Abstract:
A rotary damper, for a vehicle, for damping relative movements between vehicle wheels and the vehicle body. The at least one gear assembly has several gearwheels in functional connection by virtue of rotational movement of which hydraulic medium can be displaced for the purpose of hydraulic damping for the vehicle.

Description:
[0001]    This application is a National Stage completion of PCT/EP2014/052005 filed Feb. 3, 2014, which claims priority from German patent application serial no. 10 2013 203 331.1 filed Feb. 28, 2013. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention concerns a rotary damper for a vehicle, for damping relative movements. 
       BACKGROUND OF THE INVENTION 
       [0003]    From automotive technology linear dampers are known, for the damping of linear movements. Furthermore, from the document DE 10 2008 042 389 A, a rotary damper is also known, which consists of an inner, fixed part and an outer part that can rotate relative to the inner part and that is connected to a lever for producing the rotation. Between the inner part and the outer part there is arranged a frictional clutch in the form of a disk clutch, whose disks are connected fixed, in alternation, to the two parts, In the area of the lever the outer part is fixed to a first component of a spindle gear, which can move in rotation on balls over a second component and during this, undergoes an axial movement guided by a ramp on the second component. Accordingly, rotational movement of the outer part produced by the spindle drive is converted to an axial movement of the first component and thus also of the outer part, in order to bring the friction surfaces of the clutch into contact, This brings about a coupling of the inner and outer parts, which brakes the outer part and therefore damps the rotary movement. 
       SUMMARY OF THE INVENTION 
       [0004]    The purpose of the present invention is to propose a rotary damper with as compact a structure as possible. 
         [0005]    According to the invention, that objective is achieved by virtue of the characteristics and advantageous design features that emerge from the description and the drawings. 
         [0006]    For a compact structure, a rotary damper preferably for a vehicle, for damping relative movements between the vehicle wheels and the vehicle body is proposed, which comprises at least one gear assembly with several functionally connected components or gearwheels, through whose rotary movement, for example by virtue of the rotary movement of which, media (such as hydraulic media) are set into motion with a hydraulic damping effect of hydrodynamic, hydrostatic or rheological nature upon the movement. 
         [0007]    In this way the rotary movement and thus also a relative movement, for example transmitted by means of a gear system or suchlike, can be hydraulically damped as desired. Thanks to the use of a lever the vertical movement can be changed to a pivoting movement, whereby the pivoting movement is translated into a more rapid rotational movement by the gear system. By virtue of the fact that a hydraulic pump integrated in the gear system is provided, a corresponding hydraulic damping action can be produced for example by short-circuiting the suction and pressure sides. The short-circuiting can take place for example by way of a throttle or even by way of an electrically actuated proportional valve or the like, which is opened according to the degree of damping desired or closed completely. 
         [0008]    For example, it can also be provided that the short-circuiting is achieved through an approximately leakproof housing without any inlet or outlet, so that the throttle is provided by leakage. This is particularly advantageous when the proposed rotary damper is intended to produce the maximum damping effect for most of the operating time. 
         [0009]    In an advantageous embodiment variant of the invention it can be provided that for additional damping or for the active control of the damping at least one electric machine is connected to the rotary damper. For example a permanently energized synchronous machine (PSM) can be used. However, other types of electric machines can also be used. To adjust the damping, the electric machine can advantageously be short-circuited by way of controllable resistances, or operated as a generator. It is also conceivable that the electric machine is driven by a motor in order to enable active regulation of the movement, for example, of the vehicle body or the vehicle wheels, 
         [0010]    When the proposed rotary damper is combined with an electric machine, this has the advantage that a passive basic damping by means of the hydraulic pump integrated in the gear assembly can be combined with the passively or actively operated electric machine. This makes it possible to avoid overloads, loads due to misuse or the like, which with known active dampers cannot be kept under control, or only so with very considerable design effort and complexity. 
         [0011]    As the gearing assembly, one or more of the gear systems mentioned below, for example a spur gear assembly, a planetary gear assembly, a cycloid gear assembly or suchlike, can be combined with one another. Preferably, as the hydraulic pump at least one gear pump, annular gear pump, sickle pump, gerotor pump or the like can be used. Alternatively, rotary piston pumps, reversing piston pumps, circular piston pumps, rotary vane pumps or suchlike assemblies can be used. 
