drukrekcurve

Drukrekcurve is a term used in mechanical engineering to describe a characteristic curve that relates applied pressure (druk) to the displacement or position of a rack (rek) in rack‑and‑pinion or rack‑based actuators. The concept appears in the analysis and design of compact actuation systems and in studies of control responses in hydraulic or pneumatic devices.

The curve expresses how a controlled pressure input P produces displacement x, reflecting system stiffness, clearance, friction, damping, and structural compliance. In simple cases the relation is approximately linear (x ≈ kP). In more realistic assemblies, the curve can exhibit nonlinear behavior, saturation at high pressure, and hysteresis depending on load history and friction state. Temperature and lubrication can affect the curve by altering friction coefficients and material properties.

Mathematically, linear models use x = kP with a stiffness factor k. Nonlinear models may employ exponential or power-law forms, or phenomenological representations such as x = a(1 − e^{−bP}) for initial approach, often combined with a hysteresis operator to account for path dependence. Data for a drukrekcurve is obtained from controlled bench tests or simulations, and is commonly plotted with pressure on one axis and displacement on the other, depending on convention.

Applications include sizing actuators, informing controller design, and predicting end-of-travel or stall conditions. The concept is particularly relevant in compact devices where mechanical play and friction dominate behavior, and it has appeared in Dutch‑language engineering literature as a descriptive model in actuation studies.

Etymology: The term combines Dutch druk (pressure) and rek (rack) with curve, referencing the input–output relationship of a pressure‑driven rack mechanism.