The centuries-old principle of transforming rotational into linear motion and vice-versa was used in ancient times to move heavy loads and in pumping stations and sawmills. Initially the constructions were made of wood, while later on combinations of different metals brought enormous advances in power.
Linear drives are still used in a wide range of applications: examples include for adjusting wheels and seats in cars, for moving doors and gates as well as in solar and shading systems. Usually made of a spindle and spindle nut, metal constructions required time-consuming lubrication. Now that these drive components are manufactured using plastics with inherent lubrication, this costly application of synthetic grease is no longer necessary.
By selectively combining various additives such as carbon fibres and incorporable lubricants with different base polymers, LUVOCOM® engineers have succeeded in developing plastics capable of performing their tasks in a broad temperature range and under a wide variety of loads and chemical conditions. Ultimately, it is essential to avoid the combination of high loads and high rotational speeds leading to plastic deformation of the thread and hence to jamming of the linear drive. Endurance tests with two million cycles at a linear velocity of 50cm/s have revealed a very low level of heating in the plastic spindle nut of 4 to 5 Kelvin and practically no abrasion of the metal spindle or plastic nut!
Other advantages of these materials for linear drives are the degree of design freedom, the inexpensive parts manufacture using injection moulding, avoidance of expensive mechanical reworking as well as a long service life and absence of maintenance. Added to these are a reduction in the number of assembly states, savings in weight and noise suppression.