Study On Measure Technology And Device For Movement Parameter Of Stranded Wire Hellical Spring

The purpose of this research is to find out the dynamic parameters, movement, velocity and acceleration, of a stranded Wire Helical Spring. This work is a continuity of research, done by the Laboratory of Manufacturing Automation of College of Mechanical Engineering of Chongqing University, on the Stranded-Wire Helical Springs.Stranded Wires Helical Spring, is composed of three to seven wires, carbon- steel wire tied up to form a strand which is then twisted to form an helical spring. The diameter of the wire can vary between 0.5 to 3.0 mm. The spring has two kinds of structures in accordance with whether it has central wire or not. The helical direction of the compression spring is opposite to that of the strand, while it has the same direction for the extension spring.A lot of researches have been done so far, on the Design and Modeling of the Stranded Wire Helical Spring in which is proposed its formation by giving the mathematic model while the Dynamic Tension of Stranded Wires Helical Spring during reeling relates to the control of dynamic tension of wires during the manufacturing process. The Axial Response of Stranded Wire Spring outlines a procedure for determining the static, large strain, axial (extensional and rotational) response of a helical spring formed from a strand made of any number of smooth wires twisted together. It has also been shown that Stranded-Wire Helical Springs, when compared with conventional single helical spring, exhibit more damping and have longer fatigue life in certain dynamic applications .They have been used successfully in machine guns and small weapons to damp the high-velocity displacement of the coils. To that effect it becomes interesting to study the dynamic parameters of the Stranded Wire Helical Spring for better use.To achieve our goal the Stranded Wire Helical Spring has been impacted with a Mass and the movement of some of its particles has been studied. When Stranded-Wire Helical Springs are impacted, the movement of every spring coil will be very complicated owing to various factors, such as the mass, inertia and resonance of spring, the internal friction of steel wires, and also the relative slipping due to different steel wires of stranded-wire helical springs. Base on that, a non-contact and multi-channel detection device of the dynamic parameters of stranded-wire helical springs is proposed, which involves the design of the mechanical structure, the lectotype and installation of sensors, the hardware and software module of signal acquisition and analysis. This device, combining a new algorithm of data processing, can be used to measure the relationships between displacement and time, velocity and time, acceleration and time for every spring coil.The results show that when stranded-wire helical springs are impacted, every spring coil will vibrate. In the beginning of impact, there is a large deformation in the active end, while a little deformation is observed in the fixed end. Then at the end of the compression phase, we notice a huge deformation at the fixed end which can lead to the conclusion that the energy is well transmitted from the impact point to the fixed end of the Stranded Wire Helical Spring in the form of longitudinal waves. It appears also that the relationship between the movements of the Stranded wire Helical Spring with its axial length is non-linear. The same result show up between the velocity and axial length.Therefore, in practical design work of stranded-wire helical springs, it is necessary to analyze the impact response, in order to avoid the phenomenon of excessive deformation of some spring coils by selecting reasonable parameters. For this kind of spring, it is impossible to calculate the impact response just based on the theory, so an experimental analysis is essential.