Abstract: A two-speed gerotor motor (10) including motor valve means (19,43) to communicate fluid to and from expanding (33E) and contracting (33c) fluid volume chambers. The motor includes a shift valve spool (61) to cause the motor to operate either in the normal, low-speed, high-torque (LSHT) mode (FIG. 3) or in a high-speed, low-torque (HSLT) mode (FIG. 4). When the motor operates in HSLT mode, certain of the volume chambers comprise recirculating volume chambers (33R). The motor (10) defines a supplemental fluid passage (89) through which fluid is communicated from a system charge pump (73) to each of the recirculating volume chambers (33R). A control valve (83) is operable, in a shift mode (S) to permit fluid communication from the charge pump (73) to the supplemental fluid passage (89), thus preventing cavitation during shifting of the motor (10), especially when shifting from the HSLT mode to the LSHT mode.

Abstract: A multiple speed ratio gerotor motor having first (13) and second (19) gerotor gear sets as the displacement mechanisms, and a commutating valve member (43) of the well known type. In one embodiment (FIGS. 1-5) there is provided a selector valve section (15) disposed between the first and second gerotor gear sets, and in a low speed mode (FIG. 5A), fluid flows from the commutating valve member (43) through the first volume chambers (39), then through the selector valve section, then through the second volume chambers (66). In a high speed mode (FIG. 5B), flow out of the first volume chambers (39) is blocked by the selector valve section (15), and fluid in the second volume chambers (66) flows through the selector valve section to the case drain region (106). In a free wheel mode (FIG. 5C), both the first and second volume chambers are open to case drain. In another embodiment (FIG.

Abstract: A fluid pressure device including a housing (13) defining a high pressure port (31) and a low pressure port (33). The housing defines a shuttle bore (35) and disposed therein is a shuttle valve assembly (51) including a shuttle spool (63). The shuttle spool (63) defines a fluid passage (87) disposed to provide fluid communication from the low pressure chamber (57) to the shuttle outlet port (85) as the shuttle spool moves from its neutral position (FIG. 2) to the end of its centered range of positions (FIG. 3). The low pressure fluid from the chamber (57) is communicated through the fluid passage (87) and acts on a shuttle poppet member (75), aiding the shuttle spool (63) and its shoulder (67) and unseating (opening) the poppet member (75), thus reducing the fluid pressure in the high pressure chamber (55) required to begin opening the shuttle valve assembly (51).

Abstract: A multiple speed ratio gerotor motor having first (13) and second (19) gerotor gear sets as the displacement mechanisms, and a commutating valve member (43) of the well known type. In one embodiment (FIGS. 1-5) there is provided a selector valve section (15) disposed between the first and second gerotor gear sets, and in a low speed mode (FIG. 5A), fluid flows from the commutating valve member (43) through the first volume chambers (39), then through the selector valve section, then through the second volume chambers (66). In a high speed mode (FIG. 5B), flow out of the first volume chambers (39) is blocked by the selector valve section (15), and fluid in the second volume chambers (66) flows through the selector valve section to the case drain region (106). In a free wheel mode (FIG. 5C), both the first and second volume chambers are open to case drain. In another embodiment (FIG.

Abstract: A rotary fluid pressure device (11) comprising a gerotor motor of the type including a spool valve member (51) cooperating with a housing (13) to define a nominal valve overlap (X). The motor has a drive shaft (53) for transmitting the rotational movement of a gerotor star (27) to the spool valve member (51) and output shaft (49), such that, under high torque loads, the drive shaft (53) is subjected to drive twist, which would normally effect valve timing. In accordance with the invention, the spool valve member (51) and the housing are provided with a valve overlap (Y) which is substantially greater than the nominal overlap (X). The star (27) defines, on its profile (85), first (87) and second (89) recesses which permit communication between the minimum (30) and maximum (32) volume transition chambers and the respective expanding (29) and contracting (31) volume chambers (FIG. 8).

Abstract: A two-speed gerotor motor of the type having a stationary valve member (19) defining a plurality of stationary valve passages, each including an upstream passage portion for commutating fluid communication with a moveable valve member (43), and a downstream passage portion in continuous fluid communication with a volume chamber (33) of the gerotor gear set. In some of the stationary valve passages (113), the upstream (115) and downstream (117) passage portions are blocked from direct fluid communication. A control valve spool (89) has a first position (FIG. 8) permitting unrestricted fluid communication between the upstream and downstream passage portions, for normal low-speed operation. The control valve spool has a second position (FIG.

Abstract: A fluid pressure operated device including a gerotor (17) including an orbiting and rotating star (27). A balancing plate (19) is biased into engagement by means of pressurized fluid in a space (102), with an adjacent end surface (28) of the star (27). Adjacent the balancing plate (19) is a housing member (21) defining a seal chamber (83), in which is disposed a seal assembly (89), including a support member (91) and a seal member (93) disposed radially inward from the support member. The outer periphery (92) of the support member (91) is disposed radially outward of a tangent circle (TC) of the bolts (11), thereby moving the pivot point (PP) of the balancing plate (19) further outward radially. This results in an improved ability of the balancing plate to follow the end surface of the gerotor star, whether the height of the star is more or less than that of the gerotor ring (23). As a result, volumetric efficiency is improved, even while the manufacturing cost of the gerotor gear set (17) may be reduced.

