Abstract: A fluid coupling device is disclosed of the type including an output coupling assembly (13) which defines a fluid operating chamber (37) and a fluid reservoir chamber (41). Rotatably disposed within the operating chamber is an input coupling member (11), including a disc-like portion (31), which defines rearward lands (61) and forward lands (65). The lands defined by the input coupling member cooperate with the lands (63 and 67) defined by the output coupling assembly to define rearward and forward shear spaces, operable to transmit torque from the input member to the output assembly. The disc-like portion defines a plurality of fluid passages (71) which communicate between the inner and outer radial peripheries of the disc-like portion, and also communicate with both the forward and rearward shear spaces. During filling, fluid flows radially outward through the fluid passages, and directly into the shear spaces, to substantially reduce the response time of the coupling device.

Abstract: A control system is disclosed for a hydrostatic transmission of the type including a prime mover driven variable displacement pump, the displacement of which is controlled by a pair of strokers (28, 30). Flow of pressurized control fluid from the charge pump to one of the strokers, and from the other stroker to tank, is controlled by a main control valve (34). The control system includes an auxiliary control valve (44) defining passages (98, 100, 102) communicating between the lines connecting the main control valve and the strokers. The auxiliary control valve includes an on-off, electro-hydraulic valve (46) which prevents flow through the auxiliary valve in response to an electrical signal in one condition, and permits flow in response to an electrical signal in another condition.

Abstract: A differential gear mechanism of the limited slip type is provided. The mechanism includes a clutch, including a plurality of discs (31 and 33), and a cam mechanism including a main cam member (43) and an intermediate cam member (45). The intermediate cam member is splined to the side gear (19), such that axial forces are not transmitted to the side gear. The main cam member (43) defines a set of internal gear teeth (81), engaging an externally toothed member (79) of an acutating mechanism (71). The arrangement of the cam members and the provision of the gear teeth on the inner periphery of the main cam member results in a differential gear mechanism having a substantially reduced "bearing span", combined with a reduced casing diameter.

Abstract: A differential gear mechanism of the limited slip type is provided, and includes a mechanism for locking up the differential gear set, and a mechanism for actuating the lockup mechanism. The actuating mechanism includes a flyweight mechanism (71) and a latch mechanism (111). The latch mechanism includes a latch member (115) defining a pair of latch surfaces (125 and 127). The latch mechanism further includes a frame member (113) and a weighted member (117) which is oppositely disposed from the latch member about the axis of rotation of the differential gear set. The weighted member is operable to move the latch mechanism, in opposition to the biasing force of a spring (123), along a straight, generally diametrally-oriented path, in response to increasing rotational speed of the differential gear mechanism. Such movement causes movement of the latch member from an operative position (FIGS. 4 and 5) to an inoperative position (FIG.

Abstract: A vehicle hydraulic system is disclosed of the type including a steering control valve (29), a brake system (31), and an auxiliary load circuit (65). Fluid flow to these load circuits is controlled by a flow control valve assembly (11) including a priority spool valve (85) which controls the flow of fluid from the inlet port (13) to the priority fluid chamber (75). Fluid flows from the priority fluid chamber to the steering control valve and the brake load system, in parallel, and at equal levels of priority. A shuttle valve assembly (83) receives a steering load signal by means of a load signal line (44) and a brake load signal from the load signal chamber (111), and transmits the higher of the two load signals into the load signal chamber (93) which biases the priority spool valve toward a position to permit a greater flow of fluid into the priority fluid chamber.

Abstract: A fluid pressure operated wheel motor is disclosed of the type including a stationary housing assembly (11) and a rotatable housing assembly (13), which includes a gerotor displacement mechanism (29). The gerotor ring (47) is part of the rotatable housing assembly and rotates, while the gerotor star (49) is connected by a dogbone shaft (57) to the stationary housing assembly and only orbits. The dogbone shaft defines an axial bore (67), and the stationary housing defines a pair of main fluid passages (71 and 73) which cooperate with a plurality of fluid passages (91 and 93) defined by the rotatable housing assembly to form commutating valving. In either direction of operation, the system fluid flows through the chamber (19) in which the dogbone is disposed. The system fluid is divided into two portions, with one portion flowing through one spline connection (59 and 63), and the other portion flowing through the axial bore and the other spline connection (61 and 65).

Abstract: A fluid coupling device is disclosed of the type including an output coupling member, a cover, a valve plate separating the fluid reservoir chamber from the fluid operating chamber, and an input coupling member rotatably disposed in the operating chamber. Valving controls the flow of fluid between the reservoir and the operating chamber in response to variations in a condition such as temperature. The input member has a front face adjacent the valve plate and a rear face cooperating with the adjacent surface of the output member to define interdigitated lands and grooves. The input member defines a plurality of fluid passages permitting direct axial communication of fluid between the front face and the lands and grooves. This direct flow into and out of the lands and grooves is effective to reduce substantially the time required to achieve full engagement and full disengagement of the coupling.

