Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2002-04-23
2003-08-05
Denion, Thomas (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C123S090180, C123S090310, C123S090370
Reexamination Certificate
active
06601554
ABSTRACT:
DESCRIPTION
1. Field of the Invention
The invention relates to a device for varying the valve control times of an internal combustion engine in accordance with the features forming the precharacterizing clause of claim 1, and is particularly advantageously implementable on hydraulic camshaft adjusting devices with pivotal impeller wheel.
2. Background of the Invention
Such a device was generically disclosed by EP 0 845 584 A1. This device, configured as what is known as a pivotal impeller wheel adjusting device, comprises a drive wheel configured as an outer rotor and drive-connected to a crankshaft of the internal combustion engine, which drive wheel comprises a cavity formed by a hollow cylindrical peripheral wall and two lateral walls, within which cavity four hydraulic working spaces are formed by four delimitation walls starting from the inside of the peripheral wall and oriented toward the longitudinal central axis of the drive wheel. The device further comprises a pivotal impeller wheel connected in a rotationally fixed manner to a camshaft of the internal combustion engine and inset into the cavity of the drive wheel, and in turn having on the periphery of its wheel hub four radially disposed, solid blades, which each extend into a working space of the drive wheel and divide the latter into pairs of hydraulic pressure chambers working in opposition to one another. The pressure chambers are sealed off from one another by sealing elements disposed between the free end surface of each blade of the pivotal impeller wheel and the peripheral wall of the drive wheel and between the free end surface of each delimitation wall of the drive wheel and the wheel hub of the pivotal impeller wheel and, when selectively or simultaneously subjected to the action of pressure by means of a hydraulic pressure medium, effect a pivot movement or fixing of the pivotal impeller wheel relative to the drive wheel and hence of the camshaft relative to the crankshaft. When the internal combustion engine is switched off, moreover, the pivotal impeller wheel can be mechanically coupled to the drive wheel, with minimization of the volume of a pressure chamber of each hydraulic working space, in a preferred basic position for the starting of the internal combustion engine, a locking element configured as an axial locking pin being disposed within one of the radial blades of the pivotal impeller wheel or on the drive wheel and being axially movable by a spring element, configured as a helical compression spring, into a coupling position within a complementary seating configured as an axial engagement aperture in a lateral wall of the drive wheel. The axial engagement aperture of the locking pin is hydraulically connected to the pressure medium feed to a pressure chamber of a hydraulic working space of the device, in such a manner that when the internal combustion engine is started, as a result of the subjection to the action of pressure of one pressure chamber of the hydraulic working spaces, the engagement aperture of the locking pin is simultaneously subjected to the action of pressure and as a result of action on its end surface located in the engagement aperture is moved hydraulically into an uncoupling position within the blade of the pivotal impeller wheel.
A further possible form of mechanical coupling between the impeller wheel and the drive wheel of a hydraulic camshaft adjusting device is proposed by the solution disclosed in U.S. Pat. No. 4,858,572. This device, which is of the type known as a vane cell adjusting device and is comparable in structural terms with a pivotal impeller wheel adjusting device but differs therefrom in having lighter blades on the impeller wheel and, in most cases, a larger number of hydraulic working spaces, comprises a total of six hydraulic working spaces, of which the first three working spaces can be subjected to the action of a hydraulic pressure medium only in one direction of rotation and the second three working spaces only in the other direction of rotation. In this device, in contrast to the device described initially, the mechanical coupling of the impeller wheel to the drive wheel of the device in a preferred basic position for the starting of the internal combustion engine is effected by two locking elements configured as radial locking pins, each of which is disposed in a radial bore in two mutually opposite delimitation walls of the drive wheel. These radial locking pins are alternately movable by a spring element configured as a helical compression spring into, in each case, a complementary seating disposed between two blades in the wheel hub of the impeller wheel and configured as a radial receiving bore, when the blades of the impeller wheel, in one of their two end positions, encounter the delimitation walls of the drive wheel, and the first or second working spaces, when the internal combustion engine is switched off, are no longer subject to the action of the pressure of a pressure medium. The radial receiving bores of the locking pins are hydraulically connected to the pressure medium feed to the first three or the second three hydraulic working spaces in a manner such that, within a filling channel to each of the working spaces, they are upstream of the latter in series, so that when the first three or second three working spaces are subjected to the action of pressure the locked locking pin is first subjected to the action of pressure by the pressure medium against the force of its spring element and is moved hydraulically into an uncoupling position within the delimitation wall of the drive wheel, and filling of the hydraulic working spaces is only subsequently possible.
These locking elements, designed in one case as an axial locking pin and in the other as a radial locking pin, for mechanical coupling between the impeller wheel and the drive wheel of a pivotal impeller wheel or vane cell adjusting device have, however, the disadvantage that they are formed from a plurality of individual parts which, in conjunction with necessarily increased production and assembly effort, sometimes substantially increase the cost of a pivotal impeller wheel or vane cell adjusting device configured in this way.
OBJECT OF THE INVENTION
It is an object of the invention to design a device for varying the valve control times of an internal combustion engine, especially a camshaft adjusting device, in which the mechanical coupling between the pivotal impeller wheel and the drive wheel can be achieved with a minimum number of individual parts and a low production effort, and the production and assembly costs of the device can thus be reduced to a minimum.
SUMMARY OF THE INVENTION
According to the invention, this object is achieved with a device in accordance with the preamble of claim 1, in that at least one of the sealing elements between the pivotal impeller wheel and the drive wheel of the device is simultaneously configured as a locking element for the mechanical coupling of the pivotal impeller wheel to the drive wheel of the device.
In an expedient further development of the invention, the pressure chambers of the device are preferably sealed off from one another only by sealing elements disposed between the free end surface of each blade of the pivotal impeller wheel and the peripheral wall of the drive wheel and configured as conventional sealing strips or sealing rolls, of which preferably only one is simultaneously provided as a locking element. Such a sealing of the pressure chambers, in conjunction with their further sealing by sealing joints between the free end surface of each delimitation wall of the drive wheel and the wheel hub of the pivotal impeller wheel, has proven sufficient to meet requirements and, at the same time, cost-effective, an arrangement, of further sealing elements instead of the sealing joints, for example further sealing elements disposed within an axial groove in the free end surface of the delimitation walls, not being ruled out.
However, a particularly preferred embodiment of the sealing elements between the free end surf
Haag Michael
Schäfer Jens
Denion Thomas
Ina Walzlager Schaeffler oHG
Muserlian Lucas and Mercanti
Riddle Kyle
LandOfFree
Device for varying the valve control times of an internal... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for varying the valve control times of an internal..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for varying the valve control times of an internal... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3109199