Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Patent
1993-06-07
1994-07-19
Kamen, Noah P.
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
123 9031, 464 2, 74568R, F01L 134
Patent
active
053298900
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic control device for rotation of a camshaft of an internal combustion engine.
More particularly, it relates to such hydraulic control device which has a couple member longitudinally displaceable under the action of pressure and having a toothing engaging with a toothing of a cam shaft and supported by a sprocket wheel driven by an internal combustion engine with a central hole having a toothing engaging a toothing at another location of the couple member, with a piston acted upon by pressure medium delivered by a pump via an electromagnetic valve. In such a known control device in particular the pump and the electromagnetic valve are arranged externally, which is relatively complicated, particularly in view of the necessary pressure-medium connections, but also brings about considerable construction costs (DE-OS 32 47 916).
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a hydraulic control device for rotation of a cam shaft of an internal combustion engine, 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 of the above mentioned type in which a hydraulic body is mounted on a widened end part of a camshaft on which a driving toothed wheel sits, a radial piston part receiving pistons is arranged in the hydraulic body with external spherical caps of the pistons sliding at an inner circumference of a ball bearing arranged eccentrically to the axis of the camshaft, and pressure medium connections lead to a cylinder space in the hydraulic body from a compression space of a piston bore hole via outlet valves, while a double-action piston is arranged in the cylinder space and has a pressure limiting valve producing a duct connection from an annular pressure space on one side of the piston to a large pressure space on the other side of the piston, so that the double-action piston continuously contacts the couple member.
When the hydraulic control device is designed in accordance with the present invention, it has the advantage over the prior art that it has a very compact construction and is very easy to install in an internal combustion engine or its engine compartment.
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 drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a longitudinal section of a hydraulic control device for the rotation of the camshaft of an internal combustion region; FIG. 2 shows a section along II--II according to FIG. 1.
DESCRIPTION OF A PREFERRED EMBODIMENT
In FIG. 1, one end of a camshaft 10 which is supported in a camshaft bearing block 11 is designated by 10A. The camshaft is driven by a driving toothed wheel 12 to which is connected a hydraulic housing 13. The latter, as well as the toothed wheel 12 and the camshaft 10 are connected so as to be movable through a rotational angle by screws 14 and sleeves 15, specifically in that the sleeves 15 are arranged with play in curved slots 12A of the driving toothed wheel 12. Only one screw and one sleeve are shown in FIG. 1. The screws will be described in greater detail below.
The driving toothed wheel 12 has a hub 17. A helical or spiral toothing or set of gear teeth 18 is constructed at the bore hole of the hub 17. An identical toothing of a couple member 19 engages with the spiral toothing 18. The couple member 19 has a continuation 20 which is reduced in diameter and has a straight toothing 21 at the outer circumference. The straight toothing 21 engages with an identical toothing at a sleeve 22 whi
REFERENCES:
patent: 5167206 (1992-12-01), Suga
patent: 5189999 (1993-03-01), Thoma
patent: 5247914 (1993-09-01), Imai et al.
Kamen Noah P.
Lo Weilun
Robert & Bosch GmbH
Striker Michael J.
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