Patent Abstract:
A steering and driving system ( 1, 53, 54 ) for an industrial truck with a driving engine ( 2 ), a driving transmission ( 21 ), a steering engine ( 4 ) and a steering transmission ( 5, 32, 32′ ), through that one rotor ( 23 ) arranged on a wheel hub ( 22 ) could be driven and is swivelable at a vertical axis (V). For the realization of the compact design form as well as lesser manufacturing costs for this steering and driving system is considered, that the driving engine ( 2 ), the steering engine ( 4 ) and the steering transmission ( 5, 32, 32′ ) are arranged co-axially to each other.

Full Description:
This application is a national stage completion of PCT/EP2005/000485 filed Jan. 19, 2005 which claims priority from German Application Serial No. 10 2004 006 722.8 filed Feb. 11, 2004 and German Application Serial No. 10 2004 023 341.1 filed May 12, 2004. 
   FIELD OF THE INVENTION 
   The invention concerns the steering and drive wheel for an industrial truck. 
   BACKGROUND OF THE INVENTION 
   A controllable drive wheel for an industrial truck with two drive gears is known from the DE 41 10 792 C2. A miter gear with two miter wheel gears is arranged such that a respective output spindle drives the drive gears. The miter gear is driven by an electrical drive motor on a planetary gear that is arranged parallel or co-axial to the central axis of the device. Furthermore, a steer wheel motor is provided and is mounted outside the wheel gear case directly on the chassis of the industrial truck or on an additionally arranged head, plate torque proof to the chassis. With the operation of this steer wheel motor, this turns on a steer gear stage the wheel gear case or the gear carrier in its rotating assembly journal and thus also the wheel gear with both the wheel drives at the steering axle. The disadvantage of this steerable wheel drive is that the lateral arrangement of at least the steer drive motor makes the entire device less compact. 
   In addition, DE 199 04 552 A1 shows a wheel drive for an industrial truck for which an electrical traction motor and a gear driven by this are arranged co-axial to the longitudinal axis of the hub of the wheel of rotor. The traction motor is thereby designed as an electric motor with a disc-shaped rotor. Furthermore, the wheel drive exhibits electromotor steering with a steer motor and a steer gear, by which the steer motor is necessarily arranged perpendicular to the stage and is mounted by the turning of the rotor by the entire longitudinal axle of the wheel hub, traction motor and gear. The steer gear is a Wolfram-gear. 
   Although this wheel drive is very compact in the entire device, through the mentioned wheel hub drive as well as integration of the steer motor and the steer gear, its constructive formation, especially due to the cramped measure in the area of the wheel hub is comparatively complex and, therefore, costly. A further disadvantage is considered that the revealed combination of traction motor and gear, as well as steer motor and steer gear, develops a relatively large diameter size wheel drive. 
   Against this background, the task underlying the invention is to manage a constructively simple electro-motor steering and driving system for an industrial truck that exhibits a small diameter compared to known steering and driving systems and which could be manufactured at a comparatively cheaper cost with an acceptable design. 
   SUMMARY OF THE INVENTION 
   The invention concerns a steering and driving for an industrial truck with a driving engine, a traction motor, a steering engine and a steering transmission, through which at least a rotor arranged on a wheel hub of an industrial truck is drivable and is rotatable at a vertical axis. It is important with this steering and driving system that the traction motor, steering engine and the steering transmission are arranged co-axial to each other. Thereby, with an acceptable installation height, an especially radial compact design results as well as through the increased integration grade, for example, the double usage of housing components, at a comparatively lower manufacturing cost. 
   An especially preferred embodiment of the invention thereby provides that the driving engine, the steering engine and the steering transmission are arranged axially in this sequence, one after another, while the driving transmission, formed as a miter gear, is linked with a rotating assembly driven by a steering engine on the steering transmission and is arranged axially behind the steering transmission. 
   In a further constructive training of the specified design principle, it is considered that the driving engine is formed as a solid shaft and the steering engine shaft as a hollow shaft, as well as that the traction motor is led co-axially through the steering motor shaft. 
   Furthermore, it is considered that the traction motor carries a spur-wheel on its further end from the traction motor, which is there in tooth engagement with a spur-wheel on the input shaft of the traction gear, formed as a miter gear. The output shaft of this motor gear is linked with a wheel hub of at least a rotor. 
   In a further design of the invention, the steering transmission is designed as a multi-leveled planetary gears and/or a Wolfram-gear, whereby the latter exhibits an advantage due to its axially shorter length with higher gear reduction. 
   Furthermore, the invention concerns the drive-technical link between the steering engine and the steering transmission, as well as between the steering transmission and the swivel drive of the driving transmission or of a rotor at least linked with the latter. In this context, it is considered that the steering engine shaft is designed as the first sun wheel, whose external tooth system is in tooth engagement with the teeth of planetary wheels of the steering transmissions. 
