Eaton Corporation

Oliver W Johnson

Herman P Schutten

Dwight B Stephenson

Marvin L Bernstrom

Sohan L Uppal

James K Yip

Bernard J Larson

Marvin Flaschenriem

A gerotor motor (11) of the valve-in in-star type is provided wherein a stationary valve member (17) is disposed immediately adjacent the gerotor gear set (19). The stationary valve member defines a shuttle bore (81) and disposed therein is a shuttle member (107) which moves between two operating positions (FIGS. 6 and 7) under the influence of system pressure. The shuttle valve member (107) communicates system pressure from whichever of the ports (39 or 41) is at high pressure to a pressure balancing recess (63). At the same time, the shuttle valve (107) provides fluid communication between whichever of the ports is at low pressure and a low pressure passage (83) which may be in communication with a lubrication circuit (95), or may be in communication with a case drain port, to divert a small amount of fluid to a heat exchanger. The invention provides a very small shuttle valve arrangement comprising only a single part, and eliminating a substantial amount of the machining previously required in the motor endcap (15).

Rotary fluid pressure device and improved shuttle arrangement therefor

Apparatus for automatically steering a farm crop vehicle between rows of corn by sensing the locations of the rows ahead of the vehicle. The apparatus senses the location of the plants as the crop vehicle approaches them. The data thus obtained are processed by an on-board microcontroller to determine the lateral location of the crop vehicle relative to the rows and provide a feedback signal. Another feedback signal is provided by integrating that lateral error data. In addition to the plant sensors, the harvester has a Doppler radar system on its left side that provides ground-velocity information for the left side, and a similar system on the right side. The radar outputs enable the microcontroller to measure the turning of the vehicle. This is used to produce yet another feedback signal that improves the automatic steering. This turning-feedback signal stabilizes the loop. The microcontroller provides steering commands for automatically tracking the rows.

Automatic steering apparatus using reflected signals

Apparatus for automatically steering a farm crop vehicle into rows of corn by sensing the locations of the rows ahead of the vehicle on both sides of the vehicle. The apparatus senses the plants of each row by means of contact sensors that touch the plants as the crop vehicle approaches them. The data thus obtained are processed by an on-board microcontroller to determine the lateral location of the crop vehicle relative to the rows. Also, the frequencies of encountering plants in laterally spaced-apart rows provided information regarding turning of the vehicle, i.e., incipient changes of lateral position. This is used to produce a further feedback signal that improves the automatic steering, especially where the rows are curved. Having the turning-feedback signal in the servo loop also permits higher loop gain without instability, which reduces tracking error even further. The microcontroller provides steering commands that automatically maintain the crop vehicle on a proper course for stripping the corn, cutting the crop, etc. The control system also provides indications for the operator of single row dropout, vehicle out of field, and field entry.

Automatic steering apparatus for crop vehicle

A pilot control valve (35) is provided for use in a load sensing system including a priority flow control valve (21). The pilot valve includes a flow orifice (47) through which passes flow from the priority outlet port (23) to the motor (13). The pilot valve includes a valve sleeve (73) and a relatively rotatable valve spool (75). This valving controls fluid communication between the load signal port (49) and the system reservoir and main flow path, upstream and downstream of the flow orifice. Movement of the valve spool from a minimum flow position to a maximum flow position progressively varies the load signal (51) from reservoir pressure to system pressure, thus causing the output of the priority valve (21) to progressively increase from a minimum flow to a maximum flow.

Pilot control valve for load sensing hydraulic system

A system is disclosed for controlling the flow of fluid from a pair of pumps (15,15') to a steering system (11) and a pair of auxiliary load circuits (13,13'). The steering system includes valving (43) defining a variable flow control orifice (45), and the steering system normally operates with a pressure differential X across the variable orifice, and provides load pressure signals (47,49,49',53,53') representative of demand for fluid by the steering system. Fluid flow from the pumps is controlled by a pair of priority flow control valves (21,21') including a pair of valve members (27,27') each of which is biased by a spring (29,29') toward a position permitting flow to the steering system. The spring (29) exerts a biasing force equivalent to the pressure differential X while the spring (29') exerts a biasing force equivalent to a pressure differential Y, which is less than X. When the output of the pump (15) is unable to maintain the pressure differential X across the flow control orifice, the differential across the orifice drops to Y, at which point the valve member (27') is biased by the spring (29') to permit flow from the pump (15') to the steering system.

