Fluid reversing mechanism and pump machine

The fluid reversing mechanism comprises an inner pipe, one end of the inner pipe is closed, and a first through hole, a second through hole, a third through hole, a fourth through hole and a fifth through hole which communicate with an inner cavity of the inner pipe are formed in the side wall of the inner pipe; a partition plate is arranged in an inner cavity of the inner pipe and divides the inner cavity of the inner pipe into a first cavity and a second cavity. The first through hole, the third through hole and the open port of the inner pipe are communicated with the first chamber; the second through hole, the fourth through hole and the fifth through hole are communicated with the second chamber; the outer pipe is coaxially connected with the inner pipe in a sleeving mode, the inner wall of the outer pipe is attached to the outer wall of the inner pipe, and a first connector, a second connector, a third connector and a fourth connector are arranged on the outer wall of the outer pipe; the inner pipe can