ( ) ( ) ( ) S V d ϕ ϕ ϕ ϕ =ò , (15) Graphs of kinematic characteristics for the roller center of the cam mechanism are shown in Fig. 4.
RkJQdWJsaXNoZXIy MTk0ODM1