Patent Publication Number: US-11639190-B2

Title: Center load steering rack support

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application entitled “CENTER LOAD STEERING RACK SUPPORT,” Ser. No. 17/113,233, filed Dec. 7, 2020, which is a continuation of U.S. patent application entitled “CENTER LOAD STEERING RACK SUPPORT,” Ser. No. 16/786,036, filed on Feb. 10, 2020, now U.S. Pat. No. 10,858,035, issued Dec. 8, 2020, which is a continuation of U.S. patent application entitled “CENTER LOAD STEERING RACK SUPPORT,” Ser. No. 16/550,016, filed on Aug. 23, 2019, now U.S. Pat. No. 10,556,615, issued on Feb. 11, 2020, which claims priority to U.S. Provisional Patent Application entitled: “CENTER LOAD STEERING RACK SUPPORT APPARATUS,” Ser. No. 62/722,666, filed Aug. 24, 2018, the disclosures of which are hereby incorporated entirely herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Technical Field 
     This invention relates generally to rack and pinion steering mechanisms and particularly to a support apparatus for a center load steering rack. 
     State of the Art 
     UTV&#39;s, ATV&#39;s, and other vehicles having center load rack and pinion steering mechanisms are often driven off road, either professionally or recreationally. It is common for the steered wheels to engage rough and uneven terrain. It is also common for the steered wheels to become airborne, such as in response to contacting a bump on the ground at high speed, and then to land harshly. Under such conditions, the steering mechanism may be subjected to extreme forces and shock loads that are transmitted to the steering mechanism through the tie rods and vehicle frame in response to the steered wheels contacting the rough and uneven terrain. 
     A common problem with existing center load rack and pinion steering mechanisms is that these extreme forces and shock loads are transmitted through the tie rod mounting bolts, or, where applicable, to the center link mounting bolts, to the rack. These forces and loads result in variable twisting and jarring of the rack, and, in some cases, harsh contact of the mounting bolts with the housing, causing damage to any of the rack, the pinion, the housing, or the mounting bolts. Such damage may result in loose engagement of components and reduced efficiency and overall functionality of the rack and pinion steering mechanism. Such damage may also result in a feeling of “softness” or “play” in the steering linkage to the driver and prevented positive steering reaction. 
     Accordingly, what is needed is a support apparatus for the rack and the center link mounting bolts, or the tie rod mounting bolts, that is able to withstand these extreme forces and shock loads and better maintain the position of the mounting bolts relative to the rack and to the housing to minimize damage to components of the steering mechanism. 
     SUMMARY OF THE INVENTION 
     The present invention relates generally to rack and pinion steering mechanisms and particularly to a support apparatus for a center load steering rack. 
     Embodiments of a center load rack and pinion steering mechanism, of the present invention, comprise an elongate housing coupled to the frame of a vehicle. The housing contains a pinion gear that engages a geared section of an elongate rack such that the rack travels longitudinally within a longitudinal passage in the housing in response to rotation of the pinion gear. The pinion gear is coupled to a steering column that extends through an aperture in the housing to a steering wheel in the passenger compartment of the vehicle. Rotation of the steering wheel by a driver of the vehicle results in rotational forces being transmitted to the pinion gear through the steering column to rotate the pinion gear. Travel of the rack within the passage is limited by closed left and right ends of the housing. 
     The housing further comprises a longitudinal slot through the front surface thereof. A center link is coupled to the rack by a pair of center link mounting bolts that extend through a pair of spaced apertures in the center link, through the slot, to the rack. A pair of tie rods are operationally coupled to the center link by a pair of heim joints. The center link moves longitudinally along the front surface of the housing in response to the longitudinal motion of the rack within the passage of the housing. In turn, the tie rods move to steer the steered wheels of the vehicle in response to motion of the center link. 