   With the usage of multi-leveled planetary gears as steering transmission, it is preferably considered that the planetary wheels of the first planetary wheel are level with the first mentioned sun wheel and are stored on a first planetary carrier, which is linked slip free with a second sun wheel. On this second planetary carrier, rotary stored planetary wheels of the second planet wheel stage are meshed with the external tooth system of the second sun wheels, whereby the planet wheels of the first and the second planet wheel level are located in tooth engagement with a fixed hollow wheel or two fixed hollow wheels. Additionally, it is considered that the second planetary carrier is linked slip free with a third sun wheel, that the third sun wheel is in tooth engagement with planet wheels of the third planet wheel stage, that the planet wheels of the third planet wheel stage are stored rotating on a third planetary carrier, which is linked slip free with the hollow wheel and that the planet wheels of the third planet wheel set is in tooth engagement with an internal tooth system of the journal internal ring of rotary assembly journal, which is linked slip free with the rotary assembly or directly with the housing of the traction gear. 
   Another detail of the invention is thereby indicated that the journal external ring of rotary assembly journal is slip free linked with a vehicle framework of an industrial truck. 
   It could be further considered that the housing of the steering engine is held on with the fastener axially on the journal outer ring. Further, the compact design of this steering and driving system thereby prefers that the specified hollow wheel and the radial external end of third planetary carrier are arranged between the external wall of the steering engine housing and the journal external ring, behind each other. In this manner, the steering engine housing can be fixed against the journal external ring of rotary assembly by the mentioned fastener that are simultaneously linked as a hollow wheel affecting as a steering transmission housing as well as the third planetary carrier axially with each other. 
   In addition, it can be planned in a deviation that the steering transmission housing is fixed slip free on the separate fastener on the journal external ring of rotary assembly. 
   A preferred variation of the invention is thereby given, that a brake is arranged affecting the driving engine shaft on the driving transmission&#39;s farther end of the steering and driving system. This brake is preferably designed as electrically activated, while it is considered possible regarding the steering engine to design this as an electric motor with a disc-shaped rotor. 
   Further, it could be considered that the housing of the driving engine is fixed on the housing of the driving engine or an entire housing is used by both the engine elements. This housing and/or the single housing is designed as a sheet construction. 
   Additionally, it is profitably assessed if the steering transmission housing, the journal external ring of rotary assembly or the rotary assembly exhibits a bore for recording by swiveling angle sensors; with its help the swiveling of the rotor is ascertainable at its steering axle and is communicated to a control device. 
   Regarding the recording of the steering angle for usage in a control device allocated to the steering and driving system, it can be considered on the rotor of the steering engine, on the fixed journal outer ring of the rotary assembly and/or on the rotary assembly signal indicator as a magnet, which interacts together with the specified swiveling angle sensors for swiveling angle detection. 
   As per another aspect of the invention, it is considered that a flange, pointing radially outward, especially a ring flange, is formed on the steering transmission housing as well as on the steering engine housing, respectively, through which respective axial bores, fixing screws are fed for fixing the same on the journal external ring. 
   Such an example, with one or all the specified features of highly integrated steering and driving system, as a further advantage, exhibits reduced noise pressure, especially at the time of changing the pressure, and has low maintenance and/or is maintenance free, because the steering transmission could be filled with a lifetime lubricant, and also the steering engine can be of a maintenance free design by using a brushless dc motor or alternating current motor in standard or shrunk-on-disc design. 
   For the reduction of manufacturing costs, it is further advised to design the planetary carrier as a sheet construction with an open or closed design. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described, by way of example, with reference to the accompanying drawings in which: 
       FIG. 1  is a partial section represented with a lateral view of an electromotor steering and driving system for an industrial truck, and 
       FIG. 2  is a representation as in  FIG. 1 , however related to a second design example of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   According to  FIG. 1 , a steering and driving system  1  designed according to the invention, as the main component, an industrial truck (of vehicle) initially has a driving engine (traction motor)  2 , by which a driving shaft (traction motor shaft)  3  is driven on a driving transmission (traction gear)  21  of a rotor  23 . The rotor  23  is rotatable, together with the driving transmission  21 , along a vertical axis V. For the execution of this swivel movement, the steering and driving system  1  allotted on an electric steering engine (steering motor)  4 , on which a steering transmission (steering gear)  5  is arranged. For gear reduction of the steer motor revolution, the output of this steering transmission gear  5  affects a rotary assembly  27  that is linked slip free with a housing  51  of driving transmission  21 . Particularly, it is of importance for the steering and driving system  1  designed according to the invention that the driving engine  2 , the steering engine  4  and the steering transmission  5  are arranged co-axial with each other. 
