BRIEF DESCRIPTION OF THE DRAWINGS
The invention is subsequently described with reference to figures. Therein the following is illustrated.
FIG. 1 illustrates the basic layout of a system according to the invention for active vibration damping in a simplified schematic depiction;
FIG. 2 illustrates a possible design implementation of an embodiment according to FIG. 1 in a simplified schematic depiction.
FIG. 1 illustrates the basic layout of a device 1 for damping vibrations with an integrated ramp mechanism 2 in a schematic simplified depiction. The device 1 comprises a primary component 3 and a secondary component 4, which are coupled through means 5 for torque transfer and furthermore through means 6 for damping coupling. Thus the ramp mechanism 2 comprises an input section and an output section, wherein these are either formed by the primary section 3, or the secondary section 4, depending on the force transmission device, or at least form a physical unit, this means they are coupled torque proof, with these elements as ramp elements. Typically, the primary part 3 and the secondary part 4 are provided as flywheels. At least one of the two flywheels, preferably both, or the ramp elements connected torque proof with them, have lens shaped indentations symmetrically extending in circumferential direction at the face sides 7 and 8, pointing toward each other, in which indentations at least one roller element 11 is disposed, preferably in the form of a ball, which is in contact, also at the deepest point of the lens shaped indentation, with the respective adjacent face surface 8 or 7 at the other component, the primary component 3 or the first ramp element, or the secondary component 4, or the second ramp element, or vice versa, and thus serves for torque transmission. The ramp elements are either the primary component 3, or the secondary component 4, or elements connected torque proof with them, on which the ramp surfaces 9, 10 are provided. The indentations are not shown here in detail. Only the ramp surfaces 9 and 10, which are created by them, and which are disposed in parallel with each other, and movable relative to each other in circumferential direction, are visible, which operate like slanted surfaces movable relative to each other. Since the primary component 3 is typically connected torque proof with the input side, and it is provided in axial direction without a possibility for axial translatoric movement, this means it is fixated in axial direction with respect to its position, a rotation of the primary component 3 in circumferential direction causes an axial thrust upon the secondary component 4, which is transferred through the roller elements 11. This axial thrust, which is caused by an axial force, Faxial, generated due to the imparted input torques Min, is supported by an opposite force Faxial-opposing, so that a torque is transferred, depending on the magnitude of the opposing force. Ideally, an opposing force Faxial-opposing is created, which corresponds to the axial force Faxial, which results from the mean input torque Min, wherein, due to the force equilibrium, this mean input torque Min is then transferred through the roller elements 11. The generation of the opposing force Faxial-opposing is performed by a hydraulic control device 15. It comprises a piston element 14, which is associated with the secondary component 4, or directly formed by it, and a pressure cavity 12. The piston element 14 is actuated through the pressure in the pressure cavity 12. The pressure cavity 12 can thus be loaded by a pressure medium. The secondary component 4, or the ramp element connected therewith, is loaded with a pressure p at its front face 13, facing away from the primary component 3 as a piston surface, generating the corresponding opposing force Faxial-opposing with respect to the force Faxial, thus holding the system in equilibrium by supporting the secondary component 4 in axial direction. The opposing force Faxial-opposing) caused by the pressure p onto the piston surface, is thus provided, so that at least the mean input torque Min-mean is reliably transmitted through the device 1. In case of deviations from the mean input torque Min-mean, compensation can be performed through pressure control in the pressure cavity 12. To avoid complex detections of the actual value of the mean input torque, Min-mean, and to perform a respective control of the pressure p in the pressure cavity 12, there is a possibility to solve this from a design point of view by performing the control hydraulically. The hydraulic control device 15 comprises next to the pressure cavity 12, associated at least indirectly with the secondary component 4, or the second ramp element, a storage 16, coupled with the pressure cavity 12, and means 17 for selective coupling of the pressure medium storage with a pressure medium source 19, in particular a pressure ramp or a relief device 20, in particular, a pressure sink, e.g. provided as a tank, or in general for decoupling both. The means 17 thus comprise in the simplest case a valve assembly 18, comprising at least three operating positions, a first operating position I, in which the storage 16, or the pressure cavity 12 is decoupled from the pressure medium source 19 and the relief device 20, a second operating position II, in which the storage 16, or the pressure cavity 12 is connected with a pressure medium source 19, and a third operating position III, in which the storage 16 or the pressure cavity 12 is connected with a relief device 20. The means 12 thus function as actuation device 35 for adjusting the compression pressure in the pressure chamber 12 for creating the required opposing force Faxial-opposing.
