Patent Publication Number: US-2022219755-A1

Title: Steering Knuckle of a Utility Vehicle

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to a steering knuckle, composed of a casting material, of a utility vehicle. 
     Steering knuckles for utility vehicles are usually made of steel, in particular by virtue of the high, diverse and changing loads. The shaping and fine detailing are usually highly limited in the design of forged parts. 
     Such forged steering knuckles are usually composed of a simple main body having journals and arms, which are usually embodied so as to be rectilinear, attached thereto, because the desired geometry has to be achieved by forming in as few strokes as possible in order for the shape to be produced from a forged blank such as, for example, a cylindrical bar or a rectangular billet. 
     The steel is imparted the high load bearing capability thereof by alloying elements and the forming process is, however, limited in terms of shaping and is highly cost intensive by virtue of the heat that has to be introduced into the material and the production process when forging. 
     The high load bearing capability here is necessary for being able to absorb loads of a lateral crash in which a vehicle wheel impacts an edge, such as a curb, for example, transversely to the running direction. Such a load is in particular tested during the so-called curb-impact test, the latter simulating the utility vehicle sliding and impacting a curb perpendicularly to the travel direction. 
     In order for the above-mentioned disadvantages to be avoided, a steering knuckle which is made from a casting material and has a main body that in regions is configured in the shape of a plate, a steering knuckle bearing, as well as hub-type receptacle for receiving a roller bearing and an axle journal is known from DE 10 2004 034 565 A1. Moreover, a brake mount bridge for receiving brake pads that are disposed on both sides of a brake disc is molded on the steering knuckle. 
     It is an object of the present invention to improve a steering knuckle, composed of a casting material, of a utility vehicle in particular in terms of the weight and the stability of said steering knuckle such that the latter withstands the stress of a lateral impact even at temperatures below zero, in particular at temperatures below −40° Celsius. 
     This object is achieved by a steering knuckle, composed of cast iron, having the features of the independent claim. 
     The steering knuckle according to the invention has a main body, a steering knuckle bearing, as well as a hub-type receptacle which, in the shape of a pot for receiving a roller bearing and an axle journal, is open toward a rim of a vehicle wheel. 
     The steering knuckle furthermore has a pad receptacle for receiving a brake pad. The pad receptacle has a support face and two support elements that are disposed in succession in the rotating direction of the vehicle wheel. 
     A control arm attachment for attaching an axle control arm is furthermore molded on the main body of the steering knuckle. 
     Such a steering knuckle is distinguished by the great variability in terms of shaping the latter by virtue of the casting material. Simple assembly is enabled by molding a pad receptacle and a control arm attachment thereon, because the control arm attachment and at least a part of a brake mount serving for receiving the pad do not have to be separately assembled. 
     Moreover, doubling up of material, in particular in the region of the pad receptacle and of the control arm attachment, can be dispensed with. 
     Advantageous variants of embodiment of the invention are the subject matter of the dependent claims. 
     According to one advantageous variant of embodiment of the invention, the control arm attachment is molded laterally to the steering knuckle bearing, so as to extend from the main body. 
     According to one advantageous refinement, the control arm attachment is configured as an arm protruding from a main body of the steering knuckle, having a bore on the free end of said arm. 
     According to one further advantageous variant of embodiment, the main body has at least one cutout, this enabling further optimization in terms of the weight of the steering knuckle. 
     According to one further advantageous variant of embodiment, a cavity provided with ribs is molded on the main body in the region of the steering knuckle bearing. 
     Further optimization in terms of weight is made possible as a result of the molding of the cavity, on the one hand. 
     The cavity with ribs guarantees the required stability of the steering knuckle. 
     According to one further advantageous variant of embodiment, a cavity is molded on the main body in the region of the pad receptacle, between the support faces. 
     This cavity also enables further optimization in terms of the weight of the steering knuckle. 
     According to one further advantageous variant of embodiment, the main body has an overlap region for engaging across a brake disc. 
     In one further embodiment, the control arm attachment is fitted in the region of the disc overlap. 
     According to one advantageous refinement, this overlap region on the end face thereof that faces the vehicle wheel is configured as a flange for fitting a portion of a brake mount. 
