OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 5 No. 1 2023 Introduction In works [1–7], much attention is paid to the process of a product mixing and it is noted that the process itself occurs under stationary conditions, i.e. at constant angular rates of the mixing devices. And this is a main roadblock on the way to obtaining a high-quality mixture, and it is noted that during the mixer operation, after a while, the speed of the mixture becomes equal to the speed of the working body of the mixer. As a result, the mixture moves in layers: particles of larger mass components move along orbits of a larger radius, particles of smaller mass move along orbits of a smaller radius. At the same time, there are zones in the mixers where there is little or no material movement; as a result, the quality of the fi nished product is reduced. When the variable angular velocity is imparted to the working body, the mass of the product passes from one layer to another, which contributes to an increase in the quality and intensity of the mixing process [2]. There are various designs of drive mechanisms for continuous mixers [8–10]. One of it [8] is a working chamber made in the form of a half-cylinder, inside which a working shaft with blades is placed along its axis. The mixture fi lls the chamber evenly across its entire width. The drive to the working shaft is carried out from the electric motor by means of V-belt and gear drives and has a constant rotation speed. Known design with two working shafts [9], which perform a complex movement due to a combination of rotational and reciprocating movements. The rotation is transmitted from the engine to the working shafts by means of a belt drive and a double-reduction gear unit; and the reciprocating motion is transmitted through a single-reduction gear and worm-gear and an eccentric mechanism. The disadvantages of these designs of mixers include the following: during machine downtime, the mixture in the working chamber is compacted, the machine restarting is diffi cult, and in some cases it becomes impossible due to increased loads on the kneading blades during its progressive motion. The loads become so heavy that it leads to signifi cant deformations of the blades, and therefore, repair of the working bodies is required. This problem was encountered at a pasta factory in Novosibirsk, where a two-shaft continuous mixer (kneading mixer) is operated as part of an automatic line. One of the solutions to this problem was proposed in [10], according to which the drive to the working shafts includes a motor, a mechanism for imparting rotational motion to the working shafts, and a transmission mechanism for imparting reciprocating motion to it. At the same time, an overload release clutch is installed on the shaft between the worm and the gear wheel of the single-reduction gear. Such a design of the kneading mixer allows increasing its productivity by reducing downtime due to the absence of the need to unload the compacted dough mass from the working chamber and reload it. The presence of uneven rotation of the working bodies, and, consequently, of the product, will also improve the quality of the product due to the elimination of zones of non-mixing [1–7]. The design of mechanisms that provide uneven rotation of the working shafts is a complex problem and depends on a number of factors, such as the raw material being processed, its density, and the shape of the elements interacting with the raw material. In this paper, it is proposed to use a cam-rocker mechanism, including a cam group and an Assur group of the second class of the third type, as a kinematic scheme for driving the working shafts of a kneading machine. It should be noted that the rotational movement from the motor shaft is transmitted to the crank carrying a two-arm lever, on one arm of which there is a roller located in the groove of a fi xed cam, and on the other there is a collet, which is located in the groove of the rocker, having an axis of rotation coinciding with axis of rotation of the working shaft of the machine. The purpose of the work is to improve the quality of the processed mixture on horizontal blade mixers (kneading machines). To achieve this purpose, the following tasks were solved: 1. Development of a technique for synthesizing a drive to the working shafts of a machine, including: structural synthesis and development of the kinematic scheme of the mechanism; parametric synthesis, which consists in choosing the main dimensions of the cam and rocker mechanisms, which ensure the uneven movement of the working shafts; determination of the necessary and suffi cient kinematic characteristics of the working shafts of the machine. 2. Refi nement of the quality characteristics of the mixture.
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