The system is provided, so that for transferring a mean input torque Min-mean at the device 1 for damping vibrations, in particular, in the primary component 3, an opposite force Faxial-opposing is provided, which opposes the resulting axial force Faxial, generated in the pressure cavity 12, relative to the piston element 14. In this case, the actuation device 35 is in the first operating position I. There is equilibrium and torque peaks can be compensated through the storage 16. When the mean input torque Min-mean to be transferred increases a higher opposing force is required for torque transfer. The pressure in the pressure chamber 12 has to be adapted. According to the invention this is not realized through complex control systems, but the force difference directly impacts the control variable Y for controlling the control device 35 through a conversion device 38. Preferably a conversion is performed into a variable, characterizing the change in position, as e.g. a travel distance or an angle. As a conversion device, an element, e.g. the second ramp element can function, which is subject to a translatoric motion due to the force difference.
In the simpliest case, the force difference between the axial force Faxial, generated by the input torque Min-mean, to be transferred, and the preset opposing force Faxial-opposing is converted into a translatoric motion of an element, in particular, into a translatoric motion of the second ramp element, by a travel distance s, which is proportional or equal to the required stroke of the actuating element 35 of the valve device 18. Thus, the valve device 18 is actuated in the direction of the second operating position II, and the pressure source 19 is connected with the pressure cavity 12, when the mean torque Min-mean to be transferred increases. Analogously, a connection with the relief device 20 is performed, when the input torque Min-mean to be transferred is reduced. Depending on the embodiment, the change between the particular operating positions, I, II, III, is preferably performed continuously, so that through changing the free cross sections, a fine adjustment of the pressure in the pressure chamber 12 is possible.
FIG. 2 illustrates a particularly advantageous engineering design of the integration of the hydraulic control device 15 according to the invention into a device 1 for damping vibrations in a simplified schematic depiction. This also comprises a primary part 3 and a secondary part 4, which are connected amongst each other through the ramp mechanism 2. The ramp mechanism 2 thus comprises at least two ramp elements, designated here with 21 and 22, wherein they are either connected torque proof with the primary component 3 and the secondary component 4, or they form the respective primary component 3, or the secondary component 4. Both possibilities are feasible. The primary component 3 and the secondary component 4 are typically provided as flywheels. They are provided as disc shaped elements. In the illustrated embodiment, only torque proof couplings are illustrated between the particular elements. Thus, the ramp element 21 forms a so-called fixed ramp 23 with the primary component 3. The secondary component 4 forms the so-called travel ramp 24 with the second ramp element 22. The fixed ramp 23 forms the input E, and the travel ramp 24 forms the output A of the ramp mechanism 2. Also here, a physical unit of the secondary component 4 and the ramp element 22, or an integral design is feasible. The coupling for torque transfer is performed through the roller elements 11, which are provided in indentations at the respective ramp elements 21 and 22.