Abstract: A gerotor motor of the valve-in-star type in which the star (27) is disposed adjacent a stationary valve plate (15). The stationary valve plate (15) defines a plurality N+1 of valve passages (69), extending through the valve plate. On the surface (73) of the valve plate (15) adjacent the endcap member (14), the valve plate defines a plurality of pressure relieving recesses (79), each one being disposed between a pair of adjacent valve passages (69). Each of the recesses (79) is in fluid communication with an O-ring groove (81), which is at low pressure. Thus, any leakage from a high pressure passage (69) to an adjacent low pressure passage (69) is received within the intervening relieving recess (79), substantially eliminating any separating forces between the endcap member (14) and the stationary valve plate (15) This results in substantially improved volumetric efficiency of the motor at higher pressure differentials.

Abstract: A gerotor motor of the valve-in-star type in which the star (27) is disposed adjacent a stationary valve plate (15). The stationary valve plate (15) defines a plurality N+1 of stationary ports (65) in communication with the inlet port (55). The gerotor star (27) defines a plurality N of fluid ports (51) each including a radially inner portion (53). The inner portions (53) and the stationary port (65) are in commutating fluid communication as the star (27) orbits and rotates, in accordance with an important aspect of the invention. As a result, the star member (27) is exposed to a smaller area of pressurized fluid at the stationary valve plate (15), thus making it possible to achieve more consistent overbalance of the star, for either direction of rotation. This results in substantially improved overall efficiency of the motor.

Abstract: An improved gerotor device is disclosed, usable as either a pump or a motor, of the type including a gerotor gear set (17), and a movable valve member which may have either purely rotary motion (55), or may have both orbital and rotational motion (127). The valve member defines two groups of valve ports (63,65; 163,165) communicating with an inlet port (57) and an outlet port (61). The movable valve member is in sliding, sealing valving action with and an adjacent stationary valve plate (19'; 119') which defines a set of stationary fluid passages (67a-67g; 167a-167i) which communicate with the gerotor volume chambers (29a-29g). The stationary valve plate, in accordance with the invention, also defines a plurality of secondary fluid passages (77a-77g; 177a-177i) each of which is diametrically opposite one of the primary fluid passages (67a-67g; 167a-167i).

Abstract: A rotary fluid pressure device is provided of the type including a housing portion (13), a gerotor gear set (15), and an endcap member (17). The gerotor gear set includes an internally-toothed ring member (19) and an externally-toothed star member (23) which orbits and rotates within the ring member. The star includes an end surface (24) disposed adjacent a stationary valve member (65), and another end surface (26) disposed adjacent the shaft housing. The star (23) defines high-pressure ports (93) and low-pressure ports (95) which engage in commutating fluid communication with valve passages (83) defined by the stationary valve member. The star (23) defines passages (101) and (103) which communicate with the fluid ports (93) and (95), respectively, and feed high pressure to a fluid chamber (113) having a transverse area (B).

Abstract: A rotary fluid pressure device of the type including a gerotor gear set (115) including a ring member (119) and a star (123). Adjacent to the gerotor set are endcap members (117) each having an end surface (141) in engagement with an adjacent end surface of the star. The disclosed invention relates to valve-in-star type valving whereby both the manifold valving action and the commutating valving action occur at the interfaces of the end surfaces of the star and endcap members. Specifically, fluid is communicated from the inlet port (137) in one endcap member through an annular fluid pressure chamber (143) into a manifold zone (157) defined by the star, then through a passage (165) into a fluid port (161). The fluid ports are in commutating fluid communication with a plurality of stationary valve passages (151) define by the endcap member, each of which is in communication with one of the gerotor volume chambers.

Abstract: A rotary fluid pressure device of the type including a gerotor gear set (15) including a ring member (19) and a star (23). Adjacent the gerotor set is an endcap member (17) having an end surface (41) in engagement with the adjacent end surface (42) of the star. The disclosed invention relates to valve-in-star type valving whereby both the manifold valving action and the commutating valving action occur at the interface of the surfaces (41) and (42). Specifically, fluid is communicated from the inlet port (37) through a pressure chamber (43) into a manifold zone (57) defined by the star, then through a passage (65) into fluid port (61). The ports (61) are in commutating fluid communication with a plurality of stationary valve passages (51) defined by the endcap member (17), each of which is in communication with one of the gerotor volume chambers.

Abstract: A rotary fluid pressure device is disclosed of the type including a gerotor gear set including a ring member (19) and a star member (23). Both manifold valving and commutator valving are accomplished at an interface between an end surface (42) of the star (23) and an end surface (41) of an endcap member (17). The endcap (17) defines three concentric pressure chambers (43), (51) and (47), and the star defines three concentric manifold zones (63), (67), and (65) which are in continuous communication with the pressure chambers (43), (51) and (47), respectively. The various manifold zones (63), (67), and (65) defined by the star communicate with fluid ports (69), (77) and (73), respectively which are also defined by the end surface (b 42) of the star (23).

Abstract: A rotary fluid pressure device is provided of the type in which a valve spool (47) is axially movable within a spool bore (35). In the normal operating position of the valve spool (47), torque output is transmitted from the gerotor gear set (17) by means of a main drive shaft 53 through one spline connection (51, 49) then through a second spline connection (49, 75) to the output device. The valve spool (47) may be moved axially to a position in which the second spline connection (49, 54) is disengaged, and the device operates in a free-wheel mode. The valve spool (47) may also be moved axially to a position in which a set of teeth (71) on the valve spool engage a set of teeth (69) on the stationary housing, such that the device operates in a locked mode.