Abstract: A hydraulic pump is disclosed of the type including a by-pass valve to limit the fluid volume output of the pump. The by-pass valve is disposed within a portion of the pump housing which extends axially into the fluid reservoir and defines a pair of by-pass ports. The pump is preferably balanced and includes a pair of diametrically opposed inlet kidney ports. A tubular member is used to direct a portion of the by-pass fluid from each of the by-pass ports toward the adjacent inlet kidney. Each of the tubular members is disposed to direct the by-pass flow axially into the inlet kidney, thus improving filling of the pumping pockets, and reducing cavitation and the resultant noise.

Abstract: A controller for fluid pressure operated devices such as vehicle power steering systems. The controller is of the type having a primary, rotatable valve member and a follow-up valve member and including a fluid meter having a metering member coupled to the follow-up valve member. The valving defines a central reference plane perpendicular to the axis of rotation of the valving and the various ports and passages defined by the primary and follow-up valve members are generally oppositely and equally disposed about the central reference plane. This valving symmetry reduces internal leakage and steering wheel precession. The controller includes a load signal circuit, including a pair of load sensing grooves oppositely and equally disposed about the central plane.

Abstract: A load sensing hydraulic system is disclosed of the type in which a load signal is communicated from downstream of a main flow control orifice to a device which is operable to vary the fluid delivery rate in response to changes in the load signal. Disposed in the load signal conduit is a load signal modulating valve which, in one position, communicates the load signal, substantially unchanged, to the variable fluid source. In another position of the modulating valve, the load signal chamber of the variable fluid source is drained to tank, while in intermediate positions of the modulating valve, a portion of the load signal is communicated to the variable fluid source, and a portion is bled to tank. Modulation of a load signal permits flow control in an hydraulic system, independent of the position or movement of the main spool valve. The input to the modulating valve may be manual or electric, and if electric, may be remote, or may be automatic in response to certain predetermined system conditions.

Abstract: A fluid coupling device is disclosed of the type including a valve member actuated by a valve shaft extending through the cover, the position of the valve and valve shaft being controlled by a temperature responsive bimetal coil. The coil has a first end attached to the valve shaft and a second end received within a clip member to prevent circumferential movement of the second end of the coil. The clip member includes wing portions which are generally parallel to the adjacent surface of the cover. After the clip and the bimetal coil are assembled, the coil is permitted to achieve its neutral position in both the radial and circumferential direction, and subsequently, each of the wing portions is attached to the adjacent portion of the cover without causing substantial radial or circumferential movement of the second end of the coil. As a result, the coil is able to withstand extreme vibration conditions, but is not subject to the high hysteresis which normally occurs with a rigid mounting of the coil.

Abstract: A vehicle engine accessory drive system is disclosed including a hydraulic fan motor (41) and a power steering gear mechanism SG in series flow relationship. The vehicle power steering pump P is the sole source of fluid for the system and has its flow control setting at a flow rate X, which is substantially greater than the flow rate Z required by the power steering gear SG. The motor-valve apparatus includes a valve portion (43), including a bypass valve portion (43), including a bypass valve piston (113) connected in parallel across the fan motor (41), and operable to permit fluid flow from the inlet passage (83) to the outlet passage (91) at a flow rate which is at least a portion of X. The bypass valve piston (113) is biased toward the bypass position by the fluid pressure in the inlet passage (83), and is biased toward the closed position by fluid pressure in a signal chamber (115).

Abstract: A hydraulic controller for a hydrostatic transmission to control a number of functions of a variable displacement pump or motor of the transmission. A valve includes a spool biased in one direction by a spring and in the opposite direction by fluid pressure in a chamber communicating with the charge pump. A variable orifice communicates the chamber with a drain. The size of the orifice is controlled electrically by a signal representative of swashplate position. Depending upon the pressure of the fluid in the chamber, the valve will directly vary the pressure ported from the charge pump to the standard controller. A needle roller has one end in contact with the end of the spool communicating with the chamber. A high pressure signal is provided via a shuttle valve across the high and low pressure conduits of the transmission to the other end of the needle roller.