FIG. 2 illustrates a particularly advantageous embodiment, in which the hydraulic control device 15 is integrated in the secondary component 4, in particular in the travel ramp 24. The hydraulic control device 15 comprises a pressure chamber provided as the compression chamber 25, impacting a piston element, coupled with the second ramp element 22, and movable relative to it, or forming the second ramp element 22 according to a particularly advantageous embodiment. In this case the piston element 26 is used for forming the compression chamber 25. The piston element 26 is therefore guided at the secondary component 4 in a sealing and axially translatoric manner. The piston element 26 comprises a piston surface 27 which operates together with the roller element 11, wherein a support at the secondary component 4 is performed through it. The positioning device 35 in the form of a valve assembly 18 is integrated in the secondary component 4, or in the travel ramp 24, through which the compression chamber 25 can be selectively coupled with a pressure medium souce 19, or a relief device 20, or it is decoupled from both. The piston element 26 thus has a pass-through opening 29, which can be selectively coupled with the particular connections at the secondary component 4 or the fixed ramp 24, forming the valve assembly 18. The coupling is thus performed depending on the position of the piston element 26 in axial direction, relative to the secondary component 4. The piston element 26 is thus provided axially movable at the secondary component 4 for this purpose. At the secondary component 4 radially facing connections 30 through 32 are provided, which are used for coupling with the compression chamber 25. The secondary component 4 is thus provided as a cylindrical element 28, through whose walls the channels for the connections 30 to 32 extend up to the outer circumference 33. Through the pass-through opening 29, which is also preferably provided in radial direction in the wall of the piston element 26, defining the compression chamber 25, the connection with the compression chamber 25 can be generated. The compression chamber 25 and the actuating device 35 are preferably provided coaxial with each other. The particular connections with the pressure source 19, or the relief device 20 are created through establishing flush positioning or overlapping positioning between the particular connections 30 through 32 and the pass-through opening 29. In the shown embodiment the connection 31 can be coupled with the pressure medium source 19 and the connection 32 can be coupled with the relief device 20. The connector 30 can be connected with a hydraulic storage 16, wherein the storage 16 comprises a piston element 37, supported at a spring unit 34, wherein the piston element 37 is loaded by the pressure in the compression chamber 25. According to FIG. 2, the coupling of the pressure chamber 12 with the other connections is always performed through the storage 16.
The system is designed, so that for the transfer of a mean input torque Min-mean at the device 1 for damping vibrations, in particular in the primary component 3, relative to the resulting axial force Faxial, an opposing force Faxial-opposing is provided, which is generated relative to the piston element 26 in the compression chamber 25, wherein the particular connections 31 and 32 are not connected to the compression chamber 25 in this position. Only a coupling between the compression chamber 25 and the storage 16 exists. This is realized through the first connection 30. The second connection 31 can be coupled with the source of the pressure means 19, while the third connection 32 can be connected with the relief device 20. Depending on the position of the piston element 26, the particular connections are more or less covered, which generates the particular functions of the valve device. The function of the valve piston of the valve device 18 is taken over by the piston 26 in this case, which simultaneously also generates the compression force relative to the second ramp element.
The solution according to the invention is not limited to the embodiment shown in FIG. 2. Any possibility of a direct conversion of a position change, caused by the difference between the axial force resulting from the input moment and the predefined opposing force is conceivable. In the simplest case the force difference is used, which is directly converted into a travel distance.
The integration of the travel ramp 24 into the secondary component 4 provides a particularly compact embodiment, which is characterized by a minimal design and control complexity. Furthermore, it is conceivable to connect the compression chamber with the compression volume of another unit, e.g. a continuously variable transmission, provided in the form of a CVT, which is disposed subsequent to the device for damping vibrations, and thus to integrate the function of a moment sensor into the damper right away.
DESIGNATIONS
1 device for damping vibrations
2 ramp mechanism
3 primary component
4 secondary component
5 torque transfer device
6 damping coupling device
7 front face
8 front face
9 ramp surface
10 ramp surface
11 roller element
12 pressure cavity
13 front face
14 piston surface
15 hydraulic control system
16 storage
17 selective coupling or decoupling to/from a pressure medium source, or a relief device
18 valve assembly
19 pressure medium source
20 relief device
21 fixed ramp
22 ravel ramp
23 compression chamber
24 piston element
25 piston surface
26 cylindrical element
27 pass-through opening
28 connection
29 connection
30 connection
31 outer circumference
32 spring unit
33 actuation device
34 actuator
35 piston
38 conversion device
Patent Application
20080087516
