摘要 |
<p>A gear pump or a motor comprises: an externally meshing gear pair (1) which is composed of a driving helical gear (6) and a driven helical gear (7) which mesh with each other; a casing (2) which has therein a gear housing chamber (2a) for housing the externally meshing gear pair (1) and which has bearings (25, 26) for receiving a driving shaft (8) which supports the driving helical gear (6) in a rotatable manner and also receiving a driven shaft (9) which supports the driven helical gear (7) in a rotatable manner; a pair of side plates (31, 32) which are housed within the casing (2) and which are each provided in contact with side surfaces (6a, 7a, 6b, 7b) of each of the helical gears (6, 7) of the externally meshing gear pair (1); a hydraulic mechanism (4) which has hydraulic chambers (41a, 41b) and which, by means of hydraulic pressure introduced into the hydraulic chambers (41a, 41b), presses the driving shaft (8) and the driven shaft (9) in the direction opposite the direction in which a thrust load acts; and a high-pressure hydraulic fluid introduction passage (5) which introduces hydraulic fluid from the high-pressure side into the hydraulic chambers (41a, 41b) of the hydraulic mechanism (4). Pressing pressure generated by the hydraulic mechanism (4) is set so that the driving shaft (8) and the driven shaft (9) are pressed at a value exceeding the maximum value of a changing thrust load, the driving shaft (8) and the driven shaft (9) being pressed in the direction opposite the direction in which the thrust load acts.</p> |