Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2000-12-06
2001-10-09
Schwartz, Christopher P. (Department: 3613)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C248S550000, C267S136000
Reexamination Certificate
active
06299149
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to a spring rate-switchable engine bearing with a supporting bearing and a supporting element, which has at least two spring elements arranged in parallel or in series between the supporting bearing and the supporting element, wherein one of the spring elements can be blocked by a switching device.
BACKGROUND OF THE INVENTION
Engine bearings of this type have been generally known in the state of the art and are preferably intended for mounting the internal combustion engine of a motor vehicle and to prevent disturbing vibrations from being transmitted from the engine to the body.
Disturbing vibrations of essentially two types, caused by the engine, occur during the operation of the vehicle and they therefore require different stiffnesses of the engine bearings used for the vibration damping. To embody the different damping characteristics, hydraulically damped engine bearings can be used, in which a second spring element is connected in parallel or in series to the first spring element, which is designed, e.g., as a conventional rubber bearing. If the spring action of the two spring elements connected in series is effective, the overall stiffness of the engine bearing is lower than the individual spring stiffness of the two spring elements used. If such an engine bearing is blocked by means of a corresponding switching device, this means that the flux of force flowing through the engine bearing flows only over one spring element, whose stiffness alone is effective and is substantially higher than when both spring elements are effective at the same time.
Various possible embodiments for blocking one ofthe spring elements have been known in the state of the art. For example, DE 41 30 362 discloses an engine bearing comprising two elastomeric spring elements, in which one spring element is blocked by means of a hydraulically pressurized pressure pad such that two housing elements, which enclose the spring element to be blocked between them, are brought into contact with one another in a non-positive manner by pumping up the pressure pad. This type of blocking of a spring element has the drawback that an external hydraulic energy source, which requires a relatively large installation space with the corresponding connection lines to the engine bearing and whose installation is also labor-intensive and expensive, is always necessary for such engine bearings.
The above-mentioned prior-art document also discloses the possibility of embodying the blocking of a spring element by a motor operator with a pressure piston which is actuated by same. Two support plates are brought into non-positive contact with one another by the motor operator with the pressure piston, so that the second spring element in the form of a rubber body is thus bridged over and is put out of operation.
Since the motor operator moves the piston for blocking the second spring element by means of a screw spindle, the axial and radial forces that can be transmitted are limited in this exemplary embodiment or the switching means occupies a rather substantial mounting space because of it being dimensioned for stronger forces, which in turn limits the use of the entire engine bearing.
Moreover, DE 34 03 002 discloses an engine bearing which is based on the cooperation of two spring elements with different spring characteristics and a switching coupling. The switching coupling, which can be actuated electromagnetically, is connected in series with the relatively harder spring element. The switching coupling is used to compress a disk packet by magnetic forces in the switched-on state in order to thus establish a rigid connection between the first spring element and the supporting element, so that the second spring element is put out of operation. The transmission of axial and radial forces is limited in this engine bearing as well because of the friction forces to be applied between the individual disks of the switching coupling, which can be compensated by a bulkier design in certain ranges, but these engine bearings are, on the whole, disadvantageous because of their size and weight.
SUMMARY AND OBJECTS OF THE INVENTION
The object ofthe present invention is therefore to improve an engine bearing of this type such that a desired, hard spring characteristic is obtained for operation during travel and a gentle spring characteristic is obtained for the idling of the engine. The different spring characteristics are of great significance especially in the direct injection diesel engines which have been used for some time, because the vibrations occurring during idling in these engines are substantially greater than in the diesel or gasoline engines used hitherto in automotive engineering. Moreover, the bearing shall have small dimensions and a low weight. In addition, the switching device used is required to be able to transmit strong axial forces on the order of magnitude of approx. 10 kN as well as radial forces, and the switching device shall have short switchover times for blocking and releasing the spring element to be blocked, and complicated external auxiliary units are no longer necessary.
According to the invention, a spring rate-switchable engine bearing is provided with a supporting bearing element and a supporting element. The bearing has at least two spring elements arranged in parallel or in series between the supporting bearing element and the supporting element. One of the said spring elements can be blocked by a switching device. Provisions are made in the spring rate-switchable engine bearing according to the present invention for the switching device to have a double toggle mechanism.
The double toggle mechanism is characterized in that an extraordinarily great power amplification can be generated by the mechanism due to suitable dimensioning, so that the very strong pretensioning force generated by the toggle mechanism guarantees the desired high transmission of axial forces in the range of >10 kN in the blocked state. It proved to be particularly advantageous for the design of the double toggle mechanism for a plurality of double toggle lever elements with two pressure levels each and with one adjusting lever each, which can be moved by a common actuating member, to be arranged concentrically to the central axis of the engine bearing, wherein the adjusting lever is connected by its outer end facing away from the actuating member to one end each of the two pressure levers in a pivot bearing and the outer free ends of the pressure levers, which ends are facing away from the pivot bearing, are connected to the supporting element and an intermediate plate, respectively, which are arranged between the first and second spring elements. Due to this design, the engine bearing according to the present invention can be made especially compact because the double toggle mechanisms used can be small and their cooperation nevertheless guarantees a sufficient stiffness of the bearing in the blocked state of the spring element. If, moreover, a design is used in which the blockable spring element comprises a plurality of coil springs, which are arranged concentrically to the central axis of the engine bearing directed in the longitudinal direction in parallel to the said axis and at spaced locations from one another, wherein the coil springs and the double toggle lever elements are arranged alternatingly concentrically around the central axis of the engine bearing, the engine bearing according to the present invention can thus be made even more compact.
It also proved to be advantageous to displace the actuating member responsible for moving the adjusting lever by an electric motor operator with a linear spindle in the longitudinal direction of the central axis of the engine bearing. The use of such a drive is possible only because only weak adjusting forces on the order of magnitude of 300 N are to be applied in the axial direction because of the double toggle mechanism being used. These adjusting forces can be brought about without problems with the drive being u
Ersoy Metin
Siemer Hubert
McGlew and Tuttle , P.C.
Schwartz Christopher P.
ZF Lemforder Metallwaren AG
LandOfFree
Springrate controlled motor bearing does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Springrate controlled motor bearing, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Springrate controlled motor bearing will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2571596