Abstract:
The invention relates to a stabilizer for a motor vehicle. Known one-piece stabilizers are designed either solely for operation in road traffic or solely for off-road operation. Two-piece stabilizers that comprise an engaging and disengaging clutch have disadvantages regarding quality and safety. The invention provides a clutch, drivers ( 14, 17 ) of which form at least two adjustable gaps in the peripheral direction. The gaps can be filled by at least two locking elements ( 25 ) that can be displaced to a certain extent. The locking elements ( 25 ) and said drivers ( 14, 17 ) are constantly in positive engagement with one another in the peripheral direction and are adjusted to one another in such a manner that the locking elements ( 25 ) and the drivers ( 14, 17 ) are interlocked without play in the locked final position and that they can be rotated towards one another across a limited angle in the unlocked final position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   (not applicable) 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   (not applicable) 
   INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
   (See 37 CFR 1.52(e)(5) and MPEP 608.05. Computer program listings (37 CFR 1.96(c)), “Sequence Listings” (37 CFR 1.821(c)), and tables having more than 50 pages of text are permitted to be submitted on compact discs.) or REFERENCE TO A “MICROFICHE APPENDIX” (See MPEP § 608.05(a). “Microfiche Appendices” were accepted by the Office until Mar. 1, 2001.) 
   (not applicable) 
   BACKGROUND OF THE INVENTION 
   (1) Field of the Invention 
   The invention relates to a stabilizer with the features of the preamble of claim  1 . 
   (2) Description of Related Art including information disclosed under 37 CFR 1.97 and 1.98. 
   Such stabilizers are employed in motor vehicle technology. 
   In principle a stabilizer working according to the torsion bar principle is coordinated to each axle of a motor vehicle, wherein the stabilizer runs parallel to the axle and is attached at two ends at a wheel suspension. These stabilizers have the task to prevent or, respectively, diminish the transfer of rolling motions caused by the road situation and starting at the wheels onto the vehicle. Such rolling motions are generated mainly in the curves of the road or at the unevenness of the road, such as for example potholes or ruts. 
   Single part stabilizers exist, which are constructed in their dimensioning and in their material properties such that they receive torsion forces of a predetermined order of magnitude and that they can furnish corresponding counter forces. Single part stabilizers react however to different loads either too soft or too hard, which is disadvantageous for the driving comfort and single part stabilizers cannot accept increased loads. 
   Therefore increasingly two part stabilizers are employed, wherein the two part stabilizers are connected to each other by an axially fixed and rotary elastical clutch. Such a clutch is shown for example in the German printed patent DE 43 42 360 C2, wherein a rubber spring element is interposed between the two stabilizer parts. This rubber spring elements exhibits a softer spring constant and the thereby increases the possible twist angle between the two stabilizers. This way larger road loads can be opposed. The twist angle however is insufficient in case of road unevenness problems acting extremely different onto the wheels, such as they occur cross-country. In addition a slippage exists between the two stabilizer parts because of the rubber spring element, which operates disadvantageously onto the driving behavior in case of a straight driving and planar road. 
   Increasingly two part stabilizers with a switchable clutch are employed for such extreme load situations, such as there are described for example in the German printed patent document DE 19705809 A1. This coupling is furnished as a friction clutch and is controlled hydraulically depending on the load of the wheels. The two halves of the clutch are frictionally engaged connected in case of a high outer load and are separated in case of a lacking load. A slippage occurs between the two stabilizer halves upon a small load of the wheels. Such friction clutches are not safe, since also a slippage of the clutch cannot be excluded in the closed position and since an unlimited twist angle is possible in the separated position under an exclusion of the stabilizer function. This is a safety risk. 
   There exists no switchable clutch in all known constructions, which connects the two stabilizer halves without play in the block condition and which safely separates the two stabilizer halves in the released condition and which admits only a limited twist angle of as desired plus/minus 40 degrees in the released state. 
   BRIEF SUMMARY OF THE INVENTION 
   Therefore, it is an object of the invention to develop a stabilizer of the kind recited, which eliminates the recited disadvantages of the state-of-the-art and which automatically closes in a fail-safe-situation and which does not automatically separate in a coupled state. 
   This object is accomplished by the characterizing features of claim  1 . 
   Advantageous embodiments of the invention result from the features of the claims  2  through  10 . 
   The invention eliminates the recited disadvantages of the state of the art. A particular advantage results therefrom that the two radial catches are disposed on a common plane and also remain in a common plane in each operating state and that only the adjustment piston with its locking elements is disposed axially shiftable. A play free and slippage free connection of the two stabilizer parts occurs thereby in the coupled state. No further force transfer planes, which would shorten the effective length of the stabilizer parts, exist as a result of the arrangement of the two radial catches in the common plane. 
