The invention relates to a large-stroke tensioning device in a wheel machining process. The large-stroke tensioning device in the wheel machining process comprises a base, a servo motor, a mounting plate, a connecting plate, a shaft sleeve, an oil cylinder, a gland, hearings, a connecting shaft, a chassis, positioning pins, a flange plate, springs, expanding sections, an expanding core, a protector and the like. The large-stroke tensioning device can meet requirements of clamping and positioning of a wheel, and meanwhile has the characteristics of simple structure, convenience in manufacturing, stable performance and capability of meeting machining requirements on precision.

The invention relates to a large-stroke tensioning device in a wheel machining process. The large-stroke tensioning device in the wheel machining process comprises a base (1), a servo motor (2), a mounting plate (3), a connecting plate (4), a shaft sleeve (5), an oil cylinder (6), a gland (7), bearings (8), a connecting shaft (9), a chassis (10), positioning pins (11), a flange plate (12), springs (13), sliding pedals (14), an expanding core (15), a protector (16) and the like. The large-stroke tensioning device can meet requirements of clamping and positioning of a wheel, and meanwhile has the characteristics of simple structure, convenience in manufacturing, stable performance and capability of meeting machining requirements on precision.

This invention relates to a maintaining device for mechanical pieces, comprising a slider-holder formed by a body and a head with a central bore in which a part of the piece to be maintained is placed, the piece to be maintained exceeding the head, the head comprising a conical area, the maintaining device having at least two sliders and an actuation element for the sliders, wherein the head comprises at least two lateral bores, one leading into the conical area and the other to the central bore, the sliders are placed in the lateral bores, the sliders being adjustable in the lateral bores, the sliders exceeding the conical area of the head, the actuation element of the sliders being arranged to move the sliders in the corresponding lateral bores along an axis perpendicular to a longitudinal axis of the central bore.