Abstract: A fluid coupling device is disclosed of the type including a valve member actuated by a valve shaft extending through the cover, the position of the valve and valve shaft being controlled by a temperature responsive bimetal coil. The coil has a first end attached to the valve shaft and a second end (free end) received within a receiving portion of a clip member. Disposed between the second end of the coil and the receiving portion of the clip member is a resilient elastomeric member having a relatively thin wall. The clip member includes at least one wing portion which is attached to the cover to define an enclosure. The enclosure is configured to engage the elastomeric member which is compressed against the second end portion of the coil on at least two sides. The elastomeric member fills the clearance between the coil and the clip, even if the thickness of the clearance is not uniform, to increase the coefficient of friction, and the total gripping force, between the clip and coil.

Abstract: A control system for a hydrostatic transmission is disclosed of the type including an engine driven fluid pump and a fluid motor. The control system includes a main control operable in response to an electrical command signal to vary the displacement of the pump, and a command signal generator for generating the command signal. The anti-stall control includes means for comparing electrical signals representative of engine speed and a reference speed, and generating an electrical anti-stall signal representative of the maximum percentage of commanded pump displacement which is permissible without causing the engine to drop below the reference speed. The anti-stall control includes means for electrically multiplying the anti-stall signal and the command signal, downstream of the shaping and rate limiting circuits. The invention provides a simple, inexpensive anti-stall control which can be adjusted to have the maximum possible gain (responsiveness) without inducing circuit instability.

Abstract: A vehicle engine accessory drive system is disclosed including a hydraulic fan motor and a power steering gear mechanism in series flow relationship. The vehicle power steering pump is the sole source of fluid for the system and has its flow control setting at a flow rate X, which is substantially greater than the flow rate Z required by the power steering gear. A temperature responsive bypass valve is connected in parallel across the fan motor and the bypass flow and motor outlet f1ow recombine, then flow to a steering gear flow control which communicates a flow rate Z to the steering gear mechanism and all fluid in excess of Z bypasses the steering gear, recombining with the output flow from the steering gear and returning to the pump inlet. This system provides a flow to the fan motor resulting in a fan speed-versus-engine speed similar to a "viscous curve".

Abstract: A steering control system is disclosed for use on a dual path, hydrostatic drive vehicle. The steering control system includes a steering signal generator, the steering signal representing commanded steering ratio and direction. The system senses vehicle direction and steering direction and generates an electrical switch signal having a first or second condition, depending upon which transmission must have its speed reduced to achieve the desired vehicle orientation. The steering signal and the main speed command signal are multiplied to generate a speed modification signal and an electrical switch transmits the modification signal to one transmission or the other depending upon whether the switch signal is in the first or second condition. The disclosed steering system permits use of a T-handle control, for both speed and steering, such that vehicle orientation may be maintained generally perpendicular to handle orientation for both forward and reverse vehicle travel.

Abstract: A fluid pressure operated motor is disclosed of the type utilizing a gerotor gear set and an internal output shaft and spool valve. The motor includes a housing defining a fluid inlet port and an endcap defining a fluid output port. The motor further includes a dogbone shaft defining an axial bore and having a spline connection to the output shaft at one end and a spline connection to the externally-toothed member of the gerotor at its other end. In one direction of operation of the motor, the fluid exhausted from the contracting volume chambers passes through a radial passage of the spool valve into the interior of the spool valve. A portion of this system fluid flows through the forward spline connection, then through the bore in the dogbone shaft toward the endcap, while the other portion of the system fluid flows through the rear spline connection. The two portions recombine and flow through the fluid port in the endcap.

Abstract: A fluid coupling device and fan mounting arrangement is disclosed. The fan is of the type having a hub portion and a plurality of fan blades integrally molded therewith from a plastic material and an annular spider having its outer periphery attached to the hub portion and a plurality of inwardly extending tabs bolted to bolt bosses projecting forwardly from the front surface of the output coupling member. The bolt bosses define a bolt circle having a radius R.sub.1 and the output coupling member includes a plurality of pilot portions defining a pilot diameter of radius R.sub.2, wherein R.sub.2 is greater than R.sub.1. The annular spider includes a plurality of inwardly extending pilot tabs, each of which engages the outer periphery of one of the pilot portions of the output member.

Abstract: A fluid coupling device of the type including a rotatable coupling body defining a fluid operating chamber and a coupling member rotatable relative to the coupling body. A cover is associated with the coupling body and coupling member to define a fluid reservoir chamber, and a valve is operable to control fluid communication between the operating chamber and the reservoir chamber. The valve is mounted on a shaft which is rotatable relative to the cover and the rotational position of the shaft is controlled by a bimetallic coil having one end connected to the shaft and a second end which must be fixed relative to the cover. A bracket is fixedly attached to the cover and a clip member, in movable engagement with the bracket, receives the second end of the bimetal coil to prevent substantial rotational movement of the second end relative to the bracket.