A handpiece head comprising a zero-suckback device for a disposable high-speed turbine dental drill handpiece, the zero-suckback device jointly comprising;
- a first suckback prevention device installed on a side of the handpiece head equipped with a drill pin;
- and
- a second suckback prevention device installed on a side of the handpiece head equipped with a head cover,
- wherein the head cover comprises a head housing and a button housing;
- a power wind wheel and a wind wheel shaft which drive the drill pin to rotate are disposed in a space formed by fastening the handpiece head and the head cover;
- the wind wheel shaft is supported by two bearings;
- O-shaped rubber damping rings are disposed between the bearings and the handpiece head;
- the wind wheel shaft is provided with the head cover at the upper end;
- a neck of the head is provided with a water duct, an air intake passage and an air exhaust passage;
- and an opening of the air intake passage is positioned at the power wind wheel;
- wherein the second suckback prevention device comprises an annular clamping slot disposed between the head housing and the button housing and positioned on an inner side of the head housing, the clamping slot internally embedded with an O-shaped sealing ring;
- and a one-way air exhaust mechanism provided in the button housing;
- wherein the O-shaped sealing ring and the one-way air exhaust mechanism together prevent contaminants from entering into the button housing;
- wherein the wind wheel shaft disposed in the handpiece head has one end connected to the drill pin while the end is a conical brake face, a lower end of the wind wheel shaft is retractably disposed in the handpiece head;
- wherein the first suckback prevention device comprises an elastic shaft sealing casing and a non-elastic shaft sealing casing on an end face connected to one side of the drill pin, the elastic shaft sealing casing is centrally formed with a drill pin hole with a size which is a little greater than a size of an outer diameter of the drill pin, an outer edge of the non-elastic shaft sealing casing is in connected with an outer edge of the handpiece head through screw threads, the non-elastic shift sealing cover is centrally formed with a drill pin hole with a size which is a little greater than the size of the outer diameter of the drill pin;
- wherein a thickness of the elastic shaft sealing casing close to a central portion is greater than a thickness of a ring-shaped portion between the central portion and the edge of the elastic shaft sealing casing, an inner surface of the central portion of the elastic shaft sealing casing is a tapered face matched with a brake surface of the wind wheel shaft;
- and
- wherein the elastic shaft sealing casing is disposed in the non-elastic shaft sealing casing, and a shape of the inner wall of the non-elastic shaft sealing casing is matched with the exterior shaft of the elastic shaft sealing casing in the inflated state.