   In detail, this steering and driving system  1  is designed in such a manner that the driving engine shaft  3  is a solid shaft and is fed through a hollow shaft placed by a steering engine shaft (steering motor shaft)  9 . A first spur-wheel  19  is fixed on the driving engine shaft  3  on the far end its traction motor, which meshes with a second spur-wheel  20  that is on a gearbox input shaft of the driving transmission (traction gear)  21  (not shown here). In this traction gear, the drive torque is managed in the known manner on an angle drive to a gear output shaft that is linked slip free with a wheel hub  22 . The rotor  23  is fixed on this wheel hub  22  with screws. 
   Further, a brake  42  is fixed on the traction motor housing above driving engine  2  co-axial to the vertical axis V which affects the driving engine shaft  3  if required and is particularly activated with elasticity and is electrically ventilated. 
   The steering engine  4  is designed here as a shrunk-on-disk rotor and is available on a stator  6  and a rotor  7 , which are placed in a steering engine housing  8 ,  8 ′. Thereby the stator  6  is linked on a fixing element which not indicated further with the steering engine housing  8 ,  8 ′, while the rotor  7  is fixed on the already-mentioned steering engine shaft  9 . 
   As represented in  FIG. 1  on left of vertical axis V, the gear housing of the driving engine  2  can be fixed on the steering engine housing  8  by way of fixation screws  28 , while the right figure half could be extracted from the deviating design, for which the steering engine  4  and the driving engine  2  display a total housing  8 ′. 
   Further,  FIG. 1  shows that the driving engine far side of steering engine  4  is covered by a cap  47 , which is clamped axially between the housing  8 ,  8 ′ of steering engine  2  and a hollow wheel  16  serving as a housing element. 
   The steering engine shaft  9  is on a roller bearing  30 ,  31  on which the cap  47 , serving as a bearing shield, and on the housing  8 , 8 ′ of steering and driving is supported revolving as well as packed on seal. It serves in a technical multi-level planetary steering transmission  5  as first sun wheel on the steering engine  4  drive. The outer teeth of this first sun wheel  9  meshes thereby with the teeth of planet wheels  10  of the first planetary wheel stage that are supported revolving on a first planetary carrier  11 . This first planetary carrier  11  is linked slip free with a second sun wheel  13  which axially connects to the spur wheel  19  on the first sun wheel  9  (steering engine shaft  9 ). 
   The outer teeth of the second sun wheel  13  are engaged with teeth of the planet wheels  12  of the second planet stage, which is supported revolving on a second planetary carrier  14 . Thereby the planet wheels  10 ,  12  of the first and the second planet wheel stage is engaged with the fixed hollow wheel  16 . 
   The second planetary carrier  14  is linked slip free with a third sun wheel  15  which meshes with planet wheels  17  of the third planet wheel stage. This planet wheel  17  of the third planet wheel stage is revolving supported on a third planetary carrier  18 , which is linked slip free with the mentioned hollow wheel  16 . 
   Eventually the planetary carrier  18  of the third planet wheel set stands effectively engaged with the inner teeth of a bearing inner ring  25  of a rotary assembly  24 , which is linked slip free on a fixation screw  44  with the rotary assembly  27 . An outer ring  50  as well as a rolling element  29 , enclosed between the rings  25 ,  50  belong to the rotary assembly  24 . 
   Further, it is seen in  FIG. 1  that preferably the traction gear housing  51  is linked slip free by fixation screws  46  with the rotary assembly  27 . Furthermore, this representation clarifies that the driving engine shaft  3  is supported above the spur-wheel  19  on a roller bearing  48  with the rotary assembly  24  and below the same on a roller bearing  49  in the traction gear housing  51 . 
   The outer ring  50  of the rotary assembly  24  is firmly combinable with the chassis C of the industrial truck whereby in this outer ring  50 , a bore  26  is designed with a screw thread, in which a fixation screw is screwed in, meshing these two parts. 
   Finally,  FIG. 1  shows that on housing  8  of steering engine  4 , an outward radial flange  52 , that can be built from one or more plates, is arranged, fastened by a fixation screw  37  led through its axial bore. The thread section of the fixation screw  37  is screwed in a thread in the outer ring  50  of rotary assembly  24 ,  50  that the housing  8 ′ of steering engine is ascertained with the hollow wheel  16  serving as housing section and the third planetary carrier  18  as well as the cap  47  axial against the bearing outer ring  50  and thus against the chassis C of the industrial truck. 
   The design represented in  FIG. 2  of two further variations of the invention formed steering and driving system  53 ,  54  differs from the steering and driving system  1 , represented in  FIG. 1 , in that the steering transmission is designed as a Wolfram-gear  32 ,  32 ′ and not as a multi-level planet gear. 