         [0012]    In a related embodiment of the invention it can be provided that, for example on the front-side housing of the gearing assembly, for example two electrodes electrically insulated from one another and of different polarity, or suchlike, can be provided. As the medium for the hydraulic pump integrated in the gearing assembly, for example an electro-rheological fluid (ERF or ERP) can be used, whose viscosity can be changed by the electric field between the electrodes provided in order to influence the damping additionally or alternatively to the valve or throttle. 
         [0013]    As a preferred alternative a magneto-rheological fluid can also be used, whose viscosity in the line or in the pump space can be changed by a magnetic field. Advantageously, the viscosity is influenced directly in the hydraulic pump, in that for example the fluid in the pump spaces is polarized by a magnetic flux, for example in opposite directions. Advantageously, the pump spaces can be in magnetically functional connection with the pole-pieces of the electric machine in such manner that the coils in the electric machine produce the magnetic polarization of the pump spaces. 
         [0014]    With the proposed rotary damper, in accordance with a related further development of the invention either one central, or several decentralized control units or suchlike can be used for control purposes, which for example are connected to the vehicle-internal data bus system or the like. For the signals available as standard in the vehicle, acceleration sensors on the wheel and on the vehicle body, or more generally on the masses to be damped, are provided. The sensors measure accelerations in the direction of the movements to be damped. On the vehicle body there are provided at least one and advantageously several sensors, in order to pick up all the modal degrees of freedom. Alternatively, at least one sensor can be arranged on the rotary damper, whereby additional cable connections can be saved. Furthermore a temperature sensor can be provided for each partially active rotary damper. By virtue of those sensors the electric machine can be monitored for safety and at the same time the temperature-dependence of the viscosity of the hydraulic medium in the hydraulic pump can be taken into account. 
         [0015]    The rotary damper proposed can preferably be used for damping relative movements between vehicle wheels and the vehicle body. However, other possible uses are conceivable, for example in other machines, assemblies or the like. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0016]    Below, the present invention is explained in more detail with reference to the drawings, which show: 
           [0017]      FIG. 1 : A schematic view of a first embodiment variant of a rotary damper according to the invention with a gear pump integrated in a gear assembly; 
           [0018]      FIG. 2 : A schematic view of a further embodiment variant of the rotary damper, with two sickle pumps integrated in a gear assembly; 
           [0019]      FIG. 3 : A diagrammatic representation of the embodiment variant shown in  FIG. 2 ; 
           [0020]      FIG. 4 : A schematic view of a related embodiment variant of the rotary damper, with several gear pumps integrated in a planetary gear assembly; 
           [0021]      FIG. 5 : A further schematic view of the embodiment variant according to  FIG. 4 ; and 
           [0022]      FIG. 6 : Another embodiment variant of the rotary damper, with a gerotor pump integrated into a cycloid gear assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]      FIG. 1  shows a first embodiment variant of a rotary damper according to the invention, in which the gear assembly is in the form of a spur gear assembly and is enclosed by a housing  1  in such manner that at the same time a hydraulic pump in the form of a gear pump with a corresponding pump space  2  is provided, The gear pump has a suction side  3  and a pressure side  4 . The suction side  3  and the pressure side  4  are short-circuited by a line  5  provided with an adjustable throttle  6  or valve in order to be able to adjust the hydraulic damping as desired. 
         [0024]    The relative movement, for example between the vehicle wheels and the vehicle body, is converted by a lever  7  (not shown in more detail) into a rotary movement of a first spur gear  8  of the spur gear assembly. The first spur gear  8  engages with a smaller, second spur gear  9  so that the rotary movement of the first spur gear  8  is translated into a faster rotary movement of the second spur gear  9 . On the shaft of the second spur gear  9  there is in addition an electric machine  10  (not shown in more detail), with which the hydraulic damping can be additionally actively controlled. 
         [0025]    It is also possible for a multi-stage gear assembly to be used, which at the same time forms several hydraulic pumps. Preferably, the hydraulic pumps can be interconnected with one another in such manner that a hydraulic circuit with the same flow directions is produced, in that a control valve determines the degree of damping. It is also possible for the pressure sides of the pumps to be connected with one another in order to reinforce the short-circuit effect. 