     The slot is lined with a bushing that is made of a material that is resistant to damage from heat and resistant to bending, such as brass, for example. The bushing has opposed upper and lower inner surfaces and opposed left and right ends. A center link pad extends through the slot and surrounds the center link mounting bolts. The center link pad has a pair of spaced apertures through which the center link mounting bolts extend within the slot. The mounting bolt center link pad has an upper surface that engages the upper surface of the bushing and a lower surface that engages the lower surface of the bushing. The upper surface of the center link pad is biased against the upper surface of the bushing and the lower surface of the center link pad is biased against the lower surface of the bushing to prevent upward and downward motion of the center link relative to the housing in response to varied upward and downward forces and shock loads in the center link resulting from contact of the steered wheels with the ground while the vehicle is in motion. The flush contact of the center link pad with the bushing also prevents twisting and varied upward and downward movements of the rack relative to the housing, thus minimizing damage to components of the steering mechanism. 
     Alternative embodiments do not comprise a center link, nor a pair of center link mounting bolts. In such embodiments, each of a pair of tie rod mounting bolts engages the rack directly, the tie rod mounting bolts extending through the center link pad to the rack. Each of the pair of tie rod mounting bolts is also coupled to one of a pair tie rods by a heim joint. The interfaces between the center link pad and the bushing similarly act to prevent twisting and varied upward and downward movements of the tie rod mounting bolts and the rack relative to the housing, thus minimizing damage to components of the steering mechanism. 
     The foregoing and other features and advantages of the present invention will be apparent from the following more detailed description of the particular embodiments of the invention, as illustrated in the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present invention may be derived by referring to the detailed description and claims when considered in connection with the Figures, wherein like reference numbers refer to similar items throughout the Figures, and: 
         FIG.  1    is a perspective view of a center load rack and pinion steering mechanism, according to an embodiment; 
         FIG.  2    is an alternative perspective view of a center load rack and pinion steering mechanism, according to an embodiment; 
         FIG.  3    is an exploded view of a center load rack and pinion steering mechanism, according to an embodiment; 
         FIG.  4    is a perspective view of a rack with a pinion gear of a center load rack and pinion steering mechanism, according to an embodiment; 
         FIG.  5    is a perspective view of a housing of a center load rack and pinion steering mechanism, according to an embodiment; 
         FIG.  6    is a perspective view of a cover plate of a center load rack and pinion steering mechanism, according to an embodiment; 
         FIG.  7    is a perspective view of a center link pad of a center load rack and pinion steering mechanism, according to an embodiment; 
         FIG.  8    is a perspective view of a center link of a center load rack and pinion steering mechanism, according to an embodiment; 
         FIG.  9    is a section view of a center load rack and pinion steering mechanism, according to an embodiment; and 
         FIG.  10    is a perspective view of a center load rack and pinion steering mechanism, according to an alternative embodiment. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     As discussed above, embodiments of the present invention relate generally to rack and pinion steering mechanisms and particularly to a support apparatus for a center load steering rack. 
     A rack and pinion is commonly found in the steering mechanism of wheeled, steered vehicles. A rack and pinion is a type of linear actuator that comprises a circular gear, known as the pinion, that engages a linear gear bar, known as the rack. Rotational forces applied to the pinion, in response to a driver turning the steering wheel of the vehicle, cause the rack to move relative to the pinion, thereby translating the rotational motion of the pinion into linear motion of the rack. Tie rods are operably coupled with the rack and transfer the movement of the rack to the steered wheels for steering of the vehicle. Most racks, commonly known as end load racks, are configured such that the tie rods couple to the ends of the rack, most commonly with a pair of heim joints. Some racks, commonly known as center load racks, are configured such that the tie rods couple to the rack at a location near the midpoint of the rack, also commonly with a pair of heim joints. 
     Some vehicles, including many Utility Task Vehicles (“UTV&#39;s”) and All-Terrain Vehicles (“ATV&#39;s”), have steered wheels that are relatively close together, leaving little room for a rack and pinion steering mechanism with an end load rack, together with the tie rods, to fit into the limited space between the steered wheels. Many such vehicles have rack and pinion steering mechanisms with center load racks because such steering mechanisms with center load racks require less space between the steered wheels to function due to the central mounting location of the tie rods on the rack. 
