Abstract: The gear machine comprises a housing in which two gears mounted on shaft journals mesh. The shaft journals are supported in bushing or eyeglass-shaped bearing members. Located between the latter and the lateral surfaces of the gears are sealing plates which are brought into sealing contact with the lateral surfaces of the gears by axially-acting pressure fields. Relief grooves are formed circumferentially in the outer circumference of the bearing members and are spaced from and adjacent to the sealing plates. These relief grooves communicate with the low-pressure sdide of the gear machine and attain an optimal sealing action.

Abstract: An arrangement for centering an end wall of a housing of a hydraulic gear machine, such as a pump or a motor, with respect to the open end of an internal chamber provided in a housing body forming the circumferential wall of the housing includes a plurality of pins which are received in a press-fitting manner in bores of the end wall and protrude beyond an end face of the end wall which faces and closes the open end of the chamber in the mounting position. The pins may have contact surfaces which are turned to the same diameter as the corresponding inner surface of the housing body which bounds the open end of the chamber, or they may exactly fit into the open end, or overlap slightly with the inner surface in which event some material displacement or deformation takes place during the assembly of the end wall with the housing body.

Abstract: A multi-partite assembly, for example an assembly including a housing and a cover, has a centering sleeve received in bores formed, respectively, in the housing and in the cover. The diameter of the bore made in the housing is relatively smaller than the diameter of the bore formed in the cover and the diameter of the centering sleeve. The sleeve is slidably received in the bore of the cover and press-fitted in the bore made in the housing, thereby the reliable alignment of the housing and the cover is obtained.

Abstract: A pair of mating gears are mounted for rotation about respective axes in a gear-type fluid displacing pump or motor. Each gear has a pair of shaft portions at opposite axial ends of the respective gear, and bearing members surround respective ones of the shaft portions for journalling the gears. Each bearing member of one of the gears is juxtaposed with a respective bearing member of the other of said gears and, during rotation of the gears, the juxtaposed bearing members are subjected to forces which urge the bearing members to move relative to each other, particularly in direction towards each other. An arrangement is provided to counteract such forces and to oppose such relative movement of the juxtaposed bearing members.

Abstract: An external gear type hydraulic pump or motor wherein the trunnions of gears in the chamber of the housing are surrounded by annular bearing members. The peripheral surface of each bearing member defines with the adjacent internal surface of the housing an arcuate gap whose width increases in a direction toward the respective end face of the corresponding gear. To this end, portions of or the entire peripheral surfaces of bearing members and/or portions of or the entire internal surfaces of the housing have a conical or spherical shape. The gaps are located in the low-pressure zone and reduce the likelihood of wear upon those end faces of bearing members which are adjacent to the end faces of the gears because the bearing members can tilt in response to increasing load without localized rubbing against the gears. Additional gaps can be provided between the end faces of the gears and the adjacent end faces of the bearing members to further reduce the likelihood of uneven wear upon the bearing members.

Abstract: A hydraulic gear-type machine has two meshing gears with axis-defining shafts received in respective journals having end faces turned axially toward the respective gears and formed with cutouts opening in opposite directions in line with input and output passages formed in a housing carrying the journals and enclosing the gears. The journals abut flatly at the cutouts along surfaces extending axially to immediately adjacent gears and chordally to cylindrical continuations of the outer surfaces of the journals. Each of the journals on each axial side of each gear is therefore formed with a recess opening toward the inlet passage and with a recess opening toward the outlet passage.

Abstract: An external gear pump wherein the gears are installed in an eight-shaped compartment of a central housing section which is flanked by two covers. The outlet port of the housing communicates with two arcuate recesses for metallic inserts which are biased against the adjacent gears by fluid pressure in the outlet port whereby the inserts urge the gears against those portions of the internal surface of the central housing section which are located opposite the recesses. Such portions of the internal surface are formed with narrow first cutouts which communicate with the outlet port. The internal surface is further formed with relatively wide additional cutouts which are located between the first cutouts and the recesses and communicate with the inlet port. The force which is produced by fluid in the cutouts opposes the force which urges the gears against the internal surface of the central housing section to thus reduce the force with which the stubs of the gear shafts are urged against the housing.