Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Patent
1993-05-14
1994-05-17
Nelli, Raymond A.
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
123 9031, 464 2, 74568R, F01L 134
Patent
active
053118464
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic control device for rotating a cam shaft of an internal combustion engine.
More particularly it relates to a hydraulic control device which has a couple member which is longitudinally displaceable by pressure force and has a first toothing engaging a toothing at an inner circumference of a cam shaft and supported in a sprocket wheel driven by the internal combustion engine and a second toothing engaging with an inner toothing of a sprocket wheel bore, wherein the couple member is actually displaceable by a liquid pressure controlled by a magnet valve.
Hydraulic control devices of the above-mentioned general type are known in the art. One such hydraulic control device is disclosed in the German patent document DE-OS 32 47 916. In such a known control device in particular the pump and the magnet valve are arranged externally, which is relatively complicated particularly in view of the necessary pressure medium connections and also entails a considerable cost in construction.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a hydraulic control device of the above-mentioned type, which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a hydraulic control device for rotating a cam shaft of an internal combustion engine, in which the liquid pressure acts on a piston acting on the couple member, in that a hydraulic body is flanged on at the drive wheel to which the cam shaft is also connected, an axial piston pump being arranged in the hydraulic member and receiving a plurality of pistons which slide in axial bore holes and have outer rounded portions contacting a wobble plate, outer valves are arranged at the outlet side of the bore holes and connected to a pressure space defined by the piston and controlled by a magnet valve, and a mechanical force acting against the force of the piston acts on the couple member.
When the hydraulic control device is designed in accordance with the present invention, it has the advantage over the prior art of a very compact construction and a very simple installation in an internal combustion engine or its engine compartment.
In accordance with another feature of the present invention, the bore holes receiving the pistons slide in pump bodies which are formed in axially extending bore holes of the hydraulic body and extend concentrically to each longitudinal axis. The pump bodies can have web-like prolongations by which they dip into recesses of the wobble plate.
An intermediate part can be connected between the cam shaft and the sprocket wheel and have a continuation which dips into a longitudinal bore hole of the cam shaft, while the spur toothing can be formed at an inner periphery. The cam shaft can be provided with a widened, flange-like end adjoined by the intermediate part and, coaxially thereto the sprocket wheel and the hydraulic body, and these parts can be connected by screws.
In accordance with still another feature of the present invention, the electromagnetic valve can be arranged coaxially relative to the hydraulic body and located partially within the same. The hydraulic body can include two parts, namely a first body directly adjoining the sprocket wheel and connected to at least one pump body held by a screw penetrating the widened end part of the cam shaft.
The mechanical force can be generated by a spring, or by a spiral toothing on the couple member whose pitch angle can be approximately 30.degree.-45.degree..
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying d
REFERENCES:
patent: 5167206 (1992-12-01), Suga
patent: 5178106 (1993-01-01), Suga
patent: 5189999 (1993-03-01), Thoma
Lo Weilun
Nelli Raymond A.
Robert & Bosch GmbH
Striker Michael J.
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