Telescopic adjusting mechanism

The invention discloses a telescopic adjusting mechanism. A two-dimensional adjusting mechanism (3) and a support (16) are arranged on a base (1), an outer pipe (25) is supported in the two-dimensional adjusting mechanism (3) and the support (16) jointly, a precision ball screw (2) is arranged in the outer pipe (25), the tail of the precision ball screw (2) is connected with a step motor (8), a screw nut (4) matched with the precision ball screw is fixedly connected with a hollow spline shaft (6) which is sleeved on the surface of the precision ball screw (2), and the head of the hollow spline shaft (6) is connected with a needle-shaped simulated pipe (7). By combination of the step motor and the screw nut pair, angular displacement of the step motor is charged into controllable linear displacement, then the two-dimensional adjusting mechanism adjust the final position of the needle-shaped simulated pipe further, and the requirement for accurate positioning is met. Meanwhile, the telescopic adjusting mechanism has the advantages of simple structure, convenience in operation and high precision and the like.