摘要:
An improvement in apparatus for lifting an agricultural implement carried by a tractor provides for automatic rapid level adjustment of the implement relative to the terrain under control of a valve system which comprises a regulator valve controlling inlet flow to the pump responsive to a comparator valve carried by the implement. A continuous throtted flow from the regulating valve to the comparator valve is maintained at constant pressure tending to open a valve in the comparator while a sensor or feeler contacting the ground serves to effect a greater or lesser opposing force. A servo valve is provided which effects a back pressure acting together with feeler actuation. An equilibrium position of the valve determines the level to which the implement is changed, holding it constant on level ground until the feeler is actuated by encountering a rise or fall in the terrain. The construction provides for varying the elevation of an implement by either raising it or lowering it to meet rise or fall of terrain.
摘要:
A control valve for a hydraulic booster steering system provides gradual control of inlet flow to the system pump to complete cut off of output, or by throttling of inlet flow to effect a pilot stream through the pressure pump. This occurs in the neutral position of the control valve during straight ahead steering. Where flow through the pump intake feed means is thus impeded, the pump simply cavitates in a known manner and to be of a type which is suction regulated, having a check valve means at the pressure outlet side. The advantage of cutting off inlet flow to the pump during straight ahead steering, or at least throttling of such inlet flow by a constantly open throttle passage, is to save energy otherwise wasted in heating the fluid.
摘要:
A pair of inlet valves held closed in the neutral position of a valve actuator are opened under control of a valve operating force transmitted through a regulating spring in response to displacement of the valve actuator from the neutral position. The valve operating force applied is opposed by the pressure in a servomotor chamber to regulate the chamber pressure within a predetermined range above a limiting value of the valve operating force applied. Outlet valves are opened under a servomotor operating pressure higher than the pressure regulated by the inlet valves to control exhaust of fluid from the operating chambers.
摘要:
A power steering multi-way control valve is provided featuring means for effecting hydraulic blocking of a power cylinder so that the wheels of the vehicle will remain in the neutral or steered angle position even though the driver removes his hands from the steering wheel in order to operate other accessories. This is necessary for heavy work vehicles in the construction industry or other vehicles used in open terrain.
摘要:
The description relates to a heatable pump housing part comprising a heat distribution sheet fixed on the housing part and a tubular heating element fixed on the heat distribution sheet. According to the invention the tubular heating element is positioned in a groove or a step on the housing part that is covered by the heat distribution sheet.
摘要:
In a servo steering unit which is designed particularly for motor vehicles, a pinion in a steering housing meshes with a steering rack. A steering valve which serves to control the pressure medium for the servo steering unit has two inlet seat valves (10, 11) and two outlet seat valves (12, 13) whose closing members (14, 18) are displaced by actuating tappets (16, 17) depending on the rotation of a steering spindle. The outlet seat valves (12, 13) are open in the neutral position of the steering valve. The inlet seat valves (10, 11) can be actuated by the force of pressure springs (15) in the closing direction and are not opened until after closing of the associated outlet seat valve (12, 13). The pressure springs of both inlet seat valves (10, 11) on one side press against the actuating tappets (16, 17) and on the other side press constantly on the closing member (14). The pressure springs (15) are designed so that they exert a closing force on the closing members (14) in the neutral position of the steering valve and so that during displacement of the steering valve away from its neutral position, one of the pressure springs (15) rests without applying force on the closing member (14) as soon as the associated outlet seat valve (12, 13) is closed. This provides a servo steering system which, to a large extent, operates irrespective of production tolerances with a desired and constant power take-off.
摘要:
In an auxiliary power steering intended especially for motor vehicles, a pinion (2) positioned in a steering housing (1) engages a steering rack (9). A steering valve (14) that is used to control the pressure medium for the auxiliary power steering provides two inlet-seat valves (15, 16) and two outlet-seat valves (17, 18) whose closing bodies (20, 21, 35, 36) can be shifted in the axial direction by a rotary movement of a steering spindle. Closing bodies (20, 21) of inlet-seat valves (15, 16) can be biased in the closing direction by the force of pressure springs (22, 23). In the process, pressure springs (22, 23) bias the closing bodies (20, 21) of inlet-seat valves (15, 16) only if the particular outlet-seat valves (17, 18) are in their neutral position. Each pressure spring (22, 23)--when steering valve (14) is in the neutral position--keeps closing body (20, 21) of the particular inlet-seat valve (15, 16) resting against a valve seat (26, 27) that is fixed on the housing. When steering valve (14) is shifted from its neutral position, then one of the outlet-seat valves (17, 18) in each case will lift the pressure spring (22, 23) of the particular inlet-seat valve (15, 16) over the disc (24, 25) and off the closing body (20, 21) of inlet-seat valve (15, 16).
摘要:
In an electrically-assisted rack and pinion auxilliary steering mechanism, an electric motor is controlled in accordance with a signal from a torque-measuring device. To prevent faulty control messages, a safety switching device is provided that contains two switches capable of being activated by a lever. A ball nut that is connected with a threaded spindle by a ball diversion channel is connected with the steering rack of the rack and pinion steering gear. The threaded spindle is connected via a spring bellows, with an output part of a coupling that can be coupled with or uncoupled from the electric motor. The threaded spindle is connected, axially movable and rotatable, opposite the fixed housing by two elastic intermediate rings and two axial bearings. If the axial movement does not coincide with the torque at the steering wheel in case of a malfunction, the coupling is disengaged by one of the two switches.
摘要:
In a servosteering arrangement, a control mechanism combines a pressure operated valve responsive to servomotor chamber pressure, and a solenoid and plunger responsive to speed of the vehicle by means of a proportional magnet solenoid for controlling reaction chamber pressure and thus the manual force required to be exerted by a driver for steering a vehicle. Thus, a variable throttle pressure responsive valve combined with a speed responsive solenoid responsive inversely to speed, controls the manual steering force necessary to effect steering at various speeds, particularly in tright curves at low speeds with high servomotor pressures. An important safety feature in the event of failure of solenoid current is the maintenance of openness of the pressure operated valve with consequent high resistance to steering.
摘要:
A booster steering valve control of the kind that comprises a pair of valve pistons reciprocal in a rotative valve body are driven by a fork shaped member at the end of a steering spindle. The fork shaped member comprises a pair of spaced actuator pins which engage in openings of the respective valve pistons. Thus, the valve body and the fork shaped member have a common axis about which the actuator pins rotate. A particular construction of the invention resides in the displacement of the actuator pins such that their axes are not in a common plane with the steering spindle axis but offset so that the surfaces of engagement between the actuator pins with the respective valve pistons and the spindle axis are coplanar. Engagement is maintained by spring bias acting on the valve pistons. Other construction provides widening the distance between the actuator pins by engaging side grooves of respective valve pistons and providing resilient clamps having a force direction acting on the valve pistons to effect surface engagement between the grooves and respective actuator pins parallel to the reciprocal axes of the valve pistons directly in line with the engaged surfaces.