Pumps – Three or more cylinders arranged in parallel – radial – or... – Radial cylinders
Patent
1984-04-24
1986-12-30
Croyle, Carlton R.
Pumps
Three or more cylinders arranged in parallel, radial, or...
Radial cylinders
417279, F04B 104
Patent
active
046326413
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
Conventional pumps have a rising discharge characteristic directly responsive to pump speed. Pumps of that kind may be vane or gear pumps. Such pumps may be used for applicant's purpose in hydraulic installations where it is not material that increase in speed is not effective to reduce pump discharge, i.e., increase in discharge with increase in speed may be desired in some circumstances. In such systems pressure is limited by a valve to permit excess discharge to bypass the oil tank.
Radial piston pumps are well known as exemplified in German Pat. No. 29 02 240 and are used for the advantage of an operating characteristic wherein outlet discharge is reduced inversely as pump speed rises, an effect caused by throttling the suction feed to the pump. However, the regulation point of the outlet flow is at a relatively low speed of about 1200 RPMs and then remains almost constant.
Where such a pump is used in booster steering systems of motor vehicles a decreasing pump output characteristic is desirable as the speed of the vehicle increases. Thus, the pump which is driven by engine speed has an increase in speed and at such times a reduced discharge of pressure oil is desired. By effecting such inverse response a vehicle traveling at high speeds at which no large steering deflections are needed, booster steering is improved in driving characteristic when the boost steering system is in use since the driver has a better feel of contact with the road bed, a very desirable condition.
It has heretofore been known from German patent OS No. 29 06 047 (FIG. 3) to provide an electrical throttling valve in the discharge line of a booster steering pump which valve automatically effects throttling of discharge responsive to an electrical signal corresponding to travel speed of the vehicle. Accordingly, an electrical control throttle valve controls pressure oil to a consumer device such as a power cylinder in such a way that in case of slow travel the full pump discharge is available. However, in the case of fast travel the pump discharge is greatly decreased whereby excess oil flows back into the oil tank. A throttle arrangement control of the pump as described is expensive and operates in combination with a pump which has no regulation of suction feed and particularly at higher speeds has a relatively high leakage current.
BRIEF DESCRIPTION OF THE INVENTION
In order to provide as simple as possible pump arrangement with least expense having an inverse characteristic line wherein discharge drops with increasing speed, the combination of a radial multi piston pump with a centrifugal impeller in series with the suction feed to the piston pump is provided. Centrifugal impeller pump has a discharge in a direction providing a countercurrent to the direction of suction feed to the piston pump. This causes development of a dynamic pressure in the suction line which opposes inlet feed to the pump and results in a dropping characteristic of discharge inversely to speed of the centrifugal impeller.
Inasmuch as the speed of the suction throttling pump is a direct function of vehicle speed, it is apparent that increasing vehicle speeds will result in decreasing discharge to a power steering cylinder, the effect desired to be achieved.
In construction the centrifugal impeller consists merely of a collar having a serrated exterior and which is carried by the piston pump cam by means of an intermediate disc. Thus, the collar rotates at shaft speed and the serrated surface of the collar effects a centrifugal countercurrent action in a narrow annular recess connecting with the suction line of the pump housing and the suction chamber of the piston pump. The construction provides a countercurrent in the suction line in a power saving manner which is free of wear since no moving parts of the centrifugal impeller are in engagement with any surfaces and a high operational safety is effected.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
A detailed description of the invention now follows in conjunction with the
REFERENCES:
patent: 368691 (1887-08-01), See
patent: 1969881 (1934-08-01), Gardner
patent: 2666393 (1954-01-01), Trogei et al.
patent: 3389660 (1968-06-01), Hearstrum et al.
patent: 3542496 (1970-11-01), Bergeson
patent: 3932057 (1976-01-01), Wadensten
patent: 4310289 (1982-01-01), Merz
patent: 4378195 (1983-03-01), Gamell
patent: 4478550 (1984-10-01), Watanabe
Croyle Carlton R.
Neils Paul F.
Zahnradfabrik Friedrichshafen AG.
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