Linear actuator with pulling action

A linear actuator and a braking system with hydraulic electronic control unit HECU 200 including the linear actuator, a valve support 18 and motor 16. The linear actuator includes: a ball screw drive including spindle 19 and nut 21; a hollow piston 26 screwed onto the nut; and a hollow anti-rotation guide 27 able to slide inside an end of the piston but preventing rotation of the piston relative to a housing 17. The housing 17 includes an axial bearing housing 20 connected to a piston housing 23 by a bearing 22. A magnet 35 is located on the end of the piston opposite to the nut and a displacement transducer 28 is placed in the hollow anti-rotation guide 27, these two parts arranged to provide information about the piston position to the motor 16. An active pressure chamber 36 is located between the outer wall of the piston 26 and the piston housing 20, sealed by two sealings (32, 33; fig. 4), allowing hydraulic brake fluid flow via the inlet/outlet port 37. There are also guiding rings (25, 31; fig. 4) to reduce friction between the piston and housing.