   The invention is to be explained in more detail in the following by way of an embodiment. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
     There is shown in: 
       FIG. 1  a simplified presentation of a vehicle axle with a stabilizer, 
       FIG. 2  the invention clutch in a sectional view, 
       FIG. 3  the clutch in a locked state, and 
       FIG. 4  the clutch in an unlocked state in the position of a maximum twist angle with a presentation of the rotary angle limitation. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Each axle of a motor vehicle comprises according to  FIG. 1  in principle the two wheels  1  and one supporting axle  2  carrying the two wheels  1 . A subdivided stabilizer  3  with its two stabilizer parts  4  and  5  is disposed parallel to the axle  2 , wherein each stabilizer part  4 ,  5  is connected with a wheel suspension not illustrated of the corresponding wheel  1  and on the other hand to the vehicle body for support position  6 . A clutch  7  is disposed between the two stabilizer parts  4  and  5 , wherein the clutch  7  connects to each other or separates from each other the two stabilizer parts  4 ,  5  to a straight continuous stabilizer  30  through a gearing. The connected stabilizer  3  is adjusted in its dimensioning and in its material properties to receive torsion forces introduced through the wheels  1  and to build up corresponding counter forces. These forces are thereby not transferred or at least dampened onto the vehicle body. 
   The clutch  7  is constructed axially switchable and shape matching. For this purpose the clutch  7  comprises a cylindrical casing  8  with a closed floor  9 , wherein a connection pin  10  for one of the two stabilizer parts  4 ,  5  connects to the closed floor  9 . The bearing position  11  for rotary hinge is disposed on the inner side of the floor  9 . The casing  8  is disposed opposite to the floor  9  and is closed fixed against rotation with a cover  12 , wherein the cover is furnished with the straight continuous bearing bore hole  13  for a further rotary hinge and with a radial catch  14  protruding into the interior of the cylindrical casing  8 . The radial catch  14  is disposed in a radial space between the straight continuous bearing bore hole  13  and the inner wall of the cylindrical casing  8 . The radial catch  14  can also be directly connected to the cylindrical casing  8  at the same arrangement. Furthermore a shaft  15  is fitted into the casing  8 , wherein the shaft  15  penetrates the interior of the cylindrical casing  8  and on the one hand is rotatably supported in the bearing position  11  in the floor  9  of the casing  8  and on the other hand in the bearing bore hole  13  in the cover of the casing  8 . The shaft  15  is connected to the other stabilizer part  4 ,  5  with the outer disposed pin of the shaft  15 . The bearing bore hole  13  in the cover  12  is sealed to the outside by corresponding sealing elements  16 . A further radial catch  17  is disposed on the shaft  15 , wherein the further radial catch  17  is rotatable with the shaft  15  and is disposed and formed in the same way as the radial catch  14  at the cylindrical casing  8 . The radial catch  14  rests thereby at the cylindrical casing  8  and the radial catch  17  rests thereby on the shaft  15  in a common plane, whereby the two radial catches  14  and  17  are swivelable relative to each other only to a limited extent. 
   Furthermore a hydraulically actuatable locking piston  18  is disposed in the interior of the cylindrical casing  8 , wherein the hydraulically actuatable locking piston  18  is guided axially shiftable and radially rotatable on the shaft  15  and wherein the hydraulically actuatable locking piston  18  subdivides the inner space of the cylindrical casing  8  on the floor side into a pressure spring chamber  19  and on the cover side into a pressure chamber  20 . A compression spring  21  is inserted into the pressure spring chamber  19 , wherein the compression spring  21  is supported at the floor  9  of the casing  8  and wherein the compression spring  21  loads the locking piston  18 . The pressure spring chamber  19  is connected to a hydraulic tank through a leakage oil connector  22 . In contrast, the pressure chamber  20  is furnished with a connection to a hydraulic pressure oil supply plant through a pressure oil connector not illustrated. The locking piston  18  is further furnished with an internal sealing element  23  and with an external sealing element  24 , which sealing elements  23 ,  24  hydraulically seal the pressure chamber  20  against the pressure spring chamber  19 . 
   Two locking elements  25  are formed on the cover side of the locking piston  18 , wherein the two locking elements  25  are disposed in the radial free space between the shaft  15  and the wall of the casing  8  in the same way as the two radial catches  14  and  17  and wherein the two locking elements  25  are disposed opposite to each other, that is staggered by 180 degrees. The shape and the dimensions of the two locking elements  25  are tuned in a particular way to the shapes and dimensions of the two radial catches  14  and  17 . 
   Thus the two locking elements  25  have a width which fills without play the two caps between the two radial catches  14  and  17  and the two locking elements  25  have a length, which allows an engagement of the locking elements  25  in the region of the two radial catches  14 ,  17  in the one end position of the adjustment piston  18 . Furthermore the locking piston  18  is furnished with a stroke limitation ( 31 ), wherein this stroke limitation prevents that the two radial catches  14 ,  17  and the two locking elements  25  become disengaged in the other end position of the locking piston  18 . Therefore, furthermore a positive longitudinal covering of the radial catches  14 ,  17  and of the locking elements  25  of the locking piston  18  exists in this end position. 