     This enables the variable use of such a steering knuckle for brake pads that are to be attached on both sides of a disc brake as well as for such brake pads that are disposed on only one side. 
     Preferred exemplary embodiments of the invention will be explained in more detail hereunder by means of the appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 and 2  are schematic perspective illustrations of a first embodiment of a steering knuckle according to the invention viewed from different perspectives; 
         FIGS. 3 and 4  are schematic perspective illustrations of a second embodiment of a steering knuckle according to the invention, said illustrations corresponding to those of  FIGS. 1 and 2 ; and 
         FIG. 5  is a schematic perspective illustration of the steering knuckle shown in  FIGS. 3 and 4 , having a disc brake disposed on said steering knuckle. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     In the description of the figures hereunder, terms such as top, bottom, left, right, front, rear, etc., refer exclusively to the exemplary illustration and position of the steering knuckle, the main body, the steering knuckle bearing, the receptacle, the pad receptacle, the control arm attachment and the like chosen in the respective figures. These terms are not to be understood as limiting, i.e. the references may change as a result of different operating positions or the mirror-symmetrical design or the like. 
     A steering knuckle of a utility vehicle is overall identified by the reference sign  1  in  FIGS. 1 to 5 , said steering knuckle being composed of a casting material. 
       FIGS. 1 and 2  here show a first embodiment of such a steering knuckle  1 , while  FIGS. 3 and 4  show an alternative embodiment of a steering knuckle  1  according to the invention. 
     Both embodiment variants of such a steering knuckle  1  have a main body  2 , a steering knuckle bearing  3  having an upper and a lower protrusion  12 , the latter having bores  11  provided therein for receiving a journal for rotatably coupling to a wheel axle, extending from said main body  2 . 
     A hub-type receptacle  4 , which in the manner of a pot is open toward the rim of the vehicle wheel, extends from the main body  2  toward the wheel rim (not shown). The receptacle  4  serves for receiving a roller bearing and an axle journal, the latter by way of screws being coupled to the wheel rim and preferably also to the brake disc. 
     As can be furthermore derived from  FIGS. 1 to 4 , a pad receptacle  5  for receiving a brake pad, having a support face  6  and two support elements  7  that are disposed in succession in the rotating direction of the vehicle wheel, is molded on the main body  2  above the one protrusion  12  that serves for receiving the journal for establishing the vehicle axle. 
     The support elements  7  here are preferably shaped in the form of support yokes. The support faces  6  in the form of planar faces are molded on the main body  2  so as to be in front of respective, mutually facing internal sides of the support elements  7 , a brake pad being able to be supported in relation to the rotation axis of the vehicle wheel on said internal sides. 
     As is shown in  FIGS. 1 and 2 , a recess  17  which serves substantially for saving weight on the steering knuckle  1  is molded between the two support faces  6 . 
     In the variant of the embodiment shown in  FIGS. 3 and 4 , the main body  2  is shaped such that a rectilinear connecting web is molded between the support faces  6 , said connecting web, by a step, being slightly lowered relative to the support faces  6 . 
     As can be moreover derived from  FIGS. 1 and 3 , a control arm attachment  8  for attaching an axle control arm, for example a transverse control arm or a tie rod, is molded on the main body  2 . The control arm attachment  8  here extends in an angular manner from the main body  2  to the protrusions  12  that form the steering knuckle bearing  3 , so as to be approximately lateral to the steering knuckle bearing  3 . 
     The control arm attachment  8  here is composed of an arm  9  which projects from the main body  2  of the steering knuckle  1  and on the free end of which a bore  10  in which a journal for attaching to the axle control arm is able to be received is provided. 
     As is furthermore shown in  FIGS. 1 to 4 , the main body  2  has at least one cutout  13 . In the exemplary embodiments shown in the figures, each of the main bodies  2  has a multiplicity of such cutouts  13 . 
     The cutouts  13  serve for saving weight on the steering knuckle  1 , on the one hand. 
     At the same time, the lattice construction of the main body  2  formed as a result ensures an improved dissipation of the heat created in a braking procedure, said heat being caused by the friction between the mating brake disc and brake pad. 
