| 摘要 |
In order to construct miniature dosing and variable delivery pumps, which operate as gear pumps, the invention proposes to design at least one of the meshing gear wheels so as to be deformable into an oval shape. This is achieved by constructing the gear wheel from plastic with limited flexibility and by attaching the gear ring to the gear hub not directly, but via spiral-shaped sprung arms. Such gear wheels can be assembled in the pump casing under tension, in order to achieve a tight seal of the gear wheel outer parts against the inner wall of the casing and in order to ensure perfect meshing of the teeth. Preferably, one of the gear wheels is also mounted in the casing so as to be moveable in a radial direction, to allow it to be pushed in an outward direction against the wall of the casing by the deformation force within the counter gear wheel. The pump chambers formed by the gear rings are closed laterally in a conventional manner by laterally arranged sliding plates, which are preferably coated with titanium nitride and on the reverse side are lined with elastic material and the application force of which can be reduced during the movement.
|