Load sensing hydraulic system

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. The valving defines various neutral orifices and operating orifices communicating with the load signal circuit resulting in different load signal levels when the valving is in neutral, when the valving is in the normal operating position, and when it is fully actuated.

Controller for fluid pressure operated devices

A fluid controller is disclosed of the type including a primary valve member, and a follow-up valve member. The controller includes a load signal port and a load signal chamber. Fluid is communicated from the inlet port to the load signal chamber, and the valve members define a neutral orifice communicating between the load signal chamber and the return port when the valving is in neutral. The valving defines operating orifices communicating fluid from the load signal chamber to the main fluid path, downstream of the main flow control orifice, when the valving is shifted away from neutral. The operating orifices have a smaller orifice area when the valving approaches maximum deflection. The result is a substantially higher differential operating pressure, and a higher flow rate than would otherwise be possible at that particular valve deflection.

Load sensing valve

A controller for fluid pressure operated devices such as 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, the primary valve member defining a pair of meter grooves oppositely and equally disposed about the plane. The follow-up valve defines pressure porting adjacent the plane and connected to the fluid inlet port. The primary valve member defines a pressure passage communicating with one of the meter grooves and extending a sufficient distance to communicate with the pressure porting for relative displacement of the valve members in one direction and another pressure passage communicating with the other meter groove and extending a sufficient distance to communicate with the pressure porting when the valve members are relatively displaced in the opposite direction.

A power steering system is disclosed which selectively controls the flow of fluid to a steering motor and an auxiliary device, and may have as its source of pressurized fluid either a fixed displacement pump, a variable displacement pump, or a load sensing pump. The system includes a steering control valve disposed between the pump and the steering motor, and an externally pilot operated flow control valve, specifically, a priority valve, disposed between the pump and the steering control valve, such that the entire system flow enters the priority valve.

Load sensing power steering system

A controller for fluid pressure operated devices such as hydrostatic power steering systems. The controller is of the type having a primary, rotatable valve member and a follow-up valve member, and further comprising a fluid meter including a metering member coupled to the follow-up valve member. The controller is of the 5-port type, having a load signal port for communicating a steering load signal and maintaining a constant pressure drop across the main control orifice of the controller. The primary and follow-up valve members define a central reference plane oriented generally perpendicular to the axes of rotation of the valve members and the various ports and passages defined by the valve members are arranged in somewhat of a mirror image of each other about the reference plane. The follow-up valve member (sleeve) includes a pair of load sensing orifices, intersected by the reference plane, and disposed to communicate to the load signal port of the controller a pressure signal from immediately downstream of the main control orifice, for either direction of relative displacement of the primary and follow-up valve member. When the valve members are in the neutral position, the load sensing orifice communicates with a drain port in the primary valve member to relieve to tank the fluid in the load sensing circuit.

A controller for fluid pressure operated devices such as power steering systems. The controller is of the type having a primary, rotatable valve member and a follow-up valve member, the valve members defining a neutral position. The follow-up valve member is coupled to the primary valve member for limited movement relative to the neutral position. The controller further comprises a fluid meter including a metering member for measuring the volume of fluid passing therethrough, the metering member being coupled to the follow-up valve member. The controller has an inlet port and first and second control fluid ports which may be connected to the opposite ends of the power steering cylinder. The primary and follow-up valve members cooperate with the housing to define a first plurality of fluid passages providing fluid communication between the inlet port and the first control fluid port through the fluid meter when the valve members are relatively displaced in one direction from the neutral position and providing fluid communicating between the inlet port and the second control fluid port through the meter when the valve members are relatively displaced in the other direction from the neutral position. The first and second pluralities of fluid passages provide substantially the same length of fluid flow path between the inlet port and the corresponding control fluid ports in either direction of displacement of the valve member from the neutral position to provide uniform response in either direction. Preferably, the first and second pluralities of fluid passages are arranged in substantially a mirror image of each other with respect to an imaginary plane perpendicular to the axes of rotation of the valve members, to minimize steering wheel precession. In addition, the valve members maintain axial separation of the fluid flowing to a control fluid port and the fluid returning from a control fluid port to minimize internal leakage.

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Chaska, MN, United States of America

Oliver W Johnson