Gear pump

The invention provides a gear pump which comprises a gear mechanism and a casing for containing the gear mechanism, wherein the casing comprises an inner pump casing and an outer pump casing; the outer pump casing is arranged on the outer side of the inner pump casing in a sleeving manner; a central axis of the inner pump casing is parallel to an axis of the gear mechanism; a first opening and a second opening penetrating through the casing wall of the pump casing are formed in the outer pump casing; a channel is formed in an outer wall of the inner pump casing; one end of the channel is communicated with the first opening; the other end of the channel is communicated with the second opening; a cooling medium circulates in the channel. The gear pump disclosed by the invention is simple instructure, excellent in heat dissipation effect and convenient to maintain. 本发明提供种齿轮泵，包括齿轮机构和容置所述齿轮机构的外壳，所述外壳包括内泵壳和外泵壳，所述外泵壳套设在所述内泵壳的外侧，且所述内泵壳的中心轴线与所述齿轮机构的轴线平行；所述外泵壳上开设有贯穿所述外泵壳壳壁的第开口和第二开口，所述内泵壳的外壁开设有槽道，所述槽道的端与所述第开口相连通，所述槽道的另端