| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an internal gear pump having good wear resistance, seizure resistance and efficiency by applying surface treatment to gears for reducing the friction coefficient while suppressing an increase in the cost.SOLUTION: An internal gear pump P is provide which includes: a driving gear 2 and a driven gear 3 having first end faces 2a, 3a on one side and second end faces 2b, 3b on the other side, respectively; and a housing having a first inner wall face 1c opposed to the first end faces 2a, 3a and a second inner wall face 1d opposed to the second end faces 2b, 3b, and in which a clearance is provided between: each of the driving gear 2 and the driven gear 3; and the housing 1. Upon driving the driving gear 2, a first pressure p1 between the first end faces 2a, 3a and the first inner wall face 1c is set to be lower than a second pressure p2 between the second end faces 2b, 3b and the second inner wall face 1d. Surface treatment is applied to the first end faces 2a, 3a for reducing the friction coefficient but no surface treatment is applied to the second end faces 2b, 3b.</p> |