   Also for both these design forms the steering engine shaft (steering motor shaft)  55  serves as sun wheel and carries an outer gearing which is engaged with the teeth of planet wheels  33  and/or  35 . For the second design variations, right near the vertical axis V, the planet wheels  33  are supported slip free on a planetary carrier  34  and are additionally engaged with an inner gearing on an inward radial section of a steering transmission housing  43 . Further, the planetary carrier  34  meshes with the inner gearing of inner ring  25  of the rotary assembly  24  already known from  FIG. 1 , so that the rotary assembly  27  is rotatable at the vertical axis V by the steering engine  4 . 
   A hollow wheel  36  is thereby fixed or integrated with it on the radial inward projecting section of the steering transmission housing  43 , which is ascertained by way of fixation screws  45  on the outer ring  50  of the rotary assembly  24 . 
   As shown in  FIG. 2  to the right of the vertical axis V, it is preferable if the fixation screws  45  penetrate the flange  52  of steering engine housing  8  as well as also a bore in flange  58  on steering transmission housing  43  so that, in this manner, both the upper engine elements  2 ,  4  are centered to the steering transmission housing  43  and are ascertained against the bearing outer ring  50  of the rotary assembly  24 . 
   At the left of the vertical axis V, a third variation represents the planet wheels  35  of Wolfram-steer transmission  32 ′ display geometry as the aforementioned planet wheels  33 . Thereby it is especially striking that this exhibits the designed rotating axis on the planet wheels  33  and not the bore for recording of rotating axis of planet wheels  33 . This intervenes in the recording opening of visible planetary carrier. 
   In addition, in  FIG. 2  it can be seen that the axial short forming steering transmission  32 ′ exhibits the hollow wheel  36 , with which the planet wheel  35  is engaged. This hollow wheel  36  is linked slip free or integrated with an inward radial section of steering transmission housing  43 . The steering transmission housing  43  is clamped on the sides under the interlayer of the cap and/or the bearing shield  47  of steering engine  4  between its housing  8  and the outer ring  50  of rotary assembly  24 . 
   Finally,  FIG. 2  shows that in the steering and driving system  32 ,  32 ′, sensors  38 ,  40  can be installed with which the rotation of rotary assembly  27  is identifiable against the lying drive elements. 
   In the case of the second variation of the steering and driving system  32 , this angle of rotation  40  is inserted in a recording opening  41  of an inward radial and section  57  serving as a bearing shield of combined housing  8 ′ by the driving and steering engines and measures the named swivel movement on the rotor  7  of the steering engine  4 . 
   For the third variation of the steering and driving system  32 ′ (left near the vertical axis V represented), the sensor  38  is inserted in a recording opening  39  in the outer ring  50  of rotary assembly  24 . In this case, the swivel between the outer ring  50  and the rotary assembly  27  is ascertained and informed to a control device (not shown here). 
   REFERENCE NUMERALS 
   
       
         1  steering and driving system 
         2  driving engine 
         3  driving engine shaft 
         4  steering engine 
         5  steering transmission 
         6  stator steer motor 
         7  rotor steer motor 
         8  steering engine housing 
         9  steering engine shaft; first sun wheel 
         10  planet wheel of first planet wheel stage 
         11  first planetary carrier 
         12  planet wheel of second planet wheel stage 
         13  second sun wheel 
         14  second planetary carrier 
         15  third sun wheel 
         16  hollow wheel 
         17  planet wheel of third planet wheel stage 
         18  third planetary carrier 
         19  spur-wheel 
         20  spur-wheel 
         21  driving transmission 
         22  wheel hub 
         23  rotor 
         24  rotary assembly 
         25  bearing inner ring with inner wheel teeth 
         26  bore 
         27  rotary assembly 
         28  fixation screw 
         29  rolling element 
         30  roller bearing 
         31  roller bearing 
         32  Wolfram-steer transmission (variation 2) 
         32 ′ Wolfram-steer transmission (variation 3) 
         33  planet wheel of Wolfram-steer transmission (variation 2) 
         34  planet carrier of Wolfram-steer transmission 
         35  planet wheel of Wolfram-steer transmission (variation 3) 
         36  hollow wheel of Wolfram-steer transmission 
         37  fixation screw 
         38  angle of rotation sensor 
         39  recording opening in outer ring of rotary assembly bearing 
         40  angle of rotation sensor 
         41  recording opening in housing section  57   
         42  brake 
         43  housing Wolfram-gear (variation 2) 
         44  fixation screw 
         45  fixation screw 
         46  fixation screw 
         47  cap of steer gear 
         48  roller bearing 
         49  roller bearing 
         50  outer ring of rotary assembly 
         51  housing of traction gear 
         52  flange on housing  8   
         53  steering and driving system 
         54  steering and driving system 
         55  steering engine motor shaft for Wolfram-gear 
         57  housing section on housing  8 ′ 
         58  plate or flange on steering transmission housing  43   
       V vertical axis

Technology Classification (CPC): 2