     As is shown in particular in the embodiment variant according to  FIG. 3 , a cavity  14  provided with ribs is molded on the main body  2 , in the region of the steering knuckle bearing  3 , said cavity  14  separating the region of that part of the steering knuckle  1  that points toward the vehicle axle from that part of the steering knuckle  1  that faces the vehicle wheel. 
     The wall of this cavity  14  that is provided with ribs here simultaneously forms the base of the receptacle  4  for receiving the roller bearing and the axle journal. 
     An overlap region  15  for engaging across a brake disc (not illustrated) is molded on the main body  2  so as to be radially further outside toward the support elements  7  in relation to the receptacle  4 . 
     This overlap region  15 , as is shown in  FIGS. 2 and 4 , on the end face  16  thereof that faces the vehicle wheel, is configured as a flange for fitting a portion of a brake mount. 
     The steering knuckle  1 , composed of a casting material, as a result of the shape thereof, in particular as a result of the hub-type receptacle  4  which in the shape of a pot, for receiving the roller bearing and the axle journal, is open toward the rim of the vehicle wheel, in which the axle journal preferably widens radially toward the wheel rim, is sufficiently stable so as to also absorb loads of a lateral crash in which a vehicle wheel, transversely to the travel direction, impacts an edge such as a curb, for example. Such a load is tested in particular in the so-called curb-impact test, the latter simulating the utility vehicle sliding as well as impacting a curb perpendicularly to the travel direction. 
       FIG. 5  shows a disc brake of a utility vehicle that is disposed on a steering knuckle  1  illustrated in  FIGS. 3 and 4 , as well as a shaft journal  23  and a wheel mount  21 . 
     The steering knuckle  1 , preferably made from spheroidal cast iron, by way of the steering knuckle bearing  3  is connected to an axle mount  10  so as to be articulated about a vertical rotation axis. A brake disc  2  here engages across the hub-type receptacle  4  of the steering knuckle  1   
       FIG. 5  furthermore shows a brake cylinder  25 , a brake caliper  26  that spans the brake disc  2 , and brake pads  27  that are disposed in the brake caliper  26  so as to be on both sides of the brake disc  20 . A kingpin  19  which is rotatably mounted in a recess of the steering knuckle bearing  3  is received in the steering knuckle bearing  3 . 
     A wheel mount  21  is provided for fitting a vehicle wheel, the rim of a vehicle wheel (not shown) being able to be assembled thereon using a multiplicity of wheel screws  24 . 
     The wheel mount  21  and the brake disc  20 , as is shown in  FIG. 5 , by way of a roller bearing  23  are mounted so as to be rotatable about a wheel rotation axis relative to the steering knuckle  1 . To this end, the roller bearing  23  is received in the hub-type receptacle  4  of the steering knuckle  1 . 
     As is furthermore shown in  FIG. 5 , the roller bearing  23  serves for mounting a shaft journal  22  which bears in a friction-fitting manner on a bearing inner ring of the roller bearing  23 . The shaft journal  22 , preferably made from cast iron, is connected in a rotationally fixed manner to the wheel mount  21 . 
     The brake disc  20  per se has a friction ring and a cover which extends perpendicularly to the friction face of the friction ring, the free end of said cover being disposed between a neck portion of the wheel mount  21  and a flanged region of the shaft journal  22 . The brake disc  20  furthermore has a flanged region which is molded on the internal circumference of the cover of the brake disc  20  and is provided with through bores, screws  28  that are screwed into the flange of the wheel mount  21  penetrating said through bores. 
     LIST OF REFERENCE SIGNS 
     
         
           1  Steering knuckle 
           2  Main body 
           3  Steering knuckle bearing 
           4  Receptacle 
           5  Pad receptacle 
           6  Support face 
           7  Support element 
           8  Control arm attachment 
           9  Arm 
           10  Bore 
           11  Bore 
           12  Protrusion 
           13  Cutout 
           14  Cavity 
           15  Overlap region 
           16  End face 
           17  Recess 
           18  Axle mount 
           19  Kingpin 
           20  Brake disc 
           21  Wheel mount 
           22  Axle journal 
           23  Roller bearing 
           24  Wheel screw 
           25  Brake cylinder 
           26  Brake caliper 
           27  Brake pad 
           28  Screw