In this study, a novel kinetic model is established to investigate the dynamic characteristic of the ball screw feed system by considering the thermal deformation of bearing joints, screw-nut joints and screw shaft. Based on the Hertz contact theory, the relationship between elastic restoring force and axial deformation of bearing joints and …

The relationship between the torque on the screw shaft, the pitch of the screw and the height of the material stack above the screw inlet: 1 -5 mm; 2 -15 mm; 3 -25 mm; 4 -50 mm; 5 -100 mm; 6 -200 ...

In Fig. 2, m is the equivalent mass of the BSFS; Pcosωt represents the cyclic load which P and ω are the excitation force amplitude and angular frequency; k be, c be, k ss, c ss, k sn, c sn, k a, c are the axial equivalent stiffness and damping coefficient of bearing joints, screw shaft, screw-nut joints and the overall system respectively. The …

Roberts [10], [11], [12] and Roberts and Manjunath [13] analyzed the volumetric characteristics and flow mechanics of screw feeders as shown in Fig. 1.The distribution of throughput along the screw and uniform draw-down patterns of a feed hopper were investigated. It was assumed that the force exerted on the screw flights is …

Ball screw feed systems serve as the feed components of machine tools, and its dynamic characteristics directly affect the machining quality of workpieces and reliability of ball screws. In this paper, the lateral equivalent dynamic model of ball screw feed systems is established considering the bending vibration of the ball screw, nut …

The axial forces exerted on the powder at four boundaries are indicated by the different material properties and geometric parameters. The axial shear-friction force is examined directly using gravity balance by ropes method in conveying process, which validates the axial force model in screw. The dynamic characteristic, variation pattern …

The cohesive bulk materials are easily compressed and agglomerated when employing a screw feeder, affecting the subsequent handling procedure. A mechanistic model is developed to predict the axial force characteristics and understand the compression behaviors of the powder in the screw. The vertical stress in silo, the forces on the shaft …

The axial forces exerted on the powder at four boundaries are indicated by the different material properties and geometric parameters. The axial shear-friction …

Based on the Hertz contact theory, the relationship between elastic restoring force and axial deformation of bearing joints and screw-nut joints is obtained, …

the front end of the screw. Pieces of raw materials up to 40 mm are loaded into the hopper, the se are picked up by a screw and moved to the grinding device. Grinding of raw materials is carried out by stationary matrices and rotating grinders. The screw is driven by an electric motor through a V- be lt drive and a reducer [7].

A ball screw transforms rotational motion into translational motion. As a result, the shaft is subject to loads: Thrust force (the sum of all external forces such as machining load, gravity, friction, inertial forces, etc.). Torque required to generate the thrust force. – Precision Machine Design – Ball Screw Calculations 4-3.

Axial forces developed by incremental increases in the torque applied to the individual screws were measured in a test apparatus incorporating an Instron machine. For the SR-PLLA screws, the relationship between applied torque and axial force development was non-linear with a marked relaxation throughout the test range. The axial forces reached ...

An analytical modeling approach for ball screw feed drives is proposed to predict the dynamic behavior of the feeding carriage of a spindle. Mainly considering the rigidity of linear guide modules, a ball-screw-feeding spindle is modeled by a mass-spring system. The contact stiffness of rolling interfaces in linear guide modules is accurately calculated …

In this study, a variable-coefficient lumped parameter dynamic model that considers the changes in the spindle system weight and the magnitude and direction of …

The screw shaft of the screw conveyor has a thrust bearing at the end of the material movement direction to give the axial reaction force of the screw with the material. …

The biomass feeding systems used in the experiments appear in Fig. 1, Fig. 2. Tapered and extended sections are shown in Fig. 1. Table 1 gives key dimensions of the hopper-screw feeder. Wood pellets, sawdust, hog fuel and wood shavings served as biomass materials. Polyethylene particles provided a reference material for comparison.

A criterion for uniform draw down performance of screw feeders was proposed by Robert and Manjunath [14] based on mechanics of screw feeder performance in relation to bulk solid draw down characteristic in the hopper.Robert [17] carried out a theoretical study considering influence of granular vortex motion on the volumetric …

Zou [14] developed a ball screw stiffness model for different screw-nut positions and used it to study the dynamic characteristics of the ball screw feeding system. Zhang [15] gave a method for ...

The screw shaft of the screw conveyor has a thrust bearing at the end of the material movement direction to give the axial reaction force of the screw with the material. When the length of the machine is long, an intermediate suspension bearing should be added. ... The particle size of the material added from the end feed port should not be ...

Secondly, the normal force and tangential force are, respectively, simulated in single/double-flight screw feeders with the discharging device at three rotating speeds (60 rpm, 90 rpm, and 120 rpm ...

The cohesive bulk materials are easily compressed and agglomerated when employing a screw feeder, affecting the subsequent handling procedure.A mechanistic model is developed to predict the axial force characteristics and understand the compression behaviors of the powder in the screw. The vertical stress in silo, the forces …

Contact of balls in screw nuts and bearings causes the nonlinearity of a ball screw feed system. The identification of nonlinear stiffness helps to understand and control the feed system. The axial vibration of the ball screw feed system can be descripted by a single-degree-of-freedom (SDOF) system with polynomial nonlinear terms. Since …

The rota-ting screw is subjected to two forces Px, Py moving along the x-axis. Px, Py are applied in the directions of the X and Y axes. Px is the axial load.

The distinguishing feature of a vertical ball screw feed system without counterweight is that the spindle system weight directly acts on the kinematic joints. Research into the dynamic characteristics under acceleration and deceleration is an important step in improving the structural performance of vertical milling machines. The …

Calculation and Formula. When dealing with axial loading on a member, the three key parameters for carrying out calculations are the axial force, axial stress, and the cross …

3) This calculator may be used with any consistent units, e.g. torque = ft-lbs with ft, in-lbs with inches, N-mm with mm. Force is calculated consistent with units used. Note: This calculator initially assumes dry and perfect threads made from steel and/or zinc plated.

The ball screw is a transmission device that converts linear motion into rotary motion or rotary motion into linear motion, and it has the advantages of high position accuracy, load capacity and fatigue life [1,2,3].The dynamic characteristic of the feed system is the key factor to determine the machining accuracy of the workpiece and …

Bin – Square or rectangular in shape with sloped bottom and large storage capacity. Silo – Cylindrical in shape with cone or mass-flow bottom and large storage capacity. Several factors must be considered when designing a screw feeder, including: Flow characteristics of bulk material being stored and metered.

For a ball-screw feed system, a hybrid dynamic model was established by Zhou et al., 15 and the dynamic characteristics variation of the screw-shaft itself with different axial stiffness of the ...