   The contact faces of the two catches  14 ,  17  and of the two locking elements  25  disposed opposite to each other and communicating with each other are composed in each case out of a conical face  26  with a smaller angle and a conical face  27  with a larger angle, wherein the conical face  26  with the smaller angle exhibits a larger axial length as compared to the conical face  27  with the larger angle and wherein the conical face  27  with the larger angle is disposed at the respective end of the catches  14 ,  17  or, respectively, of the locking elements  25 . 
   The conicity of the conus face  26  with the smaller angle allows a connection always free of play of the two catches  14 ,  17  and of the two locking elements  25 . Here the conical angle is selected such that the axial force component of a radial force entered from the outside does not surpass the spring force of the compression spring  21 . 
   The conical face  27  with the larger angle has an angle of about 45 degrees. The two radial catches  14 ,  17  obtain a radial play region in the opened position of the locking piston  18  based on the larger cone and based on the longitudinal covering of the two catches  14 ,  17  and the two locking elements  25  caused by the stroke limitation, wherein the radial play region is limited at two sides by having one of the two radial catches  14 ,  17  being supported at the other radial catch  14 ,  17  through in each case one of the two locking elements  25 . This state is shown in  FIG. 4 . The twist angle possible thereby between the two stabilizer parts  4  and  5  can be adapted to the most different situations of application and amounts to preferably 40 degrees. 
   The pressure chamber  20  in the cylindrical case  8  is maintained free from pressure under standard road conditions, for example in the street traffic, such that the compression spring  21  loads the adjustment piston  18  and shifts the adjustment piston  18  in the direction of the radial catches  14 ,  17 . 
   Side contacts between the radial catches  14 ,  17  and the two locking elements  25  occur. The radial catches  14 ,  17  are thereby centered and the locking piston  18  is also rotatable such that the two locking elements  25  penetrate to such extent into the intermediate spaces between the two radial catches  14 ,  17  until the conical faces  26  with the smaller angle come to rest. The locking piston  18  is held in this position by the force of the compression spring  21  over the full load range. The stabilizer parts  4 ,  5  coupled in this manner behave here like a single part stabilizer. 
   In case of nonstandard road conditions, as they occur for example cross-country, the torsion region of the coupled stabilizer  3  is not any longer sufficient in order to balance the rolling motions of the wheels. In such cases the pressure chamber  20  of the clutch is subjected to pressure by actuating a pressure supply plant preferably operated hydraulically, such that the locking piston  18  disengages from the contact region of the conical face  26  with the smaller angle against the force of the compression spring  21  and that the locking piston  18  shifts into its end position defined by the stroke limitation. The locking piston  18  is maintained in this position by maintaining the hydraulic pressure in the pressure chamber  20 . Thus the two stabilizer parts  4 ,  5  are separated, however the two stabilizer parts  4 ,  5  remain freely rotatable relative to each other over a predetermined swivel region. One of the two radial catches  14 ,  17  in the region of the conical faces  27  with larger angle comes into contact with a locking element  25  and rotates the locking element  25  until the locking element  25  is supported at the conical face  27  with the larger angle of the other one of the two catches  14 ,  17  in case of different loads of the two wheels of an axle. The two stabilizer parts  4 ,  5  are again connected to each other in this coupling state such that the two stabilizer parts  4 ,  5  are in a position to receive torsional forces. The relative twist motion of the two radial catches  14 ,  17  is dampened in an advantageous way by the hydraulic liquid in the pressure chamber  20  subjected to pressure. 
   Of course, the hydraulic plant for activating the locking piston  18  can be constructed such that the force of the compression spring  21  is hydraulically supported which leads to an acceleration of the coupling process. The effect of the compression spring remains in case of a failure of the hydraulic plant, wherein the compression spring maintains the couple state or induces the coupled state. 
   LIST OF REFERENCE CHARACTERS 
   
       
         1  wheel 
         2  axle 
         3  stabilizer 
         4  stabilizer part 
         5  stabilizer part 
         6  bearing position 
         7  clutch 
         8  cylindrical casing 
         9  floor 
         10  connection pin 
         11  bearing position 
         12  cover 
         13  bearing bore hole 
         14  radial catch 
         15  shaft 
         16  sealing element 
         17  radial catch 
         18  locking piston 
         19  compression spring chamber 
         20  pressure chamber 
         21  compression spring 
         22  leakage oil connector 
         23  internal sealing element 
         24  outer sealing element 
         25  locking element 
         26  conical face with a smaller angle 
         27  conical face with a larger angle