192 clutches and power-stop control – Clutches – Operators
Reexamination Certificate
2001-04-11
2003-04-01
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Operators
C192S03000R
Reexamination Certificate
active
06540057
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to an actuation device for a friction clutch which is arranged in the drivetrain of a motor vehicle between a drive unit and a transmission, comprising a pressure medium force cylinder arrangement by means of which the friction clutch can be actuated via a release member. A measuring arrangement detects an actual release and has a measuring member which is movement-coupled or can be movement-coupled with a mating member whose position represents the actual release. In particular, the invention is directed to an actuation device for a friction clutch arranged in the drivetrain of a motor vehicle between a drive unit and a transmission, comprising a release member for actuating the friction clutch, which release member is associated with a pressure medium force cylinder arrangement and is displaceable along a release path. A control/regulating valve arrangement is associated with the pressure medium force cylinder arrangement and pressure medium source and actuates the pressure medium force cylinder arrangement by a command variable and an actual quantity representing a position of the release member or depending on this position, a measuring arrangement which is associated with the control/regulating valve arrangement and serves to detect the actual quantity or a measured quantity dependent upon the actual quantity. The measuring arrangement has at least one measuring member which is arranged so as to be movable along a measurement path and which is in a movement coupling connection or can be brought into a movement coupling connection with a mating member formed by the release member or by a member of the actuation device or friction clutch which varies in position and whose position represents the actual quantity or measurement quantity.
2. Description of the Related Art
DE 198 22 285, to which U.S. Pat. No. 6,167,995 corresponds, and DE 197 16 641 disclose special actuation devices of the type mentioned in the introduction in which a measurement piston element of a hydraulic measurement cylinder (DE 198 22 285 A1) serving as measuring arrangement or a valve element of the control/regulating valve arrangement (DE 197 16 641 A1) serving at the same time as a measuring arrangement has a lateral groove in which a flange portion of a pneumatic ring piston engages, so that the measurement piston element and the pneumatic ring piston are driven along by tractive force and pressure force so as to produce the movement coupling connection. Such a construction of the movement coupling connection is disadvantageous in that in the case of a removable structural unit containing the measuring arrangement and possibly the control/regulating valve arrangement, the respective measuring member and the pneumatic piston element, after removal of the structural unit, must be moved into and held in axial positions matching one another exactly when the structural unit or an exchangeable structural unit is reinstalled so that the flange portion of the pneumatic ring piston can engage in the groove of the measuring member and so that the movement coupling connection can be produced. This is made even more difficult when no wear compensation is provided and the axial position of the pneumatic ring piston element corresponding to an engaged clutch wanders and different axial positions of the measuring member for the assembly and production of the movement coupling connection must be adjusted for different wear states of the friction clutch.
DE 198 22 285 and DE 197 16 641 disclose special actuation devices of the type mentioned in the introduction in which a measurement piston element of a hydraulic measurement cylinder (DE 198 22 285 A1) serving as measuring arrangement or a valve element of the control/regulating valve arrangement (DE 197 16 641 A1) serving at the same time as a measuring arrangement has a lateral groove in which a flange portion of a pneumatic ring piston engages, so that the measurement piston element and the pneumatic ring piston are driven along by tractive force and pressure force so as to produce the movement coupling connection. Such a construction of the movement coupling connection is disadvantageous in that in the case of a removable structural unit containing the measuring arrangement and possibly the control/regulating valve arrangement, the respective measuring member and the pneumatic piston element, after removal of the structural unit, must be moved into and held in axial positions matching one another exactly when the structural unit or an exchangeable structural unit is reinstalled so that the flange portion of the pneumatic ring piston can engage in the groove of the measuring member and so that the movement coupling connection can be produced. This is made even more difficult when no wear compensation is provided and the axial position of the pneumatic ring piston element corresponding to an engaged clutch wanders and different axial positions of the measuring member for the assembly and production of the movement coupling connection must be adjusted for different wear states of the friction clutch.
In order to facilitate assembly of the structural unit, it would be conceivable to move the pneumatic piston (generally at least one piston of the pressure medium force cylinder arrangement) and the measuring member for the assembly into a defined respective position, for example, the moved in end position, for instance, by means of a special lever mechanism provided for this purpose, e.g., through the clutch housing opening. However, a lever mechanism of this kind does not seem advantageous with respect to the elaborate construction necessitated by it.
The known solution with a groove in the measuring member, possibly the measurement piston element, which groove receives the flange portion of the actuation piston (release piston), is also disadvantageous insofar as the axial dimensioning of the groove and that of the flange portion can only be adapted to one another in a relatively expensive manner with respect to manufacturing technique to produce the engagement between the groove and flange portion without difficulty on the one hand and a tractive force driving engagement and pressure force driving engagement essentially without play between the piston and measurement piston element. Therefore, in general, separate steps are required in order to provide a displacing engagement between the measuring member and release piston essentially without play. For example, additional spring elements could be inserted into the groove which pretension the annular flange of the release piston and the measuring member in the direction of mutual contact at a surface of the measuring member limiting the groove axially and accordingly eliminate the axial movement play between the release piston and measuring member. However, the additional spring elements mean increased production costs and, beyond this, make it more difficult to introduce the annular flange of the release piston into the groove during assembly of the structural unit.
SUMMARY OF THE INVENTION
In contrast, one object of the present invention is to simplify the production of the movement coupled connection between the measuring member and the mating member. According to a first aspect of the invention, the measuring member is brought into a tractive force driving engagement with the mating member so as to be essentially free from play in that the measuring member and the mating member approach one another along the measurement path.
According to the invention, it is not required that the measuring member and the mating member are brought into and held in a defined axial position relative to one another in order to produce the movement coupled connection. Rather, the movement coupled connection can be produced by the movement of the measuring member and/or mating member along the measurement path, for example, after the assembly of a structural unit having the measuring arrangement, In the case of a hydraulic measurement cylinder, f
Ester Barbara
Konrad Andreas
Otto Thomas
Voit Herbert
Wehner Manfred
Bonck Rodney H.
Cohen & Pontani, Lieberman & Pavane
Mannesmann Sachs AG
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