Other

R.h. Sheppard Co., Inc.

Peter H Sheppard

Robert H Breeden

Mark A Sterrett

Kenneth Giurlando

A power steering system for a ground vehicle includes an accumulator that supplies high-pressure fluid through a control valve to a fluid motor that drives the steerable wheels of the vehicle. A normally open control valve between the accumulator and the fluid motor closes prior to the steerable wheels reaching an axle stop to relieve power assist.

Method of relieving power steering assist and a power steering system utilizing the method

A pump assembly includes a high-pressure pump that flows pressurized working fluid in a fuel injection system of a diesel engine. The assembly includes a pilot-operated inlet throttle valve that receives a flow of low-pressure fluid from a feed pump and controls the volume of fluid flowed to the high-pressure pump in response to an electronic control module for the diesel engine. The operation of the inlet throttle valve is independent of fluctuations in output pressure from the feed pump.

Pump assembly and method

A hydraulic power steering system for a diesel-fueled truck utilizes vehicle fuel as a working fluid. The steering system includes a power steering gear connected to the steerable wheels of the truck. A first pump flows fuel from the truck's fuel tank to both the steering gear and to the engine. A second pump increases the pressure of the fluid to the steering gear to provide power assist. The flow to the steering gear returns to the fuel tank for recirculation.

Hydraulic power steering system utilizing fuel as a working fluid

A pump assembly for mounting a high-pressure oil pump on an internal combustion engine where the pump in the assembly is mounted in a closed chamber and a solenoid controlled valve is mounted outside of the chamber.

Pump assembly useful in internal combustion engines

A hydraulic power steering gear assembly includes an assembly body defining a piston chamber having opposed chamber ends with plunger passages formed in the ends, a reciprocating piston and a chamber having opposed ends and a passage extending between the piston ends, a check valve at each end of the piston passage, and a plunger assembly in each plunger passage with each assembly including a spring frictionally holding assembly in the passage and a poppet extending into the chamber to unseat a ball valve as the piston is moved toward one end of the chamber.

Hydraulic power steering gear assembly with unloading value

A power steering system for on-the-road and off-the-road vehicles includes a positive displacement hydraulic power steering pump, a master power gear with a rotary valve and a slave power gear mounted in tandem with the master power gear. Heated return hydraulic fluid from the master power gear flows through a heat transfer passage in the slave power gear and is cooled.

Tandem power steering system with heat sink

Hydraulic power steering gear assembly with unloading valve

An apparatus for forming a slot in a workpiece is disclosed. A variable radius crank, driven by a generating head assembly imparts a reciprocating/oscillating motion to a connecting rod. The distal end of an extension of the rod includes a tool for machining the slot. The connecting rod is mounted in a reciprocable slide and is retained therein by a transverse pin. The slide translates the motion of the connecting rod to a substantially elliptical tool motion. Thus, the tool cuts a substantially elliptical slot in the workpiece. The profile of the slot can be passively modified by selection of a different ratio of the connecting rod to the extension. A computerized control system with a programmable controller governs the operation of the generating head assembly (and thus the crank throw) to actively modify the shape and length of the slot. The control system can also be utilized to further vary the throw of the crank to provide other functional modifications to the operation, such as providing additional clearance for the return stroke of the tool.

Slot forming apparatus

An easily fabricated and assembled ball-screw mechanism of compact design comprises a cylindrical member having a helical guideway on its inner circumferential surface. The cylindrical member is operatively engaged through bearing members with a screw member having a helical groove in opposed relationship with the helical guideway. A tubular bearing return connecting each end of the helical guideway is freely received in a cavity in the cylindrical member. Each end of the tubular bearing return has a ramp which cooperates with the helical guideway to receive and release the bearing members. The bearing members are held captive in the tubular ball return and between the helical groove and helical guideway. An aperture is located in the tubular bearing return for loading the bearing members. A keeper is received in the cylindrical member to retain the tubular bearing return and includes a node to guide members across the bearing loading aperture.

Ball screw mechanism

An integral power steering gear assembly includes a piston and cylinder combination having greater output efficiency through improved fluid balancing and cushioning of the piston at its ends. The improved cushioning utilizes oil capillary slots in lieu of previously proposed epoxy resin strips. The slots may be fed with high pressure fluid filled by feed grooves along the sides of the piston adjacent the output rack. The slots are designed to have a shallow depth, preferably 0.001 inch - 0.0025 inch, which is sufficient to provide for high capillary attraction of the oil molecules to the slot. The trapped oil molecules prevent slip stick action, that is molecular interaction between the piston and cylinder wall, but at the same time, the oil molecules remain trapped or isolated within the walls of the slot thereby minimizing leakage from the slot. The operating oil is delivered with higher efficiency in the power steering unit by a bifurcated oil delivery passage communicating with the inlet slot of the piston. This provides fluidized balance and cushioning of the valve within the piston, and also prevents starvation of the high pressure feed grooves and capillary slots for balancing and cushioning the piston within the cylinder. Accordingly, improved reversibility of both the piston and the valve are obtained.