         [0026]    As an example,  FIG. 2  shows a further embodiment variant of the rotary damper that has several gear assemblies. The gear assemblies form a number of sickle pumps nested in one another. To be specific, a two-stage gear system with two sickle pumps is provided. The relative movement to be damped is introduced as a rotary movement by way of a ring gear  11  which together with a toothed ring  12  form the first sickle pump or first gear pump, the toothed ring  12  being arranged eccentrically relative to the ring gear  11 . The inner teeth of the ring gear  11  engage or are functionally connected with the outer teeth of the toothed ring  12  to form a first, sickle-shaped pump space  2 A. In addition, a second sickle pump is formed between the toothed ring  12  and a spur gear  13  arranged concentrically with the ring gear  11 , the inner teeth of the toothed ring  12  engaging or being functionally connected with the outer teeth of the spur gear  13  to form a second, sickle-shaped pump space  2 B. The spur gear  13  drives the electric machine  10 , to enable active control of the damping. This type of rotary damper has seals at the ends and/or flow channels, for example with adjustable cross-sections between the wheels and the housing. 
         [0027]      FIG. 3  shows a diagrammatic representation of the embodiment variant shown in  FIG. 2 , in which for example a planetary gear assembly  14  is connected upstream from the gear assembly that forms the sickle pumps. For example, the lever  7  is connected to a ring gear  15  of the planetary gear assembly  14 , whereas the planetary gear carrier  16  is supported on the housing  1 . The sun gear  17  is connected to the ring gear  11  of the first sickle pump. The spur gear  13  of the gearing assemblies that form the hydraulic pumps is connected to the electric machine  10 . As hydraulic pumps, besides the sickle pumps gear pumps, annular gear pumps or the like can also be used. 
         [0028]    An alternative embodiment variant of the rotary damper is shown in  FIGS. 4 and 5 . This variant is an integration of several gear pumps in a specially designed planetary gear assembly  14 A, wherein additional or further planetary gearwheels  19  that act as gear pumps are arranged in the planetary gear assembly  14 A. Besides the planetary gearwheels  18  that engage with the sun gear  17 A, the further planetary gearwheels  19  are also mounted on the planetary carrier  16 A and these also engage with the ring gear  15 A of the planetary gear assembly. The planetary carrier  16 A is designed in such manner that around the further planetary gearwheels  19  in each case a pump space  20  is formed, which in each case has a pressure side and a suction side. 
         [0029]    On the axial sides of the planetary carrier  16 A there are provided at the front and at the rear respective flow channels  21 , which are indicated, for example on the suction side of the pump spaces  20 , in  FIG. 5 . Corresponding channels for the pressure side are then either on the rear side or the front side of the planetary carrier  16 A. The channels  21  open into an annular channel  22  which is connected by way of an axial duct  23  to the corresponding annular channel on the pressure side, In this way, in this embodiment variant as well, the pressure sides and the suction sides are short-circuited with one another. Here too, a controllable valve or a throttle can be provided. 
         [0030]    In particular, the diameter of the annular channel  22  is larger than that of the shaft for the gearwheel  17 A, which leads through the planetary carrier  16 A. 
         [0031]    A further alternative embodiment variant of the proposed rotary damper is illustrated in  FIG. 6 . In this case the gear assembly is in the form of a cycloid gear assembly, in which a gerotor pump is integrated. Alternatively, rotary piston pumps, reversing piston pumps, circular piston pumps, rotary vane pumps or the like can be used. 
         [0032]    With the gerotor pump, in a manner similar to the embodiment variant according to  FIG. 2  a ring gear  11 A is provided with inner teeth, which engage with a toothed ring  12 A. In turn, the inner teeth of the toothed ring  12 A engage with a spur gear  13 A designed in effect as a sun gear, for example in order to drive the electric machine  10 . The ring gear  11 A is made to rotate by the relative movement, by way of the lever  7 . 
         [0033]    Regardless of the embodiment variant concerned, a further gear assembly without any hydraulic pump function can optionally be arranged before, after or between the at least one hydraulic pump. For protection against overload, the electric machine  10  can for example be connected to the last gear assembly by way of a slipping clutch or suchlike. After the rotor of the electric machine  10  further transmission stages or hydraulic pumps can follow. 
       INDEXES 
       [0000]    
       
           1  Housing 
           2 ,  2 A,  23  Pump space 
           3  Suction side 
           4  Pressure side 
           5  Line 
           6  Throttle 
           7  Lever 
           8  First spur gear 
           9  Second spur gear 
           10  Electric machine 
           11 ,  11 A Ring gear 
           12 ,  12 A Toothed ring 
           13 ,  13 A Spur gear 
           14 ,  14 A Planetary gear assembly 
           15 ,  15 A Ring gear 
           16 ,  16 A Planetary carrier 
           17 ,  17 A Sun gear 
           18  Planetary gearwheels 
           19  Additional further planetary gearwheels 
           20  Pump spaces 
           21  Flow channels 
           22  Annular channel 
           23  Axial duct