     Conventional center load racks have a pair of tie rod mounting bolts for mounting the inner ends of the tie rods to the steering mechanism. The tie rod mounting bolts may be screwed directly into the rack, proximate the midpoint of the rack, or they may be screwed into a center link, which in turn is bolted into the rack, proximate the midpoint of the rack, typically by use of a pair of center link mounting bolts. In any case, the tie rod mounting bolts, in the first instance, or the center link mounting bolts, in the second instance, engage the rack through an elongate aperture through the exterior wall of a housing mounted to the frame of the vehicle, such that the housing encloses the rack and pinion and the heim joints of the tie rod ends remain external to the housing. 
     UTV&#39;s, ATV&#39;s, and other vehicles having center load rack and pinion steering mechanisms are often driven off road, either professionally or recreationally. It is common for the steered wheels to engage rough and uneven terrain. It is also common for the steered wheels to become airborne, such as in response to contacting a bump on the ground at high speed, and then to land harshly. Under such conditions, the steering mechanism may be subjected to extreme forces and shock loads that are transmitted to the steering mechanism through the tie rods and vehicle frame in response to the steered wheels contacting the rough and uneven terrain. 
     A common problem with existing center load rack and pinion steering mechanisms is that these extreme forces and shock loads are transmitted through the tie rod mounting bolts, or, where applicable, to the center link mounting bolts, to the rack. These forces and loads result in variable twisting and jarring of the rack, and, in some cases, harsh contact of the mounting bolts with the housing, causing damage to the any of the rack, the pinion, the housing, or the mounting bolts. Such damage results in loose engagement of components and reduced efficiency and overall functionality of the rack and pinion steering mechanism. Such damage also results in a feeling of “softness” or “play” in the steering linkage to the driver and prevented positive steering reaction. 
     Referring to the drawings, as shown in  FIGS.  1 - 10   , embodiments of a center load rack and pinion steering mechanism  10 , of the present invention, comprise an elongate housing  12  having opposed first and second closed ends  14  and  16 , opposed top and bottom surfaces  18  and  20 , and opposed front and rear surfaces  22  and  24 . The housing  12  is coupled to the frame of a vehicle (not shown) at a location proximately midway between two steered wheels (not shown) of the vehicle. In some embodiments, the housing  12  comprises a plurality of protrusions  26  with apertures  28  therethrough for receiving mounting bolts (not shown) for mounting the housing to the frame of the vehicle. Although, in some embodiments, the housing  12  is coupled to the frame of the vehicle with mounting bolts, this is not intended to be limiting. The housing  12  may be coupled to the frame of the vehicle by any means known by a person of skill in the art. 
     The housing  12  has an inner passage  30  that contains a rack  32 . As shown in  FIG.  4   , the rack  32  is an elongate member having opposed first and second ends  34  and  36 , opposed top and bottom surfaces  38  and  40 , and opposed front and rear surfaces  42  and  44 . The rack  32  may comprise a geared section  46  proximate the first end  34  of the rack, wherein the geared section  46  has a plurality of gear teeth  48  that are disposed substantially latitudinally across and protrude upward from the top surface  38  of the rack  32 . In some embodiments, the housing  12  comprises a protrusion  50  proximate the first end  14  of the housing  12  for containing a pinion gear  52  that engages the geared section  46  of the rack  32 . The pinion gear  52  is coupled to a lower end of a steering column  55 . The steering column  55  is coupled to the pinion gear  52  through an aperture  54  in the protrusion  50  of the housing  12 . The steering column  55  extends from the pinion gear  52  in a rearward and slightly upward direction through the aperture  54  in the protrusion  50  of the housing  12  to a steering wheel in a passenger compartment of the vehicle (not shown). 
     In some embodiments, the geared section  46  of the rack  32  is located proximate the midpoint of the rack  32 . In some embodiments, the geared section  46  of the rack  32  is located proximate the second end of the rack  32 . In some embodiments, the geared section  46  of the rack  32  is located on the bottom surface  40  of the rack  32 , with the gear teeth  48  extending downward therefrom. In any case, the housing  12  is configured to contain the pinion gear  52 , such that the pinion gear  52  engages the geared section  46  of the rack  32 . 