Power steering gear with balanced valve

An installation and retainer cap is disclosed for making a secure connection between an annular internally splined collar member and an externally splined shaft end. The cap includes a cap body, a threaded driving shaft extending from the inner side of the body engaging a threaded bore in the end of the shaft, and an outer flange engaging the annular collar member. When the cap is driven in to make the completed connection, the outside face of the flange is substantially flush with the outside face of the annular collar member. Recesses are provided in the end of the shaft and in the outside face of the annular collar member to accommodate the body and the flange, respectively. A washer cooperating with the outer flange allows relative turning movement during the driving of the collar into position. An indicator pin provides an indication when the annular collar is fully installed on the shaft. An alternative embodiment utilizing a separate cap and driving bolt is also disclosed.

Installation and retainer device for power steering pitman arm

An adjustable guide pin arrangement for an integral power steering gear is provided. A reciprocating valve is provided within the piston of the gear to selectively distribute pressurized fluid to the end of the piston for steering action. An input shaft engages the valve to move the valve providing the input signal. An output pinion engages the piston along the side. The guide pin is mounted in the piston and has two pairs of tapered flat guide surfaces at its distal end. One pair of guide surfaces engages a corresponding tapered slot in the valve for each adjusted position. Screw threads are provided to adjustably move the pin inward for less clearance and outwart for more clearance between the guide surfaces and the sides of the slot. The taper of the distal end of the pin is approximately 2.degree.-21/2.degree.. Each quarter turn preferably provides a differential clearance of approximately 0.001 inch. A tool-engaging slot on the head of the pin provides for easy visual adjustment during assembly.

Power steering gear with adjustable valve positioning pin

An integral power steering gear with a spool-like valve within the piston is provided with washer springs to center the valve and self locking adjusting nuts for the springs. Nylon locking balls are positioned in radial holes to perform the locking function and are equally spaced around the nut so that the nut is maintained in the centered position for accurate spring loading at all times. Each of the balls is frictionally held within the mounting hole so as to be retained prior to installation. The balls are positioned substantially flush with the top of the threads of the nut. As the nuts are installed, the mating threads in the piston deform each ball providing full frictional engagement with at least one thread, and by bulges with the sides of adjacent threads. Bulges of the deformed ball also serve to stabilize the ball in the holes.

Power steering gear with initial lockable spring adjusting nuts

An integral power steering gear assembly includes a piston and cylinder combination having greater output efficiency through improved fluid balancing and cushioning of the piston at its ends. The improved cushioning utilizes oil capillary slots in lieu of previously proposed epoxy resin strips. The slots may be fed with high pressure fluid filled by feed grooves along the sides of the piston adjacent the output rack. The slots are designed to have a shallow depth, preferably 0.001 inch-0.0025 inch, which is sufficient to provide for high capillary attraction of the oil molecules to the slot. The trapped oil molecules prevent slip stick action, that is molecular interaction between the piston and cylinder wall, but at the same time, the oil molecules remain trapped or isolated within the walls of the slot thereby minimizing leakage from the slot. The operating oil is delivered with higher efficiency in the power steering unit by a bifurcated oil delivery passage communicating with the inlet slot of the piston. This provides fluidized balance and cushioning of the valve within the piston, and also prevents starvation of the high pressure feed grooves and capillary slots for balancing and cushioning the piston within the cylinder. Accordingly, improved reversibility of both the piston and the valve are obtained.

Power steering gear with oil filled capillary balancing slots

Plastic wear strips are provided on a power steering piston or cylinder to improve the efficiency of translation movement of the piston in the cylinder during operation. The plastic surface of the strip, which is preferably on the piston, minimizes wear by providing a differential molecular structure at the interface between the cylinder wall and the surface of the piston since the cylinder wall is machined metal. The strips are positioned adjacent the ends of the rack where wear, caused by the load from the pressurized hydraulic fluid on the opposite side of the piston adjacent the inlet slot, is potentially the greatest. Plastic filling is provided in preferred arcuate grooves around the piston to form the wear strips. A single strip, or alternatively a group of independent strips, can be used and both serve to interrupt the surface of the piston so that molecular interaction of the two surfaces, or 'slip-stick' effect, is effectively prevented. The wear strips extend through a 60.degree. arc on both sides of the center line of the piston and the plastic is cured epoxy resin fixed in the grooves. Homogeneously dispersed metal chips stabilize the plastic. In a second embodiment, the plastic strips float within the grooves on a layer of hydraulic fluid provided by longitudinal channels formed on the surface of the piston. The method of preparing or manufacturing the piston and cylinder includes filling the grooves with the plastic and finishing the outer face within the mold and by milling the surface.

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Hanover, PA, United States of America

Peter H Sheppard