Hydraulic control device
AssigneeRobert Bosch GmbH
InventorMartin Muller
Life of this patent
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Abstract
The hydraulic control device for rotating the camshaft of an internal combustion engine has a couple member constructed as a piston (25) connected with the sprocket wheel of the camshaft via a spiral toothing and with the camshaft via a straight toothing. A hydraulic body is mounted on at the camshaft and receives a radial piston pump which delivers the pressure medium required for the displacement of the piston. The pressure space is closed by a controllable pressure limiting valve. An electromagnetic valve controls a pressure medium flow to the piston bores of the radial piston pump and the pressure medium is delivered by an external pump. The sprocket wheel and camshaft are rotated relative to one another by the displacement of the piston.
Claims12
A hydraulic control device for rotating a camshaft of an internal combustion engine, comprising a sprocket wheel which is driven by an internal combustion engine and having an inner circumference provided with a toothing;
- a longitudinally displaceable couple member which is acted upon by a pressure and having a first toothing provided at a first location of its outer circumference and engaging with said toothing at said inner circumference of said sprocket wheel and also having a second toothing provided at an other location of its outer circumference and engaging with a toothing of a camshaft, so as to form two toothing pairs, one of said toothing pairs being formed as a spiral toothing while another of said toothing pairs being formed as a straight toothing;
- a single acting piston which is acted upon by a pressure medium against a mechanical force and is arranged at said couple member;
- a pump and an electromagnetic valve arranged so that a pressure medium is delivered by said pump and directed via said electromagnetic valve for application of pressure on said piston, said sprocket wheel being rotated relative to the camshaft by a displacement of said couple member;
- a hydraulic body mountable at a widened end portion of the camshaft on which said sprocket wheel also sits and having substantially radially extending piston bores, said hydraulic body having a longitudinal bore hole a radial piston pump having a plurality of pistons sliding in said piston bores of said hydraulic body;
- a ball bearing arranged eccentrically relative to an axis of the camshaft and having an inner ring contacted by said pistons;
- an outlet valve connected to a pressure space of each of said piston bores and having an outlet, said single acting single-action piston being received in said longitudinal bore hole of said hydraulic body, said outlet of said outlet valve opening into a pressure space of said longitudinal bore hole;
- a pressure limiting valve having a valve housing and controlling the pressure space of said longitudinal bore hole, said valve housing closing said pressure space, said pump feeding inlet sides of said piston bores, and said electromagnetic valve controlling a feed flow and being arranged between said pump and said piston bores.
Dependencies are inferred from the claim text.