     When a driver of the vehicle rotates the steering wheel (not shown), rotational forces are transmitted through the steering column  55  to the pinion gear  52  to rotate the pinion gear  52 . The rack  32  slides longitudinally through the passage  30  of the housing  12  in response to rotation of the pinion gear  52 . In some embodiments, travel of the rack  32  within the passage  30  is limited by the first and second closed ends  14  and  16  of the housing  12 . 
     As shown in  FIG.  5   , the housing  12  further comprises a longitudinal slot  56  through the front surface  22  of the housing  12 . As shown in  FIGS.  2 - 3   , a center link  58  is coupled to the rack  32  by a pair of center link mounting bolts  60  that extend through a pair of spaced apertures  62  in the center link  58 , through the slot  56 , and engage a pair of spaced threaded recesses  64  in the rack  32  for receiving the center link mounting bolts  60 .  FIG.  8    is a perspective view of a center link of the present invention. A pair of tie rods (not shown) are operationally coupled to the center link  58  by a pair of heim joints  66 , as shown in  FIGS.  1 - 3   , one heim joint  66  being located at a first end  68  of the center link  58  and the second heim joint  66  being located at an opposing second end  70  of the center link  58 . The center link  58  moves longitudinally along the front surface  22  of the housing  12  in response to the longitudinal motion of the rack  32  within the passage  30  of the housing  12 . In turn, the tie rods (not shown) move to steer the steered wheels (not shown) in response to motion of the center link  58 . 
     Although embodiments of a housing comprise a longitudinal slot through the front surface thereof, this is not intended to be limiting. The slot may be through any surface of the housing that is consistent with the functions of a center load rack and pinion steering mechanism. For example, the slot may be through one of a top surface, a bottom surface, a rear surface, or any other surface of the housing. 
     Particular features of embodiments of the present invention relate to the manner in which the center link  58  is coupled to the rack  32  through the slot  56  through the front surface  22  of the housing  12 . The slot  56  is lined with a bushing  88  that is made of a material that is resistant to damage from heat and resistant to bending, such as brass, for example. The bushing  88  has upper and lower surfaces  78  and  80 , and may have opposed arcuate left and right ends  82  and  84 . A center link pad  90  extends through the slot  56  and surrounds the center link mounting bolts  60 . The center link pad  90  has a pair of spaced apertures  92  through which the center link mounting bolts  60  extend within the slot  56 . As more clearly shown in  FIG.  9   , the mounting bolt center link pad  90  has an upper surface  98  that engages the upper surface  78  of the bushing  88  and a lower surface  100  that engages the lower surface  80  of the bushing  88 . The upper surface  98  of the center link pad  90  is biased against the upper surface  78  of the bushing  88  and the lower surface  100  of the center link pad  90  is biased against the lower surface  80  of the bushing  88  to prevent upward and downward motion of the center link  58  relative to the housing  12  in response to varied upward and downward forces and shock loads in the center link  58  resulting from contact of the steered wheels (not shown) with the ground while the vehicle is in motion. The flush contact of the center link pad  90  with the bushing  88  also prevents twisting and varied upward and downward movements of the rack  32  relative to the housing  12 , thus minimizing damage to components of the steering mechanism  10 . 
     As shown in  FIG.  7   , the center link pad  90  may have opposed left and right arcuate ends  102  and  104 . Center link pad  90  is of sufficient length to encompass the spaced apertures  92 , through which the center link mounting bolts  60  extend, and is shorter than the length of the bushing  88 . In some embodiments, travel of the center link pad  90  is limited, and thus travel of the rack  32  within the passage  30  of the housing  12  is also limited, by contact of the left end  102  of the center link pad  90  with the left end  82  of the bushing  88  in a first direction, and by contact of the right end  104  of the center link pad  90  with the right end  84  of the bushing  88  in an opposed second direction. 
     Because the center link pad  90  is shorter than the bushing  88 , the interior portions of the housing  12  would be left exposed to dust, dirt, moisture, and other external debris, but for a cover plate  106  that covers the slot  56 . As shown in  FIG.  6   , the cover plate  106  is elongate, with opposed inner and outer surfaces  108  and  110 , having an aperture  112  through which the center link pad  90  extends, the inner surface  108  thereof engaging the front surface  22  of the housing  12 . The center link pad  90  engages the cover plate  106  such that the cover plate  106  moves longitudinally in concert with the center link pad  90  in response to longitudinal motion of the rack  32  within the passage  30 . The cover plate  106  is of sufficient length to cover the slot  56  when the center link pad  90  is in any position within its range of travel. 
