Patent Publication Number: US-6220029-B1

Title: Operating arrangement

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an operating arrangement for movable parts on motor vehicles, especially for trunk lids, folding tops and the like, which has at least one hydraulic cylinder with a piston rod as the driving means to act on the movable part either directly or indirectly, for example by a hinge, and at least one pump arrangement, including tank, motor, and similar items connected to the hydraulic cylinder. 
     2. The Prior Art 
     With hydraulic working cylinders it is customary to arrange control valves, non-return valves and safety valves or the like on the cylinder itself as needed, while the pump arrangement, including the tank which supplies pressurized hydraulic fluid to the cylinder, is placed a distance away from the cylinder and is connected to it by pressure pipes. Thus, for example, with operating arrangements for movable parts on motor vehicles, such as trunk lids, engine hoods and the like, the hydraulic cylinders as the driving means are mounted in the immediate vicinity of these parts to be directly linked to them in part, while the pump together with the motor, valve arrangements, tank, etc., can also be mounted at a distance, depending on the available space, e.g., on a mounting plate with a vibration absorber. 
     The disadvantages of such configurations include, among other things, the long connecting lines required because of the pressure drop occurring in them, the danger of damage, the space required for installation, and also the cost of construction and manufacturing. 
     The design according to U.S. Pat. No. 4,551,973 is much more compact. This invention concerns a hydraulic drive unit wherein the hydraulic cylinder and the motor-pump unit are mounted on a common base. Because of the fixed size of the common base, however, the possibilities of adapting the unit to different areas of use are very limited, and this makes maintenance and replacement of individual parts very difficult. 
     The object of the present invention is therefore to provide a compact operating arrangement which can be adapted quickly and easily to the given requirements and can also be serviced easily or repaired by replacing individual parts. 
     SUMMARY OF THE INVENTION 
     To achieve this object, in the operating arrangement according to this invention the hydraulic cylinder and the pump arrangement, being two separate parts, are joined by a releasable connection to form a single unit, with there being at least one direct tubeless flanged joint between the pump arrangement and the hydraulic cylinder connecting at least one duct in the pump arrangement and at least one duct in the end piece of the hydraulic cylinder to one of its working chambers, preferably the working chamber on the piston end, to the pump. This yields the most compact possible unit, which can be mounted and moved as a unit, while nevertheless permitting a modular design where the individual parts can be selected and combined as needed, depending on requirements. Also in the event of damage or repairs, the defective part can easily be removed or dismantled and repaired or replaced. 
     According to another feature of this invention, in the wall of the hydraulic cylinder there is at least one connecting duct leading from one end piece of the hydraulic cylinder to the other end piece and to the other working chamber, preferably from the piston end to the rod end. This further increases the compactness of the operating arrangement while maintaining the parts described above and also reducing the risk of damage and the risk of possible leakage from the system. In all cases, the hydraulic cylinder and pump arrangement are preferably connected to an end piece, especially on the piston end, and the fluid connection to the working chamber at the rod end then leads through the duct provided in the cylinder wall. 
     According to an advantageous embodiment, the pump arrangement consists of a pump carrier with the pump inserted into it, a tank placed on the side of the pump carrier opposite the pump, and a motor mounted directly on the pump or a pump flange. Thus, tanks can be exchanged as needed without any great effort or replaced by a larger or smaller tank. The pump can also be designed more simply, since it need not be submerged in hydraulic fluid when operating, and it is also better and more readily accessible for maintenance and repairs than a pump located in the tank itself. 
     A simple connection to and mounting on the motor vehicle can be achieved with this operating arrangement by providing two mounting devices, one of which is located at the end of the piston rod of the hydraulic cylinder and another being aligned with the piston rod at the other end of the hydraulic cylinder and/or the pump arrangement. This permits a cantilevered suspension between the articulated connection point on the motor vehicle and the part to be operated, e.g., the trunk lid, or its hinge arrangement. 
     At least one of the mounting devices, preferably the one opposite the piston rod, is advantageously designed as a cross hole with a damping bush inserted, preferably a rubber bearing, so that the arrangement can be mounted on the vehicle securely and with a vibration reducing effect. 
     To simplify manufacture and make it more economical, it is preferable for the hydraulic cylinder be made of an extruded section. 
     In the following description, this invention will be described in greater detail on the basis of the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a cross sectional view through an operating arrangement according to a preferred embodiment of the present invention, and 
     FIG. 2 depicts a view of FIG. 1 as seen along line  2 — 2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 depicts a hydraulic working cylinder  1 , preferably made of an extruded section, containing a piston rod  2  on which a piston  3  is mounted or otherwise provided. At the end of piston rod  2  opposite piston  3 , a mounting device  4  is provided for attachment to the part of the motor vehicle to be moved, for example the trunk lid or the like, or on a hinge carrying the part to be moved. For this purpose, the rod head  4  is designed as an angle joint, for example. Another mounting device is preferably also provided on cylinder  1 , aligned with piston rod  2 , preferably in the form of a cross hole  5 , with any rubber bearing inserted or with a rubber bushing, serving to mount the operating arrangement on the motor vehicle with a vibration damping effect. 
     As shown in FIG. 2, pump arrangement  7  through  11  is mounted as a separate module on working cylinder  1  of the operating arrangement by screws  20  passing through flanges  1   a,  so that ultimately a compact unit that can be handled and moved as a unit is obtained. Due to the easy separability and connectability of the individual parts, the operating arrangement is easily adaptable to any requirement, not only during assembly but also afterwards, through selection and use of optimally suitable parts, and maintenance and repairs are greatly facilitated. Thus, a releasable mounting of pump carrier  7  on the piston end of the working cylinder is provided in an advantageous manner, and the necessary valve arrangements, e.g., reversing and control valves, safety valves and pressure relief valves, etc. (not shown here for the sake of simplicity) can also be built into the pump carrier  7 . On one side of pump carrier  7  are the pump flange  8  and pump  9 , which may in principle be of any desired design, in particular a radial piston pump. The electric motor  10  for driving the pump is located directly on pump flange  8  and/or on pump  9 . Pump  9  and the electric motor  10  may turn in either direction to advantage, in order to be able to operate the double-acting working cylinder  1 . 
     The tank  11  for hydraulic fluid is mounted on the side of the pump carrier  7  opposite pump  9 , preferably removably and replaceably, and is connected to pump  9  via suction lines, pressure lines and valves (not shown) in the pump carrier  7 . Pump carrier  7  also contains at least one duct  12  through which hydraulic fluid is supplied by pump  9  through at least one additional duct  13  in an end piece of working cylinder  1  to its working chambers, which is preferably the piston end, where the pump arrangement is mainly mounted. Preferably, at least one additional duct is also provided in pump carrier  7  conducting the working fluid through at least a second duct (preferably running in the wall of working cylinder  1  toward the opposite end piece) to the second working chamber. The extruded section from which working cylinder  1  is manufactured offers enough space in its corner areas for connecting ducts, which could be mounted in principle on the outside of working cylinder  1  in any desired manner. Ducts  12  in pump carrier  7  and ducts  13  in working cylinder  1  are connected to one another during the assembly and joining of working cylinder  1  and pump arrangement  7  through  11  by a tubeless flange connection which provides optimal sealing. 
     The invention has been described with reference to a preferred embodiment. Obviously, various modifications, alterations, and other embodiments will occur to others upon reading and understanding this specification. It is our intention to include all such modification, alterations, and alternate embodiments insofar as they come within the scope of the appended claims, or the equivalent thereof.