     Although the left and right ends  82  and  84  of the bushing  88  and the left and right ends  102  and  104  of the center link pad  90  are shown as being arcuate, this is not intended to be limiting. The left and right ends  82  and  84  of the bushing  88  and the left and right ends  102  and  104  of the center link pad  90  may be of any shape that is consistent with the functions of the bushing  88  and the center link pad  90 . 
     Some embodiments do not comprise a center link  58 , nor a pair of center link mounting bolts  60 . In such embodiments, as shown in  FIG.  10   , a pair of tie rod mounting bolts  122  engage the rack  32  directly, the tie rod mounting bolts  122  extending through the center link pad  90  and being threaded into the threaded recesses  64  of the rack  32 , each of the pair of tie rods (not shown) being coupled to one of the tie rod mounting bolts  122  by a heim joint  66 . The interfaces between the center link pad  90  and the bushing  88  similarly act to prevent twisting and varied upward and downward movements of the tie rod mounting bolts  122  and the rack  32  relative to the housing  12 , thus minimizing damage to components of the steering mechanism  10 . 
     In some embodiments, the cover plate  106  comprises an aperture  128  therethrough and the front surface  22  of the housing  12  further comprises a corresponding threaded recess  126  therein for receiving a bolt (not shown) for preventing movement of the cover plate  106  relative to the housing  12  while the center load rack and pinion steering mechanism  10  is not in use, such as during shipping. 
     The components defining any center load steering rack support apparatus may be formed of any of many different types of materials or combinations thereof that can readily be formed into shaped objects provided that the components selected are consistent with the intended operation of a center load steering rack support apparatus. For example, the components may be formed of: rubbers (synthetic and/or natural) and/or other like materials; glasses (such as fiberglass) carbon-fiber, aramid-fiber, any combination thereof, and/or other like materials; polymers such as thermoplastics (such as ABS, Fluoropolymers, Polyacetal, Polyamide; Polycarbonate, Polyethylene, Polysulfone, and/or the like), thermosets (such as Epoxy, Phenolic Resin, Polyimide, Polyurethane, Silicone, and/or the like), any combination thereof, and/or other like materials; composites and/or other like materials; metals, such as zinc, magnesium, titanium, copper, iron, steel, carbon steel, alloy steel, tool steel, stainless steel, aluminum, any combination thereof, and/or other like materials; alloys, such as aluminum alloy, titanium alloy, magnesium alloy, copper alloy, any combination thereof, and/or other like materials; any other suitable material; and/or any combination thereof. 
     Furthermore, the components defining any center load steering rack support apparatus may be purchased pre-manufactured or manufactured separately and then assembled together. However, any or all of the components may be manufactured simultaneously and integrally joined with one another. Manufacture of these components separately or simultaneously may involve extrusion, pultrusion, vacuum forming, injection molding, blow molding, resin transfer molding, casting, forging, cold rolling, milling, drilling, reaming, turning, grinding, stamping, cutting, bending, welding, soldering, hardening, riveting, punching, plating, and/or the like. If any of the components are manufactured separately, they may then be coupled with one another in any manner, such as with adhesive, a weld, a fastener (e.g. a bolt, a nut, a screw, a nail, a rivet, a pin, and/or the like), wiring, sewing, any combination thereof, and/or the like for example, depending on, among other considerations, the particular material forming the components. Other possible steps might include sand blasting, polishing, powder coating, zinc plating, anodizing, hard anodizing, and/or painting the components for example. 
     The embodiments and examples set forth herein were presented in order to best explain the present invention and its practical application and to thereby enable those of ordinary skill in the art to make and use the invention. However, those of ordinary skill in the art will recognize that the foregoing description and examples have been presented for the purposes of illustration and example only. The description as set forth is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the teachings above without departing from the spirit and scope